Health effects of concentrated ambient air particulate matter (CAPs) and its components

Development and performance evaluation of online monitors for near real-time measurement of total and water-soluble organic carbon in fine and coarse ambient PM

In this study, we developed two online monitors for total organic carbon (TOC) and water-soluble organic carbon (WSOC) measurements in fine (dp < 2.5μm) and coarse (2.5μm < dp < 10μm) particulate matter (PM), respectively. Their performance has been evaluated in laboratory and field tests to demonstrate the feasibility of using these monitors to measure near real-time concentrations, with consideration of their potential for being employed in long-term measurements. The fine PM collection setup was equipped with a versatile aerosol concentration enrichment system (VACES) connected to an aerosol-into-liquid-sampler (AILS), whereas two virtual impactors (VIs) in tandem with a modified BioSampler were used to collect coarse PM. These particle collection setups were in tandem with a Sievers M9 TOC analyzer to read TOC and WSOC concentrations in aqueous samples hourly. The average hourly TOC concentration measured by our developed monitors in fine and coarse PM were 5.17 ± 2.41 and 0.92 ± 0.29 μg/m3, respectively. In addition, our TOC readings showed good agreement and were comparable with those quantified using Sunset Lab EC/OC analyzer operating in parallel as a reference. Furthermore, we conducted field tests to produce diurnal profiles of fine PM-bound WSOC, which can show the effects of ambient temperature on maximum values in the nighttime chemistry of the winter, as well as on increased photochemical activities in afternoon peaks during the summer. According to our experimental campaign, WSOC mean values during the study period (3.07 μg/m3 for the winter and 2.7 μg/m3 for the summer) were in a comparable range with those of earlier studies in Los Angeles. Overall, our results corroborate the performance of our developed monitors in near real-time measurements of TOC and WSOC, which can be employed for future source apportionment studies in Los Angeles and other areas, aiding in understanding the health impacts of different pollution sources.

Air pollution associated with incidence and progression trajectory of chronic lung diseases: a population-based cohort study

BACKGROUND

No prior study has examined the effects of air pollution on the progression from healthy to chronic lung disease, subsequent chronic lung multimorbidity and further to death.

METHODS

We used data from the UK Biobank of 265 506 adults free of chronic lung disease at recruitment. Chronic lung multimorbidity was defined as the coexistence of at least two chronic lung diseases, including asthma, chronic obstructive pulmonary disease and lung cancer. The concentrations of air pollutants were estimated using land-use regression models. Multistate models were applied to assess the effect of air pollution on the progression of chronic lung multimorbidity.

RESULTS

During a median follow-up of 11.9 years, 13 863 participants developed at least one chronic lung disease, 1055 developed chronic lung multimorbidity and 12 772 died. We observed differential associations of air pollution with different trajectories of chronic lung multimorbidity. Fine particulate matter showed the strongest association with all five transitions, with HRs (95% CI) per 5 µg/m3 increase of 1.31 (1.22 to 1.42) and 1.27 (1.01 to 1.57) for transitions from healthy to incident chronic lung disease and from incident chronic lung disease to chronic lung multimorbidity, and 1.32 (1.21 to 1.45), 1.24 (1.01 to 1.53) and 1.91 (1.14 to 3.20) for mortality risk from healthy, incident chronic lung disease and chronic lung multimorbidity, respectively.

CONCLUSION

Our study provides the first evidence that ambient air pollution could affect the progression from free of chronic lung disease to incident chronic lung disease, chronic lung multimorbidity and death.

PM2.5 source apportionment identified with total and soluble elements in positive matrix factorization

Source apportionments of urban aerosols identified with positive matrix factorization (PMF) are sensitive to input variables. So far, total elements were frequently included as effective factors in PMF-based source apportionment. We investigated the advances to involve soluble parts of elements in the source apportionment with four data sets of PM_2.5 composition observed at a coastal city (Qingdao) in northern China: water-soluble ions plus organic and elemental carbon (IC set), the IC set plus total elements (ICTE set), the IC set plus soluble elements (ICSE set), and the IC set plus both total elements and soluble elements (ICAE set). The apportionments of six sources, including secondary sulfate, secondary nitrate, secondary oxalate, sea salt, biomass burning and dust, were identified with the IC set. In comparison, pollutants from vehicle + coal combustion, ship emissions, waste incineration and industrial activities were also identified with the ICTE, ICSE, or ICAE sets. We found that the PMF solutions of the ICAE set could distinguish aged and fresh dust, and identify fly ash and aged pollutants from industrial sources. The profiles and corresponding time series of vehicle + coal combustion, secondary aerosols, ship emissions, sea salt, and biomass burning emissions identified with the four data sets were very similar, while discrepancies were encountered for waste incineration, dust, and industrial sources. These results indicate the benefits and potentials with total and soluble elements involved in PMF-based source apportionments.

The Oxidative Potential of Fine Particulate Matter and Biological Perturbations in Human Plasma and Saliva Metabolome

Particulate oxidative potential may comprise a key health-relevant parameter of particulate matter (PM) toxicity. To identify biological perturbations associated with particulate oxidative potential and examine the underlying molecular mechanisms, we recruited 54 participants from two dormitories near and far from a congested highway in Atlanta, GA. Fine particulate matter oxidative potential ("FPMOP") levels at the dormitories were measured using dithiothreitol assay. Plasma and saliva samples were collected from participants four times for longitudinal high-resolution metabolic profiling. We conducted metabolome-wide association studies to identify metabolic signals with FPMOP. Leukotriene metabolism and galactose metabolism were top pathways associated with ≥5 FPMOP-related indicators in plasma, while vitamin E metabolism and leukotriene metabolism were found associated with most FPMOP indicators in saliva. We observed different patterns of perturbed pathways significantly associated with water-soluble and -insoluble FPMOPs, respectively. We confirmed five metabolites directly associated with FPMOP, including hypoxanthine, histidine, pyruvate, lactate/glyceraldehyde, and azelaic acid, which were implications of perturbations in acute inflammation, nucleic acid damage and repair, and energy perturbation. The unique metabolic signals were specific to FPMOP, but not PM mass, providing initial indication that FPMOP might constitute a more sensitive, health-relevant measure for elucidating etiologies related to PM_2.5 exposures.

Acute cardiovascular effects of inhaled ambient particulate matter: Chemical composition-related oxidative stress, endothelin-1, blood pressure, and ST-segment changes in Wistar rats

Short-term increases in particulate matter (PM) are associated with heightened morbidity and mortality from cardiovascular causes. Inhalation of PM is known to increase endothelin (ET)-1 levels. Yet, less is known about particle composition-related changes at the molecular level including the endothelinergic system and relationship with cardiovascular function changes. In this work, adult Wistar male rats were exposed for 4 h by nose-only inhalation to clean air, Ottawa urban particles (EHC-93, 48 mg/m³) and water-leached (EHC-93L, 49 mg/m³) particles, to examine the effect of particle compositional changes on oxidative stress, circulating ETs, blood pressure, and heart electrophysiology. Particle deposition in the respiratory compartment was estimated at 85 μg (25 ng/cm²). Lung cell proliferation was low in both treatment groups, indicating absence of acute injury. Inhalation of EHC-93 caused statistically significant elevations (p < 0.05) of oxidative stress markers, ET-1, ET-3, blood pressure, and a decrease of ST-segment duration in the ECG at 1.5 days post-exposure. Leached particles (EHC-93L) caused rapid but transient elevation (p < 0.05) of oxidative stress, ET-1, ET-2, and ET-3 at earlier time points, with no changes in blood pressure or ST-segment. These results demonstrate that inhalation of urban particles at an internal dose inadequate to cause acute lung injury can induce oxidative stress, enhance vasoactive endothelins, leading to vasopressor response, affecting cardiac electrophysiology in Wistar rats, consistent with the cardiovascular impacts of ambient particles in human populations. Change in particle potency after removal of soluble species, notably cadmium, zinc and polar organics suggests that the toxicodynamics of cardiovascular effects can be modified by physicochemical properties of particles.

Unveiling the Toxicity of Fine and Nano-Sized Airborne Particles Generated from Industrial Thermal Spraying Processes in Human Alveolar Epithelial Cells

High-energy industrial processes have been associated with particle release into workplace air that can adversely affect workers’ health. The present study assessed the toxicity of incidental fine (PGFP) and nanoparticles (PGNP) emitted from atmospheric plasma (APS) and high-velocity oxy-fuel (HVOF) thermal spraying. Lactate dehydrogenase (LDH) release, 2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1) metabolisation, intracellular reactive oxygen species (ROS) levels, cell cycle changes, histone H2AX phosphorylation (γ-H2AX) and DNA damage were evaluated in human alveolar epithelial cells at 24 h after exposure. Overall, HVOF particles were the most cytotoxic to human alveolar cells, with cell viability half-maximal inhibitory concentration (IC₅₀) values of 20.18 µg/cm² and 1.79 µg/cm² for PGFP and PGNP, respectively. Only the highest tested concentration of APS-PGFP caused a slight decrease in cell viability. Particle uptake, cell cycle arrest at S + G₂/M and γ-H2AX augmentation were observed after exposure to all tested particles. However, higher levels of γ-H2AX were found in cells exposed to APS-derived particles (~16%), while cells exposed to HVOF particles exhibited increased levels of oxidative damage (~17% tail intensity) and ROS (~184%). Accordingly, APS and HVOF particles seem to exert their genotoxic effects by different mechanisms, highlighting that the health risks of these process-generated particles at industrial settings should not be underestimated.

Mass size distributions, composition and dose estimates of particulate matter in Saharan dust outbreaks

The present study highlights the importance of examining the contribution of Saharan dust (SD) sources not only in terms of overall mass contribution but also in terms of composition, size distribution and inhaled dose. The effect of SD intrusions on PM and the respective major and trace metals mass concentrations and size distributions was investigated in a suburban site in Athens, Greece. SD events were associated, on average, with lower boundary layer heights (BLH) compared to the non-Sahara (nSD) dust days. During SD events, PM_1-10 concentrations showed an increasing trend with increasing atmospheric BLH, in contrary to the fine PM (PM₁). Generally, increased PM₁ and CO (i.e. anthropogenic origin) levels were observed for BLH lower than around 500 m. The average contribution of SD to PM₁₀ and PM_2.5 mass concentration was roughly equal to 30.9% and 19.4%, respectively. The mass size distributions of PM and specific major and trace elements (Na, Al, Si, S, Cl, K, Ca, Fe, and Zn) displayed a somewhat different behavior with respect to the mass origin (Algeria-Tunisia vs Libya-Egypt), affecting in turn the regional deposition of inhaled aerosol in the human respiratory tract (HRT). The average PM deposited mass in the upper and lower HRT was 80.1% (Head) and 26.9% (Lung; Tracheobronchial and Pulmonary region) higher for SD days than for nSD days. Higher doses were estimated in the upper and lower HRT for the majority of the elements, when SD intrusions occurred, supporting the increasingly growing interest in exploring the health effects of SD. Only the mass deposition for S, and Na in the lower HRT and Zn in the upper HRT was higher in the case of nSD.

Lab-on-a-Chip Platforms for Airborne Particulate Matter Applications: A Review of Current Perspectives

Lab-on-a-Chip (LoC) devices are described as versatile, fast, accurate, and low-cost platforms for the handling, detection, characterization, and analysis of a wide range of suspended particles in water-based environments. However, for gas-based applications, particularly in atmospheric aerosols science, LoC platforms are rarely developed. This review summarizes emerging LoC devices for the classification, measurement, and identification of airborne particles, especially those known as Particulate Matter (PM), which are linked to increased morbidity and mortality levels from cardiovascular and respiratory diseases. For these devices, their operating principles and performance parameters are introduced and compared while highlighting their advantages and disadvantages. Discussing the current applications will allow us to identify challenges and determine future directions for developing more robust LoC devices to monitor and analyze airborne PM.

Molecular and elemental marker-based source apportionment of fine particulate matter at six sites in Hong Kong, China

Source apportionment of PM_2.5 was performed using positive matrix factorization (PMF) based on chemical speciation data from 24-h filters collected throughout 2015 at six sampling sites of varying urban influences in Hong Kong. The input data include major inorganic ions, organic and elemental carbon, elements, and organic tracers. Nine factors were resolved, including (1) secondary sulfate formation process, (2) secondary nitrate formation process, (3) industrial emissions, (4) biomass burning, (5) primary biogenic emissions, (6) vehicle emissions, (7) residual oil combustion, (8) dust, and (9) aged sea salt. The PMF-resolved factor contributions in conjunction with air mass back trajectories showed that the two major sources for PM_2.5 mass, secondary sulfate (annual: 41%) and secondary nitrate (annual: 9.9%), were dominantly associated with regional and super-regional pollutant transport. Vehicular emissions are the most important local source, and its contributions exhibit a clear spatial variation pattern, with the highest (6.9 μg/m³, 24% of PM_2.5) at a downtown roadside location and the lowest (0.4 μg/m³, 2.0% PM_2.5) at two background sites away from city centers. The ability of producing a more reliable source separation and identifying new sources (e.g. primary biogenic source in this study) was a direct advantageous result of including organic tracers in the PMF analysis. PMF analysis conducted on the same dataset in this study but without including the organic tracers failed to separate the biomass burning emissions and industrial/coal combustion emissions. PMF analysis without the organic tracers would also over-apportion the contribution of vehicular emissions to PM_2.5, which would bias the evaluation of the effectiveness of vehicle-related control measures. This work demonstrates the importance of organic markers in achieving more comprehensive and less biased source apportionment results.

The impact of organic extracts of seasonal PM2.5 on primary human lung epithelial cells and their chemical characterization

Lung epithelial cells serve as the first line of defense against various inhaled pollutant particles. To investigate the adverse health effects of organic components of fine particulate matter (PM2.5) collected in Seoul, South Korea, we selected 12 PM2.5 samples from May 2016 to January 2017 and evaluated the effects of organic compounds of PM2.5 on inflammation, cellular aging, and macroautophagy in human lung epithelial cells isolated directly from healthy donors. Organic extracts of PM2.5 specifically induced neutrophilic chemokine and interleukin-8 expression via extracellular signal-regulated kinase activation. Moreover, PM2.5 significantly increased the expression of aging markers (p16, p21, and p27) and activated macroautophagy. Average mass concentrations of organic and elemental carbon had no significant correlations with PM2.5 effects. However, polycyclic aromatic hydrocarbons and n-alkanes were the most relevant components of PM2.5 that correlated with neutrophilic inflammation. Vegetative detritus and residential bituminous coal combustion sources strongly correlated with neutrophilic inflammation, aging, and macroautophagy activation. These data suggest that the chemical composition of PM2.5 is important for determining the adverse health effects of PM2.5. Our study provides encouraging evidence to regulate the harmful components of PM2.5 in Seoul.

Different sized particles associated with all-cause and cause-specific emergency ambulance calls: A multicity time-series analysis in China

BACKGROUND

Compared with mortality and hospital admission, emergency ambulance calls (EACs) could be a more accurate outcome indicator to reflect the health effects of short-term air pollution exposure. However, such studies have been scarce, especially on a multicity scale in China.

METHODS

We estimated the associations of different diameter particles [i.e., inhalable particulate matter (PM₁₀), coarse particulate matter (PM_c), and fine particulate matter (PM_2.5)] with EACs for all-cause, cardiovascular, and respiratory diseases in seven Chinese cities. We collected data on EACs and air pollution from 2014 to 2019. We used generalized additive models and random-effects meta-analysis to examine the city-specific and overall associations. Stratified analyses were conducted to examine the effect modifications of gender, age, and season.

RESULTS

Significant associations of PM₁₀ and PM_2.5 with EACs were observed, while the PM_c associations were positive but not statistically significant in most analyses. Specifically, each 10 μg/m³ increase in 2-day moving average concentration of PM₁₀ was associated with a 0.25% [95% confidence interval (CI): 0.04%, 0.47%] increase in all-cause EACs, 0.13% (95% CI: -0.01%, 0.26%) in cardiovascular EACs, and 0.35% (95% CI: 0.04%, 0.66%) in respiratory EACs. The corresponding increases in daily EACs for PM_2.5 were 0.30% (95% CI, 0.03%, 0.57%), 0.13% (95% CI, -0.07%, 0.33%), and 0.46% (95% CI, 0.01%, 0.92%). Season of the year also modifies the association between particulate matter pollution and EACs.

CONCLUSIONS

Short-term exposure to PM₁₀ and PM_2.5 were positively associated with daily all-cause and respiratory-related EACs. The associations were stronger during warm season than cold season. Our findings suggest that the most harmful fraction of particulate matter pollution is PM_2.5, which has important implications for current air quality guidelines and regulations in China.

Toxicity assessment of industrial engineered and airborne process-generated nanoparticles in a 3D human airway epithelial in vitro model

The advanced ceramic technology has been pointed out as a potentially relevant case of occupational exposure to nanoparticles (NP). Not only when nanoscale powders are being used for production, but also in the high-temperature processing of ceramic materials there is also a high potential for NP release into the workplace environment. In vitro toxicity of engineered NP (ENP) [antimony tin oxide (Sb₂O₃•SnO₂; ATO); zirconium oxide (ZrO₂)], as well as process-generated NP (PGNP), and fine particles (PGFP), was assessed in MucilAir™ cultures at air-liquid interface (ALI). Cultures were exposed during three consecutive days to varying doses of the aerosolized NP. General cytotoxicity [lactate dehydrogenase (LDH) release, WST-1 metabolization], (oxidative) DNA damage, and the levels of pro-inflammatory mediators (IL-8 and MCP-1) were assessed. Data revealed that ENP (5.56 µg ATO/cm² and 10.98 µg ZrO₂/cm²) only caused mild cytotoxicity at early timepoints (24 h), whereas cells seemed to recover quickly since no significant changes in cytotoxicity were observed at late timepoints (72 h). No meaningful effects of the ENP were observed regarding DNA damage and cytokine levels. PGFP affected cell viability at dose levels as low as ∼9 µg/cm², which was not seen for PGNP. However, exposure to PGNP (∼4.5 µg/cm²) caused an increase in oxidative DNA damage. These results indicated that PGFP and PGNP exhibit higher toxicity potential than ENP in mass per area unit. However, the presence of a mucociliary apparatus, as it occurs in vivo as a defense mechanism, seems to considerably attenuate the observed toxic effects. Our findings highlight the potential hazard associated with exposure to incidental NP in industrial settings.

An overview of methods of fine and ultrafine particle collection for physicochemical characterisation and toxicity assessments

Particulate matter (PM) is a crucial health risk factor for respiratory and cardiovascular diseases. The smaller size fractions, ≤2.5 μm (PM_2.5; fine particles) and ≤0.1 μm (PM_0.1; ultrafine particles), show the highest bioactivity but acquiring sufficient mass for in vitro and in vivo toxicological studies is challenging. We review the suitability of available instrumentation to collect the PM mass required for these assessments. Five different microenvironments representing the diverse exposure conditions in urban environments are considered in order to establish the typical PM concentrations present. The highest concentrations of PM_2.5 and PM_0.1 were found near traffic (i.e. roadsides and traffic intersections), followed by indoor environments, parks and behind roadside vegetation. We identify key factors to consider when selecting sampling instrumentation. These include PM concentration on-site (low concentrations increase sampling time), nature of sampling sites (e.g. indoors; noise and space will be an issue), equipment handling and power supply. Physicochemical characterisation requires micro- to milli-gram quantities of PM and it may increase according to the processing methods (e.g. digestion or sonication). Toxicological assessments of PM involve numerous mechanisms (e.g. inflammatory processes and oxidative stress) requiring significant amounts of PM to obtain accurate results. Optimising air sampling techniques are therefore important for the appropriate collection medium/filter which have innate physical properties and the potential to interact with samples. An evaluation of methods and instrumentation used for airborne virus collection concludes that samplers operating cyclone sampling techniques (using centrifugal forces) are effective in collecting airborne viruses. We highlight that predictive modelling can help to identify pollution hotspots in an urban environment for the efficient collection of PM mass. This review provides guidance to prepare and plan efficient sampling campaigns to collect sufficient PM mass for various purposes in a reasonable timeframe.

Chemical characterization and source apportionment of PM1 and PM2.5 in Tianjin, China: Impacts of biomass burning and primary biogenic sources

The submicron particulate matter (PM₁) and fine particulate matter (PM_2.5) are very important due to their greater adverse impacts on the natural environment and human health. In this study, the daily PM₁ and PM_2.5 samples were collected during early summer 2018 at a sub-urban site in the urban-industrial port city of Tianjin, China. The collected samples were analyzed for the carbonaceous fractions, inorganic ions, elemental species, and specific marker sugar species. The chemical characterization of PM₁ and PM_2.5 was based on their concentrations, compositions, and characteristic ratios (PM₁/PM_2.5, AE/CE, NO₃^-/SO₄^2-, OC/EC, SOC/OC, OM/TCA, K+/EC, levoglucosan/K⁺, V/Cu, and V/Ni). The average concentrations of PM₁ and PM_2.5 were 32.4 µg/m³ and 53.3 µg/m³, and PM₁ constituted 63% of PM_2.5 on average. The source apportionment of PM₁ and PM_2.5 by positive matrix factorization (PMF) model indicated the main sources of secondary aerosols (25% and 34%), biomass burning (17% and 20%), traffic emission (20% and 14%), and coal combustion (17% and 14%). The biomass burning factor involved agricultural fertilization and waste incineration. The biomass burning and primary biogenic contributions were determined by specific marker sugar species. The anthropogenic sources (combustion, secondary particle formation, etc) contributed significantly to PM₁ and PM_2.5, and the natural sources were more evident in PM_2.5. This work significantly contributes to the chemical characterization and source apportionment of PM₁ and PM_2.5 in near-port cities influenced by the diverse sources.

Evaluation of a high flow rate electrostatic precipitator (ESP) as a particulate matter (PM) collector for toxicity studies

In this study, we investigated the performance of an electrostatic precipitator (ESP) operating at high flow rates (i.e., 50-100 lpm) as a fine particulate matter (PM_2.5) collector for toxicological studies. The ESP optimum configuration (i.e., flow rate of 75 lpm and applied voltage of +12 kV) was determined based on maximum particle collection efficiencies and minimum ozone emissions associated with the instrument using different laboratory-generated aerosols. This configuration resulted in particle collection efficiencies above 80% for almost all particles in the size range of 0.015-2.5 μm while the ozone concentration was 17 ppb. The ESP was then deployed to our sampling site in central Los Angeles to evaluate its performance using ambient particles under the optimum configuration. Chemical composition and oxidative potential of PM_2.5 samples collected on the foils placed inside the ESP tube were compared with those collected concurrently on filters and aerosol slurries using the versatile aerosol concentration enrichment system (VACES) operating in parallel. Our results demonstrated that the ESP was more efficient in preserving labile inorganic ions and total organic carbon (TOC) compared to filters. PM samples collected on ESP substrates also showed higher intrinsic oxidative potential compared to the filters, which might be the result of better preservation of redox active semi-volatile organic compounds on the ESP substrates. However, the TOC concentrations and intrinsic oxidative potential of PM samples collected on ESP substrates were somewhat lower than the aerosol slurries collected by the VACES, probably due to deficiency of water-insoluble compounds in extracted PM samples from ESP substrates. In conclusion, while particle collection for toxicological purposes by the ESP is somewhat inferior to a direct aerosol-into-liquid collection, the ESP performs equally well, if not better, than conventional filter samplers and can be utilized as a simple and adequately efficient PM collector for toxicological studies.

The role of receptor models as tools for air quality management: a case study of an industrialized urban region

Evidence suggesting the association between the atmospheric particulate matter (PM) and health problems stress the need for the establishment of policies and actions aiming the improvement of air quality. As a start point, the knowledge of the main PM contributors is fundamental. Receptor models are frequently used for the identification and apportionment of local sources, nevertheless, some features of these models must be considered. For instance, whether the region has sources with similar chemical profiles and/or whether there is source temporal or spatial similarity, which can generate collinearity, affecting the sensibility of the models. In this work, it is presented some study of cases showing some strengths of the chemical mass balance model (CMB), such as to infer specific sources acting over specific locations in a same region, and its weaknesses for separating collinear sources. Besides, this work shows some study of cases reporting that the identification of specific PM markers (organic, inorganic, and crystallographic) and determined in the receptor samples can lead to better sources separation and improvements in the interpretation of the results using positive matrix factorization model. This work also highlights for the importance of the information provided by receptor models, in which should be carefully considered by the environmental agencies for decision-making concerning air quality management.

Association between the incidence of acute respiratory diseases in children and ambient concentrations of SO2, PM10 and chemical elements in fine particles

The aim of this study consists of investigating the effects of the SO₂, PM₁₀, inorganic chemical elements and black carbon (BC) present in fine particulates on the acute outcomes of respiratory diseases in children up to 12 years of age living in Brazilian urban area in the southern hemisphere during the winter (2013) and summer (2013-2014) months. SO₂ and PM₁₀ concentration data were obtained from six air quality monitoring stations spatially distributed in the area. PM_2.5 samples were collected at the same locations with a MiniVol sampler over a 24-h period on alternating days. The PM_2.5 components were analysed using the energy dispersive X-ray fluorescence and reflectance techniques. Hospital care and admission events due to acute respiratory diseases (n = 8,987) of the coded groups JJ00-JJ99 of the International Code of Diseases (ICD-10) were obtained from three hospitals (one public and two private hospitals). To quantify the association of acute respiratory disease events with pollutant concentrations, a generalized additive model (GAM) with a Poisson distribution was applied. The results showed a greater risk of acute respiratory events due to exposure to SO₂ with a relative risk of 1.28 (95% CI: 1.22-1.34) and to PM₁₀ with a risk of 1.14 (95% CI: 1.09-1.20) on the day of exposure (lag 0). The chemical constituents present in the fine particles with the highest risk for acute respiratory diseases were Si with a risk of 1.22 (95% CI: 1.15-1.29), S with a risk of 1.09 (95% CI: 1.06-1.12), Ti with a risk of 1.09 (95% CI: 1.01-1.17), BC with a risk of 1.07 (95% CI: 1.03-1.11), Se with a risk of 1.03 (95% CI: 0.96-1.10) and Ni with a risk of 1.03 (95% CI: 0.96-1.10).

Particulate Matter Induces Tissue OxInflammation: From Mechanism to Damage

Significance: Oxidative stress and oxidative damage are central hypothetical mechanisms for the adverse effects of airborne particulate matter (PM). Activation of inflammatory cells capable of generating reactive oxygen and nitrogen species is another proposed damage pathway. Understanding the interplay between these responses can help us understand the adverse health effects attributed to breathing polluted air. Recent Advances: The consequences of PM exposure on different organs are oxidative damage, decreased function, and inflammation, which can lead to the development/exacerbation of proinflammatory disorders. Mitochondrial damage is also an important event in PM-induced cytotoxicity. Critical Issues: Reactive oxygen species (ROS) are generated during phagocytosis of the particles, leading to enhancement of oxidative stress and triggering the inflammatory response. The activation of inflammatory signaling pathways results in the release of cytokines and other mediators, which can further induce ROS production by activating endogenous enzymes, leading to a positive feedback loop, which can aggravate the effects triggered by PM exposure. Future Directions: Further research is required to elucidate the exact mechanisms by which PM exposure results in adverse health effects, in terms of the relationship between the redox responses triggered by the presence of the particles and the inflammation observed in the different organs, so the development/exacerbation of PM-associated health problems can be prevented.

Pathogenic Role of Air Pollution Particulate Matter in Cardiometabolic Disease: Evidence from Mice and Humans

Significance: Air pollution is a considerable global threat to human health that dramatically increases the risk for cardiovascular pathologies, such as atherosclerosis, myocardial infarction, and stroke. An estimated 4.2 million cases of premature deaths worldwide are attributable to outdoor air pollution. Among multiple other components, airborne particulate matter (PM) has been identified as the major bioactive constituent in polluted air. While PM-related illness was historically thought to be confined to diseases of the respiratory system, overwhelming clinical and experimental data have now established that acute and chronic exposure to PM causes a systemic inflammatory and oxidative stress response that promotes cardiovascular disease. Recent Advances: A large body of evidence has identified an impairment of redox metabolism and the generation of oxidatively modified lipids and proteins in the lung as initial tissue response to PM. In addition, the pathogenicity of PM is mediated by an inflammatory response that involves PM uptake by tissue-resident immune cells, the activation of proinflammatory pathways in various cell types and organs, and the release of proinflammatory cytokines as locally produced tissue response signals that have the ability to affect organ function in a remote manner. Critical Issues: In the present review, we summarize and discuss the functional participation of PM in cardiovascular pathologies and its risk factors with an emphasis on how oxidative stress, inflammation, and immunity interact and synergize as a response to PM. Future Directions: The impact of PM constituents, doses, and novel anti-inflammatory therapies against PM-related illness is also discussed.

Comparison of fine particulate matter level, chemical content and oxidative potential derived from two dissimilar urban environments

Urban airborne particles contain a wide spectrum of components, known to have harmful effects on human health. This study reports a detailed investigation of fine particulate matter (PM_2.5), chemical content and oxidative potential derived from two different urban environments. During summer and winter, 20-day campaigns were conducted at Belgrade city center (urban-background site - UB) and Bor (urban-industrial site - UI). Using various analytical techniques, carbonaceous compounds, water-soluble inorganic ions, major and trace elements were determined, while the oxidative potential of PM_2.5 was estimated by dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay (OP^DCFH values). The mean PM_2.5 concentrations in both urban environments were above the recommended daily value, and the dominant PM_2.5 mass contributor was organic matter (29-55%). The OC/EC ratio was significantly higher at UB site during winter, which was an indication of a considerable contribution of secondary organic carbon to the overall organic carbon (OC). Water-soluble organic carbon (WSOC) was also higher at UB than at UI site, and it probably came from the same sources as OC. In general, the different partition of secondary organic aerosol (SOA) in warm and cold periods affected the number of organic components. Sulfates and nitrates were the most abundant ions at both sites and they counted approximately 40% (summer) and 50% (winter) of total ions. Further, the concentrations of the most elements, particularly some potentially carcinogenic elements such as As, Cd and Pb were significantly higher at UI, due to the emissions from the copper smelter complex in the vicinity. The mean OP^DCFH values were similar during the summer at both sampling sites, whereas a statistically significant difference between sites was noticed in favor of UB environment in winter.

Atmospheric particulate matters in an Indian urban area: Health implications from potentially hazardous elements, cytotoxicity, and genotoxicity studies

The nature of the atmospheric particulate matters (PMs) varies depending on their sizes and their origin from different activities in the background environment. These PMs are associated with potentially hazardous elements (PHEs) such as organic compounds (e.g. Polyaromatic Hydrocarbons) that can be harmful to health. The main objective of this work is the identification and investigation of the toxicological aspects of PHEs in PMs during pre-monsoon and post-monsoon season in an urban area of Northeast region (NER) of India. In the course of the study, the 24 -hs average concentrations of PMs were detected to be more than two-times higher than the Indian standard limit (NAAQ, category) which indicates poor air quality in both the seasons around the sampling sites. This study demonstrates that the concentrations of PM-bound PAHs are mutagenic and that the Excess Cancer Risks exceed the USEPA standard limits. PMs cause cytotoxicity and can also induce genotoxicity to human health analyzed by cell culture and gel electrophoresis. This study helps to promote research to evaluate the PMs bound PHEs toxicity in diverse human cell lines and also their relationship with climatic factors as well as quantitative source apportionment for mitigation purposes.

Association between coarse particulate matter (PM10-2.5) and nasopharyngeal carcinoma among Taiwanese men

The nasopharyngeal tract traps mainly coarse particles in inhaled air. Soluble carcinogenic compounds, endotoxins, and trace metals contained in these particles are potential causes of inflammation and oxidative stress which could enhance carcinogenesis. The aim of this study was to determine the association between coarse particulate matter (PM10-2.5) and nasopharyngeal cancer (NPC). A total of 521,098 men (355 cases and 520,743 non-cases), aged ≥40 years were included in this study. Data were retrieved from the Taiwan Cancer Registry, the Adult Preventive Medical Services Database, and the Air Quality Monitoring Database. PM10-2.5 was significantly associated with a higher risk of NPC after adjusting for SO2, NOx, O3, age, body mass index, smoking, alcohol drinking, betel nut chewing, exercise, hypertension, diabetes, and hyperlipidemia. With PM10-2.5<20.44 μg/m3 as the reference, the ORs and 95% CIs were 1.47; 1.03-2.11, 1.34; 0.94-1.91, and 1.68; 1.16-2.44 for 20.44≤PM10-2.5<24.08, 24.08≤PM10-2.5<29.27, and PM10-2.5≥29.27 μg/m3, respectively. PM10-2.5 remained significantly associated with a higher risk of NPC after further adjustments were made for the aforementioned covariates and PM2.5 The ORs; 95% CIs were 1.42; 0.96 to 2.12, 1.41; 0.94 to 2.10, and 1.71; 1.10 to 2.66 for 20.44≤PM10-2.5<24.08, 24.08≤PM10-2.5<29.27, and PM10-2.5≥29.27 μg/m3, respectively. In conclusion, PM10-2.5 was significantly associated with a higher risk of NPC in Taiwanese men.

Associations of daily mortality with short-term exposure to PM2.5 and its constituents in Shanghai, China

Epidemiological studies have shown that fine particulate matter (PM_2.5) has adverse impacts on human health. However, limited studies have investigated the effects of short-term exposure to PM_2.5 and its constituents on mortality in China. This study used the generalized linear model (GLM) to investigate the effects of PM_2.5 and its constituents, including organic carbon (OC), element carbon (EC), ammonium (NH₄⁺), nitrate (NO₃^-), sulfate (SO₄^2-), on different causes of mortality in Shanghai from January 1, 2013 to December 31, 2015. The single-day lagged model and the moving average lagged model were used to examine the lagging effects of pollutants on mortality. At lag0 day, PM_2.5 had a significant effect on all-cause mortality, and a 10 μg/m³ increase leads to 0.68% increase in all-cause mortality (RR 1.0068, 95%CI 1.0013-1.0123). Among the five constituents, EC had the greatest impact on all-cause mortality in Shanghai, with 10.48% increase of mortality (RR 1.1048, 95%CI 1.0266-1.1891) per 10 μg/m³ increase of concentrations, followed by OC (RR 1.0577, 95%CI 1.0277-1.0886), NH₄⁺ (RR 1.0272, 95%CI 1.0028-1.0522) and SO₄^2- (RR 1.0104, 95%CI 1.0003-1.0206). For respiratory diseases mortality, EC, OC, NO₃^- and NH₄⁺ had significant impacts and caused an increase of mortality by 44.99% (RR 1.4499, 95%CI 1.1813-1.7794), 10.40% (RR 1.1040, 95%CI 1.0260-1.1880), 5.338% (RR 1.0533, 95%CI 1.0097-1.0989) and 7.34% (RR 1.0734, 95%CI 1.0015-1.1505) per 10 μg/m³ increase of concentrations, respectively. The cumulative effect of PM_2.5 on mortality was significant in Shanghai. Except for SO₄^2-, the RR value of the single-day lagged model was smaller than the moving average lagged model.

In vitro toxicity evaluation of heavy metals in urban air particulate matter on human lung epithelial cells

Heavy metals are widely recognized as toxic components in urban air particulate matter (PM). However, the major toxic metals and their interactions are poorly understood. In this study, we attempted to explore the toxicity contribution and combined effects of PM-bounded metals in human lung epithelial cells (A549). Real-time cell analysis indicated that the critical toxic concentration (EC₅₀) of PM detected in this study was 107.90 mg/L (r² = 1.00, p < 0.01). The cell viability of A549 increased significantly (12.3%) after metal removal in PM, demonstrating an important contribution of metal components to PM toxicity. Among eleven elements examined (Zn, Cr, Mn, Fe, Ni, Cu, As, Se, Sr, Cd, and Pb), six heavy metals (Zn, Cr, Mn, Fe, Cu, and Pb) might account for PM toxicity in A549 cells, and their co-exposure led to a high mortality of A549 cells (36.5 ± 7.3%). For combination treatments, cell mortality caused by single or multiple metal mixtures was usually alleviated by Fe addition, while it was often aggravated in the presence of Mn. The varying effects of other metals (Zn, Cu, Pb and Cr) on different metal mixtures might be explained by their interactions (e.g., similar or dissimilar membrane transporters and intracellular targets). Furthermore, the concentration addition model (CA), independent action model (IA), integrated addition model (IAM) and integrated addition and interaction model (IAI) were used to predict mixture toxicity, and the IAI model exhibited the least variation between observed and predicted toxic effects (r² = 0.87, p < 0.01). Our results highlight the potential contribution from heavy metals and their interactions to PM toxicity, and promote the application of toxicity prediction models on metal components in PM.

A systematic review of cardiovascular responses associated with ambient black carbon and fine particulate matter

BACKGROUND

Exposure to fine particulate matter (PM_2.5), an ambient air pollutant with mass-based standards promulgated under the Clean Air Act, and black carbon (BC), a common component of PM_2.5, are both associated with cardiovascular health effects.

OBJECTIVES

To elucidate whether BC is associated with distinct, or stronger, cardiovascular responses compared to PM_2.5, we conducted a systematic review. We evaluated the associations of short- and long-term BC, or the related component elemental carbon (EC), with cardiovascular endpoints including heart rate variability, heart rhythm, blood pressure and vascular function, ST segment depression, repolarization abnormalities, atherosclerosis and heart function, in the context of what is already known about PM_2.5.

DATA SOURCES

We conducted a stepwise systematic literature search of the PubMed, Web of Science and TOXLINE databases and applied Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines for reporting our results.

STUDY ELIGIBILITY CRITERIA

Studies reporting effect estimates for the association of quantitative measurements of ambient BC (or EC) and PM_2.5, with relevant cardiovascular endpoints (i.e. meeting inclusion criteria) were included in the review. Included studies were evaluated for risk of bias in study design and results.

STUDY APPRAISAL AND SYNTHESIS METHODS

Risk of bias evaluations assessed aspects of internal validity of study findings based on study design, conduct, and reporting to identify potential issues related to confounding or other biases. Study results are presented to facilitate comparison of the consistency of associations with PM_2.5 and BC within and across studies.

RESULTS

Our results demonstrate similar associations for BC (or EC) and PM_2.5 with the cardiovascular endpoints examined. Across studies, associations for BC and PM_2.5 varied in their magnitude and precision, and confidence intervals were generally overlapping within studies. Where differences in the magnitude of the association between BC or EC and PM_2.5 within a study could be discerned, no consistent pattern across the studies examined was apparent.

LIMITATIONS

We were unable to assess the independence of the effect of BC, relative the effect of PM_2.5, on the cardiovascular system, nor was information available to understand the impact of differential exposure misclassification.

CONCLUSIONS

Overall, the evidence indicates that both BC (or EC) and PM_2.5 are associated with cardiovascular effects but the available evidence is not sufficient to distinguish the effect of BC (or EC) from that of PM_2.5 mass.

Development of a novel aerosol generation system for conducting inhalation exposures to ambient particulate matter (PM)

In this study, we developed a novel method for generating aerosols that are representative of real-world ambient particulate matter (PM) in terms of both physical and chemical characteristics, with the ultimate objective of using them for inhalation exposure studies. The protocol included collection of ambient PM on filters using a high-volume sampler, which were then extracted with ultrapure Milli-Q water using vortexing and sonication. As an alternative approach for collection, ambient particles were directly captured into aqueous slurry samples using the versatile aerosol concentration enrichment system (VACES)/aerosol-into-liquid collector tandem technology. The aqueous samples from both collection protocols were then re-aerosolized using commercially available nebulizers. The physical characteristics (i.e., particle size distribution) of the generated aerosols were examined by the means of a scanning mobility particle sizer (SMPS) connected to a condensation particle counter (CPC) at different compressed air pressures of the nebulizer, and dilution air flow rates. In addition, the collected PM samples (both ambient and re-aerosolized) were chemically analyzed for water-soluble organic carbon (WSOC), elemental and organic carbon (EC/OC), inorganic ions, polycyclic aromatic hydrocarbons (PAHs), and metals and trace elements. Using the aqueous filter extracts, we were able to effectively recover the water-soluble components of ambient PM (e.g., water-soluble organic matter, and water-soluble inorganic ions); however, this method was deficient in recovering some of the important insoluble components such as EC, PAHs, and many of the redox-active trace elements and metals. In contrast, using the VACES/aerosol-into-liquid collector tandem technology for collecting ambient PM directly into water slurry, we were able to preserve the water-soluble and water-insoluble components very effectively. These results illustrate the superiority of the VACES/aerosol-into liquid collector tandem technology to be used in conjunction with the re-aerosolization setup to create aerosols that fully represent ambient PM, making it an attractive choice for application in inhalation exposure studies.

Use of inorganic and organic markers associated with their directionality for the apportionment of highly correlated sources of particulate matter

Particulate matter source identification using receptor models is one of the tools applied in air quality management. These models have limitations such as the collinearity effects, hindering their application and interpretation. Positive Matrix Factorization (PMF) models use chemical markers for the definition of likely sources, leaving to users the factors interpretation. This can lead to biased interpretations, as chemical species can be markers for several sources, particularly when there is source similarity. The Region of Greater Vitória, located southeast of Brazil, is a complex site in which similar industrial activities are installed, such as a pelletizing plant and a steel plant, that produce iron pellets and sinter, both iron-agglomerates with similar chemical profiles. To minimize the effects of collinearity between those sources, a new PMF approach is proposed by using inorganic and organic chemical species and the directionality of pollutant using wind roses. The proposed methodology determines the following consolidated markers: elemental carbon (EC) and organic carbon (OC) for vehicular sources; chloride (Cl) and sodium (Na) for sea salt; iron (Fe) for industrial sources. This association was possible by identifying the directionality of the chemical species. Cl a typical sea salt marker also attributed to industrial sintering activities. Some PMF factors showed high OC loadings, a typical marker for both vehicular exhaust and coal burning. The definition of the most appropriate sources for those factors was only possible due to the assessment of the pollutant roses. Pollutant roses generally showed that higher concentrations of potassium (K), a marker of biomass burning, was predominantly associated with winds from an industrial park, and are most likely associated with sintering emissions. Results showed that combining both organic and inorganic markers with the pollutant roses for identification of the directionality of predominant sources improved the interpretation of PMF factor numbers in source apportionment studies.

Application of multiple-path particle dosimetry model for quantifying age specified deposition of particulate matter in human airway

Particulate matter (PM) is crucial among six criteria air pollutants, and it is frequently associated with human morbidity and mortality. According to the aerodynamic diameter, PM is classified as coarse (PM₁₀) and fine (PM_2.5). PM with these smaller sizes can easily enter and get deposited in the human airways. This deposited PM fraction commences the development of respiratory diseases such as asthma, chronic obstructive pulmonary disease, and even cancer. Thus, the quantification of PM deposition and its clearance in the human airway are essential for evaluating health risks. This study aims to investigate the size-segregated PM (PM₁₀, PM_2.5, and PM₁) deposition in human lungs. Size-segregated PM is collected using the Grimm portable environmental dust monitor during winter season near an arterial road located in Chennai city of Tamil Nadu state, India. Multiple-Path Particle Dosimetry (MPPD) Model version 3.04 is utilized for quantifying PM deposition. In MPPD, airway structures of infants (3 and 28 months), children (3, 8, 9 and 14 years) and adults (18 and 21 years) are considered for the study. The values of PM concentration, body orientation, breathing scenario, tidal volume, pause fraction, inspiration fraction, and breathing frequency are specified in the MPPD for quantifying PM depositions. Results showed that 8-year children and 28 months infant groups are recorded with maximum and minimum size-segregated PM deposition respectively. The coarse particles (PM₁₀) are primarily deposited in the head (55-95%) and tracheobronchial (3-44%) regions whereas fine particles (PM_2.5 and PM₁) depositions are observed maximum in the head (36-63%) and pulmonary (28.2-52.7%) regions. Except for the adult age group, PM_2.5 has the maximum deposition percentage in tracheobronchial and pulmonary regions. In the case of lobar depositions, lower lobes receive maximum deposition (66.4%) than the upper (27.2%) and middle lobes (6.4%). PM_2.5 dominated the deposition in all five lobes of infant, children, and adults. The clearance rate of deposited PM is high in the tracheobronchial region whereas it is low in the pulmonary region. This study also concludes that PM_2.5 is the important size fraction in lung deposition. Further, the study results can be used for human health risk assessments such as oxidative potential and toxicity of deposited PM.

Oxidative potential of fine ambient particles in various environments

The oxidative potential (OP) and chemical characteristics of fine particles collected from urban, roadside, rural, and industrial sites in Korea during spring, summer, fall, and winter seasons and an urban site in the Philippines during dry and wet seasons were examined. Significant differences in the OP of fine particles among sites and seasons were found. The industrial site yielded the highest OP activity (both mass and volume-normalized OP) among the sites, suggesting the strongest reactive oxygen species (ROS)-generating capability of industry source-dominant PM_2.5. Seasonal data show that OP activities increased during the spring and summer possibly due to increased heavy metals caused by dust events and secondary organic aerosols formed by strong photochemical activity, respectively. The strength of the OP association with the chemical components highlights the influence of organic carbon and transition metals on the OP of ambient fine particles. The two OP assays (dithiothreitol (DTT) and electron spin resonance (ESR)) having different ROS-generating mechanisms were found to have different sensitivities to the chemical components facilitating a complementary analysis of the OP of ambient fine particles. Multiple linear regression model equations (OP as a function of chemical components) which were dependent on the sites were derived. A comparison of the daily OP and hazard index (HI) (the ratio of the measured mass concentration to the reference mass concentration of fine particles) suggests that the HI may not be sufficient to accurately estimate the health effects of fine particles, and a direct or indirect measurement of toxicity such as OP should be required in addition to the concentration level.

Biological and chemical compositions of atmospheric particulate matter during hazardous haze days in Beijing

Particulate matter (PM), a major air pollutant in Beijing in recent years, poses a formidable public health threat. Even through many studies have documented the chemical and biological characteristics of PM, less is known about these characteristics on hazardous haze days (Air Quality Index, AQI 301-500) and the difference with sunny or unhealthy haze day (AQI 151-200) characteristics. Herein, studies were performed during a red alert air pollution event (continuous hazardous haze days) and the first few days following the event (sunny days first and then unhealthy haze days) in Beijing from December 19 to 25, 2016. A laser particle counter and an ANDERSEM-6 sampler were used to study the concentration and size distributions dynamics of the PM and the culturable airborne bacteria and fungi, respectively. PM_2.5 was sampled by a high-volume air sampler and the chemical compositions, bacterial and fungal community structures, and endotoxin levels were analyzed. The results showed that the PM concentrations on the hazardous haze days and unhealthy haze days were 10.7 and 8.0 times higher, respectively, than those on the sunny days. The chemical composition of PM_2.5 was highly correlated with the AQI. The concentration and percentage of water-soluble inorganic ions (WSII), which dominated the PM_2.5 constituents, as well as the levels of endotoxin were higher on hazardous haze days than on unhealthy haze days and sunny days. Interestingly, the abundances of bacteria and fungi demonstrated the following order: unhealthy haze days> sunny days> hazardous haze days. Most culturable bacteria and fungi were distributed in particles with aerodynamic diameters of 2.1-4.7 μm. Redundancy analysis found total organic carbon explained 30.0% and 27.1% of total variations in bacterial composition and fungal composition at the genera level, respectively. Our results facilitate a better understanding of the biological and chemical composition dynamics of PM in Beijing.

Japanese Nationwide Study on the Association Between Short-term Exposure to Particulate Matter and Mortality

Background

From around 2012, the use of automated equipment for fine particulate matter (PM_2.5) measurement with equivalence to a reference method has become popular nationwide in Japan. This enabled us to perform a national health effect assessment employing PM_2.5 concentrations based on the standardized measurement method. We evaluated the association between non-accidental mortality and short-term exposure to PM_2.5 and coarse particulate matter (PM), with the latter estimated as the difference between suspended particulate matter and PM_2.5, for the fiscal years 2012–2014.

Methods

This was a time-stratified case-crossover study in 100 highly-populated Japanese cities. Mortality data was obtained from the Ministry of Health, Labour and Welfare. City-specific estimates of PM-mortality association were calculated by applying a conditional logistic regression analysis, and combined with a random-effects meta-analysis.

Results

The respective averages of daily mean concentration were 14.6 µg/m³ for PM_2.5 and 6.4 µg/m³ for coarse PM. A 10 µg/m³ increase in PM_2.5 concentrations for the average of the day of death and the previous day was associated with an increase of 1.3% (95% confidence interval (CI), 0.9–1.6%) in total non-accidental mortality. For cause-specific mortality, PM_2.5 was positively associated with cardiovascular and respiratory mortality. After adjustment for PM_2.5, we observed a 1.4% (95% CI, 0.2–2.6%) increase in total mortality with a 10 µg/m³ increase in coarse PM.

Conclusion

The study revealed that short-term exposure to PM_2.5 had adverse effects on total non-accidental, cardiovascular, and respiratory mortality in Japan. Coarse PM exposure also increased the risk of total mortality.

Ambient air particulates-bound metallic elements sources identifications during winter and summer at a Science Park

The ambient air particulates pollutants of total suspended particulates (TSP) and PM_2.5 were collected by using PS-1 and Wilbur PM_2.5 sampler, simultaneously during the year of 2015-2017 at a photoelectric factory in Science Park of central Taiwan. And those of the ambient air atmospheric metallic elements (Cr, Mn, Ni, Cu, Zn, Pb) concentrations which attached on the TSP and PM_2.5 were analyzed by using inductively coupled plasma optical emission spectrometer. In addition, identifying anthropogenic and natural pollutants sources were conducted by using the enrichment factor (EF) and principal component analysis (PCA) methods. The results indicated that the average TSP and PM_2.5 concentrations were ranked highest in winter season, while summer season was ranked lowest during the year of 2015-2016. In addition, the average highest metallic element concentrations were occurred in winter season for both TSP and PM_2.5 during the year of 2015-2016, while the average lowest metallic elements concentrations in TSP and PM_2.5 were also occurred in winter season during the year of 2016-2017. Moreover, the EF analysis results showed that the metallic element Zn came from anthropogenic emission source. As for metallic element Mn, the results showed that metallic element Mn was mainly attributed to natural emission in this study. Finally, the PCA results showed that metallic elements Cr, Zn and Pb were the dominant emissions metallic elements in this study. As for PM_2.5, the results showed that the metallic elements Cr, Cu and Pb were the dominant emissions metallic elements at this HPB sampling site.

Rethink potential risks of toxic emissions from natural gas and oil mining

Studies have showed the increasing environmental and public health risks of toxic emissions from natural gas and oil mining, which have become even worse as fracking is becoming a dominant approach in current natural gas extraction. However, governments and communities often overlook the serious air pollutants from oil and gas mining, which are often quantified lower than the significant levels of adverse health effects. Therefore, we are facing a challenging dilemma: how could we clearly understand the potential risks of air toxics from natural gas and oil mining. This short study aims at the design and application of simple and robust methods to enhance and improve current understanding of the becoming worse toxic air emissions from natural gas and oil mining as fracking is becoming the major approach. Two simple ratios, the min-to-national-average and the max-to-national-average, are designed and applied to each type of air pollutants in a natural gas and oil mining region. The two ratios directly indicate how significantly high a type of air pollutant could be due to natural gas and oil mining by comparing it to the national average records, although it may not reach the significant risks of adverse health effects according to current risk screening methods. The min-to-national-average and the max-to-national-average ratios can be used as a direct and powerful method to describe the significance of air pollution by comparing it to the national average. The two ratios are easy to use for governments, stakeholders, and the public to pay enough attention on the air pollutants from natural gas and oil mining. The two ratios can also be thematically mapped at sampled sites for spatial monitoring, but spatial mitigation and analysis of environmental and health risks need other measurements of environmental and demographic characteristics across a natural gas and oil mining area.

Seasonal and spatial variations in the chemical components and the cellular effects of particulate matter collected in Northern China

The health effects of airborne particulate matter (PM) are likely to be strongly influenced by its components. The relationship between the composition of PM and its biological effects has been investigated in vitro/vivo, but more studies are needed to achieve a better understanding of the relationship. Such studies are limited in Northern China, where severe air pollution causes significant health impacts. In this study, we analyzed seasonal PM₁₀ (PM, aerodynamic diameter less than 10μm) samples from five typical cities in Northern China for their physicochemical properties and their in vitro effects on A549 (human lung epithelial cell line) and RAW264.7 (murine monocyte macrophage) cells, including cytotoxicity, oxidative stress and inflammatory effects. Principal component analysis and multiple linear regressions were used to investigate the relationship between the PM components and the cellular responses. The cellular responses of A549 cells were more closely related to the endotoxin content and the levels of polycyclic aromatic hydrocarbons (PAHs) and their derivatives, while the cellular responses of RAW264.7 cells were largely related to PM₁₀-bound metals, and the chalcophile elements (Pb, Cu, Zn, Cd) were more related to the PM-induced oxidative stress, whereas the lithophile and siderophile elements (Al, Fe, Mg, Co, V, Mn, Ca) were more related to PM-induced inflammation and cytotoxicity. As PM compositions changed seasonally, more intense cellular responses were seen when A549 cells were exposed to winter samples that contained higher levels of those components. The autumn and winter samples induced higher levels of oxidative stress in RAW264.7 cells, possibly due to higher contents of chalcophile elements, whereas the spring and/or summer samples were more cytotoxic and proinflammatory, possibly due to higher contents of lithophile and siderophile elements. The study suggests that the evaluation of health impacts induced by air pollution should take into account different physiochemical properties other than the mass concentration, and that public health would benefit greatly from effective, prioritized control of the sources that are the major producers of the central species.

Characterization of metals in PM1 and PM10 and health risk evaluation at an urban site in the western Mediterranean

PM₁ and PM₁₀ samples collected in the urban center of Elche during two years were analyzed by Energy Dispersive X-Ray Fluorescence in order to determine the concentrations of the following metals: K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Ba. The influence of traffic and Saharan dust intrusions on PM levels and metal content was studied in this work. The results indicate that the coarse fraction was affected more by variations in traffic intensity than the submicron fraction. The concentrations of Ca, commonly used as a tracer of road dust, showed the highest decreases during the weekends due to the reduction in traffic-induced resuspension. In contrast, Saharan events had a greater impact on the levels of other metals such as Ti and Fe, significantly affecting their seasonal variability. High concentrations of V and Ni compared with the values found at larger urban areas were observed. This could be attributed to a significant contribution from soils, Saharan dust and even ship emissions. Enrichment factors calculated using Ti as a reference element indicate that Zn and Cu are predominantly emitted by anthropogenic activities. In fact, Saharan dust intrusions had a minor influence on the average concentrations of these metals. Non-carcinogenic health hazards associated with exposure to airborne metals were lower than the safety threshold (hazard quotient < 1). Carcinogenic risks for Cr (VI) and Ni were between 10^-6 and 10^-4 and, therefore, within the range considered acceptable by the US EPA.

Trends in analytical techniques applied to particulate matter characterization: A critical review of fundaments and applications

Epidemiological studies have shown the association of airborne particulate matter (PM) size and chemical composition with health problems affecting the cardiorespiratory and central nervous systems. PM also act as cloud condensation nuclei (CNN) or ice nuclei (IN), taking part in the clouds formation process, and therefore can impact the climate. There are several works using different analytical techniques in PM chemical and physical characterization to supply information to source apportionment models that help environmental agencies to assess damages accountability. Despite the numerous analytical techniques described in the literature available for PM characterization, laboratories are normally limited to the in-house available techniques, which raises the question if a given technique is suitable for the purpose of a specific experimental work. The aim of this work consists of summarizing the main available technologies for PM characterization, serving as a guide for readers to find the most appropriate technique(s) for their investigation. Elemental analysis techniques like atomic spectrometry based and X-ray based techniques, organic and carbonaceous techniques and surface analysis techniques are discussed, illustrating their main features as well as their advantages and drawbacks. We also discuss the trends in analytical techniques used over the last two decades. The choice among all techniques is a function of a number of parameters such as: the relevant particles physical properties, sampling and measuring time, access to available facilities and the costs associated to equipment acquisition, among other considerations. An analytical guide map is presented as a guideline for choosing the most appropriated technique for a given analytical information required.

Seasonal variation and source apportionment of PM2.5-bound trace elements at a coastal area in southwestern Taiwan

The aim of this study is to investigate the seasonal variations and source apportionment on atmospheric fine particulate matter (PM_2.5) mass and associated trace element concentrations at a coastal area, in Chiayi County of southwestern Taiwan. Particle measurements were conducted in 2015. Twenty-three trace elements in PM_2.5 were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Multiple approaches of the enrichment factor (EF) analysis and positive matrix fraction (PMF) model were used to identify potential sources of PM_2.5-bound trace elements. Daily mean concentration of PM_2.5 in cold season (25.41 μg m^-3) was higher than that in hot season (13.10 μg m^-3). The trace elements contributed 11.02 and 10.74% in total PM_2.5 mass concentrations in cold season and hot season, respectively. The results of EF analysis confirmed that Sb, Mo, and Cd were the top three anthropogenic trace elements in the PM_2.5; furthermore, carcinogenic elements (Cr, Ni, and As) and other trace elements (Na, K, V, Cu, Zn, Sr, Sn, Ba, and Pb) were attributable to anthropogenic emissions in both cold and hot seasons; however, highly enriched Li and Mn were observed only in cold season. The PMF model identified four main sources: iron and steel industry, soil and road dust, coal combustion, and traffic-related emission. Each of these sources has an annual mean contribution of 8.2, 27.5, 11.2, and 53.1%, respectively, to PM_2.5. The relative dominance of each identified source varies with changing seasons. The highest contributions occurred in cold season for iron and steel industry (66.2%), in hot season for traffic-related emission (58.4%), soil and road dust (22.0%), and coal combustion (2.8%). These findings revealed that the PM_2.5 mass concentration, PM_2.5-bound trace element concentrations, and their contributions were various by seasons.

Toxicity of Urban PM10 and Relation with Tracers of Biomass Burning

The chemical composition of particles varies with space and time and depends on emission sources, atmospheric chemistry and weather conditions. Evidence suggesting that particles differ in toxicity depending on their chemical composition is growing. This in vitro study investigated the biological effects of PM₁₀ in relation to PM-associated chemicals. PM₁₀ was sampled in ambient air at an urban traffic site (Borgerhout) and a rural background location (Houtem) in Flanders (Belgium). To characterize the toxic potential of PM₁₀, airway epithelial cells (Beas-2B cells) were exposed to particles in vitro. Different endpoints were studied including cell damage and death (cell viability) and the induction of interleukin-8 (IL-8). The mutagenic capacity was assessed using the Ames II Mutagenicity Test. The endotoxin levels in the collected samples were analyzed and the oxidative potential (OP) of PM₁₀ particles was evaluated by electron paramagnetic resonance (EPR) spectroscopy. Chemical characteristics of PM₁₀ included tracers for biomass burning (levoglucosan, mannosan and galactosan), elemental and organic carbon (EC/OC) and polycyclic aromatic hydrocarbons (PAHs). Most samples displayed dose-dependent cytotoxicity and IL-8 induction. Spatial and temporal differences in PM₁₀ toxicity were seen. PM₁₀ collected at the urban site was characterized by increased pro-inflammatory and mutagenic activity as well as higher OP and elevated endotoxin levels compared to the background area. Reduced cell viability (−0.46 < r_s < −0.35, p < 0.01) and IL-8 induction (−0.62 < r_s < −0.67, p < 0.01) were associated with all markers for biomass burning, levoglucosan, mannosan and galactosan. Furthermore, direct and indirect mutagenicity were associated with tracers for biomass burning, OC, EC and PAHs. Multiple regression analyses showed levoglucosan to explain 16% and 28% of the variance in direct and indirect mutagenicity, respectively. Markers for biomass burning were associated with altered cellular responses and increased mutagenic activity. These findings may indicate a role of biomass burning in the observed adverse health effect of particulate matter.

Morphologic and chemical composition of particulate matter in motorcycle engine exhaust

Despite the fact that environmental pollution due to motorcycle exhaust gases reports a great increase, motorcycle production exhibits a great increase through the last years. Countries of Asia and Africa are reported to be the major regions where two-wheeled vehicles are a major transportation mode, with tens of millions of units sold per year. Motorcycle exhaust particles are considered to be the major contributor to environmental pollution due to their airborne dispersion, containing great amount of polycyclic aromatic hydrocarbons (PAHs). This study aims at reporting an objective analysis of the main sources of the ambient air pollution as also particle size distribution and chemical composition analysis of particulate matter originated from the exhausts of two-wheeled vehicles used in the territory of Vladivostok, Russia. Various types of two-wheeled vehicles were examined (motorcycles, ATVs, scooters and wet bikes) using different types of engine and fuel system. Experimental results showed that there was no clear relation to the particle size distribution with the engine displacement of motorcycle and the number of strokes and the fuel system. Instead, there were reported two clear assumptions. The first one is that regarding to the motorcycle brand, a few samples did not exhibit a great percentage of PM10 fraction. The second one is that more modern vehicles, that have a harmful gas afterburning system, are usually the source of an increased percentage of PM10 emitted particles. At last, it should be mentioned that the laser particle size analysis method is capable of determining the particle sizes after their agglomeration whereas the optical morphometry method allows to determine the real particle size of emissions. In conclusion, it can be pointed out that the agglomeration of particles can lead to the reduction in the toxicity of particles emissions originated from two wheeled-vehicles.

Foliar heavy metal uptake, toxicity and detoxification in plants: A comparison of foliar and root metal uptake

Anthropologic activities have transformed global biogeochemical cycling of heavy metals by emitting considerable quantities of these metals into the atmosphere from diverse sources. In spite of substantial and progressive developments in industrial processes and techniques to reduce environmental emissions, atmospheric contamination by toxic heavy metals and associated ecological and health risks are still newsworthy. Atmospheric heavy metals may be absorbed via foliar organs of plants after wet or dry deposition of atmospheric fallouts on plant canopy. Unlike root metal transfer, which has been largely studied, little is known about heavy metal uptake by plant leaves from the atmosphere. To the best of our understanding, significant research gaps exist regarding foliar heavy metal uptake. This is the first review regarding biogeochemical behaviour of heavy metals in atmosphere-plant system. The review summarizes the mechanisms involved in foliar heavy metal uptake, transfer, compartmentation, toxicity and in plant detoxification. We have described the biological and environmental factors that affect foliar uptake of heavy metals and compared the biogeochemical behaviour (uptake, translocation, compartmentation, toxicity and detoxification) of heavy metals for root and foliar uptake. The possible health risks associated with the consumption of heavy metal-laced food are also discussed.

Exposure and health risk assessment of PM2.5-bound trace metals during winter in university campus in Northeast China

In order to better understand the risk to students' health caused by pollution derived from fine particulate matter with an aerodynamic diameter <2.5mm (PM_2.5), this study collected 189 samples in one outdoor and four different functional indoor environments of a research center in a university campus. Trace metals (TMs) bound to PM_2.5 in outdoor and indoor environments were measured using X-ray fluorescence spectrometry. The TMs measured were: As, Co, Cd, Cr, Ni, Cu, Zn, Mn, Hg, and Pb. The measurements of PM_2.5-bound TMs before and during the 2015 Spring Festival held in Northeast China were compared. Results showed that pollution due to PM_2.5-bound TMs in outdoor and indoor environments was higher before than during the Spring Festival. Cu (in three indoor environments) and Zn (in an outdoor environment) showed the highest concentrations among the ten TMs that were measured. Hg showed the lowest concentrations in all the environments analyzed. The concentrations of PM_2.5-bound TMs declined among four indoor environments in the following order: the atrium, the students' office (sampled just nine days before the Spring Festival), the laboratory, and an empty room. The potential carcinogenic and non-carcinogenic health risks derived from PM_2.5-bound TMs were within safe limits for graduate and undergraduate students, according to the standards established by the United States Environmental Protection Agency (USEPA).

Effect of Short-Term Exposure to High Particulate Levels on Cough Reflex Sensitivity in Healthy Tourists: A Pilot Study

BACKGROUND

Previous studies have reported a relationship between particulate air pollution and respiratory symptoms or decline in lung function, but information about acute effects of short-term exposure to airborne particulate matter (PM) on cough and pulmonary function is scarce.

OBJECTIVE

To investigate the effect of short-term exposure to high concentrations of PM on the cough reflex threshold, urge-to-cough, pulmonary function, and cough-related quality of life in a group of healthy non-resident volunteers visiting Beijing, China.

METHODS

Seventeen healthy residents of Sendai, Japan, who planned to attend a meeting in Beijing, were recruited. We checked local air quality and measured cough reflex thresholds, urge-to-cough, pulmonary function, and Leicester Cough Questionnaire-acute (LCQ-acute) scores in the volunteers before, during, and after their trip to Beijing.

RESULTS

The PM_2.5 and PM₁₀ concentrations in Beijing were significantly higher than those in Japan on the measurement days. Cough reflex thresholds, expressed as nebulized citric acid concentrations required to induce ≥ 2 and ≥ 5 coughs, were significantly lower during the stay in Beijing than before or after the visit. Vital capacity, forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), and FEV₁/FVC were significantly lower during the stay in Beijing than before the trip. Similarly, the urge-to-cough threshold was significantly lower during the stay in Beijing than after the trip, as was the total LCQ-acute score.

CONCLUSION

We tentatively concluded that short-term exposure to high PM concentrations may have adverse effects on cough reflex and urge-to-cough thresholds, pulmonary function, and cough-related quality of life.

Characterization of cardiovascular reflexes evoked by airway stimulation with allylisothiocyanate, capsaicin, and ATP in Sprague-Dawley rats

Acute inhalation of airborne pollutants alters cardiovascular function and evidence suggests that pollutant-induced activation of airway sensory nerves via the gating of ion channels is critical to these systemic responses. Here, we have investigated the effect of capsaicin [transient receptor potential (TRP) vanilloid 1 (TRPV1) agonist], AITC [TRP ankyrin 1 (TRPA1) agonist], and ATP (P2X2/3 agonist) on bronchopulmonary sensory activity and cardiovascular responses of conscious Sprague-Dawley (SD) rats. Single fiber recordings show that allyl isothiocyanate (AITC) and capsaicin selectively activate C fibers, whereas subpopulations of both A and C fibers are activated by stimulation of P2X2/3 receptors. Inhalation of the agonists by conscious rats caused significant bradycardia, atrioventricular (AV) block, and prolonged PR intervals, although ATP-induced responses were lesser than those evoked by AITC or capsaicin. Responses to AITC were inhibited by the TRP channel blocker ruthenium red and the muscarinic antagonist atropine. AITC inhalation also caused a biphasic blood pressure response: a brief hypertensive phase followed by a hypotensive phase. Atropine accentuated the hypertensive phase, while preventing the hypotension. AITC-evoked bradycardia was not abolished by terazosin, the α1-adrenoceptor inhibitor, which prevented the hypertensive response. Anesthetics had profound effects on AITC-evoked bradycardia and AV block, which was abolished by urethane, ketamine, and isoflurane. Nevertheless, AITC inhalation caused bradycardia and AV block in paralyzed and ventilated rats following precollicular decerebration. In conclusion, we provide evidence that activation of ion channels expressed on nociceptive airway sensory nerves causes significant cardiovascular effects in conscious SD rats via reflex modulation of the autonomic nervous system.

Health effects of carbon-containing particulate matter: focus on sources and recent research program results

Air pollution is a complex mixture of gas-, vapor-, and particulate-phase materials comprised of inorganic and organic species. Many of these components have been associated with adverse health effects in epidemiological and toxicological studies, including a broad spectrum of carbonaceous atmospheric components. This paper reviews recent literature on the health impacts of organic aerosols, with a focus on specific sources of organic material; it is not intended to be a comprehensive review of all the available literature. Specific emission sources reviewed include engine emissions, wood/biomass combustion emissions, biogenic emissions and secondary organic aerosol (SOA), resuspended road dust, tire and brake wear, and cooking emissions. In addition, recent findings from large toxicological and epidemiological research programs are reviewed in the context of organic PM, including SPHERES, NPACT, NERC, ACES, and TERESA. A review of the extant literature suggests that there are clear health impacts from emissions containing carbon-containing PM, but difficulty remains in apportioning responses to certain groupings of carbonaceous materials, such as organic and elemental carbon, condensed and gas phases, and primary and secondary material. More focused epidemiological and toxicological studies, including increased characterization of organic materials, would increase understanding of this issue.

Mining in subarctic Canada: airborne PM2.5 metal concentrations in two remote First Nations communities

Airborne particulate matter arising from upwind mining activities is a concern for First Nations communities in the western James Bay region of Ontario, Canada. Aerosol chemical components were collected in 2011 from two communities in northern Ontario. The chemical and mass concentration data of particulate matter collected during this study shows a significant difference in PM2.5 in Attawapiskat compared to Fort Albany. Elemental profiles indicate enhanced levels of some tracers thought to arise from mining activities, such as, K, Ni, and crustal materials. Both communities are remote and isolated from urban and industrial pollution sources, however, Attawapiskat First Nation has significantly enhanced levels of particulate matter, and it is likely that some of this arises from upwind mining activities.

Land use regression models for crustal and traffic-related PM2.5 constituents in four areas of the SAPALDIA study

Many studies have documented adverse health effects of long-term exposure to fine particulate matter (PM2.5), but there is still limited knowledge regarding the causal relationship between specific sources of PM2.5 and such health effects. The spatial variability of PM2.5 constituents and sources, as a exposure assessment strategy for investigating source contributions to health effects, has been little explored so far. Between 2011 and 2012, three measurement campaigns of PM and nitrogen dioxide (NO2) were performed in 80 sites across four areas of the Swiss Study on Air Pollution and Lung and heart Diseases in Adults (SAPALDIA). Reflectance analysis and energy dispersive X-ray fluorescence (XRF) were performed on PM2.5 filter samples to estimate light absorbance and trace element concentrations, respectively. Three air pollution source factors were identified using principal-component factor analysis: vehicular, crustal, and long-range transport. Land use regression (LUR) models were developed for temporally-adjusted scores of each factor, combining the four study areas. Model performance was assessed using two cross-validation methods. Model explained variance was high for the vehicular factor (R(2)=0.76), moderate for the crustal factor (R(2)=0.46), and low for the long-range transport factor (R(2)=0.19). The cross-validation methods suggested that models for the vehicular and crustal factors moderately accounted for both the between and within-area variability, and therefore can be applied to the four study areas to estimate long-term exposures within the SAPALDIA study population. The combination of source apportionment techniques and LUR modelling may help in identifying air pollution sources and disentangling their contribution to observed health effects in epidemiologic studies.

Cytotoxicity and genotoxicity of urban particulate matter in mammalian cells

Ambient air particulate matter (PM)-associated reactive oxygen species (ROS) have been linked to a variety of altered cellular outcomes. In this study, three different PM samples from diesel exhaust particles (DEPs), urban dust standard reference material SRM1649a and air collected in Manchester have been tested for their ability to oxidise DNA in a cell-free assay, to increase intracellular ROS levels and to induce CYP1A1 gene expression in mammalian cells. In addition, the cytotoxicity and genotoxicity of PM were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and alkaline comet assay, respectively. All PM samples catalysed the Fenton reaction in a cell-free assay, but only DEP resulted in the generation of ROS as measured by dichlorodihydrofluorescein diacetate oxidation in mammalian cells. However, there was no evidence that increased ROS was a consequence of polycyclic aromatic hydrocarbon metabolism via CYP1A1 induction as urban dust, the Manchester dust samples but not DEP-induced CYP1A1 expression. Urban dust was more cytotoxic in murine embryonic fibroblasts (MEFs) than the other PM samples and also induced expression of GADD45a in the GreenScreen Human Cell assay without S9 activation suggesting the presence of a direct-acting genotoxicant. Urban dust and DEP produced comparable levels of DNA damage, as assessed by the alkaline comet assay, in MEFs at higher levels than those induced by Manchester PM. In conclusion, results from the cytotoxic and genotoxic assays are not consistent with ROS production being the sole determinant of PM-induced toxicity. This suggests that the organic component can contribute significantly to this toxicity and that further work is required to better characterise the extent to which ROS and organic components contribute to PM-induced toxicity.

Markers of inflammation and coagulation after long-term exposure to coarse particulate matter: a cross-sectional analysis from the multi-ethnic study of atherosclerosis

BACKGROUND

Toxicological research suggests that coarse particles (PM10-2.5) are inflammatory, but responses are complex and may be best summarized by multiple inflammatory markers. Few human studies have investigated associations with PM10-2.5 and, of those, none have explored long-term exposures. Here we examine long-term associations with inflammation and coagulation in the Multi-Ethnic Study of Atherosclerosis.

METHODS

Participants included 3,295 adults (45-84 years of age) from three metropolitan areas. Site-specific spatial models were used to estimate 5-year concentrations of PM10-2.5 mass and copper, zinc, phosphorus, silicon, and endotoxin found in PM10-2.5. Outcomes included interleukin-6, C-reactive protein, fibrinogen, total homocysteine, D-dimer, factor VIII, plasmin-antiplasmin complex, and inflammation and coagulation scores. We used multivariable regression with multiply imputed data to estimate associations while controlling for potential confounders, including co-pollutants such as fine particulate matter.

RESULTS

Some limited evidence was found of relationships between inflammation and coagulation and PM10-2.5. Endotoxin was the PM10-2.5 component most strongly associated with inflammation, with an interquartile range (IQR) increase (0.08 EU/m3) associated with 0.15 (95% CI: 0.01, 0.28; p = 0.03) and 0.08 (95% CI: -0.07, 0.23; p = 0.28) higher inflammation scores before and after control for city, respectively. Copper was the component with the strongest association with coagulation, with a 4-ng/m3 increase associated with 0.19 (95% CI: 0.08, 0.30; p = 0.0008) and 0.12 (95% CI: -0.05, 0.30; p = 0.16) unit higher coagulation scores before and after city adjustment, respectively.

CONCLUSIONS

Our cross-sectional analysis provided some evidence that long-term PM10-2.5 exposure was associated with inflammation and coagulation, but associations were modest and depended on particle composition.