Health effects of particulate air pollution

Air pollution, glymphatic impairment, and Alzheimer's disease

Epidemiological evidence demonstrates a link between air pollution exposure and the onset and progression of cognitive impairment and Alzheimer's disease (AD). However, current understanding of the underlying pathophysiological mechanisms is limited. This opinion article examines the hypothesis that air pollution-induced impairment of glymphatic clearance represents a crucial etiological event in the development of AD. Exposure to airborne particulate matter (PM) leads to systemic inflammation and neuroinflammation, increased metal load, respiratory and cardiovascular dysfunction, and sleep abnormalities. All these factors are known to reduce the efficiency of glymphatic clearance. Rescuing glymphatic function by restricting the impact of causative agents, and improving sleep and cardiovascular system health, may increase the efficiency of waste metabolite clearance and subsequently slow the progression of AD. In sum, we introduce air pollution-mediated glymphatic impairment as an important mechanistic factor to be considered when interpreting the etiology and progression of AD as well as its responsiveness to therapeutic interventions.

Digital outpatient health solutions as a vehicle to improve healthcare sustainability-a United Kingdom focused policy and practice perspective

Introduction

In the midst of a global climate emergency and with health care systems across the world facing extreme pressure, interest in digital approaches as a potential part-solution to these challenges has increased rapidly. The evidence base to support the role that digitalization can play in moving towards more sustainable models of healthcare is growing, as is the awareness of this key area of healthcare reform amongst policy makers, clinicians and the public.

Method and Results

In this policy and practice review we explore four domains of healthcare sustainability-environmental, economic, and patient and clinician, delineating the potential impact that digitally enabled healthcare can have on each area. Real-world examples are provided to illustrate the impact individual digital interventions can have on each pillar of sustainability and demonstrate the scale of the potential benefits which can be achieved.

Discussion

Digitally enabled healthcare solutions present an approach which offer numerous benefits, including environmental sustainability, economic benefits, and improved patient experience. There are also potential drawbacks such as the risk of digital exclusion and the need for integration with existing technology platforms. Overall, it is essential to strike a balance between the benefits and potential drawbacks of digital healthcare solutions to ensure that they are equitable, effective, and sustainable.

Dynamics and calculation of the basic reproduction number for a nonlocal dispersal epidemic model with air pollution

In order to reflect the dispersal of pollutants in non-adjacent areas and the large-scale movement of individuals, this paper proposes an epidemic model of nonlocal dispersal with air pollution, where the transmission rate is related to the concentration of pollutants. This paper checks the uniqueness and existence of the global positive solution and defines the basic reproduction number, R 0 . We simultaneously explore the global dynamics: when R 0 < 1 , the disease-free stable point is global asymptotic stability; when R 0 > 1 , the disease is uniformly persistent. Additionally, in order to approximate R 0 , a numerical method has been introduced. Illustrative examples are used to verify the theoretical outcomes and show the effect of the dispersal rate on the basic reproduction number R 0 .

Critical air pollutant assessments and health effects attributed to PM2.5 during and after COVID-19 lockdowns in Iran: application of AirQ+ models

Objectives

The aim of this study was to evaluate changes in air quality index (AQI) values before, during, and after lockdown, as well as to evaluate the number of hospitalizations due to respiratory and cardiovascular diseases attributed to atmospheric PM_2.5 pollution in Semnan, Iran in the period from 2019 to 2021 during the COVID-19 pandemic.

Methods

Daily air quality records were obtained from the global air quality index project and the US Environmental Protection Administration (EPA). In this research, the AirQ+ model was used to quantify health consequences attributed to particulate matter with an aerodynamic diameter of <2.5 μm (PM_2.5).

Results

The results of this study showed positive correlations between air pollution levels and reductions in pollutant levels during and after the lockdown. PM_2.5 was the critical pollutant for most days of the year, as its AQI was the highest among the four investigated pollutants on most days. Mortality rates from chronic obstructive pulmonary disease (COPD) attributed to PM_2.5 in 2019-2021 were 25.18% in 2019, 22.55% in 2020, and 22.12% in 2021. Mortality rates and hospital admissions due to cardiovascular and respiratory diseases decreased during the lockdown. The results showed a significant decrease in the percentage of days with unhealthy air quality in short-term lockdowns in Semnan, Iran with moderate air pollution. Natural mortality (due to all-natural causes) and other mortalities related to COPD, ischemic heart disease (IHD), lung cancer (LC), and stroke attributed to PM_2.5 in 2019-2021 decreased.

Conclusion

Our results support the general finding that anthropogenic activities cause significant health threats, which were paradoxically revealed during a global health crisis/challenge.

Particle Deposition in Large-Scale Human Tracheobronchial Airways Predicted by Single-Path Modelling

The health effects of particles are directly related to their deposition patterns (deposition site and amount) in human airways. However, estimating the particle trajectory in a large-scale human lung airway model is still a challenge. In this work, a truncated single-path, large-scale human airway model (G3-G10) with a stochastically coupled boundary method were employed to investigate the particle trajectory and the roles of their deposition mechanisms. The deposition patterns of particles with diameters (dp) of 1-10 μm are investigated under various inlet Reynolds numbers (Re = 100-2000). Inertial impaction, gravitational sedimentation, and combined mechanism were considered. With the increasing airway generations, the deposition of smaller particles (dp < 4 μm) increased due to gravitational sedimentation, while that of larger particles decreased due to inertial impaction. The obtained formulas of Stokes number and Re can predict the deposition efficiency due to the combined mechanism in the present model, and the prediction can be used to assess the dose-effect of atmospheric aerosols on the human body. Diseases in deeper generations are mainly attributed to the deposition of smaller particles under lower inhalation rates, while diseases at the proximal generations mainly result from the deposition of larger particles under higher inhalation rates.

A Review of Noble Metal Catalysts for Catalytic Removal of VOCs

Volatile organic compounds (VOCs) are important precursors for the formation of secondary pollutants, such as fine particulate matter (PM) and ozone (O3), which will lead to severe atmospheric environmental problems to restrict the sustainable development of the social economy. Catalytic oxidation is a safe, eco-friendly, and simple method for eliminating VOCs, which can be converted into CO2 and H2O without the generation of other harmful substances. The fabrication and development of catalysts are very crucial to enhance the catalytic oxidation efficiency of the removal of VOCs. The noble metal catalyst is one of the commonly used catalysts for the catalytic oxidation of VOCs because of the high reaction activity, good stability, poisoning-resistant ability, and easy regeneration. In this review, the research progress of noble metal (Pt, Pd, Au, Ag, and Ir) catalysts for the removal of VOCs in recent years was summarized with the discussion of the influence factors in the preparation process on the catalytic performance. The reaction mechanisms of the removal of VOCs over the corresponding noble metal catalysts were also briefly discussed.

Transcriptome Analysis of Particulate Matter 2.5-Induced Abnormal Effects on Human Sebocytes

Particulate matter 2.5 (PM2.5), an atmospheric pollutant with an aerodynamic diameter of <2.5 μm, can cause serious human health problems, including skin damage. Since sebocytes are involved in the regulation of skin homeostasis, it is necessary to study the effects of PM2.5 on sebocytes. We examined the role of PM2.5 via the identification of differentially expressed genes, functional enrichment and canonical pathway analysis, upstream regulator analysis, and disease and biological function analysis through mRNA sequencing. Xenobiotic and lipid metabolism, inflammation, oxidative stress, and cell barrier damage-related pathways were enriched; additionally, PM2.5 altered steroid hormone biosynthesis and retinol metabolism-related pathways. Consequently, PM2.5 increased lipid synthesis, lipid peroxidation, inflammatory cytokine expression, and oxidative stress and altered the lipid composition and expression of factors that affect cell barriers. Furthermore, PM2.5 altered the activity of sterol regulatory element binding proteins, mitogen-activated protein kinases, transforming growth factor beta-SMAD, and forkhead box O3-mediated pathways. We also suggest that the alterations in retinol and estrogen metabolism by PM2.5 are related to the damage. These results were validated using the HairSkin® model. Thus, our results provide evidence of the harmful effects of PM2.5 on sebocytes as well as new targets for alleviating the skin damage it causes.

Computational Fluid Dynamics Study of the Effects of Temperature and Geometry Parameters on a Virtual Impactor

The virtual impactor, as an atmospheric particle classification chip, provides scientific guidance for identifying the characteristics of particle composition. Most of the studies related to virtual impactors focus on their size structure design, and the effect of temperature in relation to the dynamic viscosity on the cut-off diameter is rarely considered. In this paper, a new method that can reduce the cut-off particle size without increasing the pressure drop is proposed. Based on COMSOL numerical simulations, a new ultra-low temperature virtual impactor with a cut-off diameter of 2.5 μm was designed. A theoretical analysis and numerical simulation of the relationship between temperature and the performance of the virtual impactor were carried out based on the relationship between temperature and dynamic viscosity. The effects of inlet flow rate (Q), major flow channel width (S), minor flow channel width (L) and split ratio (r) on the performance of the virtual impactor were analyzed. The collection efficiency curves were plotted based on the separation effect of the new virtual impactor on different particle sizes. It was found that the new ultra-low temperature approach reduced the PM2.5 cut-off diameter by 19% compared to the conventional virtual impactor, slightly better than the effect of passing in sheath gas. Meanwhile, the low temperature weakens Brownian motion of the particles, thus reducing the wall loss. In the future, this approach can be applied to nanoparticle virtual impactors to solve the problem of their large pressure drop.

Effects of air pollution on human health - Mechanistic evidence suggested by in vitro and in vivo modelling

Airborne particulate matter (PM) comprises both solid and liquid particles, including carbon, sulphates, nitrate, and toxic heavy metals, which can induce oxidative stress and inflammation after inhalation. These changes occur both in the lung and systemically, due to the ability of the small-sized PM (i.e. diameters ≤2.5 μm, PM_2.5) to enter and circulate in the bloodstream. As such, in 2016, airborne PM caused ∼4.2 million premature deaths worldwide. Acute exposure to high levels of airborne PM (eg. during wildfires) can exacerbate pre-existing illnesses leading to hospitalisation, such as in those with asthma and coronary heart disease. Prolonged exposure to PM can increase the risk of non-communicable chronic diseases affecting the brain, lung, heart, liver, and kidney, although the latter is less well studied. Given the breadth of potential disease, it is critical to understand the mechanisms underlying airborne PM exposure-induced disorders. Establishing aetiology in humans is difficult, therefore, in-vitro and in-vivo studies can provide mechanistic insights. We describe acute health effects (e.g. exacerbations of asthma) and long term health effects such as the induction of chronic inflammatory lung disease, and effects outside the lung (e.g. liver and renal change). We will focus on oxidative stress and inflammation as this is the common mechanism of PM-induced disease, which may be used to develop effective treatments to mitigate the adverse health effect of PM exposure.

Indirect mediators of systemic health outcomes following nanoparticle inhalation exposure

The growing field of nanoscience has shed light on the wide diversity of natural and anthropogenic sources of nano-scale particulates, raising concern as to their impacts on human health. Inhalation is the most robust route of entry, with nanoparticles (NPs) evading mucociliary clearance and depositing deep into the alveolar region. Yet, impacts from inhaled NPs are evident far outside the lung, particularly on the cardiovascular system and highly vascularized organs like the brain. Peripheral effects are partly explained by the translocation of some NPs from the lung into the circulation; however, other NPs largely confined to the lung are still accompanied by systemic outcomes. Omic research has only just begun to inform on the complex myriad of molecules released from the lung to the blood as byproducts of pulmonary pathology. These indirect mediators are diverse in their molecular make-up and activity in the periphery. The present review examines systemic outcomes attributed to pulmonary NP exposure and what is known about indirect pathological mediators released from the lung into the circulation. Further focus was directed to outcomes in the brain, a highly vascularized region susceptible to acute and longer-term outcomes. Findings here support the need for big-data toxicological studies to understand what drives these health outcomes and better predict, circumvent, and treat the potential health impacts arising from NP exposure scenarios.

Climatology and trends of morning and evening surface-based temperature inversions in southwestern Pennsylvania with air quality implications

Concerns over regional climate change include its impact on air quality. A major contributor to unhealthy air quality is surface-based temperature inversions. Poor air quality is a serious public health concern that is often addressed by public health agencies. To assist with understanding the climatology and trend of temperature inversions for a large public health department, innovative pragmatic criteria were developed and used to determine morning and evening surface-based temperature inversions from datasets derived from Pittsburgh National Weather Service (NWS) radiosonde measurements made from 1 January 1991 through 31 December 2020. During this 30-year period, the strength of the morning (7 a.m. EST; 12 UTC) inversions was 3.9 °C on average. The depth of the inversion layer measured an average height of 246 m above the ground. The inversions tended to dissipate by 10 a.m. EST. The frequency of occurrence of morning inversions averaged 47%. The mean strength of the evening (7 p.m. EST; 00 UTC) inversions was 1.1 °C with a mean depth of 101 m above the ground. The frequency of evening inversion occurrence averaged 20% during this period. The 30-year climatology revealed generally declining frequency of inversions in the Pittsburgh area. Morning surface-based inversion strengths usually declined while morning depths and break times were steady. Evening inversion strengths and depths increased overall during the 30-year period. Monthly means showed a morning-evening overlap of some months that record the most frequent substantial inversions during the fall time of the year, coinciding with the time when the worst air pollution events occur.

Infectious Diseases Associated with Desert Dust Outbreaks: A Systematic Review

Background: Desert dust outbreaks and dust storms are the major source of particulate matter globally and pose a major threat to human health. We investigated the microorganisms transported with desert dust particles and evaluated their potential impact on human health. Methods: A systematic review of all reports on the association between non-anthropogenic desert dust pollution, dust microorganisms and human health is conducted. Results: In total, 51 articles were included in this review. The affected regions studied were Asia (32/51, 62.7%) followed by Europe (9/51, 17.6%), America (6/51, 11.8%), Africa (4/51, 7.8%) and Australia (1/51, 2.0%). The Sahara Desert was the most frequent source of dust, followed by Asian and American deserts. In 39/51 studies the dust-related microbiome was analyzed, while, in 12/51 reports, the association of desert dust with infectious disease outbreaks was examined. Pathogenic and opportunistic agents were isolated from dust in 24/39 (61.5%) and 29/39 (74.4%) of the studies, respectively. A significant association of dust events with infectious disease outbreaks was found in 10/12 (83.3%) reports. The infectious diseases that were mostly investigated with dust outbreaks were pneumonia, respiratory tract infections, COVID-19, pulmonary tuberculosis and coccidioidomycosis. Conclusions: Desert dust outbreaks are vehicles of a significant number of pathogenic or opportunistic microorganisms and limited data indicate an association between dust events and infectious disease outbreaks. Further research is required to strengthen the correlation between dust events and infectious diseases and subsequently guide preventive public health measures.

Characterizing spatiotemporal variability in airborne heavy metal concentration: Changes after 18 Years in Baltimore, MD

INTRODUCTION

This study investigates the impact of changes in local industry, urban development, and proximity to suspected emission sources on airborne metal concentration in Baltimore, Maryland between 2001 and 2019 with particular focus on the urban industrial community of Curtis Bay in South Baltimore.

METHODS

Integrated PM_2.5 and PM₁₀ Harvard Impactors were set up at six locations in the Baltimore City metropolitan area in weeklong sampling sessions from January-July 2019 to assess variation in airborne metal concentration by proximity to suspected metal emission sources. PM_2.5 and PM₁₀ were collected on Teflo filters and analyzed for a panel of 12 metals and metalloids (As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sb, and Zn) using inductively coupled plasma mass spectrometry. The findings were compared against airborne metal concentrations reported by the Baltimore Supersite in 2001 and 2003 to assess changes over the 18-year period.

RESULTS

PM_2.5 concentrations reported from this study ranged from 3.27 μg/m³ to 36.0 μg/m³ and PM₁₀ concentrations ranged from 9.00 μg/m³ to 30.1 μg/m³ across all sampling sites. Metal concentrations ranged from 1.4 times (Cd) to 4.8 times (Cr) higher in PM₁₀ compared to PM_2.5. Compared to the study reference site, median PM_2.5 concentrations of Co and Fe were roughly 1.8 times and 2.1 times higher, respectively, at near-road sampling sites indicating significant variability in airborne metal concentration by proximity to local traffic emissions. PM_2.5 and PM₁₀ Sb concentrations were 3.4 times and 6.7 times higher at a near incinerator site compared to the reference, consistent with existing evidence of Sb sourcing from municipal incinerators in Baltimore City. Decreases in Cr (-40%), Ni (-73%), Pb (-55%), and Zn (-36%) concentrations were observed over the 18-year period while concentrations of Cu, Fe, and Mn were not statistically significantly different.

CONCLUSION

Declines in airborne Cr, Ni, Pb, and Zn concentration since 2001 appear to coincide with industrial decline highlighting the success of remediation and redevelopment efforts. Remaining spatial variability is related to vehicular traffic and proximity to a municipal incinerator which should be focal areas for future intervention to reduce metal exposure disparities in Baltimore City.

Long-term effects of wildfire smoke exposure during early life on the nasal epigenome in rhesus macaques

BACKGROUND

Wildfire smoke is responsible for around 20% of all particulate emissions in the U.S. and affects millions of people worldwide. Children are especially vulnerable, as ambient air pollution exposure during early childhood is associated with reduced lung function. Most studies, however, have focused on the short-term impacts of wildfire smoke exposures. We aimed to identify long-term baseline epigenetic changes associated with early-life exposure to wildfire smoke. We collected nasal epithelium samples for whole genome bisulfite sequencing (WGBS) from two groups of adult female rhesus macaques: one group born just before the 2008 California wildfire season and exposed to wildfire smoke during early-life (n = 8), and the other group born in 2009 with no wildfire smoke exposure during early-life (n = 14). RNA-sequencing was also performed on a subset of these samples.

RESULTS

We identified 3370 differentially methylated regions (DMRs) (difference in methylation ≥ 5%, empirical p < 0.05) and 1 differentially expressed gene (FLOT2) (FDR < 0.05, fold of change ≥ 1.2). The DMRs were annotated to genes significantly enriched for synaptogenesis signaling, protein kinase A signaling, and a variety of immune processes, and some DMRs significantly correlated with gene expression differences. DMRs were also significantly enriched within regions of bivalent chromatin (top odds ratio = 1.46, q-value < 3 × 10^-6) that often silence key developmental genes while keeping them poised for activation in pluripotent cells.

CONCLUSIONS

These data suggest that early-life exposure to wildfire smoke leads to long-term changes in the methylome over genes impacting the nervous and immune systems. Follow-up studies will be required to test whether these changes influence transcription following an immune/respiratory challenge.

Role of Particulate Matter from Afghanistan and Iraq in Deployment-Related Lung Disease

Approximately 3 million United States military personnel and contractors were deployed to Southwest Asia and Afghanistan over the past two decades. After returning to the United States, many developed persistent respiratory symptoms, including those due to asthma, rhinosinusitis, bronchiolitis, and others, which we collectively refer to as deployment-related lung diseases (DRLD). The mechanisms of different DRLD have not been well defined. Limited studies from us and others suggest that multiple factors and biological signaling pathways contribute to the onset of DRLD. These include, but are not limited to, exposures to high levels of particulate matter (PM) from sandstorms, burn pit combustion products, improvised explosive devices, and diesel exhaust particles. Once inhaled, these hazardous substances can activate lung immune and structural cells to initiate numerous cell-signaling pathways such as oxidative stress, Toll-like receptors, and cytokine-driven cell injury (e.g., interleukin-33). These biological events may lead to a pro-inflammatory response and airway hyperresponsiveness. Additionally, exposures to PM and other environmental hazards may predispose military personnel and contractors to more severe disease due to the interactions of those hazardous materials with subsequent exposures to allergens and cigarette smoke. Understanding how airborne exposures during deployment contribute to DRLD may identify effective targets to alleviate respiratory diseases and improve quality of life in veterans and active duty military personnel.

Association of particulate matter with autoimmune rheumatic diseases among adults in South Korea

OBJECTIVE

The primary objective of this study was to investigate adverse effects of ambient particulate matter of various sizes on the incidence of the prevalent autoimmune rheumatic diseases (AIRDs): RA, AS and SLE.

METHODS

We investigated 230 034 participants in three metropolitan cities of South Korea from the National Health Insurance Service-National Sample Cohort (NHIS-NSC). Starting from January 2010, subjects were followed up until the first event of prevalent AIRDs, death, or December 2013. The 2008-2009 respective averages of particulate matter2.5 (<2.5 μm) and particulate mattercoarse (2.5 μm to 10 μm) were linked with participants' administrative district codes. Adjusted hazard ratios (aHRs) and 95% CIs were estimated using Cox regression analysis in one- and two-pollutant models.

RESULTS

Adjusted for age, sex, region, and household income, in the two-pollutant model, RA incidence was positively associated with the 10 μg/m³ increment of particulate matter2.5 (aHR = 1.74, 95% CI: 1.06, 2.86), but not with particulate mattercoarse (aHR = 1.27, 95% CI: 0.87, 1.85). In the one-pollutant model, the elevated incidence rate of RA was slightly attenuated (particulate matter2.5 aHR = 1.61, 95% CI: 0.99, 2.61; particulate mattercoarse aHR = 1.13, 95% CI: 0.80, 1.61), with marginal statistical significance for particulate matter2.5. The RA incidence was also higher in the 4th quartile group of particulate matter2.5 compared with the first quartile group (aHR = 1.83, 95% CI: 1.07, 3.11). Adverse effects from particulate matter were not found for AS or SLE in either the one- or two-pollutant models.

CONCLUSION

The important components of particulate matter10 associated with RA incidence were the fine fractions (particulate matter2.5); no positive association was found between particulate matter and AS or SLE.

Modeling and forecasting of monthly PM2.5 emission of Paris by periodogram-based time series methodology

In this study, monthly particulate matter (PM_2.5) of Paris for the period between January 2000 and December 2019 is investigated by utilizing a periodogram-based time series methodology. The main contribution of the study is modeling the PM_2.5 of Paris by extracting the information purely from the examined time series data, where proposed model implicitly captures the effects of other factors, as all their periodic and seasonal effects reside in the air pollution data. Periodicity can be defined as the patterns embedded in the data other than seasonality, and it is crucial to understand the underlying periodic dynamics of air pollutants to better fight pollution. The method we use successfully captures and accounts for the periodicities, which could otherwise be mixed with seasonality under an alternative methodology. Upon the unit root test based on periodograms, it is revealed that the investigated data has periodicities of 1 year and 20 years, so harmonic regression is utilized as an alternative to Box-Jenkins methodology. As the harmonic regression displayed a better performance both in and out-of-sample forecasts, it can be considered as a powerful alternative to model and forecast time series with a periodic structure.

In vitro toxicity of indoor and outdoor PM10 from residential wood combustion

Particulate matter with aerodynamic diameter < 10 μm (PM₁₀) was collected, indoors and outdoors, when wood burning appliances (open fireplace and woodstove) were in operation. The PM₁₀ ecotoxicity was assessed with the Vibrio fischeri bioluminescence inhibition assay, while the cytotoxicity was evaluated by the WST-8 and lactate dehydrogenase (LDH) release assays using A549 cells. Extracts of PM₁₀-bound polycyclic aromatic hydrocarbons (PAH) were tested for their mutagenicity through the TA98 and TA100 Ames test. The bioluminescent inhibition assay revealed that indoor particles released from the fireplace were the most toxic. Indoors, the reduction in A549 cell metabolic activity was over two times higher for the fireplace in comparison with the woodstove (32 ± 3.2% and 72 ± 7.6% at the highest dose, respectively). Indoor particles from the fireplace were found to induce greater cytotoxicity than the corresponding outdoor samples. Combined WST-8 and LDH results suggest that PM₁₀ exposure induce apoptotic cell death pathway in which the cell membrane integrity is maintained. Indoor and outdoor samples lacked direct and indirect mutagenic activity in any of the tester strains. For indoor-generated PM₁₀, organic carbon and PAH were significantly correlated with cell viability and bioluminescence reduction, suggesting a role of organic compounds in toxicity.

Assessment of global and regional PM10 CAMSRA data: comparison to observed data in Morocco

Given the strong impact of air quality on health, environment, and economy, Morocco has implemented an air quality network to assess air pollutants including PM₁₀ (particulate matter with a diameter less than 10 μm). This network which is composed of 29 fixed measurement stations is spatially limited and does not provide sufficient time resolution. The scarcity of measured air quality data led to seek an optimal alternative source to conduct related data-based studies. This represents the primary objective of this paper. PM₁₀ concentrations of global Copernicus Atmosphere Monitoring Service Reanalysis (CAMSRA) data (4D Variational analysis "4v" and analysis "an"), as well as regional CAMSRA data, were examined against the average daily PM₁₀ concentrations collected from six fixed Moroccan air quality measurement stations in 2016 (i.e., observation data). The verification is carried out by studying and analyzing seasonal, extreme, and annual values. The study shows a strong seasonal dependence with a positive bias in winter and a negative bias during summer. For the study of extreme values, global CAMSRA "an" and "4v" data record significant bias of approximately 184 and 161 μg/m³, respectively. However, the annual analysis shows that the CAMSRA global "an" data have the smallest average bias (20.008 μg/m³) and hence has the closest representation of observation data. We conclude that the CAMSRA global analysis data could be used to compute climatology, study trends, evaluate models, benchmark other reanalysis, or serve as boundary conditions for regional models for past periods.

Characteristics and sources of hourly elements in PM10 and PM2.5 during wintertime in Beijing

Characteristics and sources of ambient particle elements in urban Beijing were studied by hourly observations in two size fractions (PM₁₀ and PM_2.5) during November and December 2017 using an online multi-element analyzer. The reconstructed oxide concentrations of 24 elements (from Al to Pb) comprise an appreciable fraction of PM₁₀ and PM_2.5, accounting for 37% and 17%, respectively on average. We demonstrate the benefit of using high-time-resolution chemical speciation data in achieving robust source apportionment of the total elemental PM₁₀ (PM_10el) and elemental PM_2.5 (PM_2.5el) mass using positive matrix factorization (PMF). Biomass burning, coal combustion, secondary sulfate, industry, non-exhaust traffic and dust were identified in both size fractions (with varying relative concentrations), which accounted on average for 4%, 12%, 5%, 2%, 14%, and 63%, respectively to the total PM_10el, and 14%, 35%, 21%, 6%, 12% and 12%, respectively to the total PM_2.5el. Biomass burning and coal combustion exhibited higher concentrations during haze episodes of the heating season. In contrast, secondary sulfate and industry contributed more to haze episodes during the non-heating season. The fractional contribution of dust was mostly high during clean days, while the fractional non-exhaust traffic emission contribution was similar throughout the measurement period. The non-exhaust traffic emissions contributed locally, while the remaining sources were dominated by neighboring areas. Furthermore, trajectory analysis showed that the origin of the industrial sources roughly agreed with the locations of the main point sources. Overall, this work provides detailed information on the characteristics of the elements during different haze events during heating and non-heating seasons.

Analysis on the Exhaust Air Recirculation of the Ventilation System in Multi-Story Building

In South Korea, the installation of a mechanical ventilation system is mandatory for the management of indoor air quality, and various studies concerning the ventilation rate and performance of the ventilation system have been conducted. However, only a few studies have been conducted regarding the recirculation rate of the ventilation system. If the appropriate arrangement of intake and exhaust vents in the ventilation system is not considered, the pollutants emitted from the circulation movement may be recirculated into the indoor environment and cause the degradation of the performance of the ventilation system. Therefore, this study aimed to quantitatively analyze the recirculation rate of pollutants emitted from a kindergarten building with an installed mechanical ventilation system in Seoul, South Korea, using computational fluid dynamics (CFD) analysis, and analyze the effectiveness of the guide panel installed for the prevention of the pollutants’ recirculation. The number of cases for the CFD analysis was set to a total of ten based on the ventilation rate in a mechanical ventilation system, external wind direction, and the existence of the guide panel for preventing the recirculation of exhaust air. The maximum recirculation rate of exhaust air without the installation of a guide panel was shown to be 20.0%. The maximum recirculation rate in the case where the external wind speed, direction of wind, and the ventilation rate were assumed to be identical to the other case but the guide panel for preventing the recirculation of exhaust air was assumed to be installed was 7.7%, 12.3% lower compared with the case with maximum recirculation rate.

Short-Term Associations of Ambient Fine Particulate Matter (PM2.5) with All-Cause Hospital Admissions and Total Charges in 12 Japanese Cities

The short-term association between ambient particulate matter ≤2.5 microns in diameter (PM_2.5) and hospital admissions is not fully understood. Studies of this association with hospital admission costs are also scarce, especially in entire hospitalized populations. We examined the association between ambient PM_2.5 and all-cause hospital admissions, the corresponding total charges, and the total charges per patient by analyzing the hospital admission data of 2 years from 628 hospitals in 12 cities in Japan. We used generalized additive models with quasi-Poisson regression for hospital admissions and generalized additive models with log-linear regression for total charges and total charges per patient. We first estimated city-specific results and the combined results by random-effect models. A total of 2,017,750 hospital admissions were identified. A 10 µg/m³ increase in the 2 day moving average was associated with a 0.56% (95% CI: 0.14–0.99%) increase in all-cause hospital admissions and a 1.17% (95% CI: 0.44–1.90%) increase in total charges, and a 10 µg/m³ increase in the prior 2 days was associated with a 0.75% (95% CI: 0.34–1.16%) increase in total charges per patient. Short-term exposure to ambient PM_2.5 was associated with increased all-cause hospital admissions, total charges, and total charges per patient.

Exposure to total particulate matter obtained from combustion of diesel vehicles (EURO 3 and EURO 5): Effects on the respiratory systems of emphysematous mice

Air pollution has association with chronic obstructive pulmonary disease (COPD) and reduced life expectancy. This study investigated the deleterious effects caused by tobacco smoke and diesel exhaust particles (DEP) from vehicles operating under EURO 3 and EURO 5 standards. Experiments were carried out on C57BL/6 mice divided into six groups: control group, group exposed to cigarette smoke (CS), two groups exposed to DEP (AAE3 and AAE5), and two groups exposed to tobacco smoke and vehicle DEP (CSE3 and CSE5). Results showed that, when compared to AA, groups AAE3 and AAE5 showed changes in respiratory mechanics, and that DEP originating from EURO 5 diesel vehicles was less harmful when compared to DEP originating from EURO 3 diesel vehicles. Analyses of groups CSE3 and CSE5 revealed increased inspiratory capacity and decreased tissue elastance, when compared to their respective controls, suggesting an exacerbation of changes in respiratory system mechanics compatible with COPD development.

Estimating Health Impacts Due to the Reduction of Particulate Air Pollution from the Household Sector Expected under Various Scenarios

Emissions from the household sector are the most significant source of air pollution in Poland, one of the most polluted countries in the EU. Estimated health impacts of the reduction of these emissions under three scenarios are presented. The EMEP4PL model and base year emission inventory were used to estimate average annual PM10 and PM2.5 concentrations with spatial resolution of 4 km × 4 km. The change in emissions under each of the scenarios was based on data from a survey on household boilers and insulation. Scenario 1 included replacement of all poor-quality coal-fired boilers with gas boilers; Scenario 2 included replacement of all poor-quality coal-fired boilers with low-emission boilers but still using solid fuels; and Scenario 3 included the thermal refurbishment of houses with the worst insulation. Impacts on the following health parameters were estimated: premature deaths (PD), Chronic Bronchitis (CB), Bronchitis in Children (BiC) and Work Days Lost (WDL). The concentration–response functions recommended by the WHO HRAPIE project were used. The analysis was conducted for two regions: Lower Silesia and Lodzkie province. The largest reduction of health impact was observed for Scenario 1. For Lower Silesia, the annual PD decreased by 1122 (34.3%), CB by 1516 (26.6%), BiC by 9602 (27.7%) and WDL by 481k (34.7%). For Lodzkie province, the largest impacts were estimated as decreases in PD by 1438 (29.9%), CB by 1502 (25.3%), BiC by 9880 (26.8%) and WDL by 669k (30.4%).

Lactic Acid Spectroscopy: Intra- and Intermolecular Interactions

Lactic acid, a relevant molecule in biology and the environment, is an α-hydroxy acid with a high propensity to form hydrogen bonds, both internally and to other hydrogen-bond-accepting molecules. This work includes the novel recording of infrared spectra of gas-phase lactic acid using Fourier transform infrared spectroscopy, and the vibrational absorption features of lactic acid are assigned with the aid of computationally simulated vibrational spectra with anharmonic corrections. Theoretical chemistry methods are used to relate intramolecular hydrogen-bond strengths to the relative stability of lactic acid conformers. The formation of hydrogen-bonded lactic acid dimers and 1:1 water complexes is investigated by simulated vibrational spectra and calculated thermodynamic parameters for the lactic acid monomer and dimer and its water complex in the gas phase. The results of this study are discussed in the context of environmental chemistry with an emphasis on indoor environments.

Effect of particle morphology on performance of an electrostatic air-liquid interface cell exposure system for nanotoxicology studies

Particle morphology can affect the performance of an electrostatic precipitator air-liquid interface (ESP-ALI) cell exposure system and the resulting cell toxicity. In this study, three types of monodisperse aerosols - spherical sucrose particles, nonspherical align soot aggregates, and nanosilver aggregates/agglomerates - were selected to evaluate the collection efficiency at flow rates ranging from 0.3 to 1.5 lpm. To quantify the particle morphology, the fractal dimensions (D_f) of the tested aerosols were characterized. The penetration of fine particles (d_p = 100-250 nm) under different operating conditions was correlated with a characteristic exponential curve using the dimensionless drift velocity (V_c/V_avg,r) as the scaling parameter. For nanoparticles (NPs, d_p <100 nm) with different particle morphologies, the particle penetrations in the ESP-ALI were similar, but their diffusion losses were not negligible. In contrast, for fine particles, the collection efficiency of soot nanoaggregates (D_f = 2.29) was higher than that of spherical sucrose particles. This difference might be due to the simultaneous influences of the electric field-induced and flow field-induced alignment. Furthermore, based on Zhibin and Guoquan's Deutsch model, a quadratic equation was applied to fit the experimental data and to predict the performance of the ESP-ALI.

Human Health and Economic Costs of Air Pollution in Utah: An Expert Assessment

Air pollution causes more damage to health and economy than previously understood, contributing to approximately one in six deaths globally. However, pollution reduction policies remain controversial even when proven effective and cost negative, partially because of misunderstanding and growing mistrust in science. We used an expert assessment to bridge these research–policy divides in the State of Utah, USA, combining quantitative estimates from 23 local researchers and specialists on the human health and economic costs of air pollution. Experts estimated that air pollution in Utah causes 2480 to 8000 premature deaths annually (90% confidence interval) and decreases the median life expectancy by 1.1 to 3.6 years. Economic costs of air pollution in Utah totaled $0.75 to $3.3 billion annually, up to 1.7% of the state’s gross domestic product. Though these results were generally in line with available estimates from downscaled national studies, they were met with surprise in the state legislature, where there had been an almost complete absence of quantitative health and economic cost estimates. We discuss the legislative and personal responses of Utah policy makers to these results and present a framework for increasing the assimilation of data into decision making via regional expert assessment. In conclusion, combining quantitative assessments from local experts is a responsive and cost-effective tool to increase trust and information uptake during time-sensitive policy windows.

Model for assessing health damage from air pollution in quarrying area - Case study at Tan Uyen quarry, Ho Chi Minh megapolis, Vietnam

Vietnam has a great demand for stone exploitation for the development of the country's infrastructure, reaching 181 million m³ in 2020. Mining activities are always accompanied by environmental pollution, negatively affecting public health. To accurately assess the level of pollution, as well as quantify the effect of air pollution on human health, a number of structures, methods, and models provide tools to assess the benefits of this control for public health and related economic values. However, there has been no research in Vietnam applied specifically to this type of stone exploitation. This study offers a model to evaluate the economic damage caused by dust exposure from activities related to quarrying, overcoming the lack of continuous monitoring data. The area selected for research is Binh Duong province, in the Ho Chi Minh megapolis, Vietnam, which has two construction quarries, Thuong Tan and Tan My, with a current annual production of approximately 4–5 million m³. The calculation results show that the damage to human health is estimated at approximately 9,643 billion dong a year, equivalent to 15.03 million USD. In addition, if the standard criteria are tightened, damage will continue to increase. This study also analyses some of the difficulties and limitations in the modelling process.

A Framework to Predict High-Resolution Spatiotemporal PM2.5 Distributions Using a Deep-Learning Model: A Case Study of Shijiazhuang, China

Air-borne particulate matter, PM2.5 (PM having a diameter of less than 2.5 micrometers), has aroused widespread concern and is a core indicator of severe air pollution in many cities globally. In our study, we present a validated framework to predict the daily PM2.5 distributions, exemplified by a use case of Shijiazhuang City, China, based on daily aerosol optical depth (AOD) datasets. The framework involves obtaining the high-resolution spatiotemporal AOD distributions, estimation of the spatial distributions of PM2.5 and the prediction of these based on a convolutional long short-term memory (ConvLSTM) model. In the estimation part, the eXtreme gradient boosting (XGBoost) model has been determined as the estimation model with the lowest root mean square error (RMSE) of 32.86 µg/m3 and the highest coefficient of determination regression score function (R2) of 0.71, compared to other common models used as a baseline for comparison (linear, ridge, least absolute shrinkage and selection operator (LASSO) and cubist). For the prediction part, after validation and comparison with a seasonal autoregressive integrated moving average (SARIMA), which is a traditional time-series prediction model, in both time and space, the ConvLSTM gives a more accurate performance for the prediction, with a total average prediction RMSE of 14.94 µg/m3 compared to SARIMA’s 17.41 µg/m3. Furthermore, ConvLSTM is more stable and with less fluctuations for the prediction of PM2.5 in time, and it can also eliminate better the spatial predicted errors compared to SARIMA.

Airborne Aerosols and Human Health: Leapfrogging from Mass Concentration to Oxidative Potential

The mass concentration of atmospheric particulate matter (PM) has been systematically used in epidemiological studies as an indicator of exposure to air pollutants, connecting PM concentrations with a wide variety of human health effects. However, these effects can be hardly explained by using one single parameter, especially because PM is formed by a complex mixture of chemicals. Current research has shown that many of these adverse health effects can be derived from the oxidative stress caused by the deposition of PM in the lungs. The oxidative potential (OP) of the PM, related to the presence of transition metals and organic compounds that can induce the production of reactive oxygen and nitrogen species (ROS/RNS), could be a parameter to evaluate these effects. Therefore, estimating the OP of atmospheric PM would allow us to evaluate and integrate the toxic potential of PM into a unique parameter, which is related to emission sources, size distribution and/or chemical composition. However, the association between PM and particle-induced toxicity is still largely unknown. In this commentary article, we analyze how this new paradigm could help to deal with some unanswered questions related to the impact of atmospheric PM over human health.

Evaluation on Air Purifier's Performance in Reducing the Concentration of Fine Particulate Matter for Occupants according to its Operation Methods

Fine particulate matter entering the body through breathing cause serious damage to humans. In South Korea, filter-type air purifiers are used to eliminate indoor fine particulate matter, and there has been a broad range of studies on the spread of fine particulate matter and air purifiers. However, earlier studies have not evaluated an operating method of air purifiers considering the inflow of fine particulate matter into the body or reduction performance of the concentration of fine particulate matter. There is a limit to controlling the concentration of fine particulate matter of the overall space where an air purifier is fixed in one spot as the source of indoor fine particulate matter is varied. Accordingly, this study analyzed changes in the concentration of indoor fine particulate matter through an experiment according to the discharging method and location of a fixed air purifier considering the inflow route of fine particulate matter into the body and their harmfulness. The study evaluated the purifiers' performance in reducing the concentration of fine particulate matter in the occupants' breathing zone according to the operation method in which a movable air purifier responds to the movement of occupants. The results showed the concentration of fine particulate matter around the breathing zone of the occupants had decreased by about 51 μg/m³ compared to the surrounding concentration in terms of the operating method in which an air purifier tracks occupants in real-time, and a decrease of about 68 μg/m³ in terms of the operating method in which an air purifier controls the zone. On the other hand, a real-time occupant tracking method may face a threshold due to the moving path of an air purifier and changes in the number of occupants. A zone controlling method is deemed suitable as an operating method of a movable air purifier to reduce the concentration of fine particulate matter in the breathing zone of occupants.

The impact of exposure to desert dust on infants' symptoms and countermeasures to reduce the effects

BACKGROUND

The association between particulate matter (PM), including desert dust, and allergic symptoms has not been well studied. We examined whether PM exacerbated nose/eye/respiratory symptoms in infants, with a focus on the desert dust element, and assessed possible countermeasures.

METHODS

We conducted a panel study of 1492 infants from October 2014 to July 2016 in 3 regions in Japan as an adjunct study of the Japan Environment and Children's Study. Infants' daily symptom scores and behaviors were acquired by web-based questionnaires sent to mothers, who answered within a day using mobile phones. Odds ratios (OR) for symptom development per increased fine PM or desert dust exposure were estimated. Regular use of medications and behaviors on the day of exposure were investigated as possible effect modifiers.

RESULTS

Infants developed nose/eye/respiratory symptoms significantly more often in accordance with fine particulate levels (adjusted OR per 10 µg/m³ increase: 1.04, 95% confidence interval [CI]: 1.01-1.07). A model including both fine particulates and desert dust showed reduced OR for fine particulates and robust OR for desert dust (adjusted OR per 0.1/km increase: 1.16, 95% CI: 1.09-1.23). An increased OR was observed both in infants who had previously wheezed and in those who had never wheezed. Receiving information on the particulate forecast, reducing time outdoors, closing windows, and regular use of leukotriene receptor antagonists were significant effect modifiers.

CONCLUSIONS

Transborder desert dust arrival increased the risk of nose/eye/respiratory symptoms development in infants. Regular use of leukotriene receptor antagonists and other countermeasures reduced the risk.

Concentration Variability of Water-Soluble Ions during the Acceptable and Exceeded Pollution in an Industrial Region

This study investigates the chemical composition of water-soluble inorganic ions at eight localities situated in the Moravian-Silesian Region (the Czech Republic) at the border with Poland. Water-soluble inorganic ions were monitored in the winter period of 2018 (January, 11 days and February, 5 days). The set was divided into two periods: the acceptable period (the 24-h concentration of PM₁₀ < 50 µg/m³) and the period with exceeded pollution (PM₁₀ ˃ 50 µg/m³). Air quality in the Moravian-Silesian Region and Upper Silesia is among the most polluted in Europe, especially in the winter season when the concentration of PM₁₀ is repeatedly exceeded. The information on the occurrence and behaviour of water-soluble inorganic ions in the air during the smog episodes in Europe is insufficient. The concentrations of water-soluble ions (chlorides, sulphates, nitrates, ammonium ions, potassium) during the exceeded period are higher by two to three times compared with the acceptable period. The major anions for both acceptable period and exceeded pollution are nitrates. During the period of exceeded pollution, percentages of water-soluble ions in PM₁₀ decrease while percentages of carbonaceous matter and insoluble particles (fly ash) increase.

Evaluation of the effectiveness of a portable air cleaner in mitigating indoor human exposure to cooking-derived airborne particles

Gas cooking is an important source of airborne particulate matter (PM) indoors. Exposure to cooking-derived PM can lead to adverse human health impacts on non-smokers, especially in poorly-ventilated residential homes. Most of the previous studies on gas cooking emissions mainly focused on fine particles (PM_2.5) with little information on their size-fractionation. Moreover, studies dealing with mitigation of indoor human exposure to cooking-derived PM are currently sparse. Therefore, a systematic study was conducted to investigate the characteristics of PM_2.5 and size-fractionated PM derived from five commonly used cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying in a poorly-ventilated domestic kitchen under controlled experimental conditions. Additionally, an indoor portable air cleaner was employed as a mitigation device to capture cooking-derived PM and improve indoor air quality (IAQ). Results revealed that the oil-based deep-frying cooking released the highest airborne particles which were about 170 folds higher compared to the baseline levels for PM_2.5 mass concentrations. The use of the air cleaner showed a statistically significant (p < 0.05) reduction in the indoor PM_2.5 levels. Moreover, PM_<0.25 (particles with diameter ≤ 250 nm) showed a very high mass concentration (378.2 μg/m³) during deep-frying, raising human health concern. A substantial reduction (~60-85%) in PM_<0.25 mass concentrations and their total respiratory deposition doses (RDD) in the human respiratory tract was observed while using the air cleaner during the five cooking methods. Furthermore, morphological characteristics and the relative abundance of trace elements in cooking-derived PM were also investigated. This study provides useful insights into the assessment and mitigation of indoor human exposure to cooking-derived PM.

The effects of air pollution and meteorological factors on measles cases in Lanzhou, China

By collecting daily data on measles cases, air pollutants, and meteorological data from 2005 to 2009 in Chengguan District of Lanzhou City, semi-parametric generalized additive model (GAM) was used to quantitatively study the impact of air pollutants and meteorological factors on daily measles cases. The results showed that air pollutants and meteorological factors had effect on the number of daily measles cases, and there was a certain lag effect. Except for SO₂ and relative humidity, other factors showed statistically significant associations with daily measles cases: NO₂ lag 6 days, PM₁₀ and maximum temperature lag 5 days, minimum temperature and average temperature and average air pressure lag 4 days, visibility, and wind speed lag 3 days had the greatest impact on the number of daily measles cases. Under the optimum lag conditions, the number of daily measles cases increased by 15.1%, 17.6%, 7.0%, 116.6%, 98.6%, 85.7%, and 14.4% with the increase of 1 IQR in SO₂, NO₂, PM₁₀, maximum temperature, minimum temperature, average temperature, and wind speed; with the increase of 1 IQR in average pressure, relative humidity, visibility, and daily measles cases decreased by 12.8%, 9.7%, and 13.1%, respectively. And different factors showed different seasonal effects. The effects of SO₂ and temperature factors on daily measles cases were greater in spring and winter, but PM₁₀ in summer.

Air Quality Trend of PM10. Statistical Models for Assessing the Air Quality Impact of Environmental Policies

A statistical modelling of PM10 concentration (2006–2015) is applied to understand the behaviour, to know the influence of the variables to exposure risk, to treat the missing data to evaluate air quality, and to estimate data for those sites where they are not available. The study area, Castellón region (Spain), is a strategic area in the framework of EU pollution control. A decrease of PM10 is observed for industrial and urban stations. In the case of rural stations, the levels remain constant throughout the study period. The contribution of anthropogenic sources has been estimated through the PM10 background of the study area. The behaviour of PM10 annual trend is tri-modal for industrial and urban stations and bi-modal in the case of rural stations. The EU Normative suggests that 90% of the data per year are necessary to control air quality. Thus, interpolation statistical methods are presented to fill missing data: Linear Interpolation, Exponential Interpolation, and Kalman Smoothing. This study also focuses on testing the goodness of these methods in order to find the ones that better approach the gaps. After analyzing graphically and using the RMSE the last method is confirmed to be the best option.

Atmospheric oxidation mechanism and kinetics of 2-bromo-4,6-dinitroaniline by OH radicals - a theoretical study

2-Bromo-4,6-dinitroaniline (BNA) is identified as a domestic-dust pollutant in urban environments, with deleterious atmospheric effects. In the present work, we studied the reaction pathways and kinetics for BNA oxidation by the OH radical using quantum-chemical methods and canonical-variational transition-state theory with small-curvature tunneling correction (CVT/SCT). OH-radial-mediated BNA oxidation was studied by considering OH addition to carbon atoms (C1 to C6) of BNA and H-atom abstraction at the -NH₂ group and carbon atoms (C3 and C5) of BNA by OH radicals. It is observed that an OH-addition reaction is energetically more favorable. In addition, the rate constant was calculated for the favorable initial OH-addition reactions over the temperature range of 278 to 1000 K. The subsequent reactions for the favorable BNA-OH adduct intermediate with O₂, HO₂ and NO radicals are studied. We have identified the following possible end products from this BNA-oxidation reaction: (i) 2-amino-3-bromo-6-hydroperoxy-5-methyl-1-nitro-cyclohexa-2,4 dienol, (ii) 2-amino-1-bromo-6-hydroperoxy-5-methyl-3-nitro-cyclohexa-2,4-dienol, (iii) 2-amino-1-bromo-6-hydroperoxy-5-methyl-3-nitro-cyclohexa-2,4-dienol, (iv) 3-amino-4-bromo-4-hydroperoxy-8-methyl-2-nitro-6,7-dioxa-bicyclo oct-2-en-8-ol, (v) 2-amino-1-bromo-6-hydroperoxy-5-methyl-3-nitro-cyclohexa-2,4-dienol, and (vi) 3-amino-2-bromo-8-methyl-4-nitro-6,7-dioxa-bicyclo oct-3-ene-2,8-diol.

microRNA-16 Via Twist1 Inhibits EMT Induced by PM2.5 Exposure in Human Hepatocellular Carcinoma

Epidemiological study has confirmed that PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 μm) is associated with the incidence and progression of human hepatocellular carcinoma (HCC). Accordingly, this study was undertaken to investigate the pro-metastatic effects of PM2.5 on human HCC cell line SMMC-7721 in vitro and to explore the underlying mechanisms. CCK-8 assay was performed to examine the effect of PM2.5 on the proliferation of SMMC-7721 cells; scratch wound assay and transwell matrigel system has been used to examine the effect of PM2.5 on the migration and invasion ability of SMMC-7721 cells; furthermore, effect of PM2.5 on epithelial mesenchymal transition (EMT) of SMMC-7721 cells were examined by examining the EMT markers vimentin, ɑ-smooth muscle actin (ɑ-SMA), and E-cadherin; furthermore, the roles of microRNA-16 (miR-16) and its target Twist1 in PM2.5 induced carcinogenic effects were also examined. Results of CCK-8 assay suggested that PM2.5 promoted the proliferation of SMMC-7721 cells in a dose and time dependent manner. PM2.5 also markedly promoted the migration and invasion ability of SMMC-7721 cells. Moreover, epithelial mesenchymal transition (EMT) was also triggered by PM2.5. On the other hand, microRNA-16 (miR-16) and its target Twist1 was found to be mediated by PM2.5, and miR-16 mimic could suppress the metastatic ability of SMMC-7721 cells exposure to PM2.5 via inversely regulating the expression of Twist1. Furthermore, dual Luciferase reporter assay confirmed the specifically binding of miR-16 to the predicted 3′-UTR of Twist1. The present study confirmed the pro-proliferative and pro-metastatic effect of PM2.5 on HCC cell line SMMC-7721. The possible mechanisms were EMT process induced by PM2.5 in SMMC-7721 cells, which was accompanied by a decrease in miR-16 and increase in Twist1 expression.

Pediatric Psychiatric Emergency Department Utilization and Fine Particulate Matter: A Case-Crossover Study

BACKGROUND

Acute exposure to ambient particulate matter <2.5μm in aerodynamic diameter (PM2.5) has been associated with adult psychiatric exacerbations but has not been studied in children.

OBJECTIVES

Our objectives were to estimate the association between acute exposures to ambient PM2.5 and psychiatric emergency department (ED) utilization and to determine if it is modified by community deprivation.

METHODS

We used a time-stratified case-crossover design to analyze all pediatric, psychiatric ED encounters at Cincinnati Children's Hospital Medical Center in Cincinnati, Ohio, from 2011 to 2015 (n=13,176). Conditional logistic regression models adjusted for temperature, humidity, and holiday effects were used to estimate the odds ratio (OR) for a psychiatric ED visit 0-3 d after ambient PM2.5 exposures, estimated at residential addresses using a spatiotemporal model.

RESULTS

A 10-μg/m3 increase in PM2.5 was associated with a significant increase in any psychiatric ED utilization 1 [OR=1.07 (95% CI: 1.02, 1.12)] and 2 [OR=1.05 (95% CI: 1.00, 1.10)] d later. When stratified by visit reason, associations were significant for ED visits related to adjustment disorder {e.g., 1-d lag [OR=1.24 (95% CI: 1.02, 1.52)] and suicidality 1-d lag [OR=1.44 (95% CI: 1.03, 2.02)]}. There were significant differences according to community deprivation, with some lags showing stronger associations among children in high versus low deprivation areas for ED visits for anxiety {1-d lag [OR=1.39 (95% CI: 0.96, 2.01) vs. 0.85 (95% CI: 0.62, 1.17)] and suicidality same day [OR=1.98 (95% CI: 1.22, 3.23) vs. 0.93 (95% CI: 0.60, 1.45)]}. In contrast, for some lags, associations with ED visits for adjustment disorder were weaker for children in high-deprivation areas {1-d lag [OR=1.00 (95% CI: 0.76, 1.33) vs. 1.50 (95% CI: 1.16, 1.93)]}.

DISCUSSION

These findings warrant additional research to confirm the associations in other populations. https://doi.org/10.1289/EHP4815.

lifetime exposure to traffic-related air pollution and symptoms of depression and anxiety at age 12 years

BACKGROUND

While air pollution has been associated with depression and anxiety in adults, its impact on childhood mental health is understudied.

OBJECTIVE

We examined lifetime exposure to traffic-related air pollution (TRAP) and symptoms of depression and anxiety at age 12 years in the Cincinnati Childhood Allergy and Air Pollution Study cohort.

METHODS

We estimated exposure to elemental carbon attributable to traffic (ECAT), a surrogate of diesel exhaust, at birth, age 12 years, and average exposure throughout childhood, using a validated land use regression model. We assessed depression and anxiety at age 12 years by parent report with the Behavior Assessment System for Children-2, and by child report with the Child Depression Inventory-2 (CDI-2) and the Spence Children's Anxiety Scale (SCAS). Associations between TRAP at birth, age 12 years, and childhood average and mental health outcomes were estimated using linear regression models adjusting for covariates including parent depression, secondhand smoke exposure, race, household income, and others.

RESULTS

Exposure to ECAT was not significantly associated with parent-reported depression or anxiety. However, exposure to ECAT at birth was associated with increased child-reported depression and anxiety. Each 0.25 µg/m3 increase in ECAT was associated with a 3.5 point increase (95% CI 1.6-5.5) in CDI-2 scores and 2.3 point increase (95% CI 0.8-3.9) in SCAS total anxiety scores. We observed similar associations between average childhood ECAT exposures but not for concurrent exposures at age 12.

CONCLUSIONS

TRAP exposure during early life and across childhood was significantly associated with self-reported depression and anxiety symptoms in children. The negative impact of air pollution on mental health previously reported among adults may also be present during childhood.

Impact of Population Density on PM2.5 Concentrations: A Case Study in Shanghai, China

We examine the effects of the urban built environment on PM2.5 (fine particulate matter with diameters equal or smaller than 2.5 μm) concentrations by using an improved region-wide database, a spatial econometric model, and five built environment attributes: Density, design, diversity, distance to transit, and destination accessibility (the 5Ds). Our study uses Shanghai as a relevant case study and focuses on the role of density at the jiedao scale, the smallest administrative unit in China. The results suggest that population density is positively associated with PM2.5 concentrations, pointing to pollution centralization and congestion effects dominating the mitigating effects of mode-shifting associated with density. Other built environment variables, such as the proportion of road intersections, degree of mixed land use, and density of bus stops, are all positively associated with PM2.5 concentrations while distance to nearest primary or sub-center is negatively associated. Regional heterogeneity shows that suburban jiedao have lower PM2.5 concentrations when a subway station is present.

Acute effect of fine and coarse particular matter on cardiovascular visits in Ningbo, China

Although a growing number of epidemiological studies have been conducted on size-specific health effects of particulate matter in China, results remain inconsistent. In this study, we investigated acute effect of fine and coarse particular matter on cardiovascular hospital visits in Ningbo, China. We used generalized additive models to examine short-term effects of PM_2.5 and PM_10-2.5 on cardiovascular hospital visits by adjustment for temporal, seasonal, and meteorological effects. Subgroup analyses were conducted by age, sex, and season. We also examined the stability of their effects in multi-pollutant models. We found that PM_2.5 were associated with cardiovascular hospital visits (RR = 1.006; 95% CI 1.000, 1.011) and results remained similar after adjustment for PM_10-2.5 (RR = 1.005; 95% CI 0.998, 1.013). There was a borderline association between PM_10-2.5 and cardiovascular hospital visits (RR = 1.007; 95% CI 0.997, 1.016), which disappeared after controlling for PM_2.5 (RR = 1.000; 95% CI 0.988, 1.013). The associations appeared to be stronger in the cold season and among the elderly (≥ 75 years). The findings of this study suggested significant adverse effects of PM_2.5, but no independent effects of PM_10-2.5 on cardiovascular hospital visits. Additional studies are needed to confirm these findings.

Application of Nanomaterials in Personal Respiratory Protection Equipment: A Literature Review

Exposure to air pollutants leads to a variety of health effects in humans. Inhalation is one of the most common routs of exposure to poor quality air, mostly in work environments. Respiratory masks are used to prevent breathing in hazardous gases and vapors, especially in the absence of proper controlling measures. This study aims to review the effectiveness of respiratory masks with a nanostructure. The electronic search of the genuine databases, including PubMed, Magiran, Iran Medex, Science Database (SID), Science Direct, Web of Science, and Scopus, was conducted in January and February 2017 in chronological order of publications with the keywords defined in the search strategy. Of all identified papers, nine were collected and included in the study. The results of this study indicated that the use of nanomaterials in the structure of brand new mask filters compared with conventional masks enhances the performance and efficiency of breathing air filtration, improves permeability, increases antimicrobial properties, and offers reasonable comfort to the workers.

Short-term effects of fine and coarse particles on deaths in Hong Kong elderly population: An analysis of mortality displacement

BACKGROUND

While numerous studies worldwide have evaluated the short-term associations of fine and coarse particulate matter (PM) air pollution with mortality and morbidity, these studies may be susceptible to short-term harvesting effect. We aimed to investigate the short-term association between mortality and PM with aerodynamic diameter less than 2.5 μm (PM_2.5) and those between 2.5 and 10 μm (PMc) within a month prior to death, and assess the mortality displacement by PM_2.5 and PMc among elderly population in Hong Kong.

METHODS

We obtained air pollution data from January 2011 to December 2015 from Environmental Protection Department, and daily cause-specific mortality data from Census and Statistical Department of Hong Kong. We performed generalized additive distributed lag model to examine the acute, delayed and long-lasting effects of PM_2.5 and PMc within one month on mortality.

RESULTS

We observed a statistically significant association of PM_2.5 and PMc exposure over lags 0-6 days with all natural mortality and cardio-respiratory mortality. The overall cumulative effect of PM_2.5 over 0-30 lag days was 3.44% (95% CI: 0.30-6.67%) increase in all natural mortality and 6.90% (95% CI: 0.58-13.61%) increase of circulatory mortality, which suggested the absence of mortality displacement by PM_2.5. On the other hand, no significant cumulative association with mortality was found for PMc over 0-30 lag exposure window, and thus mortality displacement by PMc cannot be ruled out. Findings remained robust in various sensitivity analyses.

CONCLUSIONS

We found adverse effect of both PM_2.5 and PMc exposure within one week prior to death. While there was no evidence of mortality displacement in the association of PM_2.5 exposure over one month prior with all natural and circulatory mortality, mortality displacement by PMc cannot be ruled out. PM_2.5 may contribute more to the longer term effect of particulate matter than PMc.

Is it the time to study air pollution effects under environmental conditions? A case study to support the shift of in vitro toxicology from the bench to the field

Air pollution and particulate matter are recognised cause of increased disease incidence in exposed population. The toxicological processes underlying air pollution associated effects have been investigated by in vivo and/or in vitro experimentation. The latter is usually performed by exposing cells cultured under submerged condition to particulate matter concentration quite far from environmental exposure expected in humans. Here we report for the first time the feasibility of a direct exposure of air liquid interface cultured cells to environmental concentration of particulate matter. Inflammatory proteins release was analysed in cell medium while differential expression of selected genes was analysed in cells. Significant association of anti-oxidant genes was observed with secondary and aged aerosol, while cytochrome activation with primary and PAHs enriched ultrafine particles. The results obtained clearly show the opportunity to move from the lab bench to the field for properly understanding the toxicological effects also of ultrafine particles on selected in vitro models.

The protective effects of selenium supplementation on ambient PM2.5-induced cardiovascular injury in rats

Substantial epidemiological and experimental studies have shown that ambient fine particulate matter (PM_2.5) exposure can lead to myocardial damage in human and animal through the mechanism of inflammation and oxidative stress. The purpose of the current study was to investigate whether selenium yeast (SeY) supplementation could prevent cardiovascular injury caused by PM_2.5 in rats. Fifty-six Sprague-Dawley rats were randomly divided into seven groups: saline control group; solvent control group, low-, middle-, and high-dose Se pretreatment groups, PM_2.5 exposure group, and high-dose Se control group. The rats were pretreated with different concentration of dietary SeY for 28 days, then were exposed to PM₂.₅ by intratracheal instillation every other day, a total of three times. The levels of inflammatory markers (tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), soluble intercellular adhesion molecule-1 (sICAM-1), and oxidative responses-related indicators total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were measured in blood and myocardium of the left ventricle. The results showed that although PM_2.5 caused a decrease of T-AOC, T-AOD, and GSH-Px and increase of MDA and sICM-1, pretreatment with SeY induced a dose-dependent increase in these anti-oxidative indicators and a decrease in oxidative indicators. In addition, the levels of TNF-α and IL-1β in Se pretreatment groups were significantly lower than that in PM_2.5 exposure group. The results indicated that Se supplementation could effectively prevent cardiovascular inflammation and oxidative stress induced by PM_2.5. The results also indicated that the nutritional supplementation might be an effective way to protecting people's health from air pollution.

Ambient coarse particulate pollution and mortality in three Chinese cities: Association and attributable mortality burden

The short-term mortality effects of ambient fine particulate matter air pollution have been widely investigated in China. However, the associations between day-to-day variation in ambient coarse particles pollution (PM_c) and mortality, as well as the corresponding mortality burden, remain understudied. We estimated the short-term PM_c-mortality association in three Chinese cities of the Pearl River Delta (PRD) region during the period of 2013-16. The city-specific association was first estimated using generalized additive models and then combined to obtain the overall effect estimates. We further estimated PM_c related attributable fraction and attributable mortality. Our study found a significant association between PM_c and mortality. Each 10μg/m³ increase of a current day's PM_c was associated with a 1.37% (95% CI: 0.55%, 2.22%) increase in total mortality, a 1.63% increase (95% CI: 0.31%, 2.98%) in cardiovascular mortality, and a 0.97% increase (95% CI: -0.17%, 2.13%) in respiratory mortality in the three cities. We estimated that 0.37% (95% CI: 0.14%, 0.61%) and 2.72% (95% CI: 1.03%, 4.50%) of total mortalities were attributable to PM_c by using China's standards and WHO's air quality guidelines as references-corresponding to 1394 (95% CI: 528, 2291) and 10,305 (95% CI: 3884, 17,000) attributable premature mortalities in the three cities, respectively. This study suggests that ambient coarse particulate pollution might be one important risk factor of total, cardiovascular, and respiratory mortality, as well as account for substantial mortality burdens in the three Chinese cities of the PRD.

Stochastic Periodic Solution of a Susceptible-Infective Epidemic Model in a Polluted Environment under Environmental Fluctuation

It is well known that the pollution and environmental fluctuations may seriously affect the outbreak of infectious diseases (e.g., measles). Therefore, understanding the association between the periodic outbreak of an infectious disease and noise and pollution still needs further development. Here we consider a stochastic susceptible-infective (SI) epidemic model in a polluted environment, which incorporates both environmental fluctuations as well as pollution. First, the existence of the global positive solution is discussed. Thereafter, the sufficient conditions for the nontrivial stochastic periodic solution and the boundary periodic solution of disease extinction are derived, respectively. Numerical simulation is also conducted in order to support the theoretical results. Our study shows that (i) large intensity noise may help the control of periodic outbreak of infectious disease; (ii) pollution may significantly affect the peak level of infective population and cause adverse health effects on the exposed population. These results can help increase the understanding of periodic outbreak patterns of infectious diseases.

Associations between Urban Sprawl and Life Expectancy in the United States

In recent years, the United States has had a relatively poor performance with respect to life expectancy compared to the other developed nations. Urban sprawl is one of the potential causes of the high rate of mortality in the United States. This study investigated cross-sectional associations between sprawl and life expectancy for metropolitan counties in the United States in 2010. In this study, the measure of life expectancy in 2010 came from a recently released dataset of life expectancies by county. This study modeled average life expectancy with a structural equation model that included five mediators: annual vehicle miles traveled (VMT) per household, average body mass index, crime rate, and air quality index as mediators of sprawl, as well as percentage of smokers as a mediator of socioeconomic status. After controlling for sociodemographic characteristics, this study found that life expectancy was significantly higher in compact counties than in sprawling counties. Compactness affects mortality directly, but the causal mechanism is unclear. For example, it may be that sprawling areas have higher traffic speeds and longer emergency response times, lower quality and less accessible health care facilities, or less availability of healthy foods. Compactness affects mortality indirectly through vehicle miles traveled, which is a contributor to traffic fatalities, and through body mass index, which is a contributor to many chronic diseases. This study identified significant direct and indirect associations between urban sprawl and life expectancy. These findings support further research and practice aimed at identifying and implementing changes to urban planning designed to support health and healthy behaviors.