Long-Term PM2.5 Exposure and Respiratory, Cancer, and Cardiovascular Mortality in Older US Adults

The prospective effects of long-term exposure to ambient PM2.5 and constituents on mortality in rural East China

Few cohort studies explored the associations of long-term exposure to ambient fine particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) and its chemical constituents with mortality risk in rural China. We conducted a 12-year prospective study of 28,793 adults in rural Deqing, China from 2006 to 2018. Annual mean PM2.5 and its constituents, including black carbon (BC), organic carbon (OC), ammonium (NH4+), nitrate (NO3-), sulfate (SO42-), and soil dust were measured at participants' addresses at enrollment from a satellite-based exposure predicting model. Cox proportional hazard model was used to estimate hazard ratios (HRs) and 95% confidence intervals (95%CIs) of long-term exposure to PM2.5 for mortality. A total of 1960 deaths were identified during the follow-up. We found PM2.5, BC, OC, NH4+, NO3-, and SO42- were significantly associated with an increased risk of non-accidental mortality. The HR for non-accidental mortality was 1.17 (95%CI: 1.07, 1.28) for each 10 μg/m3 increase in PM2.5. As for constituents, the strongest association was found for BC (HR = 1.21, 95%CI: 1.11, 1.33), followed by NO3-, NH4+, SO42-, and OC (HR = 1.14-1.17 per interquartile range). A non-linear relationship was found between PM2.5 and non-accidental mortality. Similar associations were found for cardio-cerebrovascular and cancer mortality. Associations were stronger among men and ever smokers. Conclusively, we found long-term exposure to ambient PM2.5 and its chemical constituents (especially BC and NO3-) increased mortality risk. Our results suggested the importance of adopting effective targeted emission control to improve air quality for health protection in rural East China.

Non-nutritive suck and airborne metal exposures among Puerto Rican infants

Air pollution has been shown to impact multiple measures of neurodevelopment in young children. Its effects on particularly vulnerable populations, such as ethnic minorities, however, is less studied. To address this gap in the literature, we assess the associations between infant non-nutritive suck (NNS), an early indicator of central nervous system integrity, and air pollution exposures in Puerto Rico. Among infants aged 0-3 months enrolled in the Center for Research on Early Childhood Exposure and Development (CRECE) cohort from 2017 to 2019, we examined associations between exposure to fine particulate matter (PM_2.5) and its components on infant NNS in Puerto Rico. NNS was assessed using a pacifier attached to a pressure transducer, allowing for real-time visualization of NNS amplitude, frequency, duration, cycles/burst, cycles/min and bursts/min. These data were linked to 9-month average prenatal concentrations of PM_2.5 and components, measured at three community monitoring sites. We used linear regression to examine the PM_2.5-NNS association in single pollutant models, controlling for infant sex, maternal age, gestational age, and season of birth in base and additionally for household smoke exposure, age at testing, and NNS duration in full models. Among 198 infants, the average NNS amplitude and burst duration was 17.1 cmH₂O and 6.1 s, respectively. Decreased NNS amplitude was consistently and significantly associated with 9-month average exposure to sulfur (-1.026 ± 0.507), zinc (-1.091 ± 0.503), copper (-1.096 ± 0.535) vanadium (-1.157 ± 0.537), and nickel (-1.530 ± 0.501). Decrements in NNS frequency were associated with sulfur exposure (0.036 ± 0.018), but not other examined PM components. Our findings provide new evidence that prenatal maternal exposure to specific PM components are associated with impaired neurodevelopment in Puerto Rican infants soon after birth.

Intra-city variability of fine particulate matter during COVID-19 lockdown: A case study from Park City, Utah

Urban air quality is a growing concern due a range of social, economic, and health impacts. Since the SARS-CoV-19 pandemic began in 2020, governments have produced a range of non-medical interventions (NMIs) (e.g. lockdowns, stay-at-home orders, mask mandates) to prevent the spread of COVID-19. A co-benefit of NMI implementation has been the measurable improvement in air quality in cities around the world. Using the lockdown policy of the COVID-19 pandemic as a natural experiment, we traced the changing emissions patterns produced under the pandemic in a mid-sized, high-altitude city to isolate the effects of human behavior on air pollution. We tracked air pollution over time periods reflecting the Pre-Lockdown, Lockdown, and Reopening stages, using high quality, research grade sensors in both commercial and residential areas to better understand how each setting may be uniquely impacted by pollution downturn events. Based on this approach, we found the commercial area of the city showed a greater decrease in air pollution than residential areas during the lockdown period, while both areas experienced a similar rebound post lockdown. The easing period following the lockdown did not lead to an immediate rebound in human activity and the air pollution increase associated with reopening, took place nearly two months after the lockdown period ended. We hypothesize that differences in heating needs, travel demands, and commercial activity, are responsible for the corresponding observed changes in the spatial distribution of pollutants over the study period. This research has implications for climate policy, low-carbon energy transitions, and may even impact local policy due to changing patterns in human exposure that could lead to important public health outcomes, if left unaddressed.

The cardiovascular effects of air pollution: Prevention and reversal by pharmacological agents

Air pollution is associated with staggering levels of cardiovascular morbidity and mortality. Airborne particulate matter (PM), in particular, has been associated with a wide range of detrimental cardiovascular effects, including impaired vascular function, raised blood pressure, alterations in cardiac rhythm, blood clotting disorders, coronary artery disease, and stroke. Considerable headway has been made in elucidating the biological processes underlying these associations, revealing a labyrinth of multiple interacting mechanistic pathways. Several studies have used pharmacological agents to prevent or reverse the cardiovascular effects of PM; an approach that not only has the advantages of elucidating mechanisms, but also potentially revealing therapeutic agents that could benefit individuals that are especially susceptible to the effects of air pollution. This review gathers investigations with pharmacological agents, offering insight into the biology of how PM, and other air pollutants, may cause cardiovascular morbidity.

PM2.5-induced lung injury is attenuated in macrophage-specific NLRP3 deficient mice

Fine particulate matter (PM2.5) is one of the most important components of environmental pollutants and is associated with lung injury. Pyroptosis, a form of programmed cell death mainly mediated by the NLRP3 inflammasome, has been reported to be involved in sepsis-induced or ischemia/reperfusion-induced lung injury. However, the specific mechanisms of pyroptosis in PM2.5-induced lung injury are not yet clear. We constructed macrophage-specific NLRP3 knockout mice to explore the mechanism of PM2.5-induced lung injury in terms of inflammatory response, oxidative stress, and apoptosis levels, including the relationship between these effects and pyroptosis. The results disclosed that PM2.5 exposure increased the infiltration of macrophages and leukocytes and the secretion of inflammatory cytokines, including TNF-α and IL-6, in lung tissue. The activity of antioxidant enzymes, including SOD, GSH-PX, and CAT, significantly decreased, while MDA, the end product of lipid oxidation, remarkably increased. The level of apoptosis in lung tissue, measured by the TUNEL assay and apoptosis-related proteins (BAX and BCL-2), was significantly increased. Macrophage-specific NLRP3 knockout could offset these effects. We further observed that PM2.5 treatment activated the NLRP3 inflammasome and subsequently induced pyroptosis, as evidenced by the increased production of IL-1β and IL-18 and the increase of the protein levels of NLRP3, ASC, caspase-1, and GSDMD, which were inhibited when NLRP3 was knocked out in macrophages. Taken together, these results revealed that NLRP3-mediated macrophage pyroptosis promoted PM2.5-induced lung injury through aggravating inflammation, oxidative stress, and apoptosis. Targeting the inhibition of NLRP3-mediated macrophage pyroptosis provides a new way to study lung injury induced by the exposure to PM2.5.

Toxicological Effects of Artificial Fine Particulate Matter in Rats through Induction of Oxidative Stress and Inflammation

Airborne fine particulate matter with an aerodynamic diameter equal to or smaller than 2.5 μm (abbreviated as PM_2.5) increases the risk of nasal lesions, but the underlying molecular mechanism has not been fully elucidated. In the atmosphere, the composition of PM_2.5 collected varies in physical and chemical properties, which affects its damage to human health. Thus, we constructed artificial PM_2.5 particles based on actual PM_2.5 and investigated the in vivo effects of artificial PM_2.5 exposure on the oxidative stress, inflammatory response, and nasal mucosa morphology of rats. The results showed that artificial PM_2.5 is comparable in composition ratio, size, and morphology to actual PM_2.5. This in vivo study indicated that artificial PM_2.5 exposure reduces total superoxide dismutase and glutathione peroxidase activities, elevates malondialdehyde content in the nasal mucosa, and induces increased levels of pro-inflammatory mediators, including interleukin-1, interleukin-6 and tumor necrosis factor-α. Our data shows that artificial PM_2.5 particles could be used for experimental study of PM_2.5 toxicology, ensuring that the physical and chemical properties of experimental PM_2.5 are relatively constant and allowing for repeatability of this research. Oxidative damage and inflammatory response may be the toxic mechanisms that cause nasal lesions after exposure to artificial PM_2.5.

Long-term PM2.5 exposure and survival among cardiovascular disease patients in Beijing, China

Previous studies have proved that particulate air pollution was related to adverse cardiovascular effects. However, most studies focused on the acute effects of short-term fine particulate matter (PM_2.5) exposure and the general population. Evidence from long-term cohort studies based on the cardiovascular disease (CVD) patients was scarce. Our study aimed to explore the impact of long-term exposure to PM_2.5 on the mortality among post-CVD patients. This is a cohort study that involved 5143 post-CVD patients in Beijing, China. We collected records of CVD patients from hospitals in Beijing, China from 1 January 2012 to 31 December 2012 and followed up these patients from hospital admission until December 31, 2016. The vital status of the patients was determined using the National Death Surveillance Point System (DSPs). The PM_2.5 concentrations were obtained from the Atmospheric Composition Analysis Group. The Cox regression models were used for data analyses. Our findings suggested that increased mortality of CVD patients with an HR of 1.43 (95% CI: 1.24, 1.63) was related to long-term exposure to PM_2.5. The association was stronger for cardiovascular-related mortality, especially for mortality from myocardial infarction (MI). The HR for any CVD mortality was 1.57 (95% CI: 1.27, 1.94), HR for MI mortality was 1.82 (95% CI: 1.16, 2.83). Long-term PM_2.5 exposure may significantly affect the survival of CVD patients. Compared with the general population, patients with CVD are more susceptible to PM_2.5 exposure. Increased attention to the management of CVD patients is warranted.

The impacts of long-term exposure to PM2.5 on cancer hospitalizations in Brazil

BACKGROUND

Long-term exposure to PM_2.5 has been linked to cancer incidence and mortality. However, it was unknown whether there was an association with cancer hospitalizations.

METHODS

Data on cancer hospitalizations and annual PM_2.5 concentrations were collected from 1,814 Brazilian cities during 2002-2015. A difference-in-difference approach with quasi-Poisson regression was applied to examine State-specific associations. The State-specific associations were pooled at a national level using random-effect meta-analyses. PM_2.5 attributable burden were estimated for cancer hospitalization admissions, inpatient days and costs.

RESULTS

We included 5,102,358 cancer hospitalizations (53.8% female). The mean annual concentration of PM_2.5 was 7.0 μg/m³ (standard deviation: 4.0 μg/m³). With each 1 μg/m³ increase in two-year-average (current year and previous one year) concentrations of PM_2.5, the relative risks (RR) of hospitalization were 1.04 (95% confidence interval [CI]: 1.02 to 1.07) for all-site cancers from 2002 to 2015 without sex and age differences. We estimated that 33.82% (95%CI: 14.97% to 47.84%) of total cancer hospitalizations could be attributed to PM_2.5 exposure in Brazil during the study time. For every 100,000 population, 1,190 (95%CI: 527 to 1,836) cancer hospitalizations, 8,191 (95%CI: 3,627 to 11,587) inpatient days and US$788,775 (95%CI: $349,272 to $1,115,825) cost were attributable to PM_2.5 exposure.

CONCLUSIONS

Long-term exposure to ambient PM_2.5 was positively associated with hospitalization for many cancer types in Brazil. Inpatient days and cost would be saved if the annual PM_2.5 exposure was reduced.

MicroRNA-760 resists ambient PM2.5-induced apoptosis in human bronchial epithelial cells through elevating heme-oxygenase 1 expression

PM_2.5 (particles matter smaller aerodynamic diameter of 2.5 μm) exposure, a major environmental risk factor for the global burden of diseases, is associated with high risks of respiratory diseases. Heme-oxygenase 1 (HMOX1) is one of the major molecular antioxidant defenses to mediate cytoprotective effects against diverse stressors, including PM_2.5-induced toxicity; however, the regulatory mechanism of HMOX1 expression still needs to be elucidated. In this study, using PM_2.5 as a typical stressor, we explored whether microRNAs (miRNAs) might modulate HMOX1 expression in lung cells. Systematic bioinformatics analysis showed that seven miRNAs have the potentials to target HMOX1 gene. Among these, hsa-miR-760 was identified as the most responsive miRNA to PM_2.5 exposure. More importantly, we revealed a "non-conventional" miRNA function in hsa-miR-760 upregulating HMOX1 expression, by targeting the coding region and interacting with YBX1 protein. In addition, we observed that exogenous hsa-miR-760 effectively elevated HMOX1 expression, reduced the reactive oxygen agents (ROS) levels, and rescued the lung cells from PM_2.5-induced apoptosis. Our results revealed that hsa-miR-760 might play an important role in protecting lung cells against PM_2.5-induced toxicity, by elevating HMOX1 expression, and offered new clues to elucidate the diverse functions of miRNAs.

Cohort studies of long-term exposure to outdoor particulate matter and risks of cancer: A systematic review and meta-analysis

Robust evidence is needed for the hazardous effects of outdoor particulate matter (PM) on mortality and morbidity from all types of cancers. To summarize and meta-analyze the association between PM and cancer, published articles reporting associations between outdoor PM exposure and any type of cancer with individual outcome assessment that provided a risk estimate in cohort studies were identified via systematic searches. Of 3,256 records, 47 studies covering 13 cancer sites (30 for lung cancer, 12 for breast cancer, 11 for other cancers) were included in the quantitative evaluation. The pooled relative risks (RRs) for lung cancer incidence or mortality associated with every 10-μg/m³ PM_2.5 or PM₁₀ were 1.16 (95% confidence interval [CI], 1.10–1.23; I² = 81%) or 1.22 (95% CI, 1.02–1.45; I² = 96%), respectively. Increased but non-significant risks were found for breast cancer. Other cancers were shown to be associated with PM exposure in some studies but not consistently and thus warrant further investigation.

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Updated evidence for the association between PM and lung cancer risk has been provided

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Associations between PM and cancer risks from 13 sites were summarized

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Further studies should be conducted to fill the research gaps

Effects of PM2.5 on Chronic Airway Diseases: A Review of Research Progress

The adverse effects of polluted air on human health have been increasingly appreciated worldwide. It is estimated that outdoor air pollution is associated with the death of 4.2 million people globally each year. Accumulating epidemiological studies indicate that exposure to ambient fine particulate matter (PM2.5), one of the important air pollutants, significantly contributes to respiratory mortality and morbidity. PM2.5 causes lung damage mainly by inducing inflammatory response and oxidative stress. In this paper, we reviewed the research results of our group on the effects of PM2.5 on chronic obstructive pulmonary disease, asthma, and lung cancer. And recent research progress on epidemiological studies and potential mechanisms were also discussed. Reducing air pollution, although remaining a major challenge, is the best and most effective way to prevent the onset and progression of respiratory diseases.

S-adenosylmethionine decarboxylase 1 and its related spermidine synthesis mediate PM2.5 exposure-induced neuronal apoptosis

PM2.5 exposure is considered harmful to central nerve system, while the specific biochemical mechanism underlying is still unrevealed. Neuronal apoptosis is believed the crucial event in pathogenesis of neurodegenerative diseases, but evidence supporting neuronal apoptosis as the mechanism for PM2.5 exposure induced neuronal injury is insufficient. S-adenosylmethionine decarboxylase 1 (AMD1) and its related spermidine synthesis have been shown to associate with cellular apoptosis, but its role in PM2.5 exposure induced neuronal apoptosis was rarely reported. The current study was aimed to better understand contribution of AMD1 activity and spermidine in PM2.5 exposure induced neuronal apoptosis. Sixteen C57BL/6 male mice were randomly divided and kept into ambient PM2.5 chamber or filtered air chamber for 6 months to establish the mouse model of whole-body ambient PM2.5 chronic exposure. In parallel, PC12 cells and primary hippocampal neurons were applied for various concentrations of PM2.5 treatment (0, 25, 50, 100, 200, and 400 μg/mL) to explore the possible cellular and molecular mechanism which may be critically involved in the process. Results showed that PM2.5 exposure triggered neuronal apoptosis with increased expression of Bax/Bcl-2 and cleaved caspase-3. PM2.5 exposure reduced AMD1 expression and spermidine synthesis. AMD1 inhibition could mimic PM2.5 exposure induced neuronal apoptosis. Spermidine supplementation rescued against neurotoxicity and inhibited PM2.5 induced apoptosis via impaired depolarization of mitochondrial membrane potential and reduced mitochondrial apoptosis related proteins. In summary, our work demonstrated that exposure to PM2.5 led to neuronal apoptosis, which may be the key event in the process of air pollution induced neurodegenerative diseases. AMD1 and spermidine associated with neuronal apoptosis induced by PM2.5 exposure, which was at least partially dependent on mitochondria mediated pathway.

Taurine reduction associated with heart dysfunction after real-world PM2.5 exposure in aged mice

Ambient PM_2.5 has been proved to be an independent risk factor for cardiovascular diseases; however, little information is available on the age-dependent effects of PM_2.5 on the cardiovascular system and the underlying mechanisms following chronic exposure. In this study, multi-aged mice were exposed to PM_2.5 via the newly developed real-ambient PM_2.5 exposure system to investigate age-related effects on the heart after long-term exposure. First, the chemical and physical properties of PM_2.5 used in the exposure system were analyzed. The heart rate of conscious mice was recorded, and results showed that exposure of aged mice to PM_2.5 for 26 weeks significantly increased heart rate. Histological analysis and ELISA assays indicated that aged mice were more sensitive to PM_2.5 exposure in terms of inducing cardiac oxidative stress and inflammation. Furthermore, untargeted metabolomics revealed that taurine was involved with the PM_2.5-induced cardiac dysfunction. The reduced taurine concentration in the heart was examined by LC-MS and imaging mass spectrometry; it may be due to the increased p53 expression level, ROS and inflammatory cytokines. These results emphasize the age-dependent effects of PM_2.5 on the cardiovascular system and suggest that taurine may be the novel cardiac effect target for PM_2.5-induced heart dysfunction in the aged.

The Association between Polluted Neighborhoods and TP53-Mutated Non-Small Cell Lung Cancer

BACKGROUND

Poor patients often reside in neighborhoods of lower socioeconomic status (SES) with high levels of airborne pollutants. They also have higher mortality from non-small cell lung cancer (NSCLC) than those living in wealthier communities. We investigated whether living in polluted neighborhoods is associated with somatic mutations linked with lower survival rates, i.e., TP53 mutations.

METHODS

In a retrospective cohort of 478 patients with NSCLC treated at a comprehensive cancer center between 2015 and 2018, we used logistic regression to assess associations between individual demographic and clinical characteristics, including somatic TP53 mutation status and environmental risk factors of annual average particulate matter (PM2.5) levels, and neighborhood SES.

RESULTS

277 patients (58%) had somatic TP53 mutations. Of those, 45% lived in neighborhoods with "moderate" Environmental Protection Agency-defined PM2.5 exposure, compared with 39% of patients without TP53 mutations. We found significant associations between living in neighborhoods with "moderate" versus "good" PM2.5 concentrations and minority population percentage [OR, 1.06; 95% confidence interval (CI), 1.04-1.08]. There was a significant association between presence of TP53 mutations and PM2.5 exposure (moderate versus good: OR, 1.66; 95% CI, 1.02-2.72) after adjusting for patient characteristics, other environmental factors, and neighborhood-level SES.

CONCLUSIONS

When controlling for individual- and neighborhood-level confounders, we find that the odds of having a TP53-mutated NSCLC are increased in areas with higher PM2.5 exposure.

IMPACT

The link between pollution and aggressive biology may contribute to the increased burden of adverse NSCLC outcomes in individuals living in lower SES neighborhoods.

LncRNA NEAT1 contributes to the acquisition of a tumor like-phenotype induced by PM 2.5 in lung bronchial epithelial cells via HIF-1α activation

The hazards of particulate matter (PM2.5) on human respiratory health have been previously reported. However, the molecular mechanisms underlying PM2.5-induced lung carcinogenesis have rarely been studied. In the present study, we explored the effects of PM2.5 on the epithelial-mesenchymal transition (EMT) and acquisition of cancer stem cell (CSC)-like properties in lung bronchial epithelial cells. We found that exposure of PM2.5 enhanced lung bronchial epithelial cell proliferation and EMT. In addition, the expression level of CSC-like biomarkers, CD133 and CD44, was significantly elevated by PM2.5 in vitro. Nuclear paraspeckle assembly transcript 1 (NEAT1) has been reported to participate in lung cancer. Loss of NEAT1 represses the malignant transformation of BEAS-2B and HBE cells induced by PM2.5. NEAT1 interacts with microRNA (miR)-582-5p, and miR-582-5p reverses the pro-tumor effects of NEAT1 overexpression. Hypoxia-inducible factor (HIF)-1α is an important transcription factor in the pathological responses to hypoxia. HIF-1α was a predicted target for miR-582-5p, and a direct correlation between them was identified. Inhibitors of miR-582-5p rescued HIF-1α expression, which was attenuated by a lack of NEAT1. In conclusion, PM2.5 increased NEAT1 expression, which, by binding with miR-582-5p, released HIF-1α and promoted EMT and the acquisition of CSC-like characteristics.

WITHDRAWN: Health risk assessment and countermeasure analysis of the elderly population exposed to PM2.5 microenvironment

Ahead of Print article withdrawn by publisher.

Particulate matter exposure is highly correlated to pediatric asthma exacerbation

Asthma is a heterogeneous disease in which environmental factors play an important role, and the effect of particulate matter (PM) on the occurrence and severity of asthma is drawing more attention. This study aims to identify the correlation between PM and pediatric asthma exacerbation and explore the potential mechanisms. The asthma visits data (N = 16,779,739) in a university-based tertiary children’s hospital from January 2013 to December 2017 were collected, and the relationship between asthma visits and local PM concentration was analyzed. For further study, we established a house dust mite (HDM)-induced allergic airway inflammation model with PM intervention. We detected a correlation between PM concentration and pediatric asthma visits, especially in children under 6 years old. The in vivo data showed that PM aggravated HDM-induced airway inflammation, and IL-33 neutralizing antibody exerted a protective role. Our study suggests that PM is a risk factor in promoting pediatric asthma exacerbation, in which IL-33 might be a promising target.

Aerobic exercise ameliorates particulate matter-induced lung injury in aging rats

Particulate matter 2.5 (PM_2.5) is an inflammatory-inducing factor that is considered to be related to many adverse respiratory problems, especially in the elderly. This study aimed to examine whether pre-exercise training could prevent pulmonary injury induced by urban PM_2.5 in aging rats and investigate its relationship with inflammatory pathways. Male Wistar rats (aged 16 months) were randomly divided into four groups: sedentary, exercise, sedentary + PM_2.5 exposure, and exercise + PM_2.5 exposure. All rats in exercise-related groups were treadmill-trained for 8 weeks (65%-75% VO_2max for 30 min every other day). Sedentary groups' rats lived freely in cages without exercise intervention. Rats in the PM-related groups were exposed to ambient PM_2.5 (4 h day^-1) for 2 weeks after an 8-week exercise intervention or sedentary treatment. Finally, all rats' pulmonary function, lung morphology, degree of inflammation, and relevant protein and mRNA transcript expression levels were examined. The results indicated that PM_2.5 exposure induced lung injury in the sedentary + PM_2.5 exposure group, as evidenced by the deterioration of pulmonary function, histopathological characteristics, and inflammatory changes. Aerobic exercise alleviated PM_2.5-induced airway obstruction, deterioration of pulmonary function, bronchial mucosal exfoliation, and inflammatory responses in aging rats. These effects in exercise groups were associated with the increased expression of intracellular 70 kDa heat shock protein (iHSP70) and the suppression of nuclear transcription factor-κB (NF-κB) activation, as confirmed by increased expression of inhibitor of NF-κB (IκBα) and a reduction in phospho-IKBα (p-IκBα), which is regulated by inhibiting kappa B kinase beta (IKKβ). Taken together, aerobic pre-exercise had protective effects on lung injury and reduced vulnerability to inflammation induced by PM_2.5 exposure, possibly through the toll-like receptor 4 (TLR4)/NF-κB signaling pathways mediated by the extracellular-to-intracellular HSP70 ratio. Pre-exercise training may be an effective way to protect against PM_2.5-induced lung toxicity in aging individuals.

PM2.5 induces intestinal damage by affecting gut microbiota and metabolites of rats fed a high-carbohydrate diet

PM_2.5 has a major impact on the gastrointestinal system, but the specific mechanism behind this action is not fully understood. Current studies have focused on the relationship between PM_2.5 and intestinal flora disorder, while ignoring the important influence of diet on gut microbes. In this study, SD rats were fed either a normal, high-fat, or high-carbohydrate diet for two months and exposed to PM_2.5 (7 mg/kg b.w.) by intratracheal instillation. The results showed that the body and kidney weights of the rats in the high-fat diet group were significantly increased relative to those with a normal diet, and changes in the intestinal microbes and metabolites induced by PM_2.5 were observed. Rats in the high-carbohydrate diet group had a significant response, and the diversity and richness indices of the flora were reduced (p < 0.05); additionally, intestinal Biffidobacterium and Lactobacillus were enriched, while many endogenous metabolites were found. Some amino acids derivatives and long-chain fatty acids were increased (p < 0.05). Both diet structure and PM_2.5 exposure can affect the composition of gut microbiota, and intestinal metabolites may be associated with cell membrane damage when a high-carbohydrate diet interacts with PM_2.5. This study considers multiple dietary factors to further supplement the evidence of intestinal damage via PM_2.5.

Synergistic effects of carbon nanoparticle-Cr-Pb in PM2.5 cause cell cycle arrest via upregulating a novel lncRNA NONHSAT074301.2 in human bronchial epithelial cells

Inhalation of carcinogenic PM_2.5 particles is a severe threat to all the people in both developing and developed nations. However, which components of PM_2.5 and how they perturb human cells to cause various diseases are still not understood. Here, employing a reductionism approach, we revealed that one of the crucial toxic and pathogenic mechanisms of PM_2.5 was the blocking of human bronchial cell cycle through upregulation of a novel long non-coding RNA NONHSAT074301.2 by carbon particles with payloads of Cr(VI) and Pb²⁺. We also discovered that NONHSAT074301.2 is a key regulatory molecule controlling cell cycle arrest at G2/M phase. This work highlights cellular function and molecular signaling events investigations using a 16-membered combinational model PM_2.5 library which contain carbon particles carrying four toxic pollutants in all possible combinations at environmental relevant concentrations. This work demonstrates a very powerful methodology to elucidate mechanisms at molecular level and help unlock the "black box" of PM_2.5-induced toxicities.

Association of long-term exposure to PM2.5 with blood lipids in the Chinese population: Findings from a longitudinal quasi-experiment

BACKGROUND

Although epidemiological studies on the effect of chronic fine particulate matter (PM_2.5) exposure on lipid disorders have been conducted, it is unclear if improved air quality is associated with beneficial changes in the blood lipid profile. In China, clean air actions introduced in 2013 have rapidly reduced the concentration of ambient PM_2.5.

METHODS

We conducted a change-by-change study, based on two waves (2011 and 2015) of a national survey of the same 5111 Chinese adults before and after implementation of the clean air actions. Long-term PM_2.5 exposure was assessed using a state-of-the-art estimator at the city level. Based on the within-individual differences between the two waves, we associated PM_2.5 changes with the variations of four lipid biomarkers-triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)-using a mixed-effects regression model. The robustness and homogeneity of the association were tested via sensitivity analyses.

RESULTS

For each 10 μg/m³ reduction in PM_2.5, LDL-C, and TC decreased by 2.71 (95% confidence interval [CI] 0.10-5.32) and 4.16 (95% CI 1.24-7.08)mg/dL, respectively. There was no significant association with HDL-C or TG. The results were robust among models adjusted for different covariates. PM_2.5 was a significant risk factor for dyslipidemia with an adjusted relative risk of 1.21 (95% CI 1.09-1.34). The association between PM_2.5 and LDL-C was stronger in the elderly or adults who did not take medications.

CONCLUSIONS

The results suggest that PM_2.5 exert a cardiotoxic effect by increasing the risk of lipid disorders. Improvement of air quality could prevent dyslipidemia by reducing LDL-C and TC levels. Clean air policies should be implemented as public health measures in countries with aging societies, especially developing ones with a high air pollution burden.

Acute effects of personal exposure to fine particulate matter on salivary and urinary biomarkers of inflammation and oxidative stress in healthy adults

Non-invasive bio-samples, such as saliva and urine, are promising tools for assessment of inflammation and oxidative stress biomarkers. Few studies have investigated potential responses of those biomarkers towards short-term PM_2.5 exposure. We conducted a longitudinal study with 4 repeated examinations among 40 healthy, nonsmoking adults in Shanghai, China. Personal samplings were performed for PM_2.5 exposure assessment. Then, five biomarkers, including C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), alpha-1 antitrypsin (A1AT) in saliva and 8-Iso-Prostaglanding F_2α (8-iso-PGF_2α), total antioxidant capacity (TAC) in urine, were measured. We fitted linear mixed-effect models to evaluate short-term effect of personal PM_2.5 exposure on salivary and urinary biomarkers, adjusting for potential confounders of meteorology, sociodemographic characteristics and biomarker detection. We also explored sensitive time windows of exposure for different biomarkers. We found robust associations of salivary CRP, TNF-α, and urinary 8-iso-PGF_2α with PM_2.5 exposure, and responses of salivary inflammatory markers occurred more acutely than urinary oxidative stress markers. For instance, a 10 μg/m³ increase in PM_2.5 was associated with an elevation of 5.49% (95% CI: 1.17%, 9.99%) in CRP and 7.05% (95% CI: 1.29%, 13.13%) in TNF-α both at lag 12 h, and 6.97% (95% CI: 1.33%, 12.92%) in 8-iso-PGF_2α at lag 01 d. Based on non-invasive samples, this study provided evidence on effect of PM_2.5 exposure on responses of systematic inflammation and oxidative stress. Sub-daily (6-12 h) and daily (≥24 h) period after PM_2.5 exposure might be sensitive time window to detect the responses of salivary (i.e. CRP, TNF) and urinary biomarkers (i.e. 8-iso-PGF_2α), respectively.

Relationship between Air Pollutant Exposure and Gynecologic Cancer Risk

Exposure to air pollution has been suggested to be associated with an increased risk of women's health disorders. However, it remains unknown to what extent changes in ambient air pollution affect gynecological cancer. In our case-control study, the logistic regression model was combined with the restricted cubic spline to examine the association of short-term exposure to air pollution with gynecological cancer events using the clinical data of 35,989 women in Beijing from December 2008 to December 2017. We assessed the women's exposure to air pollutants using the monitor located nearest to each woman's residence and working places, adjusting for age, occupation, ambient temperature, and ambient humidity. The adjusted odds ratios (ORs) were examined to evaluate gynecologic cancer risk in six time windows (Phase 1-Phase 6) of women's exposure to air pollutants (PM2.5, CO, O3, and SO2) and the highest ORs were found in Phase 4 (240 days). Then, the higher adjusted ORs were found associated with the increased concentrations of each pollutant (PM2.5, CO, O3, and SO2) in Phase 4. For instance, the adjusted OR of gynecological cancer risk for a 1.0-mg m-3 increase in CO exposures was 1.010 (95% CI: 0.881-1.139) below 0.8 mg m-3, 1.032 (95% CI: 0.871-1.194) at 0.8-1.0 mg m-3, 1.059 (95% CI: 0.973-1.145) at 1.0-1.4 mg m-3, and 1.120 (95% CI: 0.993-1.246) above 1.4 mg m-3. The ORs calculated in different air pollution levels accessed us to identify the nonlinear association between women's exposure to air pollutants (PM2.5, CO, O3, and SO2) and the gynecological cancer risk. This study supports that the gynecologic risks associated with air pollution should be considered in improved public health preventive measures and policymaking to minimize the dangerous effects of air pollution.

PM2.5 concentration forecasting at surface monitoring sites using GRU neural network based on empirical mode decomposition

The main component of haze is the particulate matter (PM) 2.5. How to explore the laws of PM2.5 concentration changes is the main content of air quality prediction. Combining the characteristics of temporality and non-linearity in PM2.5 concentration series, more and more deep learning methods are currently applied to PM2.5 predictions, but most of them ignore the non-stationarity of time series, which leads to a lower accuracy of model prediction. To address this issue, an integration method of gated recurrent unit neural network based on empirical mode decomposition (EMD-GRU) for predicting PM2.5 concentration was proposed in this paper. This method uses empirical mode decomposition (EMD) to decompose the PM2.5 concentration sequence first and then fed the multiple stationary sub-sequences obtained after the decomposition and the meteorological features into the constructed GRU neural network successively for training and predicting. Finally, the sub-sequences of the prediction output are added to obtain the prediction results of PM2.5 concentration. The forecast result of the case in this paper show that the EMD-GRU model reduces the RMSE by 44%, MAE by 40.82%, and SMAPE by 11.63% compared to the single GRU model.

Calycosin Alleviates Injury in Airway Epithelial Cells Caused by PM 2.5 Exposure via Activation of AMPK Signalling

Methods

Phospho-AMP-activated protein kinase (p-AMPK) and AMP-activated protein kinase (AMPK) were detected by western blot. Immunofluorescence staining was used to validate changes in the levels of nuclear factor kappa B (NF-кB) p65 nuclear translocation. Mice were administered intraperitoneally with calycosin one hour before anaesthesia and endotracheal instillation of PM 2.5. The extent of lung injury was evaluated in the H&E-stained lung sections. Apoptotic cells were detected by TUNEL staining.

Results

Administration of calycosin was increased in PM 2.5-treated B2B cells in a dose-dependent manner in vitro. Fluorescence signals from anti-NF-кB p65 were increased in nuclei of cells pretreated with calycosin. The level of p-AMPK was increased by calycosin in vitro and in vivo. After pretreatment with compound C, the inhibitory effects of calycosin on cytotoxicity, levels of inflammatory cytokines and p-AMPK, and levels of NF-кB p65 nuclear translocation were not significantly decreased in vitro or in vivo.

Conclusions

Calycosin effectively decreased the release of inflammatory cytokines and alleviated injury caused by PM 2.5. These effects were mediated through activation of AMPK to suppress NF-κB signalling.

Multiple relationships between aerosol and COVID-19: A framework for global studies

COVID-19 (Corona Virus Disease 2019) is a severe respiratory syndrome currently causing a human global pandemic. The original virus, along with newer variants, is highly transmissible. Aerosols are a multiphase system consisting of the atmosphere with suspended solid and liquid particles, which can carry toxic and harmful substances; especially the liquid components. The degree to which aerosols can carry the virus and cause COVID-19 disease is of significant research importance. In this study, we have discussed aerosol transmission as the pathway of SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), and the aerosol pollution reduction as a consequence of the COVID-19 lockdown. The aerosol transmission routes of the SARS-CoV-2 can be further subdivided into proximal human-exhaled aerosol transmission and potentially more distal ambient aerosol transmission. The human-exhaled aerosol transmission is a direct dispersion of the SARS-CoV-2. The ambient aerosol transmission is an indirect dispersion of the SARS-CoV-2 in which the aerosol acts as a carrier to spread the virus. This indirect dispersion can also stimulate the up-regulation of the expression of SARS-CoV-2 receptor ACE-2 (Angiotensin Converting Enzyme 2) and protease TMPRSS2 (Transmembrane Serine Protease 2), thereby increasing the incidence and mortality of COVID-19. From the aerosol quality data around the World, it can be seen that often atmospheric pollution has significantly decreased due to factors such as the reduction of traffic, industry, cooking and coal-burning emissions during the COVID-19 lockdown. The airborne transmission potential of SARS-CoV-2, the infectivity of the virus in ambient aerosols, and the reduction of aerosol pollution levels due to the lockdowns are crucial research subjects.

Impact of a long-term air pollution exposure on the case fatality rate of COVID-19 patients-A multicity study

Evidence in the literature suggests that air pollution exposure affects outcomes of patients with COVID-19. However, the extent of this effect requires further investigation. This study was designed to investigate the relationship between long-term exposure to air pollution and the case fatality rate (CFR) of patients with COVID-19. The data on air quality index (AQI), PM2.5, PM10, SO2 , NO2 , and O3 from 14 major cities in China in the past 5 years (2015-2020) were collected, and the CRF of COVID-19 patients in these cities was calculated. First, we investigated the correlation between CFR and long-term air quality indicators. Second, we examined the air pollutants affecting CFR and evaluated their predictive values. We found a positive correlation between the CFR and AQI (1, 3, and 5 years), PM2.5 (1, 3, and 5 years), and PM10 (1, 3, and 5 years). Further analysis indicated the more significant correlation for both AQI (3 and 5 years) and PM2.5 (1, 3, and 5 years) with CFR, and moderate predictive values for air pollution indicators such as AQI (1, 3, and 5 years) and PM2.5 (1, 3, and 5 years) for CFR. Our results indicate that long-term exposure to severe air pollution is associated with higher CFR of COVID-19 patients. Air pollutants such as PM2.5 may assist with the prediction of CFR for COVID-19 patients.

Do fine particulate air pollution (PM2.5) exposure and its attributable premature mortality differ for immigrants compared to those born in the United States?

In the United States (US), immigrants constitute a considerable and growing proportion of the general population. Compared to the US-born, immigrants have differential health risks, and it is unclear if environmental exposures contribute. In this work, we estimated disparities between immigrants and the US-born in fine particulate matter (PM2.5) exposure and attributable premature mortality, including by region of origin and time since immigration. With PM2.5 estimates from a validated model at ~1 km2 spatial resolution and residential Census tract population data, we calculated the annual area-weighted average PM2.5 exposure for immigrants overall, the US-born, and immigrants separately by geographic region of origin and time since immigration. We then calculated the premature mortality attributed to PM2.5 for each population group, assessing disparities by immigrant status in PM2.5 exposure and attributable premature mortality in the US as a whole and in each US county to evevaluate spatial heterogeneity. Overall, immigrants were exposed to slightly higher PM2.5 (0.36 μg/m3, 3.8%) than the US-born. This exposure difference translates to 2.11 more premature deaths attributable to PM2.5 per 100,000 in population for immigrants compared to the US-born in 2010. Immigrant - US-born disparities in PM2.5 and attributable premature mortality were more severe among immigrants originating from Asia, Africa, and Latin America than those from Europe, Oceania, and North America. Disparities between immigrant groups by time since immigration were comparatively small. Sensitivity analyses using 2000 data and a non-linear set of PM2.5 attributable mortality coefficients identified similar patterns. Our findings suggest that environmental exposure disparities, such as in PM2.5, may contribute to immigrant health disparities in the US.

Cytotoxicity induced by fine particulate matter (PM2.5) via mitochondria-mediated apoptosis pathway in rat alveolar macrophages

Although positive associations exist between ambient particulate matter (PM_2.5; diameter ≤ 2.5 μm) and the morbidity and mortality rates for respiratory diseases, the biological mechanisms of the reported health effects are unclear. Considering that alveolar macrophages (AM) are the main cells responsible for phagocytic clearance of xenobiotic particles that reach the airspaces of the lungs, the purpose of this study was to investigate whether PM_2.5 induced AM apoptosis, and investigate its possible mechanisms. Freshly isolated AM from Wistar rats were treated with extracted PM_2.5 at concentrations of 33, 100, or 300 μg/mL for 4 h; thereafter, the cytotoxic effects were evaluated. The results demonstrated that PM_2.5 induced cytotoxicity by decreasing cell viability and increasing lactate dehydrogenase (LDH) levels in AMs. The levels of reactive oxygen species (ROS) and intracellular calcium cations (Ca²⁺) markedly increased in higher PM_2.5 concentration groups. Additionally, the apoptotic ratio increased, and the apoptosis-related proteins BCL2-associated X (Bax), caspase-3, and caspase-9 were upregulated, whereas B cell lymphoma-2 (Bcl-2) protein levels were downregulated following PM_2.5 exposure. Cumulative findings showed that PM_2.5 induced apoptosis in AMs through a mitochondrial-mediated pathway, which indicated that PM_2.5 plays a significant role in lung injury diseases.

Systematic review and meta-analysis of recent high-quality studies on exposure to particulate matter and risk of lung cancer

BACKGROUND

Several aspects of the association between exposure to air pollution and risk of lung cancer remain unclear.

OBJECTIVE

We aimed at performing a meta-analysis of high-quality cohort studies on exposure to particulate matter (PM) 10 and PM2.5 and risk of lung cancer.

METHODS

We identified cohort studies published since 2004, that reported risk estimates of lung cancer for exposure to PM2.5 and PM10 adjusted for tobacco smoking and socioeconomic status, and conducted a meta-analysis based on random-effects models, including stratification by outcome, sex, country, tobacco smoking, and age.

RESULTS

Results on PM2.5 exposure were available from 15 studies; the summary relative risk (RR) for an increase of 10 μg/m³ was 1.16 (95% confidence interval [CI] 1.09, 1.23). The corresponding RR for PM10 exposure was 1.23 (95 CI 1.05, 1.40; seven studies). A higher risk was suggested in studies based on lung cancer mortality and in studies conducted in East Asia, while no difference was shown according to sex, smoking status or age. There was no suggestion of publication bias.

CONCLUSIONS

Our meta-analysis supported the hypothesis of an association between exposure to PM2.5 or PM10 and risk of lung cancer, and provided evidence that the magnitude of the risk might be higher than previously estimated, and might be modified by outcome and geographic region.

REDD1 (regulated in development and DNA damage-1)/autophagy inhibition ameliorates fine particulate matter (PM2.5) -induced inflammation and apoptosis in BEAS-2B cells

This study aimed to investigate the implication of REDD1 on airborne particle matter-induced lung injury and whether it is mediated through autophagy. Cell viability in BEAS-2B cells induced by PM2.5 was measured by CCK-8. RT-qPCR and Western blot were performed to determine mRNA and protein levels of REDD1 as well as inflammatory cytokines, respectively. Cell apoptosis was observed with TUNEL staining. The expression of autophagy-related genes was detected by Western blot. Autophagy level was observed with GFP-LC3 staining. PM2.5 induced the expression of REDD1 in BEAS-2B cells. The inhibition by silencing REDD1 ameliorated the viability damage, blocked the inflammatory response and reduced the number of apoptotic BEAS-2B cells all induced by PM2.5. It was also found that PM2.5 induced autophagy in BEAS-2B cells, which was reversed by interference with REDD1. Furthermore, interference with REDD1 alleviated PM2.5-induced cell damage, inflammatory response and apoptosis in BEAS-2B cells through inhibiting autophagy. REDD1/autophagy inhibition ameliorates PM2.5-induced viability damage, inflammation and apoptosis in BEAS-2B cells.

Plastic Additives in Ambient Fine Particulate Matter in the Pearl River Delta, China: High-Throughput Characterization and Health Implications

Elucidation of the chemical components of airborne fine particulate matter (PM_2.5) facilitates the characterization of atmospheric contamination sources and associated human exposure risks. In the present study, we employed a high-throughput analytical approach to investigate the abundance and distribution of 163 plastic additives in ambient PM_2.5 collected from 94 different sites across the Pearl River Delta region, China. These chemicals are from six categories, including organophosphate esters (OPEs), phthalate esters (PAEs), PAE replacements, bisphenol analogues, UV stabilizers, and antioxidants. Ninety-three of them exhibited a detection frequency greater than 50% in PM_2.5, while the combined concentrations of target plastic additives ranged from 610 to 49,400 μg/g (median: 3500 μg/g) across sites. By category, concentrations of PAEs (median: 2710 μg/g) were one to three orders of magnitude greater than those of other groups, followed by PAE replacements (540 μg/g) and OPEs (76.2 μg/g). Chemical-dependent exposure risks to PM_2.5-bound plastic additives were characterized via the estimated daily intake and hazard quotient (HQ) approaches, which resulted in two different risk prioritization systems. Although the HQ approach suggested no or very low health concerns when considering individual chemicals, the complexity of co-concurrent chemicals in PM_2.5 raises the concern on potential health risks from exposure to airborne particles and a cocktail of chemical components.

Ambient Air Pollution and Mortality among Older Patients Initiating Maintenance Dialysis

BACKGROUND

Fine particulate matter (particulate matter with diameter <2.5 µm [PM2.5]) is associated with CKD progression and may impact the health of patients living with kidney failure. While older (aged ≥65 years) adults are most vulnerable to the impact of PM2.5, it is unclear whether older patients on dialysis are at elevated risk of mortality when exposed to fine particulate matter.

METHODS

Older adults initiating dialysis (2010-2016) were identified from US Renal Data System (USRDS). PM2.5 concentrations were obtained from NASA's Socioeconomic Data and Application Center (SEDAC) Global Annual PM2.5 Grids. We investigated the association between PM2.5 and all-cause mortality using Cox proportional hazard models with linear splines [knot at the current Environmental Protection Agency (EPA) National Ambient Air Quality Standard for PM2.5 of 12 μg/m3] and robust variance.

RESULTS

For older dialysis patients who resided in areas with high PM2.5, a 10 μg/m3 increase in PM2.5 was associated with 1.16-fold (95% CI: 1.08-1.25) increased risk of mortality; furthermore, those who were female (aHR = 1.26, 95% CI: 1.13-1.42), Black (aHR = 1.31, 95% CI: 1.09-1.59), or had diabetes as a primary cause of kidney failure (aHR = 1.25, 95% CI: 1.13-1.38) were most vulnerable to high PM2.5. While the mortality risk associated with PM2.5 was stronger at higher levels (aHR = 1.19, 95% CI: 1.08-1.32), at lower levels (≤12 μg/m3), PM2.5 was significantly associated with mortality risk (aHR = 1.04, 95% CI: 1.00-1.07) among patients aged ≥75 years (Pslope difference = 0.006).

CONCLUSIONS

Older adults initiating dialysis who resided in ZIP codes with PM2.5 levels >12 μg/m3 are at increased risk of mortality. Those aged >75 were at elevated risk even at levels below the EPA Standard for PM2.5.

A Population-Based Cohort Study of Respiratory Disease and Long-Term Exposure to Iron and Copper in Fine Particulate Air Pollution and Their Combined Impact on Reactive Oxygen Species Generation in Human Lungs

Metal components in fine particulate matter (PM_2.5) from nontailpipe emissions may play an important role in underlying the adverse respiratory effects of PM_2.5. We investigated the associations between long-term exposure to iron (Fe) and copper (Cu) in PM_2.5 and their combined impact on reactive oxygen species (ROS) generation in human lungs, and the incidence of asthma, chronic obstructive pulmonary disease (COPD), COPD mortality, pneumonia mortality, and respiratory mortality. We conducted a population-based cohort study of ∼0.8 million adults in Toronto, Canada. Land-use regression models were used to estimate the concentrations of Fe, Cu, and ROS. Outcomes were ascertained using validated health administrative databases. We found positive associations between long-term exposure to Fe, Cu, and ROS and the risks of all five respiratory outcomes. The associations were more robust for COPD, pneumonia mortality, and respiratory mortality than for asthma incidence and COPD mortality. Stronger associations were observed for ROS than for either Fe or Cu. In two-pollutant models, adjustment for nitrogen dioxide somewhat attenuated the associations while adjustment for PM_2.5 had little influence. Long-term exposure to Fe and Cu in PM_2.5 and estimated ROS concentration in lung fluid was associated with increased incidence of respiratory diseases, suggesting the adverse respiratory effects of nontailpipe emissions.

Particulate Matter and Cardiovascular Risk in Adults with Chronic Obstructive Pulmonary Disease

Rationale: People with chronic obstructive pulmonary disease (COPD) have an increased risk of cardiovascular disease and may be more susceptible to air pollution exposure. However, no study has examined the association between long-term fine particulate matter exposure (≤2.5 μm in aerodynamic diameter) and risk of cardiovascular events in this potentially vulnerable population. Objectives: To estimate the association between long-term fine particulate matter and risk of cardiovascular events among adults with COPD. Methods: This retrospective cohort study included 169,714 adults with COPD who were members of the Kaiser Permanente Northern California health plan during 2007-2016. Electronic health record data were linked to 1 km modeled particulate matter ≤2.5 μm in aerodynamic diameter exposure estimates. We fit Cox proportional hazard models, adjusting for age, sex, race/ethnicity, calendar year, smoking, body mass index, comorbidities, medications, and socioeconomic status. In low exposure analyses, we examined effects below the current regulation limit (12 μg/m³). Measurements and Main Results: Among adults with COPD, a 10-μg/m³ increase in 1-year mean fine particulate matter exposure was associated with an elevated risk of cardiovascular mortality (hazard ratio, 1.10; 95% confidence interval [CI], 1.01-1.20). Effects were stronger in low exposure analyses (hazard ratio, 1.88; 95% CI, 1.56-2.27). Fine particulate matter exposure was not associated with acute myocardial infarction or stroke in overall analyses. Conclusions: Long-term fine particulate matter exposure was associated with an increased risk of cardiovascular mortality among adults with COPD. Current regulations may not sufficiently protect those with COPD.

Classification of Critical Levels of CO Exposure of Firefigthers through Monitored Heart Rate

Smoke inhalation poses a serious health threat to firefighters (FFs), with potential effects including respiratory and cardiac disorders. In this work, environmental and physiological data were collected from FFs, during experimental fires performed in 2015 and 2019. Extending a previous work, which allowed us to conclude that changes in heart rate (HR) were associated with alterations in the inhalation of carbon monoxide (CO), we performed a HR analysis according to different levels of CO exposure during firefighting based on data collected from three FFs. Based on HR collected and on CO occupational exposure standards (OES), we propose a classifier to identify CO exposure levels through the HR measured values. An ensemble of 100 bagged classification trees was used and the classification of CO levels obtained an overall accuracy of 91.9%. The classification can be performed in real-time and can be embedded in a decision fire-fighting support system. This classification of FF’ exposure to critical CO levels, through minimally-invasive monitored HR, opens the possibility to identify hazardous situations, preventing and avoiding possible severe problems in FF’ health due to inhaled pollutants. The obtained results also show the importance of future studies on the relevance and influence of the exposure and inhalation of pollutants on the FF’ health, especially in what refers to hazardous levels of toxic air pollutants.

Combined effects of increased O3 and reduced NO2 concentrations on short-term air pollution health risks in Hong Kong

The reduction of NO_x emissions in a VOC-limited region can lead to an increase of the local O₃ concentration. An evaluation of the net health effects of such pollutant changes is therefore important to ascertain whether the emission control measures effectively improve the overall protection of public health. In this study, we use a short-term health risk (added health risk or AR) model developed for the multi-pollutant air quality health index (AQHI) in Hong Kong to examine the overall health impacts of these pollutant changes. We first investigate AR changes associated with NO₂ and O₃ changes, followed by those associated with changes in all four AQHI pollutants (NO₂, O₃, SO₂, and particulate matter (PM)). Our results show that for the combined health effects of NO₂ and O₃ changes, there is a significant reduction in AR in urban areas with dense traffic, but no statistically significant changes in other less urbanized areas. The increase in estimated AR for higher O₃ concentrations is offset by a decrease in the estimated AR for lower NO₂ concentrations. In areas with dense traffic, the reduction in AR as a result of decreased NO₂ is substantially larger than the increase in AR associated with increased O₃. When additionally accounting for the change in ambient SO₂ and PM, we found a statistically significant reduction in total AR everywhere in Hong Kong. Our results show that the emission control measures resulting in NO₂, SO₂, and PM reductions over the past decade have effectively reduced the AR over Hong Kong, even though these control measures may have partially contributed to an increase in O₃ concentrations. Hence, efforts to reduce NOx, SO₂, and PM should be continued.

PM2.5 Concentration and Composition in Subway Systems in the Northeastern United States

OBJECTIVES

The goals of this study were to assess the air quality in subway systems in the northeastern United States and estimate the health risks for transit workers and commuters.

METHODS

We report real-time and gravimetric PM2.5 concentrations and particle composition from area samples collected in the subways of Philadelphia, Pennsylvania; Boston, Massachusetts; New York City, New York/New Jersey (NYC/NJ); and Washington, District of Columbia. A total of 71 stations across 12 transit lines were monitored during morning and evening rush hours.

RESULTS

We observed variable and high PM2.5 concentrations for on-train and on-platform measurements during morning (from 0600 hours to 1000 hours) and evening (from 1500 hours to 1900 hours) rush hour across cities. Mean real-time PM2.5 concentrations in underground stations were 779±249, 548±207, 341±147, 327±136, and 112±46.7 μg/m3 for the PATH-NYC/NJ; MTA-NYC; Washington, DC; Boston; and Philadelphia transit systems, respectively. In contrast, the mean real-time ambient PM2.5 concentration taken above ground outside the subway stations of PATH-NYC/NJ; MTA-NYC; Washington, DC; Boston; and Philadelphia were 20.8±9.3, 24.1±9.3, 12.01±7.8, 10.0±2.7, and 12.6±12.6 μg/m3, respectively. Stations serviced by the PATH-NYC/NJ system had the highest mean gravimetric PM2.5 concentration, 1,020 μg/m3, ever reported for a subway system, including two 1-h gravimetric PM2.5 values of approximately 1,700 μg/m3 during rush hour at one PATH-NYC/NJ subway station. Iron and total carbon accounted for approximately 80% of the PM2.5 mass in a targeted subset of systems and stations.

DISCUSSION

Our results document that there is an elevation in the PM2.5 concentrations across subway systems in the major urban centers of Northeastern United States during rush hours. Concentrations in some subway stations suggest that transit workers and commuters may be at increased risk according to U.S. federal environmental and occupational guidelines, depending on duration of exposure. This concern is highest for the PM2.5 concentrations encountered in the PATH-NYC/NJ transit system. Further research is urgently needed to identify the sources of PM2.5 and factors that contribute to high levels in individual stations and lines and to assess their potential health impacts on workers and/or commuters. https://doi.org/10.1289/EHP7202.

Transcriptomic analysis identifies dysregulated genes and functional networks in human small airway epithelial cells exposed to ambient PM2.5

Cellular models exhibiting human physiological features of pseudostratified columnar epithelia, provide a more realistic approach for elucidating detailed mechanisms underlying PM_2.5-induced pulmonary toxicity. In this study, we characterized the barrier and mucociliary functions of differentiated human small airway epithelial cells (SAECs), cultured at the air-liquid interface (ALI). Due to the presence of mucociliary protection, particle internalization was reduced, with a concomitant decrease in cytotoxicity in differentiated S-ALI cells, as compared to conventional submerged SAEC cultures. After 24-hour exposure to PM_2.5 surrogates, 117 up-regulated genes and 156 down-regulated genes were detected in S-ALI cells, through transcriptomic analysis using the Affymetrix Clariom™ S Human Array. Transcription-level changes in >60 signaling pathways, were revealed by functional annotation of the 273 differentially expressed genes, using the PANTHER Gene List Analysis. These pathways are involved in multiple cellular processes, that include inflammation and apoptosis. Exposure to urban PM_2.5 led to complex responses in airway epithelia, including a net induction of downstream pro-inflammatory and pro-apoptotic responses. Collectively, this study highlights the importance of using the more advanced ALI model rather than the undifferentiated submerged model, to avoid over-assessment of inhaled particle toxicity in human. The results of our study also suggest that reduction of ambient PM_2.5 concentrations would have a protective effect on respiratory health in humans.

Long-term effects of fine particulate matter exposure on the progression of arterial stiffness

BACKGROUND

Prior studies have investigated the association of PM_2.5 exposure with arterial stiffness measured by ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV), of which conclusions are inconsistent. Moreover, limited evidence is available on the contributory role of PM_2.5 exposure on the arterial stiffness index.

METHODS

We used the population data from the Beijing Health Management Cohort and conducted a longitudinal analysis. The annual average concentration of PM_2.5 for 35 air pollutant monitoring sites in Beijing from 2014 to 2018 was used to estimate individual exposure by different interpolation methods. Multivariate logistic regression and linear regression were conducted to assess the association of annual average PM_2.5 concentration with the incidence of higher baPWV, the progression of ABI, and baPWV, respectively.

RESULTS

The association between PM_2.5 exposure and incidence of higher baPWV was not significant (OR = 1.11, 95% CI: 0.82-1.50, P = 0.497). There was - 0.16% (95% CI: - 0.43-0.11%) decrease in ABI annually and 1.04% (95% CI: 0.72-1.37%) increase in baPWV annually with each increment of 10 μg/m³ average PM_2.5 concentration.

CONCLUSIONS

Long-term exposure to PM_2.5 was associated with the progression of arterial stiffness in Beijing. This study suggests that improvement of air quality may help to prevent arterial stiffness.

Cytotoxic Effects of Water-Soluble Extracts of Coarse and Fine Atmospheric Particulate Matter on Mast Cell Lines

Fine particulate matter (PM_2.5) pollution causes serious health disorders, because PM_2.5 becomes deposited in the tracheobronchial and alveoli regions. In the extrathoracic region, there are more deposits of coarse particulate matter than fine particulates. As adverse health issues caused by coarse particulates have not been well investigated, this study examined the cytotoxicity of water-soluble extracts of both fine (0.05-3 µm, PM_0.05-3) and coarse (> 3 µm, PM_>3) particulates collected from April 2016 to March 2019 in Fukuoka, Japan. Also evaluated were concentrations of NH₄⁺ and SO₄^2-, multi-components of well-known secondary generation substances. The findings revealed that PM_>3 showed stronger cytotoxic effects on mast cell lines than PM_0.05-3. Cytotoxic effects were observed at concentrations of over 15 mM of (NH₄)₂SO₄ and over 30 mM of NH₄Cl. In contrast, Na₂SO₄ caused few cytotoxic effects up to a concentration of 50 mM. The causative substances for this cytotoxicity may not have been NH₄⁺ and SO₄^2- because their PM_>3 concentrations indicating the largest cytotoxic effects were 1 and 0.4 mM, respectively. The cytotoxicities of PM_>3 and PM_0.05-3 were the highest in the first half of FY2016. These cytotoxicities seem to be due to cross-border pollution, although this pollution has been declining in recent years. An increasing trend of cytotoxicity was observed in the second half of FY2018. This study showed that cytotoxicity and particulate concentrations are not always correlated. Thus, we should focus not only on the quantity of atmospheric particulate matter, but also on its quality.

Ambient PM2.5 and its chemical constituents on lifetime-ever pneumonia in Chinese children: A multi-center study

The long-term effects of ambient PM_2.5 and chemical constituents on childhood pneumonia were still unknown. A cross-sectional study was conducted in 30,315 children in the China Children, Homes, Health (CCHH) project, involving 205 preschools in six cities in China, to investigate the long-term effects of PM_2.5 constituents on lifetime-ever diagnosed pneumonia. Information on the lifetime-ever pneumonia and demographics were collected by validated questionnaires. The lifetime annual average ambient PM_2.5, ozone and five main PM_2.5 constituents, including SO₄^2-, NO₃^-, NH₄⁺, organic matter (OM) and black carbon (BC), were estimated according to preschool addresses by a combination of satellite remote sensing, chemical transport modeling and ground-based monitors. The prevalence of lifetime-ever diagnosed pneumonia was 34.5% across six cities and differed significantly among cities (p = 0.004). The two-level logistic regression models showed that the adjusted odds ratio for PM_2.5 (per 10 µg/m³) and its constituents (per 1 µg/m³)-SO₄^2-, NO₃^-, NH₄⁺, and OM were 1.12 (95% CI:1.07-1.18), 1.02 (1.00-1.04), 1.06 (1.04-1.09), 1.05 (1.03-1.07) and 1.09 (1.06-1.12), respectively. Children in urban area, aged < 5 years and breastfeeding time < 6 months enhanced the risks of pneumonia. Our study provided robust results that long-term levels of ambient PM_2.5 and its constituents increased the risk of childhood pneumonia, especially NH₄⁺, NO₃^- and OM.

The short-term harvesting effects of ambient particulate matter on mortality in Taiyuan elderly residents: A time-series analysis with a generalized additive distributed lag model

The evaluation on mortality displacement and distributed lag effects of airborne particulate matter (PM) on death risks is important to understand the positive association of short-term pollution from both ambient PM₁₀ and PM_2.5 with daily mortality. Herein, short-term influences of urban PM₁₀ and PM_2.5 exposure on the mortality of respiratory diseases (RD) and cardiovascular diseases (CVD) were studied at Taiyuan, China, a typical inland city suffering from heavy ambient PM loading and having high morbidity of RD and CVD. Using a time-series analysis with generalized additive distributed lag model (DLM), the potential mortality displacement was determined and the single-day and cumulative lag-day effects of PM on mortality were estimated after the daily mass concentrations of urban PM_2.5 and PM₁₀ from January 2013 to October 2015 and the daily number of non-accidental death (NAD) and cause-specific mortality in the residents aged more than 65 years old were obtained. Results showed there were significant associations of PM_2.5 and PM₁₀ with daily mortality on the current day and within one week. And a statistically significant increase (P < 0.05) in the cumulative effect estimates of PM_2.5 and PM₁₀ on CVD, ischemic heart disease (IHD), and myocardial infarction (MI) mortality (as well as PM_2.5 on NAD) was observed, while the associations of PM_2.5 with RD and pneumonia mortality, PM₁₀ with NAD and RD mortality were not statistically significant, when the exposure window was extended to lag 0-30 days. It was concluded that there were harvesting effects and cumulative effects of ambient PM_2.5 and PM₁₀ on the elderly residents' mortality due to RD and CVD at Taiyuan and they could be estimated quantitatively when the broader time window was used, suggesting that the underestimation on the association of ambient PM with non-accidental death can be avoided using the present method in our study.

Long-Term PM2.5 Exposure and Risks of Ischemic Heart Disease and Stroke Events: Review and Meta-Analysis

Background

Fine particulate matter <2.5 µm in diameter (PM_2.5) has known effects on cardiovascular morbidity and mortality. However, no study has quantified and compared the risks of incident myocardial infarction, incident stroke, ischemic heart disease (IHD) mortality, and cerebrovascular mortality in relation to long‐term PM_2.5 exposure.

Methods and Results

We sought to quantitatively summarize studies of long‐term PM_2.5 exposure and risk of IHD and stroke events by conducting a review and meta‐analysis of studies published by December 31, 2019. The main outcomes were myocardial infarction, stroke, IHD mortality, and cerebrovascular mortality. Random effects meta‐analyses were used to estimate the combined risk of each outcome among studies. We reviewed 69 studies and included 42 studies in the meta‐analyses. In meta‐analyses, we found that a 10‐µg/m³ increase in long‐term PM_2.5 exposure was associated with an increased risk of 23% for IHD mortality (95% CI, 15%–31%), 24% for cerebrovascular mortality (95% CI, 13%–36%), 13% for incident stroke (95% CI, 11%–15%), and 8% for incident myocardial infarction (95% CI, −1% to 18%). There were an insufficient number of studies of recurrent stroke and recurrent myocardial infarction to conduct meta‐analyses.

Conclusions

Long‐term PM_2.5 exposure is associated with increased risks of IHD mortality, cerebrovascular mortality, and incident stroke. The relationship with incident myocardial infarction is suggestive of increased risk but not conclusive. More research is needed to understand the relationship with recurrent events.

Chronic Effects of High Fine Particulate Matter Exposure on Lung Cancer in China

Rationale: Limited cohort studies have evaluated chronic effects of high fine particulate matter (particulate matter with an aerodynamic diameter ≤2.5 μm [PM_2.5]) exposure on lung cancer.Objectives: To investigate the response pattern of lung cancer associated with high PM_2.5 exposure.Methods: A Chinese cohort of 118,551 participants was followed up from 1992 to 2015. By incorporating PM_2.5 exposure at 1 km spatial resolution generated using the satellite-based model during 2000-2015, we estimated the association between lung cancer and time-weighted average PM_2.5 concentration using Cox proportional hazard models.Measurements and Main Results: A total of 844 incident lung cancer cases were identified during 915,053 person-years of follow-up. Among them, 701 lung cancer deaths occurred later. The exposure-response curves for lung cancer associated with PM_2.5 exposure were nonlinear, with steeper slopes at the higher concentrations. Adjusted for age, sex, geographical region, urbanization, education level, smoking status, alcohol consumption, work-related physical activity, and body mass index, participants exposed to the second-fifth quintiles of PM_2.5 had higher risk for lung cancer incidence than those exposed to the first quintile, with hazard ratios of 1.44 (95% confidence interval [CI], 1.10-1.88), 1.49 (95% CI, 1.12-1.99), 2.08 (95% CI, 1.42-3.04), and 2.45 (95% CI, 1.83-3.29), respectively. The corresponding hazard ratios for lung cancer mortality were 1.83 (95% CI, 1.33-2.50), 1.80 (95% CI, 1.29-2.53), 2.50 (95% CI, 1.62-3.86), and 2.95 (95% CI, 2.09-4.17), respectively.Conclusions: We provide strong evidence that high PM_2.5 exposure leads to an elevated risk of lung cancer incidence and mortality, highlighting that remarkable public health benefits could be obtained from the improvement of air quality in highly polluted regions.

The effects of everyday-life exposure to polycyclic aromatic hydrocarbons on biological age indicators

BACKGROUND

Further knowledge on modifiable aging risk factors is required to mitigate the increasing burden of age-related diseases in a rapidly growing global demographic of elderly individuals. We explored the effect of everyday exposure to polycyclic aromatic hydrocarbons (PAHs), which are fundamental constituents of air pollution, on cellular biological aging. This was determined via the analysis of leukocyte telomere length (LTL), mitochondrial DNA copy number (LmtDNAcn), and by the formation of anti-benzo[a]pyrene diolepoxide (B[a]PDE-DNA) adducts.

METHODS

The study population consisted of 585 individuals living in North-East Italy. PAH exposure (diet, indoor activities, outdoor activities, traffic, and residential exposure) and smoking behavior were assessed by questionnaire and anti-B[a]PDE-DNA by high-performance-liquid-chromatography. LTL, LmtDNAcn and genetic polymorphisms [glutathione S-transferase M1 and T1 (GSTM1; GSTT1)] were measured by polymerase chain reaction. Structural equation modelling analysis evaluated these complex relationships.

RESULTS

Anti-B[a]PDE-DNA enhanced with PAH exposure (p = 0.005) and active smoking (p = 0.0001), whereas decreased with detoxifying GSTM1 (p = 0.021) and in females (p = 0.0001). Subsequently, LTL and LmtDNAcn reduced with anti-B[a]PDE-DNA (p = 0.028 and p = 0.018), particularly in males (p = 0.006 and p = 0.0001). Only LTL shortened with age (p = 0.001) while elongated with active smoking (p = 0.0001). Besides this, the most significant determinants of PAH exposure that raised anti-B[a]PDE-DNA were indoor and diet (p = 0.0001), the least was outdoor (p = 0.003).

CONCLUSION

New findings stemming from our study suggest that certain preventable everyday life exposures to PAHs reduce LTL and LmtDNAcn. In particular, the clear association with indoor activities, diet, and gender opens new perspectives for tailored preventive measures in age-related diseases.

CAPSULE

Everyday life exposure to polycyclic aromatic hydrocarbons reduces leukocyte telomere length and mitochondrial DNA copy number through anti-B[a]PDE-DNA adduct formation.

Biomass burning spatiotemporal variations over South and Southeast Asia

In this study, Moderate Resolution Imaging Spectroradiometer active fire and land use products were integrated to extract and classify biomass burning (BB) data for South Asia (SA) and Southeast Asia (SEA). Several trend and geographic distribution analyses were conducted at the grid (0.25° × 0.25°) and regional scales. As the principal local form of BB, crop residue burning (CRB) in SA increased by 844 spots/yr, and the Mann-Kendall (MK) τ reached 0.61. Additionally, the CRB in Punjab-Haryana, a region a well-known for severest CRB, presented a significant declining trend. BB in mainland SEA was much more intense and was dominated by forest and shrubland fires. Forest fires in mainland SEA declined at a rate of -209 spots/yr, and shrubland fire conversely grew at a rate of 803 spots/yr, which was likely related to the dramatic land cover change induced by the local swidden agriculture. Unlike other regions, BB in equatorial SEA primarily occurred in the second half of the year (August to October), and it was extremely vulnerable to El Niño events. When the annual sea surface temperature anomalies within the Niño 3 region improved by 1 °C, the annual BB spots and fire radiative power in equatorial SEA increased by 5.18 × 10⁴ and 2.40 × 10⁶ MW, respectively. Although the interannual variations in equatorial SEA were dramatic, the robust Siegel's repeated median estimator still revealed that equatorial SEA BB significantly declined by -1825 spots/yr. This regional decline reflects government endeavors to curb indigenous BB. However, regions with enhanced BB still need to draw more attention, and it is imperative for the Indonesian government to take substantial measures to reduce anthropogenic fire sources during El Niño events.

Acute effect of ambient fine particulate matter on heart rate variability: an updated systematic review and meta-analysis of panel studies

Background

Decreased heart rate variability (HRV) is a predictor of autonomic system dysfunction, and is considered as a potential mechanism of increased risk of cardiovascular disease (CVD) induced by exposure to particulate matter less than 2.5 μm in diameter (PM_2.5). Previous studies have suggested that exposure to PM_2.5 may lead to decreased HRV levels, but the results remain inconsistent.

Methods

An updated systematic review and meta-analysis of panel studies till November 1, 2019 was conducted to evaluate the acute effect of exposure to ambient PM_2.5 on HRV. We searched electronic databases (PubMed, Web of Science, and Embase) to identify panel studies reporting the associations between exposure to PM_2.5 and the four indicators of HRV (standard deviation of all normal-to-normal intervals (SDNN), root mean square of successive differences in adjacent normal-to-normal intervals (rMSSD), high frequency power (HF), and low frequency power (LF)). Random-effects model was used to calculate the pooled effect estimates.

Results

A total of 33 panel studies were included in our meta-analysis, with 16 studies conducted in North America, 12 studies in Asia, and 5 studies in Europe. The pooled results showed a 10 μg/m³ increase in PM_2.5 exposure which was significantly associated with a − 0.92% change in SDNN (95% confidence intervals (95%CI) − 1.26%, − 0.59%), − 1.47% change in rMSSD (95%CI − 2.17%, − 0.77%), − 2.17% change in HF (95%CI − 3.24%, − 1.10%), and − 1.52% change in LF (95%CI − 2.50%, − 0.54%), respectively. Overall, subgroup analysis suggested that short-term exposure to PM_2.5 was associated with lower HRV levels in Asians, healthy population, and those aged ≥ 40 years.

Conclusion

Short-term exposure to PM_2.5 was associated with decreased HRV levels. Future studies are warranted to clarity the exact mechanism of exposure to PM_2.5 on the cardiovascular system through disturbance of autonomic nervous function.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12199-020-00912-2.

How does China's air pollution influence its labor wage distortions? Theoretical and empirical analysis from the perspective of spatial spillover effects

OBJECTIVE

This study aims to analyze the impact of air pollution on Chinese labor wage distortions, especially the impact caused by neighboring air pollution, which is the spatial spillover effects of pollution.

METHODS

It first constructs a theoretical model to explain the effect of air pollution on wage distortions theoretically. Then, based on the measurement of wage distortions of 289 cities from 1998 to 2016, it further uses the Spatial Durbin Model to examine the influences and influencing mechanisms empirically.

RESULTS

The results show that labor wages are negatively distorted during the sample period, with the real wages being lower than the marginal product labor (MPL). Besides, local air pollution significantly exacerbates wage distortions through the production input effect that increases MPL, with a 1% increase in air pollution leading to a 0.0842% and 0.1038% increase in wage distortions and MPL, respectively. The spatial spillover effects suggest that air pollution from neighborhoods significantly reduces local wage distortions through the human capital effect that decreases MPL, and the elastic coefficients of neighboring air pollution on wage distortions and MPL are -0.6078 and - 0.8870, respectively. Besides, the heterogeneity test indicates the magnitude and the significance of the impacts vary in the eastern, central, and western regions.

CONCLUSION

Our analysis calls for collaborative governance in both air pollution and labor market liberalization and the simultaneous growth of real wages and labor productivity.