Ambient Particulate Matter Levels Research Articles

Combined Effect of Air Pollution and Genetic Risk on Incident Cardiovascular Diseases.

Whether genetic susceptibility to cardiovascular diseases (CVDs) enhances the vulnerability to adverse cardiovascular outcomes by air pollution is unknown. We assessed the combined effect of air pollution and genetic predispositions on CVD risk. From the UK Biobank cohort, we selected genetically unrelated White British participants without CVD. Levels of ambient particulate matter with a diameter of <2.5 μm (PM2.5) and <10 μm were estimated using land use regression models. An individual's genetic predisposition to CVDs was determined by polygenic risk scores for coronary artery disease, myocardial infarction, stroke, ischemic stroke, heart failure, and atrial fibrillation. We stratified mortality and CVD risk by PM2.5 exposure across high and low genetic risk groups. A total of 249 082 participants (aged 56.9±8.0 years, 46.8% men) were followed for a median of 10.8 years. The combined effect of PM2.5 exposure and the genetic predisposition of CVD demonstrated the highest risk of cardiovascular death in the high genetic risk group with the greatest PM2.5 exposure (adjusted hazard ratios ranging from 1.73 to 2.12 across the polygenic risk score of each CVD). The combination of higher exposure to ambient PM2.5 and high genetic risk was associated with higher incidence of all CVDs, although no significant interactions were observed between genetic risk and PM2.5 exposure on cardiovascular death or CVD events. A combination of greater PM2.5 exposure and higher genetic predisposition to particular CVDs was modestly associated with elevated risks of cardiovascular death and CVDs. Not only alleviating PM2.5 exposure in the general population but also implementing individualized preventive approach for those at high genetic risk might be beneficial.

Deployment-related Cigarette Smoking Behaviors and Pulmonary Function Among U.S. Veterans.

The effects of smoking on lung function among post-9/11 Veterans deployed to environments with high levels of ambient particulate matter are incompletely understood. We analyzed interim data (04/2018-03/2020) from the Veterans Affairs (VA) Cooperative Studies Program #595, "Service and Health Among Deployed Veterans". Veterans with ≥1 land-based deployments enrolled at 1 of 6 regional Veterans Affairs sites completed questionnaires and spirometry. Multivariable linear regression models assessed associations between cigarette smoking (cumulative, deployment-related and non-deployment-related) with pulmonary function. Among 1,836 participants (mean age 40.7±9.6, 88.6% male), 44.8% (n = 822) were ever-smokers (mean age 39.5 ± 9.5; 91.2% male). Among ever-smokers, 86% (n = 710) initiated smoking before deployment, while 11% (n = 90) initiated smoking during deployment(s). Smoking intensity was 50% greater during deployment than other periods (0.75 versus 0.50 packs-per-day; P < .05), and those with multiple deployments (40.4%) were more likely to smoke during deployment relative to those with single deployments (82% versus 74%). Total cumulative pack-years (median [IQR] = 3.8 [1, 10]) was inversely associated with post-bronchodilator FEV1%-predicted (-0.82; [95% CI] = [-1.25, -0.50] %-predicted per 4 pack-years) and FEV1/FVC%-predicted (-0.54; [95% CI] = [-0.78, -0.43] %-predicted per 4 pack-years). Deployment-related pack-years demonstrated similar point estimates of associations with FEV1%-predicted (-0.61; [95% CI] = [-2.28, 1.09]) and FEV1/FVC%-predicted (-1.09; [95% CI] = [-2.52, 0.50]) as non-deployment-related pack-years (-0.83; [95% CI] = [-1.26, -0.50] for FEV1%-predicted; -0.52; [95% CI] = [-0.73, -0.36] for FEV1/FVC%-predicted). Although cumulative pack-years smoking was modest in this cohort, an inverse association with pulmonary function was detectable. Deployment-related pack-years had a similar association with pulmonary function compared to non-deployment-related pack-years.

Short-term effects of high-resolution (1-km) ambient PM2.5 and PM10 on hospital admission for pulmonary tuberculosis: a case-crossover study in Hainan, China.

There is limited evidence regarding particulate matter (PM)'s short-term effects on pulmonary tuberculosis (PTB) hospital admission. Our study aimed to determine the short-term associations of the exposure to ambient PM with aerodynamic diameters <2.5 μm (PM2.5) and < 10 μm (PM10) with hospital admission for PTB in Hainan, a tropical province in China. We collected individual data on patients hospitalized with PTB, PM2.5, PM10, and meteorological data from 2016 to 2019 in Hainan Province, China. Conditional logistic regression models with a time-stratified case-crossover design were used to assess the short-term effects of PM2.5 and PM10 on hospital admission for PTB at a spatial resolution of 1 km × 1 km. Stratified analyses were performed according to age at admission, sex, marital status, administrative division, and season of admission. Each interquartile range (IQR) increases in the concentrations of PM2.5 and PM10 were associated with 1.155 (95% confidence interval [CI]: 1.041-1.282) and 1.142 (95% CI: 1.033-1.263) hospital admission risks for PTB at lag 0-8 days, respectively. The stratified analyses showed that the effects of PM2.5 and PM10 were statistically significant for patients aged ≥65 years, males, married, and those residing in prefecture-level cities. Regarding seasonal differences, the associations between PM and hospital admission for PTB were statistically significant in the warm season but not in the cold season. The effect of PM2.5 was consistently stronger than that of PM10 in most subgroups. Short-term exposure to PM increases the risk of hospital admission for PTB. The potential impact of PM with smaller aerodynamic diameter is more detrimental. Our findings highlight the importance of reducing ambient PM level to alleviate the burden of PTB.

Genome-wide DNA methylation sequencing identifies epigenetic perturbations in the upper airways under long-term exposure to moderate levels of ambient air pollution

While the link between exposure to high levels of ambient particulate matter (PM) and increased incidences of respiratory and cardiovascular diseases is widely recognized, recent epidemiological studies have shown that low PM concentrations are equally associated with adverse health effects. As DNA methylation is one of the main mechanisms by which cells regulate and stabilize gene expression, changes in the methylome could constitute early indicators of dysregulated signaling pathways. So far, little is known about PM-associated DNA methylation changes in the upper airways, the first point of contact between airborne pollutants and the human body. Here, we focused on cells of the upper respiratory tract and assessed their genome-wide DNA methylation pattern to explore exposure-associated early regulatory changes. Using a mobile epidemiological laboratory, nasal lavage samples were collected from a cohort of 60 adults that lived in districts with records of low (Simmerath) or moderate (Stuttgart) PM10 levels in Germany. PM10 concentrations were verified by particle measurements on the days of the sample collection and genome-wide DNA methylation was determined by enzymatic methyl sequencing at single-base resolution. We identified 231 differentially methylated regions (DMRs) between moderately and lowly PM10 exposed individuals. A high proportion of DMRs overlapped with regulatory elements, and DMR target genes were involved in pathways regulating cellular redox homeostasis and immune response. In addition, we found distinct changes in DNA methylation of the HOXA gene cluster whose methylation levels have previously been linked to air pollution exposure but also to carcinogenesis in several instances. The findings of this study suggest that regulatory changes in upper airway cells occur at PM10 levels below current European thresholds, some of which may be involved in the development of air pollution-related diseases.

Laboratory evaluation of the Alphasense OPC-N3, and the Plantower PMS5003 and PMS6003 sensors

Ambient levels of particulate matter (PM) are linked to numerous adverse health effects. However, fewer studies have evaluated the effects of coarse PM (larger than 2.5 μm in diameter), and ambient measurements of coarse PM are particularly sparse. Although low-cost PM sensors have been used to complement regulatory measurements of PM2.5, many of these sensors, such as the Plantower PMS5003, are ineffective in measuring coarse PM. The Alphasense OPCs have shown promise in detecting coarse PM and have been used in the field to measure PM10 concentrations. These field evaluations have identified inter-sensor variability. Although field evaluation is critical for understanding sensor performance under environmentally relevant conditions, it provides limited information about sensor response characteristics, which are essential for determining the factors that may affect sensor measurements and contribute to inter-sensor variability. This study aims to understand these factors by conducting a size-selectivity study using monodisperse particles, and evaluating the effect of instrument-specific properties, like flow rate and laser strength, on the sensor-reported sizes and number counts. This study also evaluates a common low-cost sensor, the Plantower PMS5003, and a newer version, the PMS6003, for size selectivity. Monodisperse dioctyl sebacate particles of various diameters (2, 3, 5, 6, 9, and 10 μm) were generated using a flow-focusing monodisperse aerosol generator, and the performance of nine different OPCs was evaluated. For all sizes tested, the nine OPC-N3s detected the particles, showed a peak near the target diameter, and exhibited some inter-sensor variability. The four PMS5003s and four PMS6003s detected all particle sizes but assigned all particles to the smallest size bin i.e., 0.35 μm–1 μm. With an aerodynamic particle sizer (APS) as a reference, the OPCs showed a positive bias for mean particle diameter and a coefficient of variance (CV) of less than 10%. For number concentration, the OPCs showed a negative bias, compared to the APS, and inter-sensor variability increased with the particle diameter. The laser wavelength of the OPC-N3s varied between 600 and 650 nm and appeared to have some effect on inter-sensor variability of the mean size. The flow rate reported by the OPC appeared to affect the inter-sensor variability in the number concentration.

Proinflammatory polarization of monocytes by particulate air pollutants is mediated by induction of trained immunity in pediatric asthma.

The impact of exposure to air pollutants, such as fine particulate matter (PM), on the immune system and its consequences on pediatric asthma, are not well understood. We investigated whether ambient levels of fine PM with aerodynamic diameter ≤2.5 microns (PM2.5 ) are associated with alterations in circulating monocytes in children with or without asthma. Monocyte phenotyping was performed by cytometry time-of-flight (CyTOF). Cytokines were measured using cytometric bead array and Luminex assay. ChIP-Seq was utilized to address histone modifications in monocytes. Increased exposure to ambient PM2.5 was linked to specific monocyte subtypes, particularly in children with asthma. Mechanistically, we hypothesized that innate trained immunity is evoked by a primary exposure to fine PM and accounts for an enhanced inflammatory response after secondary stimulation in vitro. We determined that the trained immunity was induced in circulating monocytes by fine particulate pollutants, and it was characterized by the upregulation of proinflammatory mediators, such as TNF, IL-6, and IL-8, upon stimulation with house dust mite or lipopolysaccharide. This phenotype was epigenetically controlled by enhanced H3K27ac marks in circulating monocytes. The specific alterations of monocytes after ambient pollution exposure suggest a possible prognostic immune signature for pediatric asthma, and pollution-induced trained immunity may provide a potential therapeutic target for asthmatic children living in areas with increased air pollution.

Highly local sources and large spatial variations in PM2.5 across a city: evidence from a city-wide sensor network in Cork, Ireland

When dominated by local emissions, levels of ambient particulate matter (PM) can vary appreciably within a city. In Ireland, residential solid fuel burning is the main PM2.5 emission source.

Association between ambient particulate matter levels and hypertension: results from the Korean Genome and Epidemiology Study.

Recently, there has been increasing worldwide concern about outdoor air pollution, especially particulate matter (PM), which has been extensively researched for its harmful effects on the respiratory system. However, sufficient research on its effects on cardiovascular diseases, such as hypertension, remains lacking. In this study, we examine the associations between PM levels and hypertension and hypothesize that higher PM concentrations are associated with elevated blood pressure. A total of 133,935 adults aged ≥ 40 years who participated in the Korean Genome and Epidemiology Study were analyzed. Multiple linear regression analyses were conducted to investigate the short- (1-14 days), medium- (1 and 3 months), and long-term (1 and 2 years) impacts of PM on blood pressure. Logistic regression analyses were conducted to evaluate the medium- and long-term effects of PM on blood pressure elevation after adjusting for sex, age, body mass index, health-related lifestyle behaviors, and geographic areas. Using multiple linear regression analyses, both crude and adjusted models generated positive estimates, indicating an association with increased blood pressure, with all results being statistically significant, with the exception of PM levels over the long-term period (1 and 2 years) in non-hypertensive participants. In the logistic regression analyses on non-hypertensive participants, moderate PM10 (particulate matter with diameters < 10 μm) and PM2.5 (particulate matter with diameters < 2.5 μm) levels over the long-term period and all high PM10 and PM2.5 levels were statistically significant after adjusting for various covariates. Notably, high PM2.5 levels of the 1 year exhibited the highest odds ratio of 1.23 (95% confidence interval: 1.19-1.28) after adjustment. These findings suggest that both short- and long-term exposure to PM is associated with blood pressure elevation.

Aerosolized aqueous dust extracts collected near a drying lake trigger acute neutrophilic pulmonary inflammation reminiscent of microbial innate immune ligands

BackgroundA high incidence of asthma is prevalent among residents near the Salton Sea, a large inland terminal lake in southern California. This arid region has high levels of ambient particulate matter (PM); yet while high PM levels are often associated with asthma in many environments, it is possible that the rapidly retreating lake, and exposed playa or lakebed, may contribute components with a specific role in promoting asthma symptoms. ObjectivesOur hypothesis is that asthma may be higher in residents closest to the Salton Sea due to chronic exposures to playa dust. Playa emissions may be concentrating dissolved material from the lake, with microbial components capable of inducing pulmonary innate immune responses. To test this hypothesis, we used a mouse model of aerosol exposures to assess the effects of playa dust. MethodsFrom dust collected around the Salton Sea region, aqueous extracts were used to generate aerosols, which were injected into an environmental chamber for mouse exposure studies. We compared the effects of exposure to Salton Sea aerosols, as well as to known immunostimulatory reference materials. Acute 48-h and chronic 7-day exposures were compared, with lungs analyzed for inflammatory cell recruitment and gene expression. ResultsDust from sites nearest to the Salton Sea triggered lung neutrophil inflammation that was stronger at 48-h but reduced at 7-days. This acute inflammatory profile and kinetics resembled the response to innate immune ligands LTA and LPS while distinct from the classic allergic response to Alternaria. ConclusionLung inflammatory responses to Salton Sea dusts are similar to acute innate immune responses, raising the possibility that microbial components are entrained in the dust, promoting inflammation. This effect highlights the health risks at drying terminal lakes from inflammatory components in dust emissions from exposed lakebed.

Peri-conceptional exposure to ambient air pollution increases risk of gestational diabetes among pregnant participants in the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) study

Background: Exposures to air pollution potentially disrupt maternal metabolic adaptation during pregnancy. However, influences of preconception and prenatal exposures to ambient air pollution on gestational diabetes mellitus (GDM) remain unclear, and even less is known about sensitive windows for these exposures’ effect on GDM. Methods: In 617 pregnant participants enrolled the Maternal and Developmental Risks from Environmental and Social Stressors (MADRES) study, we estimated daily levels of ambient particulate matter (PM₁₀; PM₂.₅), nitrogen dioxide (NO₂), ozone (O₃) using spatial interpolation. GDM was ascertained from medical records by physician diagnosis or defined as abnormally high glucose challenge and tolerance test results. We used distributed lag models (DLM) with Poisson regression to identify sensitive exposure windows by estimating weekly associations of exposures from pre-conception week (PcW) 12 to gestational week (GW) 24 with GDM risk, adjusting for maternal and meteorological factors. Analyses were additionally stratified by median prenatal Perceived Stress Scale (PSS, 14), median pre-pregnancy body mass index (BMI, 27.5 kg/m²), median age (28 years), and newborn sex to explore differential susceptibility to exposure effects. Results: Sixty (9.7%) participants were diagnosed with GDM. We identified sensitive peri-conceptional exposure windows for PM₂.₅, PM₁₀, and NO₂ ranging from PcW5 to GW3 associated with increased GDM risk. An IQR increase in each pollutant was associated with 5% (95%CI: 3.3-6.7%), 6% (5.9-7.4%), and 11% (9.3-12.2%) increased GDM risk, respectively. In stratified analyses, effects of PM₁₀ and NO₂ in the identified sensitive windows were greater among those &amp;#x2265;28 years old, with BMI&amp;#x2265;27.5 kg/m², or with PSS&amp;#x2265;14. Conclusions: Peri-conception exposures to ambient air pollutants were associated with increased risk of GDM. Stronger effects in the identified sensitive windows were seen in participants who were older, had higher BMI, or higher perceived stress. Keywords: air pollution, gestational diabetes, sensitive window, susceptibility, perceived stress, preconception

Source Identification of PM2.5 during a Smoke Haze Period in Chiang Mai, Thailand, Using Stable Carbon and Nitrogen Isotopes

Open biomass burning (BB) has contributed severely to the ambient levels of particulate matter of less than 2.5 μm diameter (PM2.5) in upper northern Thailand over the last decade. Some methods have been reported to identify the sources of burning using chemical compositions, i.e., ions, metals, polycyclic aromatic hydrocarbons, etc. However, recent advances in nuclear techniques have been limited in use due to their specific instrumentation. The aims of this study were to investigate the sources of ambient PM2.5 in Chiang Mai city using stable carbon (δ13C) and nitrogen isotopes (δ15N). The mean concentrations of total carbon (TC) and total nitrogen (TN) in PM2.5 were 12.2 ± 5.42 and 1.91 ± 1.07 μg/m3, respectively, whereas δ13C and δ15N PM2.5 were −26.1 ± 0.77‰ and 10.3 ± 2.86‰, respectively. This isotopic analysis confirmed that biomass burning was the source of PM2.5 and that C3 and C4 plants contributed about 74% and 26%, respectively. These study results confirm that the stable isotope is an important tool in identifying the sources of aerosols.

Association between ambient air pollution and blood sex hormones levels in men

Concerns are growing over time on the adverse health effects of air pollution. However, the association between ambient air pollution and blood sex hormones in men is poorly understood. We included 72,917 men aged 20–55 years from February 2014 to December 2019 in Beijing, China in this study. Blood testosterone, follicle stimulating hormone, luteinizing hormone, estradiol, and prolactin levels of each participant were measured. We collected exposure data of daily ambient levels of particulate matter ≤10 μm (PM10) and ≤2.5 μm (PM2.5), nitrogen dioxide, sulfur dioxide (SO2), carbon monoxide, and ozone. Generalized linear mixed models were used to analyze the potential association between ambient air pollution exposure and blood sex hormone levels. The results showed that both immediate and short-term cumulative PM2.5, PM10, and SO2 exposure was related to altered serum sex hormone levels in men, especially testosterone. An increase of 10 μg/m3 in PM2.5 and PM10 in the current day was related to a 1.6% (95% confidence interval [CI]: 0.9%–2.3%) and 1.1% (95% CI: 0.5%–1.6%) decrease in testosterone, respectively, and a decreasing tendency of accumulated effects persisted within lag 0–30 days. The present study demonstrated that it is important to control ambient air pollution exposure to reduce effects on the reproductive health of men.

Chemical Composition, Source Appointment and Health Risk of PM2.5 and PM2.5-10 during Forest and Peatland Fires in Riau, Indonesia

This study investigated the contributions of particulate matter (PM) from various emission sources during the dry season, which resulted from frequent fires occurring in degraded forests and peatlands in Indonesia. Samples of fine (PM2.5) and coarse (PM2.5-10) particles collected during the dry season in Riau, Indonesia were analyzed to determine the mass concentrations of metallic trace elements, ionic compound, black carbon (BC), and organic carbon (OC). The average concentrations of PM2.5 and PM2.5-10 at Riau, Indonesia were 63.85 ± 3.22 µg m-3 and 27.72 ± 2.40 µg m-3, respectively. The positive matrix factorization (PMF) model was adopted to identify possible PM sources and their contributions to the ambient PM level. The PMF results identified six major PM2.5 sources, including biomass burning (BB) (28.7%), secondary aerosols (SA) (26.9%), vehicle exhaust (VE) (12.8%), industrial emissions (IE) (12.3%), soil dust (SD) (11.9%), and sea salt (SS) (7.5%). Moreover, there were five primary PM2.5-10 sources, including VE (28.6%) and BB (24%), followed by IE (19.9%), SD (17.2%), and SA (15.3%). A conditional probability function (CPF) analysis revealed that the southeast sector dominated among source direction-dependent contributions. The noncarcinogenic health risks for both adults and children resulting from exposure to PM2.5 were mainly contributed by Co, Ni, and Mn, and carcinogenic risks were caused by the toxic metals Cr and Co. Both noncarcinogenic and carcinogenic health risks resulting from cumulative multielement exposure for both adults and children exceeded acceptable levels. Clearly, more attention should be devoted to reducing the noncarcinogenic and carcinogenic health risks caused by particulate-bound toxic elements through inhalation exposure.

Ambient particulate matter levels and health profile in residents of Choba and Mgbuoba areas of Rivers State: A cross-sectional study

ABSTRACT The study investigated the health profile of individuals exposed to particulate matter (Black) soot in Choba and Mgbuoba localities of Port Harcourt. The analysis was executed with the aid of 100 respondents (50 from Choba and 50 from Mgbuoba). A structured questionnaire with the outlined elements was utilized during data collection for the study: manner of living, type of occupation, environmental exposure, known health issues, fitness and cleanliness, and Key Informant Interviews (KII) were exploited to gain pertinent data from health professionals. A hand-held Kestrel weather tracker was employed to ascertain the wind speed, temperature, and relative humidity of the study areas while A Met One Instrument, Inc. Aerosol Mass Monitor Model GT–531 was utilized to estimate total suspended particulates. Biochemical parameters such as lipid profile, renal markers, and liver markers activities were analyzed from blood samples obtained from the subjects using spectrophotometric methods. The air quality profile of Mgbuoba showed significant (p < .05) increment in total suspended particulate matter, total suspended particulate matter (TSPM), particulate matter that is 10 microns in diameter or less (PM10), and particulate matter that is 2.5 microns in diameter or less (PM2.5) from 6 a.m. to 8 a.m. compared with Choba. The increment in Total suspended particulate matter, PM10, and PM2.5 levels were beyond the 24-hour PM10 and PM2.5 recommended level by the World Health Organization (WHO). The alanine transaminase (ALT) and low density lipoproptein (LDL) levels of Choba and Mgbuoba residents were beyond the reference limits set by the Medical Council of Canada. The study showed that residents in Mgbuoba in Port Harcourt may be more at risk and have higher vulnerability to the undesirable outcomes associated with exposures to these air contaminants. A rising and worrisome trend in respiratory and related conditions among less mobile residents call for emergency response to emission of black soot in the area. Implications: The study investigated the health profile of individuals exposed to particulate matter (Black) soot in Choba and Mgbuoba localities of Port Harcourt. This outcome clearly shows that these air pollutants are higher in concentrations early in the morning and their concentrations decreased as the day went by. Therefore, by implication, the residents in these areas may be at high risk of exposure to these air pollutants from 6 a.m. to 8 a.m. The present study has demonstrated that these air pollutants are more prominent very early in the mornings and variations in meteorological conditions at a particular time, and anthropogenic activities might have contributed to the elevations in the concentration of TSPM, PM10, and PM2.5 in Choba and Mgbuoba.

Properties and emission factors of cloud condensation nuclei from biomass cookstoves – observations of a strong dependency on potassium content in the fuel

Abstract. Residential biomass combustion is a significant source of aerosol particles on regional and global scales influencing climate and human health. The main objective of the current study was to investigate the properties of cloud condensation nuclei (CCN) emitted from biomass burning of solid fuels in different cookstoves mostly of relevance to sub-Saharan east Africa. The traditional three-stone fire and a rocket stove were used for combustion of wood logs of Sesbania and Casuarina with birch used as a reference. A natural draft and a forced-draft pellet stove were used for combustion of pelletised Sesbania and pelletised Swedish softwood alone or in mixtures with pelletised coffee husk, rice husk or water hyacinth. The CCN activity and the effective density were measured for particles with mobility diameters of ∽65, ∽100 and ∽200 nm, respectively, and occasionally for 350 nm particles. Particle number size distributions were measured online with a fast particle analyser. The chemical composition of the fuel ash was measured by application of standard protocols. The average particle number size distributions were by number typically dominated by an ultrafine mode, and in most cases a soot mode was centred around a mobility diameter of ∽150 nm. The CCN activities decreased with increasing particle size for all experiments and ranged in terms of the hygroscopicity parameter, κ, from ∽0.1 to ∽0.8 for the ultrafine mode and from ∽0.001 to ∽0.15 for the soot mode. The CCN activity (κ) of the ultrafine mode increased (i) with increasing combustion temperature for a given fuel, and (ii) it typically increased with increasing potassium concentration in the investigated fuels. The primary CCN and the estimated particulate matter (PM) emission factors were typically found to increase significantly with increasing potassium concentration in the fuel for a given stove. In order to link CCN emission factors to PM emission factors, knowledge about stove technology, stove operation and the inorganic fuel ash composition is needed. This complicates the use of ambient PM levels alone for estimation of CCN concentrations in regions dominated by biomass combustion aerosol, with the relation turning even more complex when accounting for atmospheric ageing of the aerosol.

Diurnal Variations of Size-Resolved Bioaerosols During Autumn and Winter Over a Semi-Arid Megacity in Northwest China.

Bioaerosols have a major negative effect on air quality and on public health by causing the spread of diseases. This study evaluated the bioaerosol composition and variation in a semi‐arid megacity of northwest China from October 2019 to January 2020 using an Andersen six‐stage impactor sampler. The size distribution, diurnal variations of the concentrations of airborne bacteria, airborne fungi, and total airborne microbes (TAM) were investigated in autumn and winter. The mean concentrations of airborne bacteria, fungi, and TAM were 523.5 ± 301.1 colony‐forming units (CFU)/m3, 1318.9 ± 447.8 CFU/m3, and (7.25 ± 1.90) × 106 cells/m3, respectively, in autumn and 581 ± 305.4 CFU/m3, 1234.4 ± 519.9 CFU/m3, and (5.96 ± 1.65) × 106 cells/m3, respectively, in winter. The mean bioaerosol concentrations were slightly higher on nonhaze days than on haze days, but the difference was not statistically significant. Higher ambient particulate matter levels and atmospheric oxidation capacity inhibited bacteria survival. The diurnal maximum bioaerosol concentration was observed in the morning in autumn, whereas in winter, bioaerosols did not exhibit such a distribution, the impact of human activities on bioaerosols was still uncertain. The size of airborne bacteria exhibited a bimodal distribution, whereas a unimodal pattern was observed for fungi and TAM. Most bacteria, fungi, and TAM were distributed in the respirable ranges from trachea and primary bronchi to alveoli, indicating that bioaerosols have a high risk of being inhaled and causing respiratory diseases in Xi’an.

Air pollution and breast cancer risk in the Black Women's Health Study

BackgroundAir pollution contains numerous carcinogens and endocrine disruptors which may be relevant for breast cancer. Previous research has predominantly been conducted in White women; however, Black women may have higher air pollution exposure due to geographic and residential factors. ObjectiveWe evaluated the association between air pollution and breast cancer risk in a large prospective population of Black women. MethodsWe estimated annual average ambient levels of particulate matter <2.5 μm (PM2.5), nitrogen dioxide (NO2) and ozone (O3) at the 1995 residence of 41,317 participants in the Black Women's Health Study who resided in 56 metropolitan areas across the United States. Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for an interquartile range (IQR) increase in each pollutant. We evaluated whether the association varied by menopausal status, estrogen receptor (ER) status of the tumor and geographic region of residence. ResultsWith follow-up through 2015 (mean = 18.3 years), 2146 incident cases of breast cancer were confirmed. Higher exposure to NO2 or O3 was not associated with a higher risk of breast cancer. For PM2.5, although we observed no association overall, there was evidence of modification by geographic region for both ER- (p for heterogeneity = 0.01) and premenopausal breast cancer (p for heterogeneity = 0.01). Among women living in the Midwest, an IQR increase in PM2.5 (2.87 μg/m3), was associated with a higher risk of ER- (HR = 1.53, 95% CI: 1.07–2.19) and premenopausal breast cancer (HR = 1.32, 95% CI: 1.03–1.71). In contrast, among women living in the South, PM2.5 was inversely associated with both ER- (HR = 0.74, 95% CI: 0.56–0.97) and premenopausal breast cancer risk (HR = 0.75, 95% CI: 0.62–0.91). DiscussionOverall, we observed no association between air pollution and increased breast cancer risk among Black women, except perhaps among women living in the Midwestern US.

Associations between changes in adipokines and exposure to fine and ultrafine particulate matter in ambient air in Beijing residents with and without pre-diabetes

ObjectiveExposure to particulate matter (PM) is a risk factor to diabetes, but the underlying mechanism is unclear. Adipokines play important roles in glucose metabolism. This study examined the associations between...

Air pollution and breast cancer risk in the Black Women’s Health Study

Background. Air pollution contains numerous carcinogens and endocrine disruptors which may be relevant for breast cancer risk. Previous research on air pollution and breast cancer risk has predominately been conducted in white women; however, Black women may have higher exposure to air pollution. Methods. Using land-use regression models, we estimated annual average ambient levels of particulate matter &lt; 2.5 µm (PM2.5), nitrogen dioxide (NO2) and ozone (O3) at the 1995 residence of 41,325 participants in the Black Women’s Health Study who resided in 56 metropolitan areas across the United States. Cox proportional hazards regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for an interquartile range (IQR) increase in each pollutant. We evaluated whether the association varied by menopausal status at diagnosis, invasiveness, and estrogen receptor (ER) status of the tumor and by geographic region of residence. Results. With follow-up through 2015 (mean=18.3 years), 2,216 incident cases of breast cancer were confirmed. Higher exposure to PM2.5, NO2, or O3 was not significantly associated with breast cancer risk overall or by ER status. However, an IQR increase in NO2 (10 ppb) was associated with a higher risk of premenopausal breast cancer (N=571, HR=1.15, 95% CI: 1.02-1.31). For the association between PM2.5 and invasive breast cancer, we observed significant modification by geographic region (p for heterogeneity=0.02). Among women living in the Midwest, but not other geographic regions, an IQR increase in PM2.5 (2.87 µg/m3), was associated with a higher risk of invasive breast cancer (HR=1.27, 95% CI: 1.04-1.55). Conclusions. These results support the hypothesis that higher exposure to specific air pollutants may be a risk factor for breast cancer among Black women, particularly for premenopausal women and women living in the Midwest.

Association of combined effects of physical activity and air pollution with diabetes in older adults

BackgroundPhysical activity (PA), especially outdoor PA, may have twofold effects on diabetes risk: the health benefits of PA and the potential detrimental effects caused by augmented exposure to air pollution. We examined the association of combined effects of PA and air pollution with diabetes in older adults. MethodsThe study participants consisted of 1,259,871 older adults aged 58 years or more from the Korean National Health Insurance Service database. The exposure to air pollution was estimated by the average ambient levels of particulate matter (PM) of the participants’ residence area. Cox proportional hazards models were used to evaluate the adjusted hazard ratios and 95% confidence intervals of developing diabetes according to the combined effect of moderate to vigorous physical activity (MVPA) and air pollution exposure. ResultsEngaging in 5 or more times of MVPA/week was associated with decreased risk of diabetes within groups with both high and low/moderate levels of exposure to PM10 (low/moderate PM10 aHR 0.91, 95% CI 0.89–0.93; high PM10 aHR 0.97, 95% CI 0.94–0.99) or PM2.5 (low/moderate PM2.5 aHR 0.88, 95% CI 0.85–0.90; high PM10 aHR 0.95, 95% CI 0.91–0.99) exposure. The risk-reducing effects upon MVPA tended to be slightly attenuated, which showed the reverse J-shaped association, but still significant, among those who were exposed to a high level of air pollution. The association was consistent among stratified analyses according to the possible confounders. ConclusionMVPA may be inversely associated with the risk of diabetes development within groups with both high and low/moderate levels of exposure to PM10 or PM2.5 in older adults. Future studies are necessary to validate whether the positive health effects of MVPA outweigh the potential detrimental effects due to augmented exposure to air pollution during MVPA.