Size-fractionated Particulate Matter Research Articles

Association patterns for size-fractioned indoor particulate matter and black carbon and autonomic function differ between patients with chronic obstructive pulmonary disease and their healthy spouses.

The effect of health status on the relationship between particulate matter (PM) and black carbon (BC) and cardiac autonomic function has not been examined sufficiently directly comparing patients with healthy participants. To evaluate the association patterns between size-fractioned indoor PM and BC and cardiac autonomic function in chronic obstructive pulmonary disease (COPD) patients and their healthy spouses. Twenty-four-hour heart rate variability (HRV) and heart rate (HR) was measured in eight pairs of stable COPD patients and their healthy spouses. Real-time size-fractioned indoor PM and BC levels were monitored on the same, and preceding, days. Mixed-effects models were used to estimate the changes in health indices and pollutants after controlling for potential confounding variables. Increases in size-fractioned PM and BC were associated with alterations in cardiac autonomic function in both COPD patients and their healthy spouses. However, the association patterns differed between the two groups. In COPD group, an IQR (13.65 μg/m3) increase in PM0.5 at 12-h moving average was associated with reductions of 14.62% (95% CI: -21.74%, -6.86%) in total power (TP) and 10.14% (95% CI: -16.11%, -3.76%) in high frequency (HF) power. In healthy volunteers, however, TP and HF declined immediately upon exposure to PM and then returned to normal levels gradually. In this group, an IQR increase in PM0.5 at 5 min moving average was associated a 20.30% (95% CI: -25.49%, -14.73%) reduction in TP and a 31.79% (95% CI: -36.48%, -26.72%) reduction in HF. Exposure to indoor PM and BC was associated with cardiac autonomic dysfunction in COPD patients and their healthy spouses. Exposure had a greater lagged effect on HRV in COPD patients than in healthy participants. These findings will aid the formulation of targeted measures to prevent the adverse effects of indoor air pollution for individuals with different health statuses.

Quantifying particulate matter accumulated on leaves by 17 species of urban trees in Beijing, China.

Airborne particulate matter (PM) has become a serious environmental problem and harms human health worldwide. Trees can effectively remove particles from the atmosphere and improve the air quality. In this study, a washing and weighing method was used to quantify accumulation of water-soluble ions and insoluble PM on the leaf surfaces and within the wax of the leaves for 17 urban plant species (including 4 shrubs and 13 trees). The deposited PM was determined in three size fractions: fine (0.2-2.5μm), coarse (2.5-10μm), and large (> 10μm). Significant differences in the accumulation of PM were detected among various species. The leaves of Platycladus orientalis and Pinus armandi were the most effective in capturing PM. Across the species, 65 and 35% of PM, on average, deposited on the leaf surface and in the wax, respectively. The greatest PM accumulation by mass on leaves was in the largest PM size fraction, while the accumulation of coarse and fine particle size fractions was smaller. Water-soluble ions accumulated on the leaf surfaces contributed 28% to the total PM mass, on average. This study demonstrated that leaves of woody plants accumulate PM differently, and the most effective plant species should be selected in urban areas for attenuating ambient PM.

C-reactive protein (CRP) and long-term air pollution with a focus on ultrafine particles.

Long-term exposure to ambient air pollution contributes to the global burden of disease by particularly affecting cardiovascular (CV) causes of death. We investigated the association between particle number concentration (PNC), a marker for ultrafine particles, and other air pollutants and high sensitivity C-reactive protein (hs-CRP) as a potential link between air pollution and CV disease. We cross-sectionally analysed data from the second follow up (2013 and 2014) of the German KORA baseline survey which was conducted in 1999-2001. Residential long-term exposure to PNC and various other size fractions of particulate matter (PM10 with size of <10 μm in aerodynamic diameter, PMcoarse 2.5-10 μm or PM2.5 < 2.5 μm, respectively), soot (PM2.5abs: absorbance of PM2.5), nitrogen oxides (nitrogen dioxide NO2 or oxides NOx, respectively) and ozone (O3) were estimated by land-use regression models. Associations between annual air pollution concentrations and hs-CRP were modeled in 2252 participants using linear regression models adjusted for several confounders. Potential effect-modifiers were examined by interaction terms and two-pollutant models were calculated for pollutants with Spearman inter-correlation <0.70. Single pollutant models for PNC, PM10, PMcoarse, PM2.5abs, NO2 and NOx showed positive but non-significant associations with hs-CRP. For PNC, an interquartile range (2000 particles/cm3) increase was associated with a 3.6% (95% CI: -0.9%, 8.3%) increase in hs-CRP. A null association was found for PM2.5. Effect estimates were higher for women, non-obese participants, for participants without diabetes and without a history of cardiovascular disease whereas ex-smokers showed lower estimates compared to smokers or non-smokers. For O3, the dose-response function suggested a non-linear relationship. In two-pollutant models, adjustment for PM2.5 strengthened the effect estimates for PNC and PM10 (6.3% increase per 2000 particles/cm3 [95% CI: 0.4%; 12.5%] and 7.3% per 16.5 μg/m3 [95% CI: 0.4%; 14.8%], respectively). This study adds to a scarce but growing body of literature showing associations between long-term exposure to ultrafine particles and hs-CRP, one of the most intensely studied blood biomarkers for cardiovascular health. Our results highlight the role of ultrafine particles within the complex mixture of ambient air pollution and their inflammatory potential.

Association of size-fractionated indoor particulate matter and black carbon with heart rate variability in healthy elderly women in Beijing.

Associations between size-fractionated indoor particulate matter (PM) and black carbon (BC) and heart rate variability (HRV) and heart rate (HR) in elderly women remain unclear. Twenty-nine healthy elderly women were measured for 24-hour HRV/HR indices. Real-time size-fractionated indoor PM and BC were monitored on the same day and on the preceding day. Mixed-effects models were applied to investigate the associations between pollutants and HRV/HR indices. Increases in size-fractionated indoor PM were significantly associated with declines in power in the high-frequency band (HF), power in the low-frequency band (LF), and standard deviation of all NN intervals (SDNN). The largest decline in HF was 19% at 5-minute moving average for an interquartile range (IQR) increase (24μg/m3 ) in PM0.5 . The results showed that smaller particles could lead to greater reductions in HRV indices. The reported associations were modified by body mass index (BMI): Declines in HF at 5-minute average for an IQR increase in PM0.5 were 34.5% and 1.0% for overweight (BMI ≥25kg/m2 ) and normal-weight (BMI <25kg/m2 ) participants, respectively. Moreover, negative associations between BC and HRV indices were found to be significant in overweight participants. Increases in size-fractionated indoor PM and BC were associated with compromised cardiac autonomic function in healthy elderly women, especially overweight ones.

Metallic Fumes at Indoor Military Shooting Ranges: Lead, Copper, Nickel, and Zinc in Different Fractions of Airborne Particulate Matter

AbstractSmall firearm shooting emits residues of energetic materials as well as heavy metals of different particle sizes into the air, posing a risk to human health. The current study assessed concentrations of Pb, Cu, Ni and Zn in 14 different size fractions of particulate matter at indoor military shooting ranges. Air samples were collected using ELPI+ over two hour period and filters analysed with ICP‐MS and ICP‐OES.

The short-term effects of indoor size-fractioned particulate matter and black carbon on cardiac autonomic function in COPD patients

BackgroundPrevious studies have reported adverse health effects of indoor air pollutants especially particulate matter (PM) and black carbon (BC). Patients with chronic obstructive pulmonary disease (COPD) have been shown to be more likely with cardiovascular comorbidities in which cardiac autonomic dysfunction plays an important role. However, there is little evidence for the effect of indoor PM and BC exposures on cardiac autonomic function in COPD patients. ObjectivesTo evaluate the association between exposure to indoor size-fractioned PM and BC and changes in HRV and HR in COPD patients. MethodsForty-three doctor diagnosed, stable COPD patients were recruited and measured for 24-h HRV and HR. Real-time indoor size-fractioned PM and BC were monitored on the day before and the day of performing health measurements. Mixed-effects models were used to estimate the associations between indoor PM and BC and HRV indices and HR after controlling for potential confounders. ResultsIncreasing levels of size-fractioned PM and BC were associated with decreased HRV indices and increased HR. An IQR (3.14μg/m3) increase in 8-h BC moving average and an IQR (20.72μg/m3) increase in 5-min PM0.5 moving average concentrations were associated with declines of 7.45% (95% CI: −10.89%, −3.88%) and 16.40% (95% CI: −21.06%, −11.41%) in LF, respectively. The smaller the particles size, the greater effects on HRV indices and HR. Patients' BMI modified the associations between size-fractioned PM and BC and their HRV and HR. For an IQR increase in PM0.5, there was decline in HF of 34.85% (95% CI: −39.08%, −30.33%) in overweight patients, compared to a 2.01% (95% CI: −6.44%, 11.19%) increase in normal-weight patients. ConclusionsExposures to indoor PM and BC were associated with altered cardiac autonomic function in COPD patients, and the associations for HRV measures of parasympathetic activity (e.g., HF) were more apparent in overweight patients.

Research on chromium and arsenic speciation in atmospheric particulate matter: short review

Atmospheric particulate matter (PM) plays an important role in the distribution of elements in the environment. The PM-bound elements penetrates into the other elements of the environment, in two basic forms - those dissolved in the atmospheric precipitation and those permanently bound to PM particles. Those forms differs greatly in their mobility, thus posing a potential threat to living organisms. They can also be an immediate threat, while being inhaled. Chromium (Cr) and arsenic (As) belong to the group of elements whose certain chemical states exhibit toxic properties, that is Cr(VI) and As(III). Thus, recognition of the actual threat posed by Cr and As in the environment, including those present in PM, is possible only through the in depth speciation analysis. Research on the Cr and As speciation in PM, more than the analogous studies of their presence in other compartments of the environment, have been undertaken quite rarely. Hence the knowledge on the speciation of PM-bound As and Cr is still limited. The state of knowledge in the field of PM-bound Cr and As is presented in the paper. The issues related to the characterization and occurrence of Cr and As species in PM, the share of Cr and As species mass in different PM size fractions, and in PM of different origin is also summarized. The analytical techniques used in the speciation analysis of PM-bound Cr and As are also discussed. In the existing literature there is no data on the physical characteristics of Cr and As (bound to a different PM size fractions), and thus it still lack of data needed for a comprehensive assessment of the actual environmental and health threat posed by airborne Cr and As.

Size-fractionated Particulate Matter in Indoor and Outdoor Environments during the 2015 Haze in Singapore: Potential Human Health Risk Assessment

Landscape fires in Indonesia during the 2015 resulted in large-scale emissions of airborne particulate matter (PM) that degraded ambient air quality of several countries in Southeast Asia (SEA) including Singapore. During this transboundary haze episode, the general public was advised to remain indoors as much as possible in order to mitigate their exposure to high concentrations of PM in the outdoor environment. To understand the quantitative relationship between outdoor and indoor air quality, we measured PM2.5 as well as the size-fractionated PM (coarse, accumulation and quasi-ultrafine (q-UF) particles) simultaneously inside and outside a naturally ventilated apartment and studied the potential health risk associated with exposure to PM of different sizes under the three levels of smoke haze (light, moderate and severe). PM mass concentrations increased with a decrease in particle size, and the q-UF particles (diameter ≤ 250 nm) were observed to be as high as 80 to 85 µg m–3 both indoors and outdoors. Estimation of PM deposition patterns along the human respiratory tract revealed that q-UF particles were mainly deposited in the deeper alveolar region, thereby posing severe health threats. Potential human health risk assessment results based on bioavailable concentrations of toxic elements in PM raised further concerns about health impacts of q-UF particles deposited in the alveolar region. Moreover, uncertainty analysis of exposure parameters used in potential carcinogenic health risk assessment model indicated much higher exceedance of potential health risk than the threshold limit for 95th percentile values of the health risk (11.5 times higher for PM2.5) during severe-haze episodes. The potential health risk estimated in this study indicates the need to conduct further studies focused upon mitigation of human exposure to achieve health benefits during haze episodes.

Size-resolved particle measurements of polybrominated diphenyl ethers indoors: Implications for sources and human exposure.

Polybrominated diphenyl ethers (PBDEs) are flame retardant polymer additives that are widely detected in outdoor and indoor environments. Release of PBDEs from consumer products leads to high concentrations indoors, but mechanisms of release are poorly understood. Although ingestion of dust is a well-studied indoor PBDE exposure route, the importance of inhalation exposure is uncertain. To address these unknowns, dust was collected from household vacuum cleaners, and suspended particulate matter was collected from the same homes in St. John's, Newfoundland, Canada, using a cascade impactor. Size-fractionated particulate matter samples (0.01-18 μm diameter) were analyzed for PBDEs. The sum of PBDEs in all particulate matter ranged from 8.7 ± 0.5 to 15.7 ± 0.5 pg/m3 , with >50% of PBDE mass in respirable particulate matter (<1 μm). Mass loadings as a function of particle size suggested that both abrasion and off-gassing led to the presence of PBDEs in particulate matter. Variability in the particulate matter mass loadings indicated that emission mechanisms were both product- and location-dependent. Congener profiles in colocated vacuum dust and particulate matter samples were different, indicating that vacuum dust cannot accurately predict PBDE congeners in respirable particulate matter. A calculated lower limit inhalation exposure to PBDEs (0.19 ng/d) is lower than exposure via diet or ingestion of dust, although the different biochemical pathways for inhalation compared with ingestion may have different biological effects. The present study highlights the importance of contaminant analysis in size-fractionated particulate matter to assess human exposure via inhalation compared with traditional vacuum dust methods. Environ Toxicol Chem 2018;37:481-490. © 2017 SETAC.

Exposure to particulate matter air pollution and risk of multiple sclerosis in two large cohorts of US nurses

BackgroundAir pollution is thought to raise the risk of neurological disease by promoting neuroinflammation, oxidative stress, glial activation and cerebrovascular damage. Multiple Sclerosis is a common auto-immune disorder, primarily affecting young women. We conducted, to a large prospective study of particulate matter (PM) exposure and multiple sclerosis (MS) risk in two prospective cohorts of women: the Nurses Health Study (NHS) and the Nurses Health Study II (NHS II). MethodsCumulative average exposure to different size fractions of PM up to the onset of MS was estimated using spatio-temporal models. We used multivariable Cox proportional hazards models to estimate the hazard ratios (HR) and 95% confidence intervals (CI) of MS associated with each size fraction of PM independently. Participants were followed from 1998 through 2004 in NHS and from 1988 through 2007 for NHS II. We conducted additional sensitivity analyses stratified by smoking, region of the US, and age, as well as analyses restricted to women who did not move during the study. Analyses were adjusted for age, ancestry, smoking, body mass index at age 18, region, tract level population density, latitude at age 15, and UV index. ResultsWe did not observe significant associations between air pollution and MS risk in our cohorts. Among women in the NHS II, the HRs comparing the top vs. bottom quintiles of PM was 1.11 (95% Confidence Intervals (CI): 0.74, 1.66), 1.04 (95% CI: 0.73, 1.50) and 1.09 (95% CI: 0.73, 1.62) for PM10 (≤10μm in diameter), PM2.5 (≤2.5μm in diameter), and PM2.5–10 (2.5 to 10μm in diameter) respectively, and tests for linear trends were not statistically significant. No association between exposure to PM and risk of MS was observed in the NHS. ConclusionsIn this study, exposure to PM air pollution was not related to MS risk.

Size-segregated particulate matter and its association with respiratory deposition doses among outdoor exercisers in Dhanbad City, India

ABSTRACTRegular exercise improves physiological processes and yields positive health outcomes. However, it is relatively less known that particulate matter (PM) exposure during outdoor exercises may increase several respiratory health problems depending on PM levels. In this study, the respiratory deposition doses (RDDs) in head airway (HD), tracheobronchial (TB), and alveolar (AL) regions of various PM size fractions (<10, <2.5, and <1 μm; PM10, PM2.5, and PM1) were estimated in healthy male and female exercisers in urban outdoors and within house premises. The highest RDDs were found for PM during morning hours in winter compared with remaining periods. RDDs in AL region for males and females, respectively, were 34.7 × 10−2 and 28.8 × 10−2 µg min−1 for PM10, 65.7 × 10−2 and 56.9 × 10−2 µg min−1 for PM2.5, and 76.5 × 10−2 and 66.3 × 10−2 µg min−1 for PM1. The RDD values in AL region were significantly higher in PM1 (27%) compared with PM2.5 (13%) and PM10 (2%) during exercise in all periods. This result showed that the morning peak hours in winter are more harmful to urban outdoor exercisers compared with other periods. This study also showed that the AL region would have been the main affected zone through fine particle (PM1) to all the exercisers.Implications: Size-segregated particle concentrations in urban outdoors and within house premises were measured. The highest respiratory deposition doses (RDDs) were found for PM during morning hours in winter compared with remaining periods. During light exercise, the RDD values in alveolar (AL) region for PM10, PM2.5, and PM1 for male exercisers were significantly higher, 20.4%, 15.5%, and 15.4%, respectively, compared with female exercisers during morning peak hours in winter.

Is long-term particulate matter and nitrogen dioxide air pollution associated with incident monoclonal gammopathy of undetermined significance (MGUS)? An analysis of the Heinz Nixdorf Recall study

BackgroundExposure to air pollution activates the innate immune system and influences the adaptive immune system in experimental settings. We investigated the association of residential long-term exposure to particulate matter (PM) and NO2 air pollution with monoclonal gammopathy of undetermined significance (MGUS) as a marker of adaptive immune system activation. MethodsWe used data from the baseline (2000−2003), 5-year (2006–2008) and 10-year (2011–2015) follow-up examinations of the German Heinz Nixdorf Recall cohort study of 4814 participants (45–75years). Residential exposure to PM size fractions and NO2 was estimated by land-use regression (ESCAPE-LUR, annual mean 2008/2009) and dispersion chemistry transport models (EURAD-CTM, 3-year mean at baseline). We used logistic regression to estimate the effects of air pollutants on incident MGUS, adjusting for age, sex, education, smoking status, physical activity, and BMI. As a non-linear approach, we looked at quartiles (2–4) of the air pollutants in comparison to quartile 1. ResultsOf the 3949 participants with complete data, 100 developed MGUS during the 10-year follow-up. In the main model, only PMcoarse was associated with incident MGUS (OR per IQR (1.9μg/m3): 1.32, 95% CI 1.04–1.67). We further found positive associations between PM size fractions estimated by ESCAPE-LUR and incident MGUS by quartiles of exposure (OR Q4 vs Q1: PM2.5 2.03 (1.08–3.80); PM10 1.97 (1.05–3.67); PMcoarse 1.98 (1.09–3.60)). ConclusionsOur results indicate that an association between long-term exposure to PM and MGUS may exist. Further epidemiologic studies are needed to corroborate this possible link.

Air Pollution and Risk of Parkinson's Disease in a Large Prospective Study of Men.

Background:Exposure to air pollution has been implicated in a number of adverse health outcomes, and the effect of particulate matter (PM) on the brain is beginning to be recognized.Objectives:We aimed to examine whether exposure to PM air pollution is related to risk of Parkinson's disease (PD) in the Health Professionals Follow-up Study (HPFS), a large prospective cohort of U.S. men.Methods:We prospectively followed 50,352 men in the HPFS, a large prospective cohort of U.S. men, and identified 550 incident PD cases. Cumulative average exposure to various size fractions of PM [ ( microns in diameter), ( in diameter), and (between 2.5 and in diameter)] up to 2 years before the onset of PD was estimated using a spatiotemporal model by linking each participant’s place of residence throughout the study with location-specific PM levels. We used multivariable Cox proportional hazards models to independently estimate the risk of PD associated with each size fraction of PM.Results:In models adjusted for age, smoking, region, and population density, we did not observe statistically significant associations between exposure to PM and PD risk. In analyses considering cumulative average PM exposure, the comparing the top to the bottom quintile of PM exposure was 0.85 [95% confidence interval (CI): (0.63, 1.15)] for , 0.97 [95% CI: (0.72, 1.32)] for , and 0.88 [95% CI: (0.64, 1.22)] for hazard ratio (HR) . The results did not change markedly when restricted to men who did not move during the study or when stratified by smoking status or population density.Conclusions:In this study, we found no evidence that exposure to air pollution is a risk factor for PD in men. https://doi.org/10.1289/EHP259

Mass distribution and elemental analysis of the resultant atmospheric aerosol particles generated in controlled biomass burning processes

Air contamination resulting from bushfires is becoming increasingly important research question, as such disasters frequently occur in many countries. The objectives of this project were focused on physical and chemical characterisations of particulate emission resulting from burning of common representatives of Australian vegetation under controlled laboratory conditions. It was found that leaves are burned mostly with flaming phase and producing black smoke resulting in larger particles compared to white smoke in case of branches and grass, dominated by smouldering phase, producing finer particles. Following elemental analysis determined nine main elements in three different size fractions of particulate matter for each category of burning material, ranging from 14.1μm to particle sizes below 2.54μm. Potassium was found to be one of the main biomass markers, and sulphur was the ubiquitous element among the smoke particles followed by less prevalent trace elements like Na, Al, Mg, Zn, Si, Ca, and Fe.

Development of custom calibration factors for respirable silica using standard methods compared to photometric monitoring data

The goal of this study was to investigate the relationship between particulate matter (PM) concentrations recorded by real-time monitors and respirable crystalline silica, in the form of quartz, (RCS) concentrations measured by the standard NIOSH 7500 method using an aluminum cyclone attached to a filter-cassette. Development of correction factors for real-time monitoring instruments would provide instant estimates of RCS concentrations in order to more immediately assess worker exposures and efficacy of controls implemented for worker health and safety. Sampling occurred in two environments: (a) during iron casting at a foundry in the Western United States and (b) in a controlled testing environment, using Arizona Test Dust (ATD) in a low-speed wind tunnel. Two DustTrak DRX 853 monitors were used to collect area samples of PM1, PM2.5, PM4, PM10 and PMtotal, and two SidePak AM510 monitors were used to collect personal samples of PM2.5. Calculated r-squared (R2) values analyzed how well paired data from real-time monitors and filter-based methods fit a line of regression, and how well real-time monitor measurements predicted RCS concentrations. Among the different PM size fractions recorded by the DRX monitors, the highest coefficient of determination was between RCS quantified by XRD and PM10 for DRX-1 and DRX-2 (both R2 = 0.80), however, their respective regression equations differed. The coefficients of determination calculated for each SidePak were 0.19 and 0.016 respectively, demonstrating a poor ability for these monitors to predict RCS concentrations. There was variability among the identical real-time monitors, especially among the regression equations. Results of this study indicate that it is reasonable to determine a calibration factor for DRX direct-read monitors, enabling them to estimate concentrations of RCS in real-time. Dust containing quartz percentages that are significantly different would require calculation of separate calibration factors. Successful development of silica-dust calibration factors from this study is not intended to replace either the OSHA or NIOSH standard silica sampling and analytical methods. Future work in this area should include using test material with a known, homogenous concentration of silica in a controlled environment to more accurately determine device-specific calibration factors.

Particulate matter pollution capture by leaves of seventeen living wall species with special reference to rail-traffic at a metropolitan station

Atmospheric Particulate Matter (PM) constitutes a considerable fraction of urban air pollution, and urban greening is a potential method of mitigating this pollution. The value of living wall systems has received scant attention in this respect. This study examined the inter-species variation of particulate capture by leaves of seventeen plant species present in a living wall at New Street railway station, Birmingham, UK. The densities of different size fractions of particulate pollutants (PM1, PM2.5 and PM10) on 20 leaves per species were quantified using an Environmental Scanning Electron Microscope (ESEM) and ImageJ image-analysis software. The overall ability of plant leaves to remove PM from air was quantified using PM density and LAI (Leaf Area Index); any inter-species variations were identified using one-way Anova followed by Tukey’s pairwise comparison. This study demonstrates a considerable potential for living wall plants to remove particulate pollutants from the atmosphere. PM capture levels on leaves of different plant species were significantly different for all particle size fractions (P<0.001). Smaller-leaved Buxus sempervirens L., Hebe albicans Cockayne, Thymus vulgaris L. and Hebe x youngii Metcalf showed significantly higher capture levels for all PM size fractions. PM densities on adaxial surfaces of the leaves were significantly higher compared to abaxial surfaces in the majority of the species studied (t-test, P<0.05). According to EDX (Energy Dispersive X-ray) analysis, a wide spectrum of elements were captured by the leaves of the living wall plants, which were mainly typical railway exhaust particles and soil dust. Smaller leaves, and hairy and waxy leaf surfaces, appear to be leaf traits facilitating removal of PM from the air, and hence a collection of species which share these characters would probably optimize the benefit of living wall systems as atmospheric PM filters.

Characterization of major natural and anthropogenic source profiles for size-fractionated PM in Yangtze River Delta

Samples of size-fractionated particles were collected from local natural and anthropogenic sources in two industrial cities in the Yangtze River Delta, using either grab/resuspension sampling or ambient air sampling. The chemical characterizations of twenty one source profiles were obtained, based on elements (Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Pb and Zn), soluble ions (Cl−, NO3−, SO42−, NH4+, K+, Na+ and Ca2+) and carbonaceous material such as organic carbon (OC) and elemental carbon (EC). The profiles vary between sources from different areas, as well as between different particulate sizes. Results show that particulate matter that originated as soil dust, construction dust and fugitive dust is typically rich in crustal elements, especially Al, Ca, Fe and Mg, while the presence of calcium is found to be a hallmark of the cement industry and ceramic industry. Dominant compositions of particles from coal-fired power plants are variable, with OC ranging from 2.2%–27%. Garbage-fired power plant and cooking smoke particulate emissions are enriched in Na, Cl−, OC and K due to the presence of salty and organic matter. The element Fe, ranging from 6.1% to 26.0%, is found to be an important marker for steel production dust. Vehicle exhaust profiles are characterized by high abundances of OC (12.1%–53.6%) and EC (3.9%–20.0%). Burning of straw results in K (1.6%–7.2%) and OC (12.4%–25.9%) being the dominant composition. Preliminary work has also been done on establishing local industrial profiles such as textile, ceramic and electroplating industries. This work could be used in receptor model studies to estimate the contributions of different sources to the size-fractionated particulate matter in the Yangtze River Delta.

Commuter exposure to particulate matter for different transportation modes in Xi'an, China

Toxic air pollution on city streets is a very important issue, as pollutants are associated with adverse health effects, including respiratory and cardiovascular diseases. This study compared commuters' exposures to inhalable suspended particulate matter (PM) for different transportation modes in Xi'an City, China. Four commuting modes—private car, subway, bus and walking—were selected for the study. Commuter exposure concentrations to PM (PM10, PM2.5, PM1.0) were investigated in the following microenvironments: private cars under four ventilation modes, subway trains and station platforms, buses under two different ventilation modes, and pedestrians. Pearson correlation analysis was used to analyze the relationships between commuter PM10, PM2.5 and PM1.0 exposure concentrations under the different commuting modes. A mixed-effect linear model was used to identify the effects of different commuting modes on PM mass and number concentrations in these different traffic microenvironments. The results indicated that the concentration of particulate matter (PM) is significantly influenced by transportation mode as well as by vehicle ventilation systems. Among the four commuting modes, commuters were exposed to the lowest concentrations of PM10 (11.83 ± 7.60 μg m−3), PM2.5 (10.09 ± 6.63 μg m−3) and PM1.0 (9.52 ± 6.17 μg m−3) in a private car with air conditioning recirculation. In contrast, passengers waiting for a train on a subway station platform were exposed to the highest PM concentrations (244.99 ± 43.19 μg m−3). Size fractions of PM differed greatly across PM exposures with the ratio of fine particles to coarser particles (PM2.5/PM10) varying from 45 to 96%.

Associations of long-term exposure to air pollution and road traffic noise with cognitive function—An analysis of effect measure modification

BackgroundAdverse effects of traffic-related air pollution (AP) and noise on cognitive functions have been proposed, but little is known about their interactions and the combined effect of co-exposure. MethodsCognitive assessment was completed by 4086 participants of the population-based Heinz Nixdorf Recall cohort study using five neuropsychological subtests and an additively calculated global cognitive score (GCS). We assessed long-term residential concentrations for size-fractioned particulate matter (PM) and nitrogen oxides with land use regression. Road traffic noise (weighted 24-h (LDEN) and night-time (LNIGHT) means) was assessed according to the EU directive 2002/49/EC. Linear regression models adjusted for individual-level characteristics were calculated to estimate effect modification of associations between AP and noise with cognitive function. We used multiplicative interaction terms and categories of single or double high exposure, dichotomizing the potential effect modifier at the median (AP) or at an a priori defined threshold (road traffic noise). ResultsIn fully adjusted models, high noise exposure increased the association of AP with cognitive function. For example, for an interquartile range increase of PM2.5 (IQR 1.43), association s with GCS were: estimate (β)=−0.16 [95% confidence interval: −0.33; 0.01] and β=−0.48 [−0.72; −0.23] for low and high LDEN, respectively. The association of noise with GCS was restricted to highly AP-exposed participants. We observed stronger negative associations in those participants with double exposure compared to the addition of effect estimates of each single exposure. ConclusionsOur study suggests that AP and road traffic noise might act synergistically on cognitive function in adults.

The effect of size-segregated ambient particulate matter on Th1/Th2-like immune responses in mice.

BackgroundParticulate matter (PM) has been associated with increased pulmonary and cardiovascular mortality and morbidity. Additionally, PM is known to exacerbate asthma. However, whether ambient PM exposure contributes to the onset of asthma, especially in non-atopic children and adults, is less conclusive. The current study aimed to evaluate the effects of size-fractioned PM on lung immune responses in healthy BALB/c mice.Methods and principal findingsWe collected PM10, PM2.5, PM1 and PM0.1 samples from October 2012 to August 2013 in the Taipei Basin. These PM samples were representative of urban traffic pollution. The samples were extracted and sonicated in phosphate-buffered saline (PBS). Female BALB/c mice were exposed to the samples via intratracheal instillation at three different doses: 1.75 mg/kg (35 μg/per mouse), 5 mg/kg (100 μg/per mouse), and 12.5 mg/kg (250 μg/per mouse). The mice were exposed on days 0 and 7, and PBS alone was used as a control. Following the exposures, the expression profiles of inflammatory cells and cytokines in bronchoalveolar lavage fluid (BALF) were assessed. Exposure to PM10 resulted in inflammatory responses, including the recruitment of neutrophils and the induction of T helper 1 (Th1) cell-related cytokine release, such as TNF-α and IFN-γ. Furthermore, an allergic immune response, including the recruitment of eosinophils and the up-regulation of T helper 2 (Th2) cell-related cytokine release, such as IL-5 and IL-13, was also observed in the BALF of mice exposed to PM10.ConclusionsOur study showed that exposure to PM alone caused mixed Th1/Th2 inflammatory responses in healthy mice. These findings support the hypothesis that PM may contribute to the onset of asthma.