24-hour PM2 Research Articles

Association of uremic pruritus in hemodialysis patients with the number of days of high mean 24-hour particulate matter with a diameter of

Uremic pruritus (UP) is a common and incapacitating symptom in patients undergoing hemodialysis (HD). The pathogenesis of UP is multifactorial and complex. Particulate matter (PM), a major air pollutant, is a mixture of particles with various chemical compositions. PM is associated with several allergic diseases, including dermatitis. To assess the role of PM (PM with a diameter of <10 μm [PM10] and PM with a diameter of <2.5 μm [PM2.5]) and other clinical variables in UP in patients on HD, we recruited 866 patients on maintenance HD (MHD). We analyzed the number of days of mean 24-hour PM10 ≥125 μg/m3/12 months (NDPM10) or the number of days of mean 24-hour PM2.5 ≥35 μg/m3/12 months (NDPM2.5) exceeding the standard level in the past 12 months respectively to determine the association with UP. In a multivariate logistic regression, HD duration, serum ferritin levels, low-density lipoprotein (LDL) levels, and NDPM2.5 ≥116 days/12 months were positively associated with UP. This cross-sectional study showed that the number of days on which the environmental PM2.5 exceeds the standard level might be associated with UP in patients on MHD.

Seasonal trends, chemical speciation and source apportionment of fine PM in Tehran

Frequent air pollution episodes have been reported for Tehran, Iran, mainly because of critically high levels of fine particulate matter (PM2.5). The composition and sources of these particles are poorly known, so this study aims to identify the major components and heavy metals in PM2.5 along with their seasonal trends and associated sources. 24-hour PM2.5 samples were collected at a main residential station every 6 days for a full year from February 2014 to February 2015. The samples were analyzed for ions, organic carbon (including water-soluble and insoluble portions), elemental carbon (EC), and all detectable elements. The dominant mass components, which were determined by means of chemical mass closure, were organic matter (35%), dust (25%), non-sea salt sulfate (11%), EC (9%), ammonium (5%), and nitrate (2%). Organic matter and EC together comprised 44% of fine PM on average (increased to >70% in the colder season), which reflects the significance of anthropogenic urban sources (i.e. vehicles). The contributions of different components varied considerably throughout the year, particularly the dust component that varied from 7% in the cold season to 56% in the hot and dry season. Principal component analyses were applied, resulting in 5 major source factors that explained 85% of the variance in fine PM. Factor 1, representing soil dust, explained 53%; Factor 2 denotes heavy metals mainly found in industrial sources and accounted for 18%; and rest of factors, mainly representing combustion sources, explained 14% of the variation. The levels of major heavy metals were further evaluated, and their trends showed considerable increases during cold seasons. The results of this study provide useful insight to fine PM in Tehran, which could help in identifying their health effects and sources, and also adopting effective control strategies.

Association between Traffic Air Pollution and Reduced Forced Vital Capacity: A Study Using Personal Monitors for Outdoor Workers.

BackgroundThe effects of outdoor air pollution on lung function in adults are still controversial.ObjectiveEvaluate the effects of exposure to different levels of traffic-generated PM2.5 on workers’ lung functions in São Paulo, Brazil.MethodsTo cover a wide range of exposures, 101 non-smoking workers from three occupations (taxi drivers, traffic controllers, and forest rangers) were selected for the study. After clinical evaluation, the participants were scheduled to attend four consecutive weekly visits in which they received a 24-hour personal PM2.5 sampler and had lung function tests measured on the following day. The association between the spirometric variables and the averaged PM2.5 levels was assessed using robust regression models adjusted for age, waist circumference, time at the job, daily work hours, diabetes or hypertension and former smoking habits.ResultsRelative to workers in the lowest exposed group (all measures < 25 μg/m3), those with the highest level of exposure (all measures > 39.6 μg/m3) showed a reduction of predicted FVC (-12.2%; CI 95%: [-20.0% to -4.4%]), a marginal reduction of predicted FEV1 (-9.1%; CI 95%: [-19.1% to 0.9%]) and an increase of predicted FEF25-75%/FVC (14.9%; CI 95%: [2.9% to 26.8%]) without changes of FEV1/FVC.ConclusionsExposure to vehicular traffic air pollution is associated with a small but significant reduction of FVC without a reduction of FEV1/FVC.

PM2.5 mass and black carbon from biomass-burning cookstoves in relation to diabetic status and metabolic syndrome among Honduran women

Introduction: Household air pollution (HAP) from inefficient biomass cookstoves is hypothesized to be a risk factor for metabolic disorders; however, epidemiologic evidence is lacking. We evaluated the association of PM2.5 (particulate matter&lt;2.5μm) and black carbon (BC) exposure with diabetic status as defined by HbA1c (glycated hemoglobin) and metabolic syndrome in women in rural Honduras. Methods: We conducted a cross-sectional study of 107 female household cooks, 25-55 years of age, comparing traditional and improved-combustion biomass cookstoves. Integrated filter measures were collected to calculate area (inside the kitchen) and personal 24-hour PM2.5 and BC concentrations. HbA1c was analyzed as a binary (normal vs pre-diabetic/diabetic) variable. Metabolic syndrome was defined by a waist circumference ≥80cm plus any two of the following: triglycerides &gt;150mg/dl, HDL &lt;50mg/dl, systolic blood pressure ≥130mmHg, diastolic blood pressure ≥85mmHg or HbA1c &gt;5.6%. Age, dietary diversity score, physical activity, and socioeconomic status were included in all logistic regression models. Results: An interquartile range (IQR) increase in area PM2.5 (312.01 μg/m3) was associated with a 66% higher prevalence of pre-diabetes/diabetes (OR=1.66, 95%CI: 1.05, 2.62) and with a 47% higher prevalence of metabolic syndrome (OR=1.47, 95%CI: 0.96, 2.25). An IQR increase in area BC (20.19 μg/m3) was associated with a 94% higher prevalence of pre-diabetes/diabetes (OR=1.94, 95%CI: 1.08, 3.47); results for metabolic syndrome were also suggestive (OR=1.39, 95%CI: 0.84, 2.28). For personal exposure measurements, results were similar to those for area exposure measures for pre-diabetes/diabetes; however, no evidence of an association was observed for metabolic syndrome. Conclusions: This is the first study to evaluate the association between exposure to HAP and prevalence of pre-diabetes/diabetes and metabolic syndrome, a growing burden of disease in low- and middle-income countries.

Abstract P062: Individual Level Fine Particulate Air Pollution is Associated with Acute Impairment of Cardiac Autonomic Modulation in Adolescents

Introduction: Fine particulate (PM 2.5 ) air pollution has been associated with impaired cardiac autonomic modulation (CAM) in adults. The association between PM 2.5 exposure and CAM in adolescents is rarely investigated. Hypothesis: We assessed the hypothesis that PM 2.5 air pollution is related to acute impairment of CAM in adolescents. Methods: We used data from 421 adolescents in the Penn State Child Cohort follow-up examination. We obtained 24-hour ECG data using a 12-lead Holter ECG from each participant. After removing artifacts and arrhythmic beats, we performed heart rate variability (HRV) analysis on normal RR intervals to compute 30-min based high frequency (HF) and low frequency (LF) powers, standard deviation of RRs (SDNN), and the square root of mean of the sum of the squared differences of the adjacent RRs (RMSSD). Individual level 24-hour PM 2.5 concentration was obtained by a personal PM 2.5 monitor. We then calculated, on a 30-min basis, the corresponding time-specific exposure to PM 2.5 . Distributed lag models under a framework of linear mixed-effects model, with a first-order autoregressive covariance structure, were used to assess the segment-specific and cumulative effect of 30-min based PM 2.5 and HRV indices. Results: As shown in the table, both individual lag and cumulative effects of PM 2.5 on HRV, based on the lag 0-6 model, were significant after controlling for major covariates. For instance, for a 10 μg/m 3 increase in cumulative PM 2.5 , HF and SDNN decreased by 0.023 (SE=0.006) ms 2 and 0.61 (SE=0.16) ms, respectively. A 10 μg/m 3 increase in PM 2.5 was also significantly associated with elevated heart rate (0.25 (SE=0.09) beat/min). Individual lag effects of PM 2.5 were most consistently associated within 1.5 hours. Conclusion: Individual level exposure to PM 2.5 in adolescents is associated with impaired CAM, towards an elevated sympathetic and decreased parasympathetic outflow. The time to the apparent cumulative effect is about 3 hours, with the most consistent individual lag effects within 1.5 hours.

Ambient Air Pollution And Allergic Disease: Results From The Survey Of The Health Of Wisconsin 2008-2013

Introduction: Evidence suggests air pollutants are thought to contribute to allergic diseases, including asthma. However, prior epidemiology studies have been limited in their ability to assign fine particulate matter (PM2.5) exposure levels at a population level. A more refined air pollution measure from the Environmental Protection Agency (EPA) is used to assess whether chronic exposure to lower levels of PM2.5 are associated with allergic disease outcomes below the 12 μg/m3 National Ambient Air Quality Standard (NAAQS) for PM2.5. Methods: We used the Hierarchical Bayesian Space Time Modeling System (HBM) 12 km grid of 24-hour PM2.5 data from the EPA and data from the Survey of the Health of Wisconsin (SHOW) to examine the association between the prevalence of current allergic diseases, including asthma, and chronic air pollution among participants in a statewide representative sample of adults in Wisconsin. CENTRUS software was used to geocode SHOW participants and link participants to the nearest 12km HBM point estimates. SAS 9.3 was used for statistical analysis. Results: A total of 3,384 participants from 2008-2013 cohort were included. After controlling for gender, age, race, body mass index, smoking status, pets, indoor mold or mildew, and indoor chemical use we found those exposed to annual average PM2.5 exposure between 10-12 μg/m3 compared with those exposed to annual average PM2.5 &lt; 10 μg/m3 to have significantly greater prevalence of current asthma [OR 1.46, 95% CI (1.1, 2.0)] and current allergies [OR 1.24, 95% CI (1.0, 1.5)]. Outdoor chemical use and physical activity were not significant confounders. No effect modifications were identified when we tested for urbanicity and duration at residence. Discussion: After careful adjustment, low-level chronic exposure to air pollution has an influence on current allergy and asthma in this study. Further investigation is needed to support this finding.

Intraurban and longitudinal variability of classical pollutants in Kraków, Poland, 2000-2010.

In spite of a dramatic decrease in anthropogenic emissions, ambient concentrations of major pollutants have not changed within many urban locations. To clarify the relationship between ambient air quality trend and the population exposures, we compared the intraurban versus temporal variability of the collocated measurements of five major air pollutants including particulate matter (PM) with an aerodynamic diameter <10 µm (PM10), < 2.5 µm (PM2.5), tropospheric ozone (O3), sulfur dioxide (SO2), and nitrogen dioxide (NO2), in Kraków, Poland, during the 2000−2010 period. Strong seasonal trends and overall absence of spatial heterogeneity in PM10 and PM2.5, except in the traffic monitoring site, were observed across the monitoring network. The range of median PM2.5 concentrations during winter (54–64 µg/m3) was 3- to 4-times higher than the summer medians (15–26 µg/m3) across the sites during 2009−2010. Furthermore, large proportion of PM10 appears to be comprised of PM2.5 (PM2.5/PM10 concentration ratios range, 0.5–0.7). At each monitoring site, the Pearson’s correlation coefficients between PM2.5 and PM10 ranged between 0.944 and 0.963, suggesting a health-relevance of PM10 monitoring. One ln-unit increase in PM10 was associated with 92%–100% increase in PM2.5 concentrations in the same location. While PM10 did not demonstrate a clear temporal trend, SO2 concentrations steadily declined by 40% during the 2000–2010 period. Summertime median NO2 concentration was acutely elevated ‎(70 μg/m3 vs. 22 μg/m3) at the traffic oriented site compared to the city’s central monitoring site. The traffic and the industrial sites were associated with highest number of days during which 24-hour mean PM10 and PM2.5 concentrations exceeded the European Union standard. Steadily growing contributions by vehicular emissions appear to be associated with the absence of clear trend in PM10. Current practices of air quality control within Kraków may not be adequate for the protection of the public’s health.

Association between individual PM2.5 exposure and DNA damage in traffic policemen.

The aim of this study was to explore the association between individual PM2.5 and DNA damage in traffic policemen. The participants included 110 traffic policemen and 101 common populations. The continuous 24-hour individual PM2.5 measurement was performed in participants. BPDE (benzo[a]pyrene 7,8-diol-9,10-epoxide)-DNA adducts and 1-OHP were detected. The average concentration of 24-hour personal PM2.5 for traffic policemen was significantly higher than that in the control group. PM2.5 exposure is associated with a 1.1% increase in 1-OHP and 0.8% increase in BPDE-DNA adducts after adjusted for body mass index, educational time period, and alcohol intake. Exposure group has 2.04 times higher of 1-OHP and 1.25 times higher of BPDE-DNA adducts when compared to the control group. These results demonstrated that traffic policemen have been a high-risk group suffering DNA damage because of the high PM2.5 exposure.

Personal particulate matter exposures and locations of students in four neighborhoods in Accra, Ghana.

Air pollution exposure and places where the exposures occur may differ in cities in the developing world compared with high-income countries. Our aim was to measure personal fine particulate matter (PM2.5) exposure of students in neighborhoods of varying socioeconomic status in Accra, Ghana, and to quantify the main predictors of exposure. We measured 24-hour PM2.5 exposure of 56 students from eight schools in four neighborhoods. PM2.5 was measured both gravimetrically and continuously, with time-matched global positioning system coordinates. We collected data on determinants of exposure, such as distances of homes and schools from main roads and fuel used for cooking at their home or in the area of residence/school. The association of PM2.5 exposure with sources was estimated using linear mixed-effects models. Personal PM2.5 exposures ranged from less than 10 μg/m(3) to more than 150 μg/m(3) (mean 56 μg/m(3)). Girls had higher exposure than boys (67 vs 44 μg/m(3); P-value=0.001). Exposure was inversely associated with distance of home or school to main roads, but the associations were not statistically significant in the multivariate model. Use of biomass fuels in the area where the school was located was also associated with higher exposure, as was household's own biomass use. Paved schoolyard surface was associated with lower exposure. School locations in relation to major roads, materials of school ground surfaces, and biomass use in the area around schools may be important determinants of air pollution exposure.

A cross-sectional study of determinants of indoor environmental exposures in households with and without chronic exposure to biomass fuel smoke

BackgroundBurning biomass fuels indoors for cooking is associated with high concentrations of particulate matter (PM) and carbon monoxide (CO). More efficient biomass-burning stoves and chimneys for ventilation have been proposed as solutions to reduce indoor pollution. We sought to quantify indoor PM and CO exposures in urban and rural households and determine factors associated with higher exposures. A secondary objective was to identify chronic vs. acute changes in cardiopulmonary biomarkers associated with exposure to biomass smoke.MethodsWe conducted a census survey followed by a cross-sectional study of indoor environmental exposures and cardiopulmonary biomarkers in the main household cook in Puno, Peru. We measured 24-hour indoor PM and CO concentrations in 86 households. We also measured PM2.5 and PM10 concentrations gravimetrically for 24 hours in urban households and during cook times in rural households, and generated a calibration equation using PM2.5 measurements.ResultsIn a census of 4903 households, 93% vs. 16% of rural vs. urban households used an open-fire stove; 22% of rural households had a homemade chimney; and <3% of rural households participated in a national program encouraging installation of a chimney. Median 24-hour indoor PM2.5 and CO concentrations were 130 vs. 22 μg/m3 and 5.8 vs. 0.4 ppm (all p<0.001) in rural vs. urban households. Having a chimney did not significantly reduce median concentrations in 24-hour indoor PM2.5 (119 vs. 137 μg/m3; p=0.40) or CO (4.6 vs. 7.2 ppm; p=0.23) among rural households with and without chimneys. Having a chimney did not significantly reduce median cook-time PM2.5 (360 vs. 298 μg/m3, p=0.45) or cook-time CO concentrations (15.2 vs. 9.4 ppm, p=0.23). Having a thatched roof (p=0.007) and hours spent cooking (p=0.02) were associated with higher 24-hour average PM concentrations. Rural participants had higher median exhaled CO (10 vs. 6 ppm; p=0.01) and exhaled carboxyhemoglobin (1.6% vs. 1.0%; p=0.04) than urban participants.ConclusionsIndoor air concentrations associated with biomass smoke were six-fold greater in rural vs. urban households. Having a homemade chimney did not reduce environmental exposures significantly. Measures of exhaled CO provide useful cardiopulmonary biomarkers for chronic exposure to biomass smoke.

Gender Differences of Long-Term Exposure to Fine Particle and Ozone in Lung Function Growth.

Background: There are only a limited number of studies on the association between long-term exposure to ambient air pollutants and lung function growth among children, which, nevertheless, leave inconclusive results. Aim: To assess the effect of air pollutants on lung function growth. Methods: We conducted a prospective cohort study of 3,207 Taiwanese children aged 12 at baseline followed from October 1, 2007 through November 31, 2009. The final study population comprised 2,941 non-smoking children who completed lung function tests at both baseline and follow-up surveys. We applied spatial modeling for individual-level exposure assessment to clarify the role of potential community-level confounding. The exposure parameters were yearly average and calculated from the 24-hour PM2.5, and 10:00 AM to 6:00 PM 8-hour O3 corresponding to residential address over the 2-year follow-up period. The effect estimates were presented as annul deficit of lung function growth per interquartile ranges (IQR) for PM2.5 and O3. Results: In a multiple linear regression adjusting for confounding, deficits in FVC, FEV1, and MMEF growth were associated with exposure to PM2.5 and O3. The annual deficits in FVC of 75 ml in boys and 61 ml in girls increased with an IQR PM2.5 (17.92 ?g/m3), and annual deficits in FVC of 54 ml in boys and 40 ml in girls increased with an IQR O3 (3.59 ppb). Similar associations were found in FEV1, and MMEF growth. Conclusions: The study provides evidence that long-term exposure to PM2.5 and O3 may increase the risk of deficit in FVC, FEV1, and MMEF growth among Taiwanese children, especially among boys.

Longitudinal Relationship between Personal CO and Personal PM2.5 among Women Cooking with Woodfired Cookstoves in Guatemala

Household air pollution (HAP) due to solid fuel use is a major public health threat in low-income countries. Most health effects are thought to be related to exposure to the fine particulate matter (PM) component of HAP, but it is currently impractical to measure personal exposure to PM in large studies. Carbon monoxide (CO) has been shown in cross-sectional analyses to be a reliable surrogate for particles<2.5 µm in diameter (PM2.5) in kitchens where wood-burning cookfires are a dominant source, but it is unknown whether a similar PM2.5-CO relationship exists for personal exposures longitudinally. We repeatedly measured (216 measures, 116 women) 24-hour personal PM2.5 (median [IQR] = 0.11 [0.05, 0.21] mg/m3) and CO (median [IQR] = 1.18 [0.50, 2.37] mg/m3) among women cooking over open woodfires or chimney woodstoves in Guatemala. Pollution measures were natural-log transformed for analyses. In linear mixed effects models with random subject intercepts, we found that personal CO explained 78% of between-subject variance in personal PM2.5. We did not see a difference in slope by stove type. This work provides evidence that in settings where there is a dominant source of biomass combustion, repeated measures of personal CO can be used as a reliable surrogate for an individual's PM2.5 exposure. This finding has important implications for the feasibility of reliably estimating long-term (months to years) PM2.5 exposure in large-scale epidemiological and intervention studies of HAP.

Spatio-Temporal Variation and Deposition of Fine and Coarse Particles during the Commonwealth Games in Delhi

The Indian Government implemented the project “System of Air quality Forecasting And Research (SAFAR)” for the “Commonwealth Games” 2010 in Delhi. It was adopted by the Global Urban Research Meteorology and Environment of World Meteorological Organization as its pilot project. We used data from a dense network of stations built over 2500 km2 in Delhi under the SAFAR project to investigate temporal and spatial variations of fine (PM2.5) and coarse (PM10–2.5) particles, and discuss their deposition and the airborne mass fractions that were retained after a certain amount of time. The 24-hour coarse particle (PM10–2.5) means during the Games period were always above the National Ambient Air Quality Standard NAAQS (100 μg/m3) at all the sites except the airport. In still air, initial PM10–2.5 can reach below 50 μg/m3 by deposition in an hour. The 24-hour PM2.5 means reveal that they were either around or below the NAAQS (60 μg/m3) at some sport complexes, whereas they fluctuated between 60 and 80 μg/m3 at the other sites.

Characterization and Source Apportionment of PM2.5 in an Urban Environment in Beijing

Daily 24-hour PM2.5 samples were collected continuously from January 1 to December 31, 2010. Elemental concentrations from Al to Pb were obtained using particle induced X-ray emission (PIXE) method. This was the first full year continuous daily PM2.5 elemental composition dataset in Beijing. Source apportionment analysis was conducted on this dataset using the positive matrix factorization method. Seven sources and their contributions to the total PM2.5 mass were identified and quantified. These include secondary sulphur– 13.8 μg/m 3 , 26.5%; vehicle exhaust– 8.9 μg/m 3 , 17.1%; fossil fuel combustion– 8.3 μg/m 3 , 16%; road dust– 6.6 μg/m 3 , 12.7%; biomass burning– 5.8 μg/m 3 , 11.2%; soil dust– 5.4 μg/m 3 , 10.4%; and metal processing– 3.1 μg/m 3 , 6.0%. Fugitive dusts (including soil dust and road dust) showed the highest contribution of 20.7 μg/m 3 in the spring, doubling those in other seasons. On the contrary, contributions of the combustion source types (including biomass burning and fossil fuel combustion) were significantly higher in the fall (14.2 μg/m 3 ) and in the winter (24.5 μg/m 3 ) compared to those in the spring and summer (9.6 and 8.0 μg/m 3 , respectively). Secondary sulphur contributed the most in the summer while vehicle exhaust and metal processing sources did not show any clear seasonal pattern. The different seasonal highs and lows from different sources compensated each other. This explains the very small seasonal variations (< 20%) in the total PM2.5.

El Niño and health risks from landscape fire emissions in Southeast Asia.

Emissions from landscape fires affect both climate and air quality1. In this study, we combine satellite-derived fire estimates and atmospheric modeling to quantify health effects from fire emissions in Southeast Asia from 1997 to 2006. This region has large interannual variability in fire activity due to coupling between El Niño-induced droughts and anthropogenic land use change2,3. We show that during strong El Niño years, fires contribute up to 200 μg/m3 and 50 ppb in annual average fine particulate matter (PM2.5) and ozone (O3) surface concentrations near fire sources, respectively. This corresponds to a fire contribution of 200 additional days per year that exceed the World Health Organization (WHO) 50 μg/m3 24-hour PM2.5 interim target (IT-2)4 and an estimated 10,800 (6,800–14,300) person (~2%) annual increase in regional adult cardiovascular mortality. Our results indicate that reducing regional deforestation and degradation fires would improve public health along with widely established benefits from reducing carbon emissions, preserving biodiversity, and maintaining ecosystem services.

Household Air Pollution and Children's Blood Pressure

To the Editor: Childhood blood pressure (BP) is an important predictor of hypertension and cardiovascular risk later in life1; risk factors for elevated BP in children remain mostly unknown. Ambient air pollution is associated with impaired vascular health, oxidative stress, and systemic inflammation in children.2 Limited evidence suggests that household air pollution is associated with higher BP in adult women,3–5 but this relationship has not been studied in children. Half the world's population uses biomass and coal for energy6; thus, even a small effect of household air pollution on BP in childhood could have large cardiovascular implications. We investigated the association between exposure to household air pollution from biomass combustion and BP in Chinese children. We recruited school-aged children from 180 rural households cooking with biomass in Yunnan, China. Detailed information on the study population, exposure assessment, and quality control is published elsewhere.7 Participants wore a small backpack containing equipment to measure personal exposure to particles <2.5 μg in aerodynamic diameter (particulate matter [PM]2.5) over a 24-hour period. PM2.5 samples were analyzed for mass and black carbon (BC) (eAppendix 1, https://links.lww.com/EDE/A592). We measured children's BP before and after pollution exposure measurement, using an automated device (Omron-705). We also collected household sociodemographic and health information, including caffeine intake, exposure to cigarette smoke, physical activity, and 24-hour salt and monosodium glutamate intake, and we measured each child's height and weight. Mother's BP was assessed in a 40% subsample (eAppendix 2, https://links.lww.com/EDE/A592). We investigated the associations between personal PM2.5 and BC exposures and BP using one- and two-pollutant multivariate regression models. Pollution measures were transformed to the natural log scale to account for their skewedness toward high values (eAppendix 3, https://links.lww.com/EDE/A592). We enrolled 240 children (47% girls). Mean age was 10.3 years (95% confidence interval: 10.0–10.6; range: 5–14 years), average body mass index was 15.3 kg/m2 (15.0–15.6), and 85% lived with a smoker (eTable 1, https://links.lww.com/EDE/A592). Personal 24-hour PM2.5 exposure ranged from 14 to 393 μg/m3 (geometric mean = 53 μg/m3 [46–61]). BC exposure ranged between 2.0 and 9.6 μg/m3 (geometric mean = 3.2 μg/m3 [3.1–3.3]). PM2.5 and BC exposures were moderately correlated (Pearson r = 0.41). In the single-pollutant multivariate regression models, a 1-ln(μg/m3) increase in PM2.5 was associated with small decreases in systolic BC (−1.8 mmHg [95% confidence interval: −3.6, 0.1]) and diastolic BC (−0.5 mmHg [−2.1 to 1.2]). Similarly, a 1-ln(μg/m3) increase in BC was also associated with small decreases in systolic BC (−2.2 mmHg [−5.4 to 1.0]) and diastolic BC (−0.4 mmHg [−3.3 to 2.6]). In two-pollutant models, the effect of PM2.5 exposure on BP was largely unchanged; however, the effect of BC was greatly weakened (Table). Sensitivity analyses included adjustment for maternal BP, restricting the analysis to smaller age-groups, and transforming BP into quantiles; none of these affected the qualitative interpretation of our results (eAppendix 4, https://links.lww.com/EDE/A592).Table: Multivariate Adjusted Associations of Personal PM2.5 and Black Carbon Exposure With Blood Pressure Using One- and Two-pollutant ModelsaWe found that increased PM2.5 and BC exposures were not associated with higher BP among children in households cooking with biomass. Our findings do not support our previous study of older women in this setting, showing a positive relationship between PM exposure and BP. Possible explanations include the lower levels and shorter durations of PM exposure among children compared with adult women7 (eAppendix 5, https://links.lww.com/EDE/A592). Older women would be more likely than young children to experience a resetting of BP-regulating mechanisms to higher levels, as a result of repeated acute increases in BP after PM inhalation. We also cannot rule out the possibility of residual confounding by difficult-to-measure or unmeasured covariates in this cross-sectional study. Future longitudinal studies could advance our understanding of the vascular effects of household air pollution in children and should incorporate measures of PM pollution exposure and BP over a span of years. Jill Baumgartner Institute on the Environment College of Food, Agricultural and Natural Resource Sciences University of Minnesota St. Paul, MN [email protected] Yuanxun Zhang College of Resources and Environment Graduate University of the Chinese Academy of Sciences Beijing, China James J. Schauer Department of Civil and Environmental Engineering College of Engineering University of Wisconsin Madison, WI Majid Ezzati MRC-HPA Centre for Environment and Health Department of Epidemiology and Biostatistics School of Public Health, Imperial College London, United Kingdom Jonathan A. Patz Global Health Institute School of Medicine and Public Health University of Wisconsin Madison, WI Leonelo E. Bautista Department of Population Health Sciences School of Medicine and Public Health University of Wisconsin Madison, WI

Association between fine particulate matter and the peak expiratory flow of schoolchildren in the Brazilian subequatorial Amazon: A panel study

BackgroundExposure to high levels of particulate matter with an aerodynamic diameter less than 2.5μm (PM2.5) resulting from biomass burning is frequent in the subequatorial Amazon region. ObjectiveTo investigate whether or not current exposure to PM2.5 in the Brazilian Amazon has adverse effects on the daily peak expiratory flow (PEF) of schoolchildren. MethodsThe study design consisted of a panel comprising 309 children aged 6 to 15 years from the same school. PEF was measured daily, except weekends and holidays, from August to December 2006. Each child contributed to the study up to 67 daily measurements. All together there were 19115 PEF measures. Participation rate was 90%. Daily measurements of PM2.5, temperature, and humidity as well as passive smoking, and subject features were regarded in the statistical analysis. Various exposures of PM2.5 were considered throughout the analysis, among them 24-hour, 12-hour, 6-hour, and 5-hour means. To account for subject responses to confounders, mixed effects models were applied. The effects were evaluated considering air pollution levels on the current day or at 1- or 2-day lags and the averages of 0–1-day lags, 1–2-day lags and 0-, 1-, and 2-day lags. ResultsThe 24-hour PM2.5 means ranged from 6.39 to 99.91μg/m3. The adjusted models for the entire group of children revealed adverse effects. For instance, for an increase of 10μg/m3 in PM2.5, the reduction in the PEF average varied between 0.26l/min (95% Confidence Interval (CI): −0.49; −0.04) and 0.38l/min (95% CI: −0.71; −0.04). Restricted to the subgroup of non-asthmatic children, classified as such according to the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire, there was a reduction in the PEF ranging from 0.38l/min (95% CI: −0.63; −0.13) to 0.53l/min (95% CI: −0.90; −0.16) for an increase of 10μg/m3 in PM2.5. There was no significant effect in the asthmatic group. When stratified by time of the day children were at school, the concurrent effects of air pollution on PEF were not significant, whereas the 6-hour exposure from 0am to 5:30am was significant for both morning and afternoon groups. Finally, the 24-hour mean lagged effect was only significant for the afternoon group of children. For an increase of 10μg/m3 in PM2.5, there was a reduction in the PEF that ranged from 0.41l/min (95% CI: −0.76; −0.06) to 0.49l/min (95% CI: −0.91; −0.07). ConclusionExposure to current levels of PM2.5 in the Brazilian Amazon was associated with reductions in the lung function of schoolchildren. The adverse effects were more consistent in non-asthmatic children and with respect to the 6-hour mean from 0am to 5.30am.

Comparative assessment of a real-time particle monitor against the reference gravimetric method for PM10 and PM2.5 in indoor air

Accurate monitoring of indoor mass concentrations of particulate matter is very important for health risk assessment as people in developed countries spend approximately 90% of their time indoors. The direct reading, aerosol monitoring device, Turnkey, OSIRIS Particle Monitor (Model 2315) and the European reference low volume sampler, LVS3 (Sven/Leckel LVS3) with size-selective inlets for PM10 and PM2.5 fractions were used to assess the comparability of available optical and gravimetric methods for particulate matter characterization in indoor air. Simultaneous 24-hour samples were collected in an indoor environment for 60 sampling periods in the town of Bor, Serbia. The 24-hour mean PM10 levels from the OSIRIS monitor were well correlated with the LVS3 levels (R2=0.87) and did not show statistically significant bias. The 24-hour mean PM2.5 levels from the OSIRIS monitor were moderately correlated with the LVS3 levels (R2=0.71), but show statistically significant bias. The results suggest that the OSIRIS monitor provides sufficiently accurate measurements for PM10. The OSIRIS monitor underestimated the indoor PM10 concentrations by approximately 12%, relative to the reference LVS3 sampler. The accuracy of PM10 measurements could be further improved through empirical adjustment. For the fine fraction of particulate matter, PM2.5, it was found that the OSIRIS monitor underestimated indoor concentrations by approximately 63%, relative to the reference LVS3 sampler. This could lead to exposure misclassification in health effects studies relying on PM2.5 measurements collected with this instrument in indoor environments.

Source Apportionment of PM2.5 in a Subarctic Airshed - Fairbanks, Alaska

ABSTRACTFairbanks, Alaska has some of the highest measured ambient PM2.5 concentrations in the United States, with wintertime levels often exceeding the 24-hour PM2.5 National Ambient Air Quality Standard (NAAQS) of 35 µg/m3. In an effort to understand the sources of PM2.5 in the Fairbanks airshed, source apportionment using Chemical Mass Balance (CMB) modeling was conducted at four locations in Fairbanks over a three-winter period (2008/2009, 2009/2010, and 2010/2011). At each of the four sites, PM2.5 concentrations averaged between 22.5 ± 12.0 µg/m3 and 26.5 ± 18.9 µg/m3, with frequent exceedances of the 24-hour NAAQS on the scheduled sample days. The results of the CMB modeling revealed that wood smoke (likely residential wood combustion) was the major source of PM2.5 throughout the winter months in Fairbanks, contributing between 60% and nearly 80% of the measured PM2.5 at the four sites. The other sources of PM2.5 identified by the CMB model were secondary sulfate (8–20%), ammonium nitrate (3–11%), diesel exhaust (not detected-10%), and automobiles (not detected-7%). Approximately 1% of the PM2.55 was unexplained by the CMB model. Additional research is needed to confirm the woodsmoke results of the CMB model, as well as determine which sources (fuel oil residential heating, coal combustion, etc.) contribute to the measured secondary sulfate.

Assessing boreal forest fire smoke aerosol impacts on U.S. air quality: A case study using multiple data sets

[1] We synthesize multiple ground-based and satellite measurements to track the physical and chemical evolution of biomass burning smoke plumes transported from western Canada to the northeastern U.S. This multiple data set case study is an advantageous methodology compared with using individual or small groups of data sets, each with their own limitations. The case study analyzed is a Canadian boreal forest fire event on July 4, 2006 with carbonaceous aerosol smoke emission magnitudes comparable to those during the summer fire seasons of the previous decade. We track long-range transport of these aerosol plumes with data from space-borne remote sensing satellite instruments (MODIS, OMI, MISR, CALIOP lidar, AIRS) and ground-based in situ and remote aerosol observations (AERONET CIMEL sky/Sun photometer, MPLNET lidar, IMPROVE, EPA AirNow). Convective lofting elevated smoke emissions above the boundary layer into the free troposphere, where high speed winds aloft led to rapid, long-range transport. Aerosol layer subsidence occurred during transport due to a region of surface high pressure. Smoke aerosols reaching the boundary layer led to surface fine particulate matter (PM2.5) enhancements accompanied by changes in aerosol composition as the plume mixed with anthropogenic aerosols over the northeastern U.S. The extensive coverage of this smoke plume over the northeastern U.S. affected regional air quality, with increases of 10–20 μg m−3 PM2.5 attributable to biomass burning smoke aerosols and EPA 24-hour PM2.5 standard exceedances along the U.S. East Coast. Although each data set individually provides a limited view of the transport of smoke emissions, we demonstrate that a multi–data set approach results in a more comprehensive view of potential impacts due to long-range transport of smoke from a less extreme fire event. Our case study demonstrates that fires emit smoke aerosols that under certain meteorological conditions can degrade regional air quality 3000 km from the source region, with additional implications for aerosol radiative forcing and regional haze over the northeastern U.S.