Microns In Aerodynamic Diameter Research Articles

High ambient temperature in pregnancy and risk of childhood acute lymphoblastic leukaemia: an observational study

High ambient temperature is increasingly common due to climate change and is associated with risk of adverse pregnancy outcomes. Acute lymphoblastic leukaemia is the most common malignancy in children, the incidence is increasing, and in the USA disproportionately affects Latino children. We aimed to investigate the potential association between high ambient temperature in pregnancy and risk of childhood acute lymphoblastic leukaemia. We used data from California birth records (children born from Jan 1, 1982, to Dec 31, 2015) and California Cancer Registry (those diagnosed with childhood cancer in California from Jan 1, 1988, to Dec 31, 2015) to identify acute lymphoblastic leukaemia cases diagnosed in infants and children aged 14 years and younger and controls matched by sex, race, ethnicity, and date of last menstrual period. Ambient temperatures were estimated on a 1-km grid. The association between ambient temperature and acute lymphoblastic leukaemia was evaluated per gestational week, restricted to May-September, adjusting for confounders. Bayesian meta-regression was applied to identify critical exposure windows. For sensitivity analyses, we evaluated a 90-day pre-pregnancy period (assuming no direct effect before pregnancy), adjusted for relative humidity and particulate matter less than 2·5 microns in aerodynamic diameter, and constructed an alternatively matched dataset for exposure contrast by seasonality. 6849 cases of childhood acute lymphoblastic leukaemia were identified and, of these, 6258 had sufficient data for study inclusion. We also included 307 579 matched controls. Most of the study population were male (174 693 [55·7%] of the 313 837 included in the study) and of Latino ethnicity (174 906 [55·7%]). The peak association between ambient temperature and risk of acute lymphoblastic leukaemia was observed in gestational week 8, where a 5°C increase was associated with an odds ratio of 1·07 (95% CI 1·04-1·11). A slightly larger effect was seen among Latino children (OR 1·09 [95% CI 1·04-1·14]) than non-Latino White children (OR 1·05 [1·00-1·11]). The sensitivity analyses supported the results of the main analysis. Our findings suggest an association between high ambient temperature in early pregnancy and risk of childhood acute lymphoblastic leukaemia. Further replication and investigation of mechanistic pathways might inform mitigation strategies. Yale Center on Climate Change and Health, The National Center for Advancing Translational Science, National Institutes of Health.

Visualizing Field Data Collection Procedures of Exposure and Biomarker Assessments for the Household Air Pollution Intervention Network Trial in India

Here, we present a visual representation of standard procedures to collect population-level data on personal exposures to household air pollution (HAP) from two different study sites in a resource-constrained setting of Tamil Nadu, India. Particulate matter PM2.5 (particles smaller than 2.5 microns in aerodynamic diameter), carbon monoxide (CO), and black carbon (BC) were measured in pregnant mothers (M), other adult women (OAW), and children (C) at various times over a 4 year period. In addition, stove usage monitoring (SUMs) with data-logging thermometers and ambient measurements of air pollution were carried out. Furthermore, the feasibility of collecting biological samples (urine and dried blood spots [DBSs]) from study participants at the field sites was successfully demonstrated. Based on findings from this and earlier studies, the methods used here have enhanced the data quality and avoided issues with household air pollution and biological sample collection in resource-constrained situations. The procedures established may be a valuable educational tool and resource for researchers conducting similar air pollution and health studies in India and other low- and middle-income countries (LMICs).

Modified effects of air pollutants on the relationship between temperature variability and hand, foot, and mouth disease in Zibo City, China.

Hand, foot, and mouth disease (HFMD) poses a great disease burden in China. However, there are few studies on the relationship between temperature variability (TV) and HFMD. Moreover, whether air pollutions have modified effects on this relationship is still unknown. Therefore, this study aims to explore the modified effects of air pollutants on TV-HFMD association in Zibo City, China. Daily data of HFMD cases, meteorological factors, and air pollutants from 2015 to 2019 were collected for Zibo City. TV was estimated by calculating standard deviation of minimum and maximum temperatures over the exposure days. We used generalized additive model to estimate the association between TV and HFMD. The modified effects of air pollutants were assessed by comparing the estimated TV-HFMD associations between different air stratums. We found that TV increased the risk of HFMD. The effect was strongest at TV03 (4days of exposure), when the incidence of HFMD increased by 3.6% [95% CI: 1.3-5.9%] for every 1℃ increases in TV. Males, children aged 0-4years, were more sensitive to TV. We found that sulfur dioxide (SO2) enhanced TV's effects on all considered exposure days, while ozone (O3) reduced TV's effects on some exposure days in whole concerned population. However, we did not detect significant effect modification by particulate matter less than 10 microns in aerodynamic diameter (PM10). These findings are of significance in developing policies and public health practices to reduce the risks of HFMD by integrating changes in temperatures and air pollutants.

Exposure to Air Pollutants, Circulating miRNAs, and Cardiometabolic Health among Young Adults

BACKGROUND AND AIM: Prior work has linked exposure to ambient air pollutants (AAP) with cardiometabolic risk factors in young adults. This association may be mediated by changes to microRNAs (miRNAs), which regulate gene expression. This study aimed to examine relationships between circulating miRNAs with AAP exposure and cardiometabolic risk factors in young adults. METHODS: Residential exposure to AAP (particulate matter 2.5 and 10 microns in aerodynamic diameter [PM2.5, PM10]; nitrogen dioxide [NO2]; 24-hour ozone [O3]) was modeled for 113 participants from the Metabolic and Asthma Incidence Research (Meta-AIR) Study, a cohort of young adults (17-22 years) from Southern California. NanoString technology was used to measure circulating miRNAs in serum. Multivariate linear regression was performed to examine the relationships between pre-selected circulating miRNAs (miR-146a-5p, miR-148a-3p, miR-126-3p, miR-122-5p), short-term (prior 1-month) and long-term (prior 1-year) AAP exposure, and cardiometabolic risk factors (e.g., fasting glucose, fasting insulin, lipids). Models adjusted for age, sex, and body mass index. Sex interactions were tested, and effects are reported for each standard deviation increase in exposure. RESULTS:Short-term O3 exposure was associated with greater expression of miR-148a-3p and miR-122-5p (β=12.7, p=0.01 and β=0.56, p=0.04, respectively). MiR-148a-3p (pinteractions=0.001) was also associated with triglycerides and VLDL among males (β=21.8, p=0.003 and β=4.4, p=0.003, respectively), but not females (β=0.7, p=0.90 and β=0.1, p=0.90, respectively). Long-term O3 exposure was positively associated with miR-146a-5p (β=19.6, p=0.04) and miR-146a-5p was inversely associated with fasting glucose levels (β=-2.0, p=0.03). Short-term PM2.5 was inversely associated with miR-126-3p (β=-195.4, p=0.04) and miR-126-3p was also modestly inversely associated with fasting glucose levels (β=-1.7, p=0.06). CONCLUSIONS:Circulating miRNAs with putative gene targets involved in hepatic lipid metabolism (miR-122-5p, miR-148a-3p), NFκβ signaling (miR-146a), and insulin signaling (miR-126-3p) were associated with residential AAP exposure among young adults. Results suggest that miRNA expression may be a mechanistic link between AAP and cardiometabolic disease risk. KEYWORDS: Air pollution, Particulate matter, Obesity and metabolic disorders, Environmental epidemiology, Molecular epidemiology

Prenatal exposure to ambient air pollutants and early infant growth and adiposity in the Southern California Mother\u2019s Milk Study

BackgroundPrior epidemiological and animal work has linked in utero exposure to ambient air pollutants (AAP) with accelerated postnatal weight gain, which is predictive of increased cardiometabolic risk factors in childhood and adolescence. However, few studies have assessed changes in infant body composition or multiple pollutant exposures. Therefore, the objective of this study was to examine relationships between prenatal residential AAP exposure with infant growth and adiposity.MethodsResidential exposure to AAP (particulate matter < 2.5 and 10 microns in aerodynamic diameter [PM2.5, PM10]; nitrogen dioxide [NO2]; ozone [O3]; oxidative capacity [Oxwt: redox-weighted oxidative potential of O3 and NO2]) was modeled by spatial interpolation of monitoring stations via an inverse distance-squared weighting (IDW2) algorithm for 123 participants from the longitudinal Mother’s Milk Study, an ongoing cohort of Hispanic mother-infant dyads from Southern California. Outcomes included changes in infant growth (weight, length), total subcutaneous fat (TSF; calculated via infant skinfold thickness measures) and fat distribution (umbilical circumference, central to total subcutaneous fat [CTSF]) and were calculated by subtracting 1-month measures from 6-month measures. Multivariable linear regression was performed to examine relationships between prenatal AAP exposure and infant outcomes. Models adjusted for maternal age, pre-pregnancy body mass index, socioeconomic status, infant age, sex, and breastfeeding frequency. Sex interactions were tested, and effects are reported for each standard deviation increase in exposure.ResultsNO2 was associated with greater infant weight gain (β = 0.14, p = 0.02) and TSF (β = 1.69, p = 0.02). PM10 and PM2.5 were associated with change in umbilical circumference (β = 0.73, p = 0.003) and TSF (β = 1.53, p = 0.04), respectively. Associations of Oxwt (pinteractions < 0.10) with infant length change, umbilical circumference, and CTSF were modified by infant sex. Oxwt was associated with attenuated infant length change among males (β = -0.60, p = 0.01), but not females (β = 0.16, p = 0.49); umbilical circumference among females (β = 0.92, p = 0.009), but not males (β = -0.00, p = 0.99); and CTSF among males (β = 0.01, p = 0.03), but not females (β = 0.00, p = 0.51).ConclusionPrenatal AAP exposure was associated with increased weight gain and anthropometric measures from 1-to-6 months of life among Hispanic infants. Sex-specific associations suggest differential consequences of in utero oxidative stress. These results indicate that prenatal AAP exposure may alter infant growth, which has potential to increase childhood obesity risk.

Prenatal Exposure to Ambient Air Pollutants and Infant Growth Among Hispanics from Southern California

Background: Prior epidemiological and animal work has linked in utero exposure to ambient air pollutants (AAP) with accelerated postnatal weight gain. The objective of this study was to examine relationships between prenatal residential AAP exposure with infant growth.Methods: Residential exposure to AAP (particulate matter &lt;2.5 and 10 microns in aerodynamic diameter [PM2.5, PM10]; nitrogen dioxide [NO2]; ozone [O3]; oxidative capacity [Ox: redox-weighted oxidative potential of O3 and NO2]) was modeled for 123 participants from the longitudinal Mother’s Milk Study, an ongoing cohort of Hispanic mother-infant dyads from Southern California. Multivariate linear regression was performed to examine the relationships between prenatal AAP exposure and changes in infant growth, skinfold measures, and predicted body fat and lean mass (calculated using infant demographics, anthropometrics, and EchoMRI from a subset) from 1-to-6 months of life. Models adjusted for maternal age, pre-pregnancy body mass index, socioeconomic status, infant age, sex, and breastfeeding frequency. Sex interactions were tested, and effects are reported for each standard deviation increase in exposure.Results: Higher NO2 was associated with a greater increase in infant weight (β=0.14, p=0.03), predicted lean mass (β=0.05, p=0.01), and midthigh skinfold thickness (β=0.84, p=0.03). PM10 and PM2.5 were positively associated with change in umbilical circumference (β=0.84, p=0.001 and β=0.56, p=0.04, respectively) and suprailiac skinfold thickness (β=0.38, p=0.02 and β=0.34, p=0.04, respectively). Lastly, Ox (pinteractions&lt;0.02) was positively associated with change in umbilical circumference among females (β=1.23, p=0.001), but not males (β=-0.08, p=0.84) and was inversely associated with infant length change (β=-0.57, p=0.02) among males, but not females (β=0.17, p=0.48).Conclusion: Prenatal AAP exposure was associated with increased weight gain and anthropometric measures from 1-to-6 months of life. Sex-specific associations suggest differential consequences of in utero oxidative stress. These results indicate that prenatal AAP exposure may alter infant growth, which has potential to increase childhood obesity risk.

Impacts of discriminated PM2.5 on global under-five and maternal mortality

Globally, it was estimated that maternal and under-five deaths were high in low-income countries than that of high-income countries. Most studies, however, have focused only on the clinical causes of maternal and under-five deaths, and yet there could be other factors such as ambient particulate matter (PM). The current global estimates indicate that exposure to ambient PM2.5 (with ≤ 2.5 microns aerodynamic diameter) has caused about 7 million deaths and over 100 million disability-adjusted life-years. There are also several health risks that have been linked PM2.5, including mortality, both regionally and globally; however, PM2.5 is a mixture of many compounds from various sources. Globally, there is little evidence of the health effects of various types of PM2.5, which may uniquely contribute to the global burden of disease. Currently, only two studies had estimated the effects of discriminated ambient PM2.5, that is, anthropogenic, biomass and dust, on under-five and maternal mortality using satellite measurements, and this study found a positive association in Africa and Asia. However, the study area was conducted in only one region and may not reflect the spatial variations throughout the world. Therefore, in this study, we discriminated different ambient PM2.5 and estimated the effects on a global scale. Using the generalized linear mixed-effects model (GLMM) with a random-effects model, we found that biomass PM2.5 was associated with an 8.9% (95% confidence interval [CI] 4.1–13.9%) increased risk of under-five deaths, while dust PM2.5 was marginally associated with 9.5% of under-five deaths. Nevertheless, our study found no association between PM2.5 type and global maternal deaths. This result may be because the majority of maternal deaths could be associated with preventable deaths that would require clinical interventions. Identification of the mortality-related types of ambient PM2.5 can enable the development of a focused intervention strategy of placing appropriate preventive measures for reducing the generation of source-specific PM2.5 and subsequently diminishing PM2.5-related mortality.

The Inducible Role of Ambient Particulate Matter in Cancer Progression via Oxidative Stress-Mediated Reactive Oxygen Species Pathways: A Recent Perception.

Simple SummaryParticulate matter, especially the fine fraction PM2.5, is officially stated as carcinogenic to human. There are compelling evidences on the association between PM2.5 exposure and lung cancer, and there are also some preliminary data reporting the significant links between this fraction with non-lung cancers. The underlying mechanisms remain unclear. Further studies related to such scope are highly required. The purpose of this work is to systemically analyze recent findings concerning the relationship between PM2.5 and cancer, and to thoroughly present the oxidative stress pathways mediated by reactive oxygen species as the key mechanism for carcinogenesis induced by PM2.5. This will provide a more comprehensive and updated knowledge regarding carcinogenic capacity of PM2.5 to both clinicians and public health workers, contributing to preventive and therapeutic strategies to fight against cancer in human.Cancer is one of the leading causes of premature death and overall death in the world. On the other hand, fine particulate matter, which is less than 2.5 microns in aerodynamic diameter, is a global health problem due to its small diameter but high toxicity. Accumulating evidence has demonstrated the positive associations between this pollutant with both lung and non-lung cancer processes. However, the underlying mechanisms are yet to be elucidated. The present review summarizes and analyzes the most recent findings on the relationship between fine particulate matter and various types of cancer along with the oxidative stress mechanisms as its possible carcinogenic mechanisms. Also, promising antioxidant therapies against cancer induced by this poison factor are discussed.

Mortality Risks from a Spectrum of Causes Associated with Wide-ranging Exposure to Fine Particulate Matter: A Case-Crossover Study in Beijing, China

Background/Aim: Exposure to fine particulate matter (<2.5 microns in aerodynamic diameter; PM2.5) has been shown to be associated with an increased risk of mortality due to cardiovascular, respirat...

Effect of particulate matter less than 10µm (PM10) on mortality in Bogota, Colombia: a time-series analysis, 1998-2006.

To analyze the association between daily mortality from different causes and acute exposure to particulate matter less than 10 microns in aerodynamic diameter (PM10), in Bogota, Colombia. A time-series ecological study was conducted from 1998 to 2006. The association between mortality (due to different causes) and exposure was analyzed using single and distributed lag models and adjusting for potential confounders. For all ages, the cumulative effect of acute mortality from all causes and respiratory causes increased 0.71% (95%CI 0.46-0.96) and 1.43% (95%CI 0.85-2.00), respectively, per 10µg/m³ increment in daily average PM10 with a lag of three days before death. Cumulative effect of mortality from cardiovascular causes was -0.03% (95%CI -0.49-0.44%) with the same lag. The results suggest an association between an increase in PM10 concentrations and acute mortality from all causes and respiratory causes.

Effect of socioeconomic status on the association between air pollution and mortality in Bogota, Colombia.

To evaluate the modification effect of socioeconomic status (SES) on the association between acute exposure to particulate matter less than 10 microns in aerodynamic diameter (PM10) and mortality in Bogota, Colombia. A time-series ecological study was conducted (1998-2006). The localities of the cities were stratified using principal components analysis, creating three levels of aggregation that allowed for the evaluation of the impact of SES on the relationship between mortality and air pollution. For all ages, the change in the mortality risk for all causes was 0.76% (95%CI 0.27-1.26) for SES I (low), 0.58% (95%CI 0.16-1.00) for SES II (mid) and -0.29% (95%CI -1.16-0.57) for SES III (high) per 10µg/m³ increment in the daily average of PM10 on day of death. The results suggest that SES significantly modifies the effect of environmental exposure to PM10 on mortality from all causes and respiratory causes.

Household reporting of childhood respiratory health and air pollution in rural Alaska Native communities

BackgroundAir pollution is an important contributor to respiratory disease in children.ObjectiveTo examine associations between household reporting of childhood respiratory conditions and household characteristics related to air pollution in Alaska Native communities.DesignIn-home surveys were administered in 2 rural regions of Alaska. The 12-month prevalence of respiratory conditions was summarized by region and age. Odds ratios (ORs) were calculated to describe associations between respiratory health and household and air quality characteristics.ResultsHousehold-reported respiratory health data were collected for 561 children in 328 households. In 1 region, 33.6% of children aged <5 years had a recent history of pneumonia and/or bronchitis. Children with these conditions were 2 times more likely to live in a wood-heated home, but these findings were imprecise. Resident concern with mould was associated with elevated prevalence of respiratory infections in children (ORs 1.6–2.5), while reported wheezing was associated with 1 or more smokers living in the household. Reported asthma in 1 region (7.6%) was lower than national prevalence estimates.ConclusionsFindings suggest that there may be preventable exposures, including wood smoke and mould that affect childhood respiratory disease in these rural areas. Additional research is needed to quantify particulate matter 2.5 microns in aerodynamic diameter or less and mould exposures in these communities, and to objectively evaluate childhood respiratory health.

Estimation of the effects of ambient air pollution on life expectancy of urban residents in China

The air quality in China's cities has improved in recent years, but its impact on public health has rarely been investigated. This study was aimed at estimating the potential effects of air quality on life expectancy between 2003 and 2010 in China. We collected annual average concentrations of particulate matter less than 10 microns in aerodynamic diameter (PM10) in 113 key cities, covering all provinces in China, along with the national average age-specific mortality from 2003 to 2010. We constructed a cause-eliminated life table after excluding premature deaths attributable to PM10. The annual average PM10 levels in these cities decreased from 125.3 μg m−3 in 2003 to 88.3 μg m−3 in 2010. As the result, life expectancy loss due to PM10 decreased from 2.13 years in 2003 to 1.30 years in 2010. The estimated life expectancy increase due to PM10 mitigation accounted for 34% of the total increase in life expectancy in the same period. Our results suggested that air quality might have contributed substantially to life expectancy in China.

Short-term effect of ambient air pollution on COPD mortality in four Chinese cities

Ambient air pollution has been associated with increased mortality and morbidity; however, few studies have examined the short-term effect of air pollution specifically on chronic obstructive pulmonary disease (COPD), which is an important cause of mortality and morbidity world wide. In this analysis, we examined the associations between daily air pollution levels [particulate matter less than 10 microns in aerodynamic diameter (PM10), sulfur dioxide (SO2) and nitrogen dioxide (NO2)] and COPD mortality in four Chinese cities. We used Poisson regression models with natural spline smoothing functions to adjust for long-term and seasonal trends of COPD mortality, as well as other time-varying covariates. We did a meta-analysis to obtain the 4-city average estimates. Air pollution (PM10, SO2, and NO2) was found to be associated with increased risk of COPD mortality in these four cities. Using the random-effects model, an increase of 10 μg m−3 of 2-day moving average concentrations of PM10, SO2 and NO2 corresponded to a 0.78% (95% CI, 0.13–1.42), 1.30% (95% CI, 0.61–1.99), and 1.78% (95% CI, 1.10–2.46) increase of COPD mortality, respectively. The concentration–response curves indicated linear associations without threshold. Only NO2 remained significant in the multi-pollutant models. To our knowledge, this is the first multi-city study in Asian developing region to report the short-term effect of air pollution on COPD mortality. Our results contribute to very limited data on the effects of air pollution on COPD mortality for high exposure settings typical in developing countries.

Method for Measuring the Ratio of In-Vehicle to Near-Vehicle Exposure Concentrations of Airborne Fine Particles

Human exposure to fine particulate matter of less than 2.5 microns in aerodynamic diameter is causally linked to cardiovascular and pulmonary diseases. In-vehicle exposure may account for 10% to 20% of daily average exposure. However, exposure models are typically based on areawide air quality data that poorly predict in-vehicle concentration. A practical method is demonstrated for conducting field measurements to quantify the ratio of in-vehicle to outside vehicle concentration (I/O) for a wide range of conditions that affect intravehicle variability in exposure concentration. A field data collection study design is developed on the basis of sources of intravehicle variability in I/O that include ventilation air source, window status, fan setting, air-conditioning (AC) use, vehicle speed, road type, travel direction, and time of day. Three replicates of measurements were made for 16 combinations of these factors on 110 mi of roads comprising eight one-way routes between typical commuter origin–destination pairs. Two portable particle monitors recorded in-vehicle and near-vehicle ambient concentrations on 1-min averages for four particle size ranges. The comparability of the monitors was quantified. Near-vehicle concentrations varied with road type, time of day, and traffic conditions. The I/O ratio was approximately independent of near-vehicle concentration and varied with window status, source of ventilation air (fresh or recirculated), and for cases with recirculation and closed windows, fan setting, and AC use. The study design can be extended to additional vehicles to account for potential sources of inter-vehicle variability. Data collected here can be used to improve exposure simulation models.

Statistical Study of Variables Associated with Particulate Matter Exposure Levels at Bus Shelters

This study expands on previous work that examined differences in exposure to particulate matter in and around bus stop shelters for passengers waiting along a busy urban corridor in Portland, Oregon. An extensive body of literature has demonstrated the negative health effects of exposure to particulate matter. Although concentrations of particulate matter were known to be greater near busy roadways, little research has been conducted on exposure in and around bus stop shelters. Two sizes of particulate matter were examined in this study: fine particulate matter of less than 2.5 microns in aerodynamic diameter (PM2.5) and ultrafine particles. Pearson association tests were run between particulate concentrations and three categories of independent variables: location, traffic, and weather. Significant correlations were observed primarily between particulates and weather (temperature and relative humidity). With 1-min data intervals, a series of log-linear regression models with and without lagged variables was used to estimate the effects of location, traffic, and weather variables on particulate concentrations. The presence of a transit bus stopped at the shelter significantly increased both sizes of particulate matter concentrations. Wind, temperature, and shelter location also had significant effects on ultrafine and PM2.5 levels. The estimated models for particulate concentrations inside and outside the bus stop shelters were compared to demonstrate differences in particulate behavior. Suggestions are made for shelter configuration given environmental and traffic considerations.

Air emissions from organic soil burning on the coastal plain of North Carolina

Emissions of trace gases and particles ≤2.5 microns aerodynamic diameter (PM2.5) from fires during 2008–2011 on the North Carolina coastal plain were collected and analyzed. Carbon mass balance techniques were used to quantify emission factors (EFs). PM2.5 EFs were at least a factor of 2 greater than those from forest burning of above-ground fuels because of extended smoldering combustion of organic soil layers and peat fuels. This is consistent with CO2 EFs at the low end of previously reported ranges for biomass fuels, indicating less efficient combustion and enhanced emissions of products of incomplete combustion (PICs). CO EFs are at the high end of the range of previously published EFs for smoldering fuels. The biomass burning tracer levoglucosan was found to compose 1–3 percent of PM2.5 from the organic soil fires, similar to fractions measured in smoke from above-ground fine fuels reported in previous studies. Organic soil fuel loads and consumption are very difficult to estimate, but are potentially as high as thousands of tonnes ha−1. Combined with higher emission factors, this can result in emission fluxes hundreds of times higher than from prescribed fires in above-ground fuels in the southeastern US. Organic soil fuel represents a source of particles and gases that is difficult to control and can persist for days to months, jeopardizing human health and incurring considerable costs to monitor and manage. Extended fires in organic soils can contribute substantially to PM2.5 on CO emission inventories and may not be adequately accounted for in current estimates.

Lack of Association between Air Pollutant Exposure and Short-Term Risk of Ischaemic Stroke in Lyon, France

Some observational and experimental studies have suggested a short-term relationship between air pollutants and ischaemic stroke; however, the results conflict. The objective of this study was to investigate the association between particulate matter less than 2·5 and 10 microns in aerodynamic diameter, nitrogen dioxide, sulphur dioxide and ozone, and short-term risk of ischaemic stroke in Lyon, France. The AVC69 study was a multicenter cohort study in which all consecutive adult patients admitted to one of the emergency or neurological departments of the Rhône area for suspicion of stroke were included during a seven-month period. Only patients with ischaemic stroke living within the study area, composed of Lyon and 18 neighbouring communities with homogenous air pollutants exposure, formed the basis of our study. We adopted a time-stratified case-crossover design to analyse the short-term effect (up to two-days) of air pollutants on ischaemic stroke incidence. Models were adjusted for temperature, variation of atmospheric pressure, minimal relative humidity, influenza epidemics, pollen count, and holidays. Stratified analyses by gender and class age were performed. Different lag times were analysed. 376 patients were included. Mean age was 76·6 years (± 13·7). 53·7% were women. No association was observed between air pollutants and short-term risk of ischaemic stroke after adjustment for main confounding factors. Results remained unchanged whatever the gender or age. These results suggest a lack of association between air pollutant exposure and short-term risk of ischaemic stroke in a French urban area.

Air Pollution and Cardiovascular System

Air pollution is one of the environmental problems that threaten the public health. The air is a gas mixture. Air pollution is defined as the existence in the amount of pollutants harmful to humans and other organisms in the atmosphere as a result of the natural or human activity thereby changing to the gas rates in the air. The negative effects of pollution-causing particles on the health are closely related to the chemical structure of particles, whether causing a fibrotic reaction, whether having an amorphous shape and the aerodynamic diameters of particles. The particles larger than 10 microns in aerodynamic diameter can not reach up to the alveoli, and can be removed by mucociliary system. If the particles are smaller than 10 microns, these particles can reach to the alveoli, and are closely associated with the cardiovascular mortality and morbidity. The concentration of these particles (PM10) is used as an indicator of pollution, and creates the basis for air quality index. Air pollution has several negative effects such as blood pressure changes, atherosclerosis, endothelial dysfunction, autonomic dysfunction, inflammation, oxidative stress etc. In this review, the effects of air pollution on the cardiovascular system will be examined, and the importance of this issue will be emphasized.

Harmonization of Uncertainties of X-Ray Fluorescence Data for PM2.5 Air Filter Analysis

The U.S. Environmental Protection Agency (EPA)’s PM2.5 Chemical Speciation Network (CSN) and the Interagency Monitoring of Protected Visual Environments (IMPROVE) network use X-ray fluorescence (XRF) analysis to quantify trace elements in samples of fine particles less than 2.5 microns in aerodynamic diameter (PM2.5). Methods for calculating uncertainty values for XRF results vary considerably among laboratories and instrument makes and models. To support certain types of modeling and data analysis, uncertainty estimates are required that are consistent within and between monitoring programs, and that are independent of the laboratories that performed the analyses and the analytical instrumentation used. The goal of this work was to develop a consensus model for uncertainties associated with XRF analysis of PM2.5 filter samples. The following important components of uncertainty are included in the model described herein: variability in peak area, calibration, field sampling, and attenuation of X-ray intensity for light elements. This paper includes a detailed analysis of how attenuation uncertainties for light elements are derived. For the remaining uncertainty components included in the model, an approach and recommendations are presented to ensure that laboratories performing this type of analysis can use similar equations and parameterizations. By applying this uniform approach, it is illustrated how the uncertainties reported by the CSN and IMPROVE network laboratories can be brought into very good agreement. The proposed method is best applied at the time of data generation, but retrospective estimation of uncertainties in existing data-sets is also possible. This paper serves to document the equations used for calculating the uncertainties in speciated PM2.5 data currently being posted on EPA’s Air Quality System database for the PM2.5 CSN program.