Mist Concentration Measurements: An Evaluation of Sampling Methods

Sampling methods to determine occupational exposures to metalworking fluid mists are subject to bias. Light scattering devices may respond differently to variations in particle size, shape, and refractive index. Gravimetric samplers, such as filters, are prone to evaporative losses of semi-volatile components. Electrostatic precipitators, another gravimetric sampler, are designed to minimize evaporative losses of semi-volatile components. The performance of two light scattering devices, an electrostatic precipitator, and filters followed by gravimetric analysis was investigated when measuring metalworking fluid mist in laboratory and field settings. Laboratory tests with mineral oil and soluble oil, and field tests with mineral oil, soluble oil, straight oil, and semi-synthetic fluid, showed significant evaporative losses from filters which retained only 20-85% of the mass measured by the ESP. Light scattering devices tended to overestimate mist concentrations when mass median diameters were less than about 2 μm and underestimate mist concentrations when mass median diameters were larger than this. Filters will under estimate occupational exposures to metalworking fluid mists when semi-volatile components are present.Master of Science in Environmental Engineerin

Biodiesel effects on particulate radiocarbon (14C) emissions from a diesel engine

Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Aerosol Science 39 (2008): 667-678, doi:10.1016/j.jaerosci.2008.04.001.The relative amount of 14C in a sample of atmospheric particulate matter (PM), defined as percent modern carbon (pMC), allows EPA to infer the fraction of PM derived from anthropogenic pollution sources. With increased use of biofuels that contain 14C, the main assumption of the two-source model, that 14C is solely derived from biogenic sources, may become invalid. The goal of this study was to determine the 14C content of PM emitted from an off-highway diesel engine running on commercial grade biodiesel. Tests were conducted with an off-highway diesel engine running at 80% load fueled by various blends of soy-based biodiesel. A dilution tunnel was used to collect PM10 emissions on quartz filters that were analyzed for their 14C content using accelerator mass spectrometry. A mobility particle sizer and 5-gas analyzer provided supporting information on the particle size distribution and gas-phase emissions. The pMC of PM10 aerosol increased linearly with the percentage of biodiesel present in the fuel. Therefore, PM emissions resulting from increased combustion of biodiesel fuels will likely affect contemporary 14C apportionment efforts that attempt to split biogenic vs. anthropogenic emissions based on aerosol-14C content. Increasing the biodiesel fuel content also reduced emissions of total hydrocarbons (THC), PM10 mass, and particulate elemental carbon. Biodiesel had variable results on oxides of nitrogen (NOx) emissions

Dataset associated with "Unequal airborne exposure burden to toxic metals is associated with race, ethnicity, and segregation"

This dataset contains annual and county-level mean concentrations and mass proportions of fine particulate metals (aggregated from the EPA's CSN/IMPROVE networks), associated minimum detectable limit for each monitor, as well as racial and ethnic demographic population data. This dataset is aggregated from publicly available air pollutant data from the EPA (http://views.cira.colostate.edu/fed/QueryWizard/Default.aspx) and the US Census Bureau (https://data.census.gov/cedsci/). This dataset is used to examine the association of racial residential segregation with fine particulate metal concentrations. The time period ranges from year 2009 to 2019.- Columns labeled "XX_concentration" report the annual and county-level mean concentration in ug m-3 - Columns labeled 'XX_content" report the mass proportion of fine particulate metals relative to PM2.5 mass - Columns labeled "XX_mdl" report the minimum detectable limit for that species at that monitor. In the case of more than one monitor in the county, this column reports the average. - Columns labeled "DI_XX" report the dissimilarity index for the racial/ethnic group using the non-Hispanic White population as the reference population (see associated manuscript for details), where "NHB" corresponds to non-Hispanic Black and "native_amer" to "Native American". - Columns labeled "XX_pop_county" report the county population of the respective racial/ethnic group. These groupings reflect the identification made by individuals in US Census Bureau data. "NHW" refers to "non-Hispanic White". - "CountyFIPS" refers to the county FIPS code. - "Latitude" and "Longitude" reflect the coordinates of the monitor in degrees. In the case of more than one monitor per county, these columns averages.Communities of color have been exposed to a disproportionate burden of air pollution across the United States for decades. Yet, the inequality in exposure to known toxic elements of air pollution is unclear. Here, we find that populations living in racially segregated communities are exposed to a form of fine particulate matter with over three times higher mass proportions of known toxic and carcinogenic metals. While concentrations of total fine particulate matter are two times higher in racially segregated communities, concentrations of metals from anthropogenic sources are nearly ten times higher. Populations living in racially segregated communities have been disproportionately exposed to these environmental stressors throughout the past decade. We find evidence, however, that these disproportionate exposures may be abated though targeted regulatory action. For example, recent regulations on marine fuel oil not only reduced vanadium concentrations in coastal cities, but also sharply lessened differences in vanadium exposure by segregation.This work was supported financially by grants from the Health Effects Institute under grant number 4953- RFA14-3/16-4 awarded to FD, National Institute of Health under grant numbers DP2MD012722 and P50MD010428 awarded to FD, National Institute of Health and National Institute of Environmental Health Sciences under grant number R01 ES028033 awarded to FD, National Institute of Health and Columbia University under grant number 1R01ES030616 awarded to FD, the National Institute On Minority Health And Health Disparities of the National Institutes of Health under award number R01MD012769 awarded to MLB and FD, the Environmental Protection Agency under grant number 83587201-0 awarded to FD and grant number RD83587101 awarded to MLB, The Climate Change Solutions Fund, and the Harvard Star Friedman Award. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Environmental Protection Agency

Direct Particle-to-Cell Deposition of Coarse Ambient Particulate Matter Increases the Production of Inflammatory Mediators from Cultured Human Airway Epithelial Cells

Exposure of cultured cells to particulate matter air pollution is usually accomplished by collecting particles on a solid matrix, extracting the particles from the matrix, suspending them in liquid, and applying the suspension to cells grown on plastic and submerged in medium. The objective of this work was to develop a more physiologically and environmentally relevant model of air pollutant deposition on cultures of human primary airway epithelial cells. We hypothesize that the toxicology of inhaled particulate matter depends strongly on both the particulate dispersion state and the mode of delivery to cells. Our exposure system employs a combination of unipolar charging and electrostatic force to deposit particles directly from the air onto cells grown at an air-liquid interface in a heated, humidified exposure chamber. Normal human bronchial epithelial cells exposed to concentrated, coarse ambient particulate matter in this system expressed increased levels of inflammatory biomarkers at 1 hour following exposure and relative to controls exposed to particle-free air. More importantly, these effects are seen at particulate loadings that are 1-2 orders of magnitude lower than levels applied using traditional in vitro systems

Exposure to Household Air Pollution from Biomass Cookstoves and Levels of Fractional Exhaled Nitric Oxide (FeNO) among Honduran Women

Household air pollution is estimated to be responsible for nearly three million premature deaths annually. Measuring fractional exhaled nitric oxide (FeNO) may improve the limited understanding of the association of household air pollution and airway inflammation. We evaluated the cross-sectional association of FeNO with exposure to household air pollution (24-h average kitchen and personal fine particulate matter and black carbon; stove type) among 139 women in rural Honduras using traditional stoves or cleaner-burning Justastoves. We additionally evaluated interaction by age. Results were generally consistent with a null association; we did not observe a consistent pattern for interaction by age. Evidence from ambient and household air pollution regarding FeNO is inconsistent, and may be attributable to differing study populations, exposures, and FeNO measurement procedures (e.g., the flow rate used to measure FeNO)

Exposure to Household Air Pollution from Biomass Cookstoves and Blood Pressure Among Women in Rural Honduras: A Cross‐Sectional Study

Growing evidence links household air pollution exposure from biomass cookstoves with elevated blood pressure. We assessed cross‐sectional associations of 24‐hour mean concentrations of personal and kitchen fine particulate matter (PM2.5), black carbon (BC), and stove type with blood pressure, adjusting for confounders, among 147 women using traditional or cleaner‐burning Justa stoves in Honduras. We investigated effect modification by age and body mass index. Traditional stove users had mean (standard deviation) personal and kitchen 24‐hour PM2.5 concentrations of 126 μg/m3 (77) and 360 μg/m3 (374), while Justa stove users’ exposures were 66 μg/m3 (38) and 137 μg/m3(194), respectively. BC concentrations were similarly lower among Justa stove users. Adjusted mean systolic blood pressure was 2.5 mm Hg higher (95% CI, 0.7‐4.3) per unit increase in natural log‐transformed kitchen PM2.5 concentration; results were stronger among women of 40 years or older (5.2 mm Hg increase, 95% CI, 2.3‐8.1). Adjusted odds of borderline high and high blood pressure (categorized) were also elevated (odds ratio = 1.5, 95% CI, 1.0‐2.3). Some results included null values and are suggestive. Results suggest that reduced household air pollution, even when concentrations exceed air quality guidelines, may help lower cardiovascular disease risk, particularly among older subgroups