Within-Neighborhood Patterns and Sources of Particle Pollution: Mobile Monitoring and Geographic Information System Analysis in Four Communities in Accra, Ghana

BACKGROUND: Sources of air pollution in developing country cities include transportation and industrial pollution, biomass and coal fuel use, and resuspended dust from unpaved roads. OBJECTIVES: Our goal was to understand within-neighborhood spatial variability of particulate matter (PM) in communities of varying socioeconomic status (SES) in Accra, Ghana, and to quantify the effects of nearby sources on local PM concentration. METHODS: We conducted 1 week of morning and afternoon mobile and stationary air pollution measurements in four study neighborhoods. PM with aerodynamic diameters RESULTS: In our measurement campaign, the geometric means of PM2.5 and PM10 along the mobile monitoring path were 21 and 49 microg/m3, respectively, in the neighborhood with highest SES and 39 and 96 microg/m3, respectively, in the neighborhood with lowest SES and highest population density. PM2.5 and PM10 were as high as 200 and 400 microg/m3, respectively, in some segments of the path. After adjusting for other factors, the factors that had the largest effects on local PM pollution were nearby wood and charcoal stoves, congested and heavy traffic, loose dirt road surface, and trash burning. CONCLUSIONS: Biomass fuels, transportation, and unpaved roads may be important determinants of local PM variation in Accra neighborhoods. If confirmed by additional or supporting data, the results demonstrate the need for effective and equitable interventions and policies that reduce the impacts of traffic and biomass pollution

Exploring consumer exposure pathways and patterns of use for chemicals in the environment

AbstractHumans are exposed to thousands of chemicals in the workplace, home, and via air, water, food, and soil. A major challenge in estimating chemical exposures is to understand which chemicals are present in these media and microenvironments. Here we describe the Chemical/Product Categories Database (CPCat), a new, publically available (http://actor.epa.gov/cpcat) database of information on chemicals mapped to “use categories” describing the usage or function of the chemical. CPCat was created by combining multiple and diverse sources of data on consumer- and industrial-process based chemical uses from regulatory agencies, manufacturers, and retailers in various countries. The database uses a controlled vocabulary of 833 terms and a novel nomenclature to capture and streamline descriptors of chemical use for 43,596 chemicals from the various sources. Examples of potential applications of CPCat are provided, including identifying chemicals to which children may be exposed and to support prioritization of chemicals for toxicity screening. CPCat is expected to be a valuable resource for regulators, risk assessors, and exposure scientists to identify potential sources of human exposures and exposure pathways, particularly for use in high-throughput chemical exposure assessment

Ex-vivo three-dimensional assessment of carotid stenosis with ultrasound

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 71-74).Atherosclerosis causes heterogeneous remodeling of arterial structure and composition in the carotid vessel wall. It has been shown that the progression of the disease can be monitored by tracking changes in the carotid intima-media thickness (IMT). Non-invasive peripheral vascular ultrasound (U/S) of the carotid artery is a non-invasive, cost effective, accepted means of measuring IMT. Traditionally, evaluation of IMT in the carotid has been limited to 2D U/S scans. This method is disadvantageous as 2D scans are scan plane dependent, limiting the area over which one can evaluate the extent of the disease. Reproducing the identical scan plane on subsequent scans is also difficult. Evaluation of the carotid vessel wall in 3D will allow for a more complete and reproducible assessment of disease through IMT measurements. We have constructed a fully 3D image processing scheme for analyzing carotid U/S volumes to extract the inner and outer vessel wall boundaries. Sequences of 2D B-mode U/S cross sections of ex-vivo carotid specimens are collected and voxelized to create 3D U/S volumes. By applying a 3D directionally sensitive, edge preserving filter to the U/S volumes, we obtain 3D edge fields that are more distinct than traditional gradient edge fields. Initial point selection of the boundaries, together with these enhanced 3D edge fields, are used with a deformable surface to extract the final inner and outer vessel boundaries. Through intra- and inter-observer tests on IMT differences, we show that the 3D boundaries extracted using our automatic technique are more reproducible than boundaries extracted from manual point selection.by Kathie L. Dionisio.S.M

Household fuel use and biomarkers of inflammation and respiratory illness among rural South African women

Though literature suggests a positive association between use of biomass fuel for cooking and inflammation, few studies among women in rural South Africa exist. We included 415 women from the South African Study of Women and Babies (SOWB), recruited from 2010 to 2011. We obtained demographics, general medical history and usual source of cooking fuel (wood, electricity) via baseline questionnaire. A nurse obtained height, weight, blood pressure, and blood samples. We measured plasma concentrations of a suite of inflammatory markers (e.g., interleukins, tumor necrosis factor-α, C-reactive protein). We assessed associations between cooking fuel and biomarkers of inflammation and respiratory symptoms/illness using crude and adjusted linear and logistic regression models. We found little evidence of an association between fuel-use and biomarkers of inflammation, pre-hypertension/hypertension, or respiratory illnesses. Though imprecise, we found 41% (95% confidence interval (CI) = 0.72–2.77) higher odds of self-reported wheezing/chest tightness among wood-users compared with electricity-users. Though studies among other populations report positive findings between biomass fuel use and inflammation, it is possible that women in the present study experience lower exposures to household air pollution given the cleaner burning nature of wood compared with other biomass fuels (e.g., coal, dung).The Intramural Research Program of the National Institutes of Health (NIH), National Institute of Environmental Health Sciences (NIEHS).http://www.elsevier.com/locate/envres2019-10-01hj2019Urolog

Household concentrations and exposure of children to particulate matter from biomass fuels in The Gambia

Particulate matter (PM) is an important metric for studying the health effects of household air pollution. There are limited data on PM exposure for children in homes that use biomass fuels, and no previous study has used direct measurement of personal exposure in children younger than 5 years of age. We estimated PM2.5 exposure for 1266 children in The Gambia by applying the cookhouse PM2.5–CO relationship to the child’s CO exposure. Using this indirect method, mean PM2.5 exposure for all subjects was 135 ± 38 μg/m3; 25% of children had exposures of 151 μg/m3 or higher. Indirectly estimated exposure was highest among children who lived in homes that used firewood (collected or purchased) as their main fuel (144 μg/m3) compared to those who used charcoal (85 μg/m3). To validate the indirect method, we also directly measured PM2.5 exposure on 31 children. Mean exposure for this validation data set was 65 ± 41 μg/m3 using actual measurement and 125 ± 54 μg/m3 using the indirect method based on simultaneously-measured CO exposure. The correlation coefficient between direct measurements and indirect estimates was 0.01. Children in The Gambia have relatively high PM2.5 exposure. There is a need for simple methods that can directly measure PM2.5 exposure in field studies

High Throughput Heuristics for Prioritizing Human Exposure to Environmental Chemicals

The risk posed to human health by any of the thousands of untested anthropogenic chemicals in our environment is a function of both the hazard presented by the chemical and the extent of exposure. However, many chemicals lack estimates of exposure intake, limiting the understanding of health risks. We aim to develop a rapid heuristic method to determine potential human exposure to chemicals for application to the thousands of chemicals with little or no exposure data. We used Bayesian methodology to infer ranges of exposure consistent with biomarkers identified in urine samples from the U.S. population by the National Health and Nutrition Examination Survey (NHANES). We performed linear regression on inferred exposure for demographic subsets of NHANES demarked by age, gender, and weight using chemical descriptors and use information from multiple databases and structure-based calculators. Five descriptors are capable of explaining roughly 50% of the variability in geometric means across 106 NHANES chemicals for all the demographic groups, including children aged 6–11. We use these descriptors to estimate human exposure to 7968 chemicals, the majority of which have no other quantitative exposure prediction. For thousands of chemicals with no other information, this approach allows forecasting of average exposure intake of environmental chemicals

Household Concentrations and Exposure of Children to Particulate Matter from Biomass Fuels in The Gambia

Particulate matter (PM) is an important metric for studying the health effects of household air pollution. There are limited data on PM exposure for children in homes that use biomass fuels, and no previous study has used direct measurement of personal exposure in children younger than 5 years of age. We estimated PM_2.5 exposure for 1266 children in The Gambia by applying the cookhouse PM_2.5–CO relationship to the child’s CO exposure. Using this indirect method, mean PM_2.5 exposure for all subjects was 135 ± 38 μg/m³; 25% of children had exposures of 151 μg/m³ or higher. Indirectly estimated exposure was highest among children who lived in homes that used firewood (collected or purchased) as their main fuel (144 μg/m³) compared to those who used charcoal (85 μg/m³). To validate the indirect method, we also directly measured PM_2.5 exposure on 31 children. Mean exposure for this validation data set was 65 ± 41 μg/m³ using actual measurement and 125 ± 54 μg/m³ using the indirect method based on simultaneously-measured CO exposure. The correlation coefficient between direct measurements and indirect estimates was 0.01. Children in The Gambia have relatively high PM_2.5 exposure. There is a need for simple methods that can directly measure PM_2.5 exposure in field studies