Masoud Afshar

Relationship of Indoor, Outdoor and Personal Air (RIOPA) study: study design, methods and quality assurance/control results.

The Relationship of Indoor, Outdoor and Personal Air (RIOPA) Study was undertaken to evaluate the contribution of outdoor sources of air toxics, as defined in the 1990 Clean Air Act Amendments, to indoor concentrations and personal exposures. The concentrations of 18 volatile organic compounds (VOCs), 17 carbonyl compounds, and fine particulate matter mass (PM2.5) were measured using 48-h outdoor, indoor and personal air samples collected simultaneously. PM2.5 mass, as well as several component species (elemental carbon, organic carbon, polyaromatic hydrocarbons and elemental analysis) were also measured; only PM 2.5 mass is reported here. Questionnaires were administered to characterize homes, neighborhoods and personal activities that might affect exposures. The air exchange rate was also measured in each home. Homes in close proximity (<0.5 km) to sources of air toxics were preferentially (2:1) selected for sampling. Approximately 100 non-smoking households in each of Elizabeth, NJ, Houston, TX, and Los Angeles, CA were sampled (100, 105, and 105 respectively) with second visits performed at 84, 93, and 81 homes in each city, respectively. VOC samples were collected at all homes, carbonyls at 90% and PM2.5 at 60% of the homes. Personal samples were collected from nonsmoking adults and a portion of children living in the target homes. This manuscript provides the RIOPA study design and quality control and assurance data. The results from the RIOPA study can potentially provide information on the influence of ambient sources on indoor air concentrations and exposure for many air toxics and will furnish an opportunity to evaluate exposure models for these compounds.

Inhalation exposures to acrylamide in biomedical laboratories

This study evaluated airborne acrylamide exposures experienced by laboratory personnel using either crystalline or commercially available solutions of acrylamide to make polyacrylamide gels. Exposures were monitored for a short-term (15-min) sampling period, during the weighing of the crystalline acrylamide or the removal of the acrylamide solution from its original container, and a long-term period, during which a sample was collected for as long as the subject was potentially exposed to acrylamide. Mean air concentrations for the 15-min exposures were 7.20 +/- 5.64 micrograms/m3 and 5.81 +/- 4.53 micrograms/m3 for the users of crystalline and solution acrylamide, respectively, although this difference was not statistically significant (p > 0.05). Mean concentrations for the long-term exposures were 12.77 +/- 24.20 micrograms/m3 for workers employing crystalline acrylamide and 4.22 +/- 7.05 micrograms/m3 for personnel using acrylamide solutions. This difference was also not statistically significant. Although the results indicate that the research laboratory personnel were generally exposed to measurable concentrations of acrylamide, with several subjects exposed to elevated levels, the calculated 8-hour time-weighted average exposures were below current occupational exposure limits. However, because the neurotoxic effects of acrylamide are cumulative and it is a suspected carcinogen, all exposures should be kept as low as reasonably achievable.

Evaluation of the Use of Diffusive Air Samplers for Determining Temporal and Spatial Variation of Volatile Organic Compounds in the Ambient Air of Urban Communities

Abstract The Houston-Galveston metropolitan area has a relatively high density of point and mobile sources of air toxics, and determining and understanding the relationship between emissions and ambient air concentrations of air toxics is important for evaluating potential impacts on public health and formulating effective regulatory policies to control this impact, both in this region and elsewhere. However, conventional ambient air monitoring approaches are limited with regard to expense, siting limitations, and representative sampling necessary for adequate exposure assessment. The overall goal of this multiphase study is to evaluate the use of simple passive air samplers to determine temporal and spatial variability of the ambient air concentrations of selected volatile organic compounds (VOCs) in urban areas. Phase 1 of this study, reported here, was a field evaluation of 3M organic vapor monitors (OVMs) involving limited comparisons with commonly used active sampling methods, an assessment of sampler precision, a determination of optimal sampling duration, and an investigation of the utility of a simple modification of the commercial sampler. The results indicated that a sampling duration of 72 hr exhibited generally low bias relative to automated continuous gas chromatography measurements, good overall precision, and an acceptable number of measurements above detection limits. The modified sampler showed good correlation with the commercial sampler, with higher sampling rates, although lower than expected.

Post-Hurricane Katrina passive sampling of ambient volatile organic compounds in the greater New Orleans area

On August 29, 2005, Hurricane Katrina made landfall near New Orleans, Louisiana, a major metroplex with petroleum industries. In response to the potential impact of the storm on air quality and to assess the exposures to toxic air pollutants of public health concern, the United States Environmental Protection Agency conducted passive monitoring of air toxics for three months, starting in late October 2005 through early February 2006, at up to 18 sites in the New Orleans area affected by Hurricane Katrina. The overall results of the passive ambient monitoring are summarized with the concentrations for the twenty-nine observed volatile organic chemicals, which include benzene, toluene, ethylbenzene, and xylenes, and the measured concentrations are compared with available health-based screening levels. The results of passive monitoring are also compared with those of the collocated canister sampling at one of the sites. The overall results showed that the outdoor levels of atmospheric volatile organic chemcals in the post-Katrina New Orleans area were very low and far below the available screening levels. The results also confirm the effectiveness of passive monitoring in a large geographical area where conventional methods are not feasible, electrical power is not available, and the need for sampling is urgent, as in the aftermath of natural disasters and other catastrophes.

Lead and copper in drinking water fountains-information for physicians

Background: Lead and copper are potentially toxic metals. The objective of our work was to test the water from the drinking fountains of a large public access office complex in southwest Houston, Texas, for the presence of lead, copper, and microbiologic contamination. The data for the water fountains were compared with what we found in the local municipal drinking water supplies. Methods: Samples were collected as the first draw at the beginning of the work week. These samples were acidified to prevent the precipitation of heavy metals and analyzed using United States Environmental Protection Agency (USEPA) approved procedures and quality control. Results: Traces of lead were detected in 37.5% and copper in 100% of the tested water fountains. In two buildings, concentrations in some fountains exceeded the USEPA action level for lead (by up to 12-fold) and for copper (by up to 3.9 fold). One sample was positive for total coliform and Escherichia coli bacteria. Comparison with samples from the local municipal drinking water supplies indicated that both metals and bacteria were the result of secondary contamination at the water fountain sites. Conclusions: This study showed that drinking water fountains can be an unexpected and unappreciated source of intake of metal and bacterial contaminants.

Accessing Disadvantaged Pregnant Women in Houston, Texas, and Characterizing Biomarkers of Metal Exposure: A Feasibility Study

Communities of color or low socioeconomic status are disproportionately affected by metal exposure given spatial variability of the ambient levels of these contaminants. Despite this, there is little research characterizing metal concentrations in blood among disadvantaged populations in the U.S., especially among pregnant women who are particularly vulnerable and difficult to access. Thus, we conducted a pilot study among disadvantaged pregnant women in Houston, Texas to assess willingness to participate in key activities of an epidemiologic study and characterize exposures to 16 metals. Thirty-one women attending a Medicaid-serving prenatal clinic were included in this pilot study and completed an interviewer-administered questionnaire. We obtained and measured metal compounds in whole blood samples for 22 of these women during third-trimester prenatal visits. Median whole blood concentrations of Ni, As, Cd, and Pb were 27, 1.4, 0.6, and 6.3 µg/L, respectively. Most women were willing to participate in critical aspects of a research study, including wearing a personal air-sampling badge for 2–3 days (87.1%), receiving ultrasounds (83.9%), and providing blood draws (64.5%). Despite the small sample, our results provide evidence of women’s metal exposure and their willingness to participate in future research studies to elucidate exposure pathways and explore related health effects experienced among this population of disadvantaged pregnant women.