Biomedical subjects

Peter A Scheff

Publications and source records attributed to Peter A Scheff.

4 recordsLinked to original sources

PubMed2006

Demolition of high-rise public housing increases particulate matter air pollution in communities of high-risk asthmatics.

Public housing developments across the United States are being demolished, potentially increasing local concentrations of particulate matter (PM) in communities with high burdens of severe asthma. Little is known about the impact of demolition on local air quality. At three public housing developments in Chicago, IL, PM with an aerodynamic diameter < 10 microm (PM10) and < 2.5 microm were measured before and during high-rise demolition. Additionally, size-selective sampling and real-time monitoring were concurrently performed upwind and downwind of one demolition site. The concentration of particulates attributable to demolition was estimated after accounting for background urban air pollution. Particle microscopy was performed on a small number of samples. Substantial increases of PM10 occurred during demolition, with the magnitude of that increase varying based on sampler distance, wind direction, and averaging time. During structural demolition, local concentrations of PM10 42 m downwind of a demolition site increased 4- to 9-fold above upwind concentrations (6-hr averaging time). After adjusting for background PM10, the presence of dusty conditions was associated with a 74% increase in PM10 100 m downwind of demolition sites (24-hr averaging times). During structural demolition, short-term peaks in real-time PM10 (30-sec averaging time) occasionally exceeded 500 microg/m(3). The median particle size downwind of a demolition site (17.3 microm) was significantly larger than background (3 microm). Specific activities are associated with realtime particulate measures. Microscopy did not identify asbestos or high concentrations of mold spores. In conclusion, individuals living near sites of public housing demolition are at risk for exposure to high particulate concentrations. This increase is characterized by relatively large particles and high short-term peaks in PM concentration.

Air Pollutants↗

PubMed2003

Application of EPA CMB8.2 model for source apportionment of sediment PAHs in Lake Calumet, Chicago.

A chemical mass balance model developed by the U.S. EPA, CMB8.2, was used to apportion the major sources of PAHs found in the sediments of Lake Calumet and surrounding wetlands in southeast Chicago. The results indicate the feasibility of applying CMB8.2 to pollutants found in aquatic sediments. To establish the fingerprints of PAH sources, 28 source profiles were collected from the literature. Some of the source profiles were modified based on the gas/particle partitioning of individual PAHs. The profiles under the same source category were averaged, and the fingerprints of six sources were established, including coke oven, residential coal burning, coal combustion in power generation, gasoline engine exhaust, diesel engine exhaust, and traffic tunnel air. Nine model operations with a total of 422 runs were made, differing in the choice of fitting species and the sources involved. Modeling results indicate that coke ovens and traffic are the two major sources of PAHs in the area. For traffic sources, either traffic tunnel alone or both diesel and gasoline engine exhausts were entered into the model. These two groups of model operations produced comparable results with regard to the PAH contributions from road traffic. Although the steel industries have shrunk in recent years, closed and still-active coke plants continue to contribute significantly to the PAH loadings. Overall, the average contribution from coke oven emissions calculated by different operations ranges from 21% to 53% of all sources, and that from traffic ranges from 27% to 63%. The pattern of source contributions shows spatial and temporal variations.

Coal↗

PubMed2003

Adjusting tapered element oscillating microbalance data for comparison with Federal Reference Method PM2.5 measurements in region 5.

Continuous monitoring of particulate matter (PM) with a diameter less than 2.5 microm (PM2.5) is quickly gaining acceptance as an alternative means of measuring fine PM in the United States. For this project, data were taken from all monitoring sites within Region 5 that used the tapered element oscillating microbalance (TEOM) for PM2.5 and had a collocated Federal Reference Method (FRM) monitor. Scatter plots of TEOM versus FRM show that for a significant fraction of the observations, an independent factor causes the TEOM to underestimate the FRM value. This underestimation appears to increase as temperature decreases. For this analysis, a linear relationship was fit to the TEOM versus FRM data, allowing a break or knot in the relationship, modeled as a change of slope, at a site-specific temperature. To test whether the models are adequate for adjusting future measurements, models were also developed using the first year of data only, and the remaining observations were used to test the durability of the relationships. For all but one monitor in Minnesota, the models developed for each site had consistently high R2s, were predictive of future measurements, and could be used to derive "FRM-like" results from the TEOM measurements. The temperature knots fitted by the model for individual sites ranged from 12.9 to 20.6 degrees C. Data from all six sites in the state of Michigan were also combined to determine if a single model could be developed for the entire state. While the single model for the state of Michigan worked reasonably well, some of the predicted concentrations at individual sites were systematically underestimating the observed concentrations on more polluted days. The same conclusion was drawn for a Region 5-wide model. This approach was also found to work very well for six individual TEOM monitors in New York State.

Air Pollutants↗

PubMedDate not supplied

Effect of ozone and aeroallergens on the respiratory health of asthmatics.

The effect of ambient air pollutants, pollens, and mold spores on respiratory health was studied in an area with low concentrations of chemical pollutants and abundant aeroallergens. A panel of 40 asthmatic subjects living near East Moline, Illinois, recorded peak expiratory flow rates (PEFRs), respiratory symptoms, frequency of asthma attacks, and asthma medication use between April and October 1994. Daily outdoor concentrations of pollutants and aeroallergens were measured, and indoor levels of bioaerosols were measured on several occasions in each participant's home. Ozone was associated with increased morning and evening symptom scores and decreased evening PEFR, and these associations remained significant with adjustment for weather and aeroallergens. The association between ozone and asthma medication use was increased in magnitude and significance with adjustment for weather and aeroallergens; however, the association between ozone and morning PEFR became nonsignificant with weather and aeroallergen adjustment. Significant associations were also found between pollen concentration and decreased evening PEFR, as well as between increased morning and evening symptom scores and asthma medication use. In addition, associations were noted between total spore concentration and increased morning PEFR and decreased morning and evening symptom scores. The inverse associations found with mold spore concentrations were not consistent with the results of other studies; however, the associations between ozone and pollen concentration were consistent with previous studies. When results were stratified by a number of independent risk factors, no differences were noted relative to allergic status or presence of dampness or flooding in the home; however, the associations with outdoor ozone and pollens were seen mainly among participants with low levels of exposure to indoor bioaerosols (< 1,800 spores/m3) or with no environmental tobacco smoke exposure.

Adolescent↗