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MULTIYEAR REAL-TIME MONITORING OF PARTICLES, PAH, AND BLACK CARBON IN AN OCCUPIED HOUSE
Citation:
Wallace, L A., C HowardReed, AND S. J. Emmerich. MULTIYEAR REAL-TIME MONITORING OF PARTICLES, PAH, AND BLACK CARBON IN AN OCCUPIED HOUSE. Presented at ISEA 2000 Exposure Analysis in the 21st Century: Integrating Science, Policy and Quality of Life, Monterey Peninsula, CA, October 24-27, 2000.
Impact/Purpose:
The primary study objectives are:
1.To quantify personal exposures and indoor air concentrations for PM/gases for potentially sensitive individuals (cross sectional, inter- and intrapersonal).
2.To describe (magnitude and variability) the relationships between personal exposure, and indoor, outdoor and ambient air concentrations for PM/gases for different sensitive cohorts. These cohorts represent subjects of opportunity and relationships established will not be used to extrapolate to the general population.
3.To examine the inter- and intrapersonal variability in the relationship between personal exposures, and indoor, outdoor, and ambient air concentrations for PM/gases for sensitive individuals.
4.To identify and model the factors that contribute to the inter- and intrapersonal variability in the relationships between personal exposures and indoor, outdoor, and ambient air concentrations for PM/gases.
5.To determine the contribution of ambient concentrations to indoor air/personal exposures for PM/gases.
6.To examine the effects of air shed (location, season), population demographics, and residential setting (apartment vs stand-alone homes) on the relationship between personal exposure and indoor, outdoor, and ambient air concentrations for PM/gases.
Description:
Concentrations of ultrafine, fine, and coarse particles, particle-bound polycyclic aromatic hydrocarbons (PAH), and black carbon have been measured continuously (every 1 to 5 minutes) in an occupied townhouse for 2-3 years. Also, since the summer of 1999, temperature (outdoors and at 10 indoor locations), humidity (outdoors and at five indoor locations), air exchange rates (using tracer gas decay methods at 10 indoor locations), and local (rooftop) wind speed and direction have been measured at periods ranging from every six seconds (wind velocity) to every 10 minutes. The purpose has been to document particle concentrations, seasonal variations, important indoor and outdoor relationships between house characteristics (e.g., air exchange rates), personal activities (e.g., window opening behavior) and resulting concentrations of the target pollutants. Many forms of cooking (frying, deep frying, stir-frying, sauteeing, and broiling) produced order-of-magnitude increases in the number of ultrafine and fine particles, and occasionally coarse particles as well. Cooling was by far the single most important indoor source of particles in this home containing two adult non-smokers. Ultrafine particles were produced in quantity (concentrations > 1000 particles per cc for particles with diameters between 9.8 and 10.2 nm) by gas burners and by an electric toaster oven. The two most important outdoor sources of elevated indoor concentrations of PAH and black carbon were traffic (weekday mornings only) and wood smoke (fall and winter evenings only). However, these sources were not important in terms of number of mass of particles indoors. Judging from limited outdoor measurements and the persistence of nonzero indoor concentrations when no indoor sources were operating, background outdoor concentrations of ultrafine and fine particles, particularly below 1 micrometer in diameter, produced a substantial proportion of the total number of particles indoors. A powerful, though infrequent source of PAH and black carbon indoors was barbecueing on the patio. The most important indoor source of PAH and black carbon was the use of candles, although cooking could sometimes elevate these pollutants. Coarse particles were continually produced by simple activities such as sitting, walking, and other bodily motions, suggesting resuspension of particles from carpets or clothes. Approximately a million observations of fine and coarse particle number concentrations (50 sizes from 0.3-20 micrometer) and a quarter of a million observations of ultrafine particle number concentrations (100 sizes from 10-1000 nm) have been made to date.
This abstract has been reviewed and approved by EPA. Mention of brand names is not tantamount to endorsement.