Modeling ozone deposition onto indoor residential surfaces

Reiss, Richard; Pb, Ryan; Koutrakis, P.

doi:10.1021/es00052a025

Cited by 63 publications

(48 citation statements)

References 11 publications

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“…For surfaces, the mass accommodation coefficient varies with the nature of the surface, compounds adsorbed on the surface, temperature and relative humidity. Typical mass accommodation coefficients for glass, latex paint, and wall paper (vinyl and paper) are in the range of 10 -5 to 10 -7 (Reiss et al, 1994). When a ''stick'' occurs the ozone molecule can react with surface constituents to produce products, including VOCs, or the ozone molecule can decompose through a series of surface assisted steps.…”

Section: Compounds Associated With Surfacesmentioning

confidence: 99%

Ozone in Indoor Environments: Concentration and Chemistry

Weschler¹

2000

Indoor Air

638

541

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The concentration of indoor ozone depends on a number of factors, including the outdoor ozone concentration, air exchange rates, indoor emission rates, surface removal rates, and reactions between ozone and other chemicals in the air. Outdoor ozone concentrations often display strong diurnal variations, and this adds a dynamic excitation to the transport and chemical mechanisms at play. Hence, indoor ozone concentrations can vary significantly from hour-to-hour, day-to-day, and season-to-season, as well as from room-to-room and structure-to-structure. Under normal conditions, the half-life of ozone indoors is between 7 and 10 min and is determined primarily by surface removal and air exchange. Although reactions between ozone and most other indoor pollutants are thermodynamically favorable, in the majority of cases they are quite slow. Rate constants for reactions of ozone with the more commonly identified indoor pollutants are summarized in this article. They show that only a small fraction of the reactions occur at a rate fast enough to compete with air exchange, assuming typical indoor ozone concentrations. In the case of organic compounds, the ''fast'' reactions involve compounds with unsaturated carboncarbon bonds. Although such compounds typically comprise less than 10% of indoor pollutants, their reactions with ozone have the potential to be quite significant as sources of indoor free radicals and multifunctional (ªCΩO, ªCOOH, ªOH) stable compounds that are often quite odorous. The stable compounds are present as both gas phase and condensed phase species, with the latter contributing to the overall concentration of indoor submicron particles. Indeed, ozone/alkene reactions provide a link between outdoor ozone, outdoor particles and indoor particles. Indoor ozone and the products derived from reactions initiated by indoor ozone are potentially damaging to both human health and materials; more detailed explication of these impacts is an area of active investigation.Key words Ozone; I/O ratio; Indoor chemistry; Aldehydes; Particulates; Free radicals. Practical ImplicationsIndoor ozone contributes to total ozone exposures, and reactions driven by indoor ozone produce submicron particles that contribute to total particulate exposures. Indoor ozone concentrations are highly variable, but can be reasonably esti- Ozone reacts too slowly with most airborne pollutants for the process to be of practical significance. Ozone does react at a faster rate with a small subset of indoor pollutants, but the oxidation products are themselves potentially irritating to humans and damaging to materials.

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Section: Compounds Associated With Surfacesmentioning

confidence: 99%

Ozone in Indoor Environments: Concentration and Chemistry

Weschler¹

2000

Indoor Air

638

541

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“…Other researchers have also noted this aging effect. 17,18 Some evidence suggests a seasonal difference in roomaveraged ozone deposition velocity, possibly due to surface aging or regeneration. 19 Cano-Ruiz et al 20 noted the absence of data on deposition velocity or uptake coefficients for materials that line ventilation ducts.…”

Section: Ozone Depositionmentioning

confidence: 99%

Indoor Air Quality Impacts of Ventilation Ducts: Ozone Removal and Emissions of Volatile Organic Compounds

Morrison

Nazaroff

Cano-Ruiz

et al. 1998

Journal of the Air & Waste Management Association

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The concentrations of contaminants in the supply air of mechanically ventilated buildings may be altered by pollutant emissions from and interactions with duct materials. We measured the emission rate of volatile organic compounds (VOCs) and aldehydes from materials typically found in ventilation ducts. The emission rate of VOCs per exposed surface area of materials was found to be low for some duct liners, but high for duct sealing caulk and a neoprene gasket. For a typical duct, the contribution to VOC concentrations is predicted to be only a few percent of common indoor levels. We exposed selected materials to ~100-ppb ozone and measured VOC emissions. Exposure to ozone increased the emission rates of aldehydes from a duct liner, duct sealing caulk, and neoprene gasket. The emission of aldehydes from these materials could increase indoor air concentrations by amounts that are as much as 20% of odor thresholds. We also measured the rate of ozone uptake on duct liners and galvanized sheet metal to predict how much ozone might be removed by a typical duct in ventilation IMPLICATIONSThe quality of air entering a building may be affected by pollutant emissions from ventilation system materials and by pollutant reaction on duct surfaces. This paper shows that primary emissions of VOCs from materials in ventilation systems should not significantly increase the total indoor concentration. However, ozone interactions with these materials can increase the emission rate of irritating compounds, resulting in concentrations that approach the odor threshold. Ozone is also removed at duct surfaces, which can potentially improve indoor air quality. However, ozone loss on duct surfaces probably does not greatly reduce indoor concentrations.systems. For exposure to a constant ozone mol fraction of 37 ppb, a lined duct would initially remove ~9% of the ozone, but over a period of 10 days the ozone removal efficiency would diminish to less than 4%. In an unlined duct, in which only galvanized sheet metal is exposed to the airstream, the removal efficiency would be much lower, 0.02%. Therefore, ducts in ventilation systems are unlikely to be a major sink for ozone.

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“…25 For example, ozone concentrations are almost always lower indoors than outdoors because infiltration of outdoor ozone is its principal source 26 and ozone is deposited rapidly on indoor surfaces. 27 Total human exposure is best characterized by personal monitoring of pollutants. Personal monitors have been developed for only a small number of pollutants and collection of personal exposure data requires extensive resources for statistically representative population samples.…”

Section: Exposure Models Backgroundmentioning

confidence: 99%

A Socioeconomic Assessment of Human Exposure to Ozone in the South Coast Air Basin of California

Korc

1996

Journal of the Air & Waste Management Association

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The purpose of this study is to assess by age, race, ethnicity, and income the effects of air pollution control measures and population growth on human exposure to ozone in the South Coast Air Basin of California (SoCAB). A methodology to study human exposure to air pollutants from a socioeconomic perspective has been developed. Specifically, the Regional Human Exposure model (REHEX-II) has been applied to estimate historical (1980)(1981)(1982) and recent (1990)(1991)(1992) human exposure to ozone. The model accounts for time spent in different microenvironments for different age groups and incorporates long-term air quality data with high spatial resolution. The simulation results, expressed as per capita hours of exposure to ozone above various concentration thresholds, are associated with population race, ethnicity, and per capita income. The results indicate that ozone exposure differences by race and ethnicity have diminished over time.

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Modeling ozone deposition onto indoor residential surfaces

Cited by 63 publications

References 11 publications

Ozone in Indoor Environments: Concentration and Chemistry

Ozone in Indoor Environments: Concentration and Chemistry

Indoor Air Quality Impacts of Ventilation Ducts: Ozone Removal and Emissions of Volatile Organic Compounds

A Socioeconomic Assessment of Human Exposure to Ozone in the South Coast Air Basin of California

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