Indoor air exposure

Limited to residents in BRA s weatherization program Adopted OSHA standards Indoor air exposures considered in determining drinking water levels Restricts use and sales of pesticides which may cause indoor air pollution Bans on use of some potential indoor pollutants in consumer products Restricts smoking in specified indoor environments Restricts use of asl estos in VA buildings... 

Institute of Medicine. (2000). Clearing the Ar Asthma and Indoor Air Exposures. Washington, DC National Academy Press. 

Table 5 Some diseases potentially spread by indoor air exposure...

Table IV. Indoor Air Exposure Limit Guidelines or Regulations...

Indoor air exposure to automobile exhausts can arise in three ways ... 

There is some utility in having a definitive list of VOCs relevant to indoor air exposure. For example, analytical parameters can be tuned to suit defined compounds and a database of toxicological effects can be developed. The European Commission (1994) has recommended such a list (Table 3.1-6) based on field data, emission studies and frequency of presence in indoor air. This includes many of the VOCs from Table... 

In the 1990s new concepts for regulating indoor air exposure to organic compounds have been developed. Two complementary strategies have been followed ... 

Substance Odor threshold [pg/m ] Sensory irritation exposure limit estimate [pg/m ] Health-based indoor air exposure limit estimate [pg/m ] 1/40 TLV [pg/m ]... 

Total tetrachloroethylene intake for Canadians has been estimated to range from 1.2 to 2.7 pg/kg/day (CEPA 1993). Indoor air exposure (assuming 20 hours/day) from the use of household products containing tetrachloroethylene and from recently dry-cleaned clothes accounted for 1.2-1.9 pg/kg/day. 

This review summarizes occurrence and exposure studies for pollutants in house dust and related indoor air exposures. A standard sampling method and control methods to reduce these exposures are discussed, including recommendations for future research. 

Air contaminants are emitted to the indoor air from a wide variety of activities and consumer products, some of which are summarized in Table 11. Most indoor activities produce some types of pollutants. When using volatile products or engaging in the activities Hsted, care should be exercised to minimize exposure through proper use of the product and by providing adequate ventilation. 

Effects of indoor air pollutants on humans are essentially the same as those described in Chapter 7. However, there can be some additional pollutant exposures in the indoor environment that are not common in the ambient setting. From the listing in Table 23-1, radon exposures indoors present a radiation hazard for the development of lung cancer. Environmental tobacco smoke has been found to cause lung cancer and other respiratory diseases. Biological agents such as molds and other toxins may be a more likely exposure hazard indoors than outside. 

In nonindustrial settings, MCS substances are the cause of indoor air pollution and are the contaminants in air and water. Many of the chemicals which trigger MCS symptoms are known to be irritants or toxic to the nervous system. As an example, volatile organic compounds readily evaporate into the air at room temperature. Permitted airborne levels of such contaminants can still make ordinary people sick. When the human body is assaulted with levels of toxic chemicals that it cannot safely process, it is likely that at some point an individual will become ill. For some, the outcome could be cancer or reproductive damage. Others may become hypersensitive to these chemicals or develop other chronic disorders, while some people may not experience any noticeable health effects. Even where high levels of exposure occur, generally only a small percentage of people become chemically sensitive. 

Indoor air often contains a variety of contaminants at concentrations that are far below any standards or guidelines for occupational exposure. Given our present knowledge, it is difficult to relate complaints of specific health effects to exposures to specific pollutant concentrations, especially since the significant exposures may be to low levels of pollutant mixtures. 

The models in the THERdbASE CD are Chemical Source Release, Instantaneous Emission, Chemical Source Release, Timed Application, Indoor Air (2-Zone), Indoor Air (N-Zone), Exposure Patterns for Chemical Agents, Benzene Exposure Assessment Model (BEAM), Source Ba.sed Exposure Scenario (Inhalation + Dermal), and Film Thickness Based Dermal Dose. 

In all ventilation, the condition of the indoor environment, called indoor air quality (lAQ), and the exposures for the occupants are important. In industrial facilities, the contaminant emission rates may be 10-100 times higher than in nonindustrial facilities, but for many contaminants the lAQ levels may... 

Occupational and environmental exposure to chemicals can take place both indoors and outdoors. Occupational exposure is caused by the chemicals that are used and produced indoors in industrial plants, whereas nonoccupa-tional (and occupational nonindustrial) indoor exposure is mainly caused by products. Toluene in printing plants and styrene in the reinforced plastic industry are typical examples of the two types of industrial occupational exposures. Products containing styrene polymers may release the styrene monomer into indoor air in the nonindustrial environment for a long time. Formaldehyde is another typical indoor pollutant. The source of formaldehyde is the resins used in the production process. During accidents, occupational and environmental exposures may occur simultaneously. Years ago, dioxin was formed as a byproduct of production of phenoxy acid herbicides. An explosion in a factory in... 

Outdoor inhalation exposure is mainly due to traffic, energy production, heating, and natural factors such as pollen and mineral dusts. These outdoor sources of pollution also affect indoor air quality. The indoor concentration is typically 20-70% of the corresponding outdoor concentration. Occasionally the indoor concentrations of an external pollutant (especially radon) may even exceed the concentrations outdoors. ... 

Problems that rank relatively high in cancer and non-cancer health risks but low in ecological and welfare risks include hazardous air pollutants, indoor radon, indoor air pollution other than radon, pesticide application, exposure to consumer products, and worker exposures to chemicals... 

Research done by experts in the field as well as in laboratories has helped them understand the relationship between lAQ, ventilation, and energy. More research is needed to link specific health symptoms with exposure to specific or a group of pollutants. The policy challenge will be to raise awareness of indoor air quality so that healthy, comfortable environments can be provided by energy efficient technology. 

Formaldehyde is a harmful compound released from walls and furnitures in new houses because adhesives containing HCHO are often used in constmction materials. In addition, H CHO is emitted by tobacco smoke and combustion exhaust gases. Long exposure to HCHO causes serious health problems called sick house diseases. In Japan, the concentration of HCHO in indoor air is regulated [54] to under 0.08 ppm based on the recommendation of the World Health Organization (WHO). 

Trichloroethylene levels monitored in expired breath of 190 New Jersey residents were correlated with personal exposure levels, which were consistently higher than outdoor air levels and were instead attributed to indoor air levels (Wallace et al. 1985). Other studies have expanded upon and confirmed these findings, concluding that indoor air is a more significant exposure source of trichloroethylene than outdoor air, even near major point sources such as chemical plants (Wallace 1986 Wallace et al. 1986a, 1986b, 1986c,... 

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