60
Pesticides, Organic Contaminants, and Pathogens in Air
for dermal exposure, just general statements advising to avoid and wash off
when formulations are spilled on clothing or body.
Some regulations on contaminants in air are discussed in this section.
There are no enforceable national or international limits describing a permissible level of exposure to toxics in air applicable to ambient populations,
however, the U.S. Occupational Safety and Health Administration (OSHA)
issues guidance on threshold limit values (TLVs) for many chemicals including some pesticides.
Beside pesticides, there are the other airborne chemicals of concern. Termed
criteria air pollutants and regulated by the Clean Air Act (U.S. EPA), they
include particulate matter, photochemical oxidants (e.g., ozone (O 3 )), carbon
monoxide (CO), sulfur oxides (SOx), nitrogen oxides (NOx), hydrocarbons
(HxCy), and lead. EPA sets National Ambient Air Quality Standards (NAAQs)
based on the latest scientifc information (Griffth et al., 2015; Laumbach and
Kipen, 2012; Seiber et al., 1979, 2014; U.S. EPA, 2021).
Chemical manufacturing plants are a source of toxic chemicals to the air.
Examples include chlorinated solvents, monomers, and the organic contaminants in gasoline known as BETX (benzene and ethyl benzene, xylene,
toluene). These compounds are also classifed as priority pollutants by EPA
because they can contaminate groundwater, surface water, and drinking
water. Because they have high Henry’s law constants, they often wind up in
the air. They are of concern due to their acute and chronic effects on exposed
populations (e.g., workers, emergency responders, nearby residents). The
chemicals listed in Table 4.1 can contaminate drinking water and readily
undergo exchange between air, water, and surfaces due to their high Henry’s
law constants and relatively low water solubility.
Guidelines for exposure level of volatile organic compounds (VOCs) are
given by the American Council of Governmental Industrial Hygienists
(ACGIH) and various other regulatory agencies. VOCs are sometimes termed
“Purgeable Organics” (Lopez-Avila et al., 1987). U.S. EPA also classifes some
pesticides as hazardous air pollutants (HAPs). In California, many pesticides
are also classifed as toxic air contaminants (TAC) under AB 1807. Between
AB 1807 and California’s unique proposition 65, pesticides and other chemicals received multiple regulatory limitations (CARB, 2017). Of the TACs in
California, 16 are pesticides. At the international level, persistent organic
pollutants (POPs) are known to undergo transport in the air to more distant
areas via long-range transport (see Table 4.2).
4.4 Indoor vs Outdoor Chemicals
People spend most of their time indoors, in houses, buildings, stores, etc. Thus,
attention to indoor chemical exposure is warranted. The trend toward more
Pesticides, Organic Contaminants, and Pathogens in Air
for dermal exposure, just general statements advising to avoid and wash off
when formulations are spilled on clothing or body.
Some regulations on contaminants in air are discussed in this section.
There are no enforceable national or international limits describing a permissible level of exposure to toxics in air applicable to ambient populations,
however, the U.S. Occupational Safety and Health Administration (OSHA)
issues guidance on threshold limit values (TLVs) for many chemicals including some pesticides.
Beside pesticides, there are the other airborne chemicals of concern. Termed
criteria air pollutants and regulated by the Clean Air Act (U.S. EPA), they
include particulate matter, photochemical oxidants (e.g., ozone (O 3 )), carbon
monoxide (CO), sulfur oxides (SOx), nitrogen oxides (NOx), hydrocarbons
(HxCy), and lead. EPA sets National Ambient Air Quality Standards (NAAQs)
based on the latest scientifc information (Griffth et al., 2015; Laumbach and
Kipen, 2012; Seiber et al., 1979, 2014; U.S. EPA, 2021).
Chemical manufacturing plants are a source of toxic chemicals to the air.
Examples include chlorinated solvents, monomers, and the organic contaminants in gasoline known as BETX (benzene and ethyl benzene, xylene,
toluene). These compounds are also classifed as priority pollutants by EPA
because they can contaminate groundwater, surface water, and drinking
water. Because they have high Henry’s law constants, they often wind up in
the air. They are of concern due to their acute and chronic effects on exposed
populations (e.g., workers, emergency responders, nearby residents). The
chemicals listed in Table 4.1 can contaminate drinking water and readily
undergo exchange between air, water, and surfaces due to their high Henry’s
law constants and relatively low water solubility.
Guidelines for exposure level of volatile organic compounds (VOCs) are
given by the American Council of Governmental Industrial Hygienists
(ACGIH) and various other regulatory agencies. VOCs are sometimes termed
“Purgeable Organics” (Lopez-Avila et al., 1987). U.S. EPA also classifes some
pesticides as hazardous air pollutants (HAPs). In California, many pesticides
are also classifed as toxic air contaminants (TAC) under AB 1807. Between
AB 1807 and California’s unique proposition 65, pesticides and other chemicals received multiple regulatory limitations (CARB, 2017). Of the TACs in
California, 16 are pesticides. At the international level, persistent organic
pollutants (POPs) are known to undergo transport in the air to more distant
areas via long-range transport (see Table 4.2).
4.4 Indoor vs Outdoor Chemicals
People spend most of their time indoors, in houses, buildings, stores, etc. Thus,
attention to indoor chemical exposure is warranted. The trend toward more