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4.1 – Air Quality
<br />Draft Environmental Impact Report February 2021
<br />14800 W. Schulte Road Logistics Center 4.1-7
<br />Non-Criteria Air Pollutants
<br />Toxic Air Contaminants. A substance is considered toxic if it has the potential to cause adverse health effects in
<br />humans, including increasing the risk of cancer upon exposure, or acute and/or chronic noncancerous health
<br />effects. A toxic substance released into the air is considered a TAC. TACs are identified by federal and state agencies
<br />based on a review of available scientific evidence. In California, TACs are identified through a two-step process that
<br />was established in 1983 under the Toxic Air Contaminant Identification and Control Act. This two-step process of
<br />risk identification and risk management and reduction was designed to protect residents from the health effects of
<br />toxic substances in the air. In addition, the California Air Toxics “Hot Spots” Information and Assessment Act,
<br />Assembly Bill (AB) 2588, was enacted by the legislature in 1987 to address public concern over the release of TACs
<br />into the atmosphere. The law requires facilities emitting toxic substances to provide local air pollution control
<br />districts with information that will allow an assessment of the air toxics problem, identification of air toxics emissions
<br />sources, location of resulting hotspots, notification of the public exposed to significant risk, and development of
<br />effective strategies to reduce potential risks to the public over 5 years.
<br />Examples of TACs include certain aromatic and chlorinated hydrocarbons, certain metals, and asbestos. TACs are
<br />generated by a number of sources, including stationary sources such as dry cleaners, gas stations, combustion
<br />sources, and laboratories; mobile sources such as automobiles; and area sources such as landfills. Adverse health
<br />effects associated with exposure to TACs may include carcinogenic (i.e., cancer-causing) and noncarcinogenic
<br />effects. Noncarcinogenic effects typically affect one or more target organ systems and may be experienced on either
<br />short-term (acute) or long-term (chronic) exposure to a given TAC.
<br />Diesel Particulate Matter. Diesel particulate matter (DPM) is part of a complex mixture that makes up diesel
<br />exhaust. Diesel exhaust is composed of two phases, gas and particle, both of which contribute to health risks. More
<br />than 90% of DPM is less than 1 micrometer in diameter (about 1/70th the diameter o f a human hair), and thus is
<br />a subset of PM2.5 (CARB 2016b). DPM is typically composed of carbon particles (“soot,” also called black carbon)
<br />and numerous organic compounds, including over 40 known cancer-causing organic substances. Examples of these
<br />chemicals include polycyclic aromatic hydrocarbons, benzene, formaldehyde, acetaldehyde, acrolein, and 1,3 -
<br />butadiene (CARB 2016b). The California Air Resources Board (CARB) classified “particulate emissions from diesel-
<br />fueled engines” (i.e., DPM; 17 CCR 93000) as a TAC in August 1998. DPM is emitted from a broad range of diesel
<br />engines: on-road diesel engines of trucks, buses, and cars, and off-road diesel engines, including locomotives,
<br />marine vessels, and heavy-duty construction equipment, among others. Approximately 70% of all airborne cancer
<br />risk in California is associated with DPM (CARB 2000). To reduce the cancer risk associated with DPM, CARB
<br />adopted a diesel risk reduction plan in 2000 (CARB 2000). Because it is part of PM2.5, DPM also contributes to the
<br />same noncancerous health effects as PM2.5 exposure. These effects include premature death; hospitalizations and
<br />emergency department visits for exacerbated chronic heart and lung disease, including asthma; increased
<br />respiratory symptoms; and decreased lung function in children. Several studies suggest that exposure to DPM may
<br />also facilitate development of new allergies (CARB 2016b). Those most vulnerable to noncancerous health effects
<br />are children whose lungs are still developing and older adults who often have chronic health problems.
<br />Odorous Compounds. Odors are generally regarded as an annoyance rather than a health hazard. Manifestations of a
<br />person’s reaction to odors can range from psychological (e.g., irritation, anger, or anxiety) to physiological (e.g., circulatory
<br />and respiratory effects, nausea, vomiting, and headache). The ability to detect odors varies considerably among the
<br />population and overall is subjective. People may have different reactions to the same odor. An odor that is offensive to
<br />one person may be perfectly acceptable to another (e.g., coffee roaster). An unfamiliar odor is more easily detected and is
<br />more likely to cause complaints than a familiar one. Known as odor fatigue, a person can become desensitized to almost
<br />any odor, and recognition may only occur with an alteration in the intensity. The occurrence and severity of odor impacts
<br />depend on the nature, frequency, and intensity of the source; wind speed and direction; and the sensitivity of receptors.
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