Air Toxics of Greatest Concern in New England - 2011 NATA
The 2011 National Air Toxics Assessment (NATA) estimated that state average risk values of four air toxics: acetaldehyde, benzene, carbon tetrachloride, and formaldehyde exceeded health benchmarks in every state in New England, and state average risk values of three air toxics: 1, 3-butadiene, acrolein, and naphthalene exceeded health benchmarks in at least one state in New England. Diesel particulate matter is also an air toxic of concern since the estimated ambient concentrations are high in most of the New England states. Most of these chemicals are carcinogens and may also cause other health effects, such as exacerbation of asthma.
The risk values used in 2011 NATA represent the concentration of a pollutant above which there may be potential public health concerns. The risk values essentially serve as "yardsticks" to assess the potential threat to the public health posed by the Clean Air Act Hazardous Air Pollutants (HAPs) which have established risk values. These values represent the current state of scientific understanding about the health effects of the pollutants of concern. The upper-bound lifetime cancer risk value denotes the concentration of a known, probable or possible human carcinogen that will result in the potential for one excess cancer to occur in one million individuals exposed over a 70 year lifetime.
Background concentrations represented an overwhelming portion of the ambient concentrations derived for carbon tetrachloride because it persists in the environment and so we have not analyzed these emissions in great detail but have included it on our list of greatest concern. Atmospheric transformation (secondary formation) accounts for a significant portion of the ambient air concentration for acetaldehyde and formaldehyde, but are also emitted from various sources and so, we have analyzed these emissions.
NATA evaluated the inhalation route of exposure for toxic air pollutants that had established health risk values and outdoor air emission estimates. Therefore, there are other air toxics, such as: asbestos, dioxins, lead, mercury, radon and PCBs, that are also a concern due to other routes of exposure or exposure from indoor sources for which Region I has developed separate risk reduction strategies.
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|Pollutant||Health Effects||Sources in New England|
|Acetaldehyde||Health Effects||Summary (PDF) (1 pg, 129 K)|
|Acrolein||Health Effects||Summary (PDF) (1 pg, 125 K)|
|1,3-Butadiene||Health Effects||Summary (PDF) (1 pg, 130 K)|
|Benzene||Health Effects||Summary (PDF) (1 pg, 130 K)|
|Carbon Tetrachloride||Health Effects|
|Diesel||Health Effects||Summary (PDF) (1 pg, 127 K)|
|Formaldehyde||Health Effects||Summary (PDF) (1 pg, 126 K)|
|Naphthalene||Health Effects||Summary (PDF) (1 pg, 129 K)|
Summation of Carcinogenic Risk Estimate Map of New England
The map below represents a summation of carcinogenic risk estimates for inhalation exposure to 80 air toxics that have been modeled in the 2011 National Scale Air Toxic Assessment. The risk estimates in the map below are based on the census tract level average of a typical individual's exposure.
The following limitations to these carcinogenic risk estimates for exposure to these air toxics must be noted: the inhalation route of exposure is the only exposure route that has been evaluated, only inventoried outdoor air toxic sources were used in this assessment since there isn't adequate data on indoor air exposures, and the risks associated with each carcinogenic pollutant are only added together since there is inadequate information on other health effect interactions.
These carcinogenic risk estimates can not be related to an individual's risk of cancer because the estimates are restricted to 2011 estimates and the results should be reviewed across broad geographic areas such as counties and states. These risk estimate maps should not be used to obtain information on specific types of cancers or possible cancer clusters but they can provide EPA, the states and the public with information on whether we're focusing on the right pollutants and sources to protect the public health.
Summation of Noncancer Risks Map of New England
The map below represents a summation of hazard quotients that are used to provide a quantification of risks associated with noncarcinogenic chronic health effects for respiratory irritants. EPA considered adverse health effects other than cancer for 112 air toxics. A hazard quotient for a pollutant that is less than 1 indicates that no adverse health effects are expected as a result of exposure. If the hazard quotient is greater than 1, then adverse health effects are possible. The hazard index represented in the following map is a sum of all of the hazard quotients for the respiratory target organ system, with 43 air toxics evaluated as respiratory irritants. The risk estimates in the map are based on the census tract level average of a typical individual's exposure.
The following limitations to these chronic risk estimates must be noted: the inhalation route of exposure is the only exposure route that has been evaluated and only inventoried outdoor air toxic sources were used in this assessment since there isn't adequate data on indoor air emissions.