FEDERAL AIR TOXICS PROGRAM
USEPA PROGRAMS FOR AIR TOXIC EMISSIONS
USEPA’s Air Toxics Website can be found here.
Under the federal Clean Air Act Amendments of 1990, USEPA is required to adopt a number of national air toxic reduction programs that address 187 hazardous air pollutants, also known as HAPs. NJDEP will be working with USEPA to implement these programs in our state. Two of these programs are the adoption of Maximum Achievable Control Technology (MACT) standards for large sources (such as chemical manufacturing), and the Urban Air Toxics Strategy for small sources (such as hospital sterilizers). Once USEPA has issued all of the MACT standards, they are required to conduct a health risk assessment and revise a standard if it is shown to be necessary to protect public health. With the National-Scale Air Toxics Assessment (NATA), USEPA has also undertaken an effort to predict levels of hazardous air pollutants in outdoor air nationwide. This is described briefly below.
MAXIMUM ACHIEVABLE CONTROL TECHNOLOGY (MACT)
USEPA must promulgate regulations establishing emission
standards for about 174 categories of HAP sources. The
standards require the maximum degree of emission reduction
that USEPA determines to be achievable for each particular
source category. The standards are established for sources
of HAPs that emit 10 tons per year of a single HAP or
25 tons per year of combined HAPs. Different criteria
for MACT apply
for new and existing sources. At the Administrator’s
discretion, less stringent standards, known as generally
available control technology (GACT) will be promulgated.
To date, USEPA has promulgated 96 MACT emission standards.
For more information on MACT, see "National Emission Standards for Hazardous Air Pollutants Information" .
RESIDUAL RISK ASSESSMENT
Under the Clean Air Act, USEPA is required to develop
and implement a program for assessing the risk remaining
(known as "residual risk") after facilities
have implemented MACT standards. If necessary, USEPA is required to
issue regulations to reduce any residual risks in order
to protect the public health with an ample margin of
safety. USEPA must issue any risk-based regulations within
eight years after it issues an air toxics standard for
a given source category. In March of 1999, USEPA developed
Risk Report to Congress which described the methods they would use to carry out the residual risk program.
Using this guidance, on March 31, 2005, USEPA issued
its first risk-based regulation for a promulgated MACT
standard. To date, USEPA has promulgated residual risk
standards for 16 source categories. For more information, see USEPA's Air Toxics Web Page on Risk and Technology Review.
URBAN AIR TOXICS STRATEGY
In July 1999, USEPA released the Integrated Urban Air Toxics Strategy. The strategy is a framework for addressing air toxics in urban areas from stationary, mobile, and indoor sources. The air toxics strategy has three main goals: 1) attain a 75% reduction in cancer risk attributable to large and small stationary sources; 2) attain a substantial reduction of public health risks posed by HAP emissions from area sources; and 3) address disproportionate impacts of air toxics hazards across urban areas such as geographic “hot spots,” highly exposed population subgroups, and predominately minority and low-income communities (See EPA Air Toxics Strategy Fact Sheet). As part of the strategy, USEPA has identified 33 air toxics that present the greatest threat to public health in urban areas. Also identified are 70 area source categories that contribute substantially to the emissions of these air toxics. Of those 70 categories, 53 have been regulated and the remaining are under development or will be developed in the future. EPA is under a court ordered schedule to promulgate standards for the remaining source categories by December 16, 2010. For more information see USEPA's Air Toxic Web site Urban Strategy page.
USEPAS NATIONAL-SCALE AIR
TOXICS ASSESSMENT (NATA)
USEPA has carried out a national assessment of ambient concentrations of hazardous air pollutants (HAPs) and diesel particulate matter from stationary, area, and mobile sources for the years 1996, 1999, 2002, 2005, 2011 and 2014. HAP emissions are compiled in the National Emissions Inventory (NEI) every three years. Using an advanced dispersion models, USEPA uses the emissions estimates to predict ambient concentrations of HAPs and diesel PM for every census tract and county in the United States. These predicted concentrations are compared to ambient air toxic monitoring data to evaluate model accuracy. NATA also estimates exposure and evaluates the potential public health risks from inhalation of these air toxics by various populations. NATA is used to identify air toxics of greatest concern to public health, to track trends of air toxics concentrations over time, and to assist in prioritizing data collection activities.
For more information, refer to USEPA's
Mobile sources, notably cars, are a very significant source of air toxics. In early 2006, USEPA proposed the rule “Control of Hazardous Air Pollutants from Mobile Sources.” It would significantly lower emissions of air toxics by lowering the benzene content of gasoline; by reducing exhaust emissions from passenger vehicles operated at cold temperatures; and by reducing emissions from portable gasoline containers. Initiatives to reduce diesel particulate emissions are also being implemented. For more information click here.