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U.S. Environmental Protection Agency
Office of Inspector General
At a Glance
March 2, 2005
Catalyst for Improving the Environment
Why We Did This Review
We performed this review to
evaluate EPA's progress in
establishing a national network
and determine the status of
ambient air toxics monitoring
nationwide. A viable ambient
monitoring program to detect
areas of unhealthy air toxics
concentrations and to measure
national and local trends in
those concentrations is key to
assessing progress in reducing
air toxics-related health risks.
The Clean Air Act (CAA)
identifies 188 air toxics.
EPA defines air toxics as
"those pollutants that are
known or suspected to cause
cancer or other serious health
effects or adverse
environmental effects." EPA's
goal is to reduce unacceptable
health risks from air toxics for
95 percent of the population by
2020. Ambient monitoring is
important to assess progress
towards meeting this goal.
For further information, contact
our Office of Congressional and
Public Liaison at (202) 566-2391.
To view the full report,
click on the following link:
Progress Made in Monitoring Ambient Air Toxics,
But Further Improvements Can Increase Effectiveness
What We Found
The CAA does not require a national air toxics monitoring network but EPA and
State and local agencies have recognized such a network is needed. Since 2000,
EPA has significantly increased its ambient air toxics monitoring efforts and
funding to establish a national network and support State and local agencies'
monitoring activities. EPA recently established 23 national sites to assess
ambient air toxics trends, and State and local agencies have established over
300 fixed ambient air toxics monitoring stations nationwide. Further, in 2004
EPA began awarding grants to State and local agencies to conduct short-term,
local-scale monitoring projects.
Still, additional effort and improvement is needed to ensure that sufficient
ambient air toxics data is available to identify areas of unhealthy ambient air
toxics concentrations, identify national air toxics trends, and assess the
effectiveness of air toxics reduction strategies. For example, there was little
association between the location of State and local air toxics monitors and areas
estimated to have high health risks from air toxics exposure. Also, we identified
inconsistencies in the sampling frequencies and quality assurance measures for
the national trends sites. Key barriers to ambient air toxics monitoring included
adequacy of funding and lack of methods to monitor certain air toxics.
What We Recommend
We recommend a number of actions to improve the effectiveness of ambient air
toxics monitoring. For example, with respect to monitoring conducted on a
local-scale (i.e., certain State and local network monitors and EPA's local project
grant program), EPA should develop a strategy - in coordination with its State,
local, and tribal partners - for siting monitors in locations that are estimated to
present the greatest health risks from exposure to air toxics. We also recommend
several actions for improving the programmatic aspects of the national trends
sites, particularly with respect to quality assurance, quality control, and data
completeness. In addition, we recommend that EPA's Office of Research and
Development place greater emphasis on methods development for analyzing
ambient air toxics concentrations. The Agency generally agreed with our draft
report's recommendations.