EPA is concerned about the environmental and public health impacts
of air toxics in local communities. In order to better assess air toxics
risk, the Agency has developed a computer model known as
ASPEN under its Cumulative Exposure Project to estimate ambient
levels of toxic air pollutants nationally. To test the model, 1990
emissions data were used--the most recent and comprehensive
information available at the time of the analysis. Emissions of air
toxics have changed since that time. Since 1990, EPA has issued
standards that are expected to reduce emissions of air toxics from
stationary sources by over one million tons per year. Because these
data are older and the model has certain assumptions and limitations,
EPA strongly cautions against using the results of this modeling
exercise alone to draw real-world conclusions about current local
conditions. Providing the public with information they can use to
protect the health and the environment of their communities is a
guiding principle of EPA's work, but that information must be timely
if it is to be valuable for characterizing current environmental
conditions. This new national-scale air quality model, together with
other models and air quality monitoring, will be useful tools in the
future for better understanding the environmental and public health
risks from toxic air pollution both nationally and locally. EPA is
working with state and local agencies to update and improve this air
toxics emissions information, and intends to use this model with 1996
data later this year to update national estimates of ambient air toxics
levels.
Visit EPA's Cumulative Exposure Project website to learn more.
