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National Air Toxics Trends Station (NATTS) Section 103 Grant Package Template

Overview and Project Objectives

There are currently 187 hazardous air pollutants (HAPs), or air toxics, regulated under the Clean Air Act (CAA) that have been associated with a wide variety of adverse health effects, including cancer and neurological effects. These air toxics are emitted from multiple sources, including major stationary, area, and mobile sources, resulting in population exposure to these pollutants.

The National Air Toxics Trends Station (NATTS) program was developed to fulfill the need for long-term HAP monitoring data of consistent quality. This site is part of a national network of air toxics monitoring stations. The primary purpose of the NATTS network is tracking trends in ambient air toxics levels to facilitate measuring progress toward emission and risk reduction goals. The monitoring network is intended, over a multi-year period, to be able to detect a 15% difference (trend) between successive 3-year annual mean concentrations within acceptable levels of decision error.

EPA also implements the National Air Toxics Assessment (NATA) to help characterize the air toxics problem. Principal NATA activities include identification of areas of concern, characterizing risks and tracking progress. These objectives may be met in part through the measurement of technically consistent ambient concentrations of air toxics at trends monitoring sites throughout the nation. They are also met through the National-Scale Air Toxics Assessment (also referred to as NATA), a screening tool based on air quality modeling. Data from NATTS are used to evaluate the modeled concentrations from this assessment.

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