Products, Services, and Data

Air Quality

Program Overview

COMPASS conducts air quality conformity demonstrations, facilitates public education, and provides technical assistance to member agencies to help address air quality issues in the Treasure Valley.


Air Quality Conformity Demonstration for Northern Ada County

To protect our health and the quality of the air we breathe, the US Environmental Protection Agency (EPA) sets limits on the amounts of certain pollutants that can safely be in our air. These limits are called the National Ambient Air Quality Standards. When areas exceed these standards, they must take steps to lower pollutant levels.

Areas that have exceeded any of health-based air quality standards are referred to as “nonattainment areas” (they have not “attained” the standard); areas that were nonattainment areas in the past, but have re-attained the standards, are called “maintenance areas,” because they must maintain compliance with the standards.

Northern Ada County is a maintenance area for two air pollutants – coarse particulate matter (airborne dust and other particles; referred to as “PM10”) and carbon monoxide. Northern Ada County violated the federal standard for these pollutants in the 1980s and early 1990s, and has been in compliance ever since.

Amendments to the Federal Clean Air Act mandate that any transportation project that uses federal funds and/or is deemed to be “regionally significant” in nonattainment or maintenance areas cannot contribute to the degradation of air quality – that is, they must “conform” to air quality plans to maintain compliance with the standards. The process to show that projects will not degrade air quality is called an air quality conformity demonstration. COMPASS conducts the air quality conformity demonstration for Northern Ada County.

Transportation conformity is demonstrated when a nonattainment or maintenance area can show, within the applicable guidelines and regulations, that planned transportation projects listed in a transportation program or plan will not cause or contribute to exceedances of health-based air quality standards. A finding of nonconformance would prevent the implementation of certain federally funded and/or regionally significant transportation projects.

Learn more:

For more information contact: MaryAnn Waldinger, (208) 475-2242.