Region has maintained PM10 standard for 20 years

Transportation conformity requirement ends

In 1987, the industrial areas of the Seattle Duwamish River, Kent Valley and Tacoma Tideflats exceeded the standard for PM10 or coarse particulate matter that is 10 micrometers or less in diameter. These fine particles cause haze and may cause health problems when inhaled. The Environmental Protection Agency designated these places in the region as nonattainment areas.

The region and state worked with partners to reduce emissions and came back into compliance and received attainment status in 2001. This began a 20-year maintenance period in which emissions were closely tracked to ensure air pollutant concentrations remain below the federal standards.

The region has now achieved 20 years below the PM10 standard and the maintenance period is over!

This ends the transportation conformity requirement for PM10 levels to be evaluated prior to funding or approval of transportation projects, plans or programs.

While the region will no longer need to specifically address conformity for PM10, PSRC will continue to conduct an emissions analysis for VISION, the Regional Transportation Plan and the Regional Transportation Improvement Program.  This ensures that transportation activities are reviewed and evaluated for their impacts on air quality prior to approval and funding.