Oregon DEQ: Air Quality Portland Air Toxics

In 2006 DEQ completed an air quality modeling study called the Portland Air Toxics Assessment or PATA. This study used local meteorology, topography and emission information about population, neighborhood, car, truck, industrial and smaller sources to predict the level of 12 air toxics (hazardous air pollutants). Levels of ten of these pollutants are estimated to be above benchmark concentrations recommended by the Air Toxics Science Advisory Committee (ATSAC) and recently adopted by the Environmental Quality Commission (EQC).

Benchmarks are not standards, but rather planning goals and triggers for our program. We will compare the benchmarks to ambient monitoring and exposure modeling to address risk and to communicate modeling and monitoring results. Please see the EQC staff report Oregon Air Toxics Program: Benchmarks for information on benchmarks and how they are used.

PATA also included risk assessment modeling with results described and shown in maps and charts. This comprehensive assessment by DEQ is a key step in a community planning process to reduce air toxics in the Portland area. Sections of the report are below. For a full copy of the report in paper form please send an email to Monica Russell.

Portland Air Toxics Assessment (PATA)

Table of contents, Executive Summary and Introduction PDF
Emission Inventory PDF
Monitoring PDF
Dispersion Model PDF (3mb)
Comparison and Evaluation PDF
Exposure Assessment PDF
Toxicity Assessment PDF
Risk Characterization PDF (6mb)
Conclusions and Recommendations, References PDF

The initial modeling for the report was done by ICF consulting. They used information provided by Metro, EPA, DEQ and others for the modeling. The model estimated daily pollution levels under various weather conditions at the neighborhood level.

IFC Report

Air Dispersion Modeling Component of the Portland Air Toxics Assessment PDF

Further Information