Air Quality

Spokane Air Quality Boundary Map

Carbon Monoxide
CO is a colorless, odorless gas that reduces the oxygen-carrying capacity of the blood. Motor vehicle exhaust contributes about 56% of CO emissions. CO exposure can lead to chronic health issues and even death at high levels. Symptoms of CO exposure include headaches, dizziness and nausea.

Since 1999, Spokane has had no recorded violations of the CO standard. In 2005 the Environmental Protection Agency (EPA) re-designated Spokane from a “non-attainment” area to an “attainment” area for CO, currently operating under a Limited Maintenance Plan (LMP).
The LMP says there is a minimal risk that CO from vehicles would contribute to a violation of the National Ambient Air Quality Standards (NAAQS) for the next ten years. While an area with an LMP does not need to do regional emissions analysis, it still has other transportation conformity requirements such as project-level analysis. SRTC provides project-level air quality modeling to local jurisdictions and agencies using EPA approved models and procedures.

Particulate Matter
Particulate Matter (PM) are particles found in the air, such as dust, dirt, soot, smoke and liquid droplets. Particles are divided into two groups; the larger particles are called PM10 and the smaller particles PM2.5.

The big particles are between 2.5 and 10 micrometers (from about 25 to 100 times thinner than a human hair). These particles cause less severe health effects. The smaller particles are smaller than 2.5 micrometers (100 times thinner than a human hair) and are generally more toxic. These microscopic particles can damage lung tissue and affect breathing.

Spokane’s PM pollution comes from a variety of sources, including dust from unpaved roads, construction, gas and diesel powered engines, wood burning, outdoor burning and industrial/commercial operations. High PM concentrations occur in fall and winter during stagnant air periods and the increased use of wood for heating. PM can be suspended and carried in the air for long periods of time and over long distances.

In 2005 the EPA re-designated Spokane from a “non-attainment” area to an “attainment” area for PM10, currently operating under a Limited Maintenance Plan (LMP). There is minimal risk that PM10 from vehicles would contribute to a violation of the NAAQS for the next ten years. SRTC provides project-level air quality modeling services to local jurisdictions and agencies using EPA approved models and procedures.

Ground-level Ozone
In our region, ground-level ozone is considered a summertime pollutant. Hot sunny days contribute to the formation of ground-level ozone, a harmful pollutant and key ingredient in smog. Ozone is formed when nitrogen oxides and volatile organic compounds react to sunlight. Pollutants from activities such as refueling and driving cars, using gas-powered lawn equipment, and using industrial and household solvents, “cook” in hot temperatures, forming ground-level ozone. Ozone concentrations typically peak on calm, 90+degree days.

When inhaled, ozone can cause coughing, throat irritation, and pain when breathing deeply. It can also reduce lung function, inflame the lining of the lungs, and trigger asthma attacks.

Partner Agencies for Air Quality:

Spokane Regional Clean Air Agency
Environmental Protection Agency
Washington State Department of Ecology