Air Pollutants

Air Pollution in Spokane

The U.S. Environmental Protection Agency establishes National Ambient Air Quality Standards (NAAQS) to protect public health from adverse effects of air pollution. Standards are set for six outdoor air pollutants, called Criteria Air Pollutants. Of the six criteria pollutants, two are of greatest concern in Spokane: Particulate Matter and  Ozone.

Ozone	Particulate Matter PM10	Particulate Matter PM2.5

Particulate Matter (PM) is composed of solid or liquid particles from smoke, dust, and condensing vapors. PM is suspended and carried in the air for long periods of time and over long distances. There are health-based standards for particles that are 10 microns and smaller (PM10) and particles that are 2.5 microns and smaller (PM2.5). These microscopic particles travel deep in the lungs, damaging lung tissue and affecting breathing.   

Spokane’s PM pollution comes from a variety of sources, including dust stirred up from traveling on unpaved and paved roadways, construction activities, gas and diesel powered engines, wood burning, outdoor burning and industrial/commercial operations.

Wood smoke particles from wood heating become concentrated during the winter months when stable weather patterns and strong temperature inversions trap smoke near the Earth's surface. Wood smoke is the chief source of fine particle pollution in the Spokane-area during winter.

Diesel PM is produced when an engine burns diesel fuel. Diesel exhaust is a complex mixture of thousands of gases and fine particles that contains more than 40 toxic contaminants. These include many known or suspected cancer-causing substances, such as benzene, arsenic and formaldehyde. It contains other harmful pollutants, including nitrogen oxides (a component of urban smog).

Across our state and here in Spokane, cleaning up school buses has been a priority. Children are breathing healthier air while riding school buses thanks to retrofitting old buses with cleaner technology. New diesel engines are cleaner thanks to new federal standards, however diesel engines have a very long life. 

In December 2009 the Washington State Department of Ecology issued a report on fine particles, "Health Effects and Economic Impacts of Fine Particle Pollution in Washington.

Ozone (O₃) - Unlike ozone that is present in the Earth’s upper atmosphere, ozone at the Earth’s surface is a harmful air pollutant that poses a risk to human, animal and plant life. Ground-level ozone is formed as a result of photo-chemical reactions between nitrogen oxides and volatile organic compounds in the presence of sunlight and heat. Most of the ozone-forming emissions come from many small sources, spread over a wide area. Click here to see a short video on how ozone is formed. 

Motor vehicles contribute about two-thirds of these emissions that form ozone pollution. Other sources of smog-forming emissions include industrial solvents, gasoline refueling, gasoline-powered yard equipment, auto body paint shops, and consumer products such as charcoal lighter fluid, paints, etc.

Even at low concentrations, ozone causes respiratory problems and aggravates asthma in children, people with respiratory diseases, and even otherwise healthy adults who are working or exercising outside on smoggy days. Children are most at risk from exposure to ozone because they are often active outside during the summer and their lungs are not fully developed. Long-term exposure to ozone may lead to premature aging of the lungs and chronic respiratory illnesses. 

A Closer Look at Air Toxics -  In addition to the criteria pollutants, there is a category of pollutants that fall under the Air Toxics rules. Air toxics are a group of over 400 pollutants known or suspected to cause a number of health problems, including cancer and birth defects, as well as damage to lungs, and immune and nervous systems.

In our region, air toxics come primarily from particulate matter contained in diesel exhaust and smoke from wood burning. While air toxics do not have federal ambient air quality standards, our research indicates that they are present in our air at levels that pose a health risk to residents.

To better quantify toxic pollutants in Spokane's air, a team of state, local and university air quality specialists conducted a Air Toxics Study in 2005-2006.  

The Washington State Department of Ecology conducts a comprehensive Emissions Inventory for the state every three years, which includes detailed information about emissions for specific source categories (e.g. railroads or outdoor burning) by county.