Air Quality Data Summary for 2022

Fine particles and smog (ozone) are our greatest concerns in Puget Sound. These types of air pollution cause heart attacks, strokes, and even premature death. Air pollution is especially dangerous for children, the elderly, and people with lung or heart diseases.

Since 2015, we have faced unprecedented wildfire smoke—the highest fine particle levels since we started monitoring for them in 1980. In September and October 2022, we had various wildfires impacting the air quality at our monitoring sites for six and nineteen days, respectively. Due to the vicinity of some of the wildfires in the region (like Bolt Creek and White River fires), we observed air quality levels reaching very unhealthy and hazardous categories in King and Snohomish counties.

The table below shows the air quality health categories over 2022 by county.  Overall, most days were in the GOOD air quality category with some MODERATE days; however, we also observed a few days that were UNHEALTHY FOR SENSITIVE GROUPS, UNHEALTHY, VERY UNHEALTHY and HAZARDOUS from wildfire smoke.  

2022 Air Quality, Days by Health Category

Fine particles

Fine particles are tiny, microscopic pieces of pollution which are even smaller than a hair. These can easily enter the deepest part of your lungs and cause breathing and heart problems. In our region, they mainly come from wood smoke from home heating, vehicles, wildfires, and industry.

The graph below shows that all the sites had fine particle levels within the EPA standard (of 35 micrograms per cubic meter) on most days in 2022, except for the wildfire smoke and wood smoke impacted days in winter months. Wildfire smoke impacted the air quality at all sites on 6 days in September (9/9 -9/12/22, 9/21/22, 9/27/22) and 19 days in October (10/1-10/10/22, 10/12-10/20/22). The graph below shows daily fine particles level for all days in 2022; wildfire excluded days can be viewed by selecting the Wildfire Days Excluded option on the right side of the graph under the section Include Wildfire Days?.  Wildfire smoke is considered an “exceptional event” by EPA and these values are excluded from any required regulatory action.

Studies have also shown significant health impacts below the EPA standard as well. Therefore, the Agency has a health goal (of 25 micrograms per cubic meter), which was exceeded up to 5 days in September and 15 days in October due to wildfires and up to 8 days in winter months at individual sites.  

Black Carbon

Fine particles that come specifically from diesel exhaust is our greatest concern as they carry the most health risks, but we can’t directly measure them and there is no EPA standard for them.  Although not a perfect measurement, we use a “black carbon” monitor to estimate our impacts from diesel pollution. Diesel exhaust represents over 70% of the potential cancer risk from air pollution in the Puget Sound area. Most of the diesel exhaust in the Puget Sound region comes from four transportation sectors: maritime, off-road equipment, on-road vehicles, and rail. 

The graph below shows a reducing trend for black carbon since 2002. The levels have remained low in summer and higher in the winter when the air is typically more stagnant. The levels were highest during the wildfire smoke and wood smoke impacted days in the winter months. 

Ozone (also called “smog”)

Unlike fine particles and black carbon, ozone (smog) is created on hot summer days by chemical reactions with different types of air pollution from vehicles, industry, paints, solvents, and gasoline fumes. 

In 2022, we had record breaking heat, and high ozone levels that were unhealthy on six days in July.  The graph shows that the ozone levels have been within the EPA standard for the past few years.  The EPA standard is based on three years of data, and with 2022 included, ozone levels remained below the standard for most sites except Enumclaw which is at the standard value.

National and local air pollution reduction programs

Nationally, large reductions in diesel exhaust are expected to continue thanks to the newer diesel fuel and truck engine standards that took effect in 2007.  The newer trucks are 50 to 60 times cleaner than the older, dirtier trucks.  In 2011, an international agreement required incoming ships to use the cleanest shipping fuels along US coastlines (called an Emission Control Area) which also reduces diesel exhaust in our area. EPA continues to develop rules to reduce air toxics emitted from large and small industrial sources, which we ensure are implemented by the industries in our four counties through our compliance program.

Washington State recently adopted large sweeping climate actions which will help in reducing the emissions in our four-county region.  These actions include a new low carbon fuel standard, a cap-and-invest program, the WA Clean Energy Transformation Act, a future ban on new internal combustion engines by 2035, and many more.

Our Agency has also been working to further reduce air pollution on a local scale.  With our Diesel Solutions program, we partner with private and government organizations to reduce diesel exhaust.  Through our wood stove replacement program, and continuing to ensure wood heating burn ban compliance, we’ve seen levels of wood smoke come down in our region over the years.  We continue to pursue other opportunities to lower air pollution in the region, including greenhouse gas reductions.

We are currently developing the more detailed summary for 2022, but you can view the detailed 2021 Data Summary.