How does Oregon's air quality compare to the rest of the country? ​In 1980, only 30% of Oregonians lived in clean air areas that met national health standards for air pollution. Today, all areas in Oregon meet these standards.

Wildfires in the Northwest have increased since the 1980s. Scientists attribute this to human-caused climate change. This means more bad air days from wildfire smoke in Multnomah County.

Fine particles in the air (measured as PM_2.5) are so small that they can travel deeply into the respiratory tract, reaching the lungs, causing short-term health effects such as eye, nose, throat and lung irritation, coughing, sneezing, runny nose, and shortness of breath.

Causes of Air Pollution in Oregon Emissions from cars contribute to ground level ozone pollution (smog) especially on hot summer days. Woodstoves and fireplaces are a primary source of winter time smoke levels.