We monitor ozone levels at 13 locations to protect your health and the environment. Currently, all areas of Washington meet the ozone air quality standard. The Tri-Cities area is being closely monitored because recent samples near Kennewick detected periods of relatively high ozone levels.
Ozone high in the Earth's atmosphere protects us from the sun's harmful radiation. But at ground level, ozone is an air pollutant that harms people and plants. Ground-level ozone forms when nitrogen oxides and volatile organic compounds react with each other in sunlight and hot temperatures. This pollution comes from vehicles, industry, and other sources and contributes to smog formation.
Ecology and local clean air agencies monitor air to ensure ground-level ozone meets Washington's air quality standards. Ozone levels used to exceed national standards in the Seattle and Vancouver areas. Due to improvements in vehicles and other emission-reducing requirements, ozone pollution has declined even as the population continues to grow.
In the late 1970s and '80s, ozone levels downwind of some of Washington's urban areas were high enough to violate national standards. Parts of Snohomish, King, Pierce, and Clark counties failed to meet the ozone standard because air pollutant emissions from these areas contributed to high ozone levels.
By the mid-90s, all of Washington was meeting the national standard. More stringent emissions standards for vehicles, cleaner fuels, and gas station vapor controls helped reduce ozone pollution.
Generally, ozone levels tend to be higher downwind of urban areas. This is because it takes a while for pollutants to react with sunlight. Although the state currently meets the ozone standards, we continue to watch the following areas closely:
Ecology and local clean air agencies monitor air pollution throughout the state. This map illustrates areas of concern we are monitoring closely.
To make sure air continues to meet Washington standards, we partner with local clean air agencies to monitor ozone at 13 locations. We monitor ozone at:
To help prevent ozone from forming on hot days:
When pollution rises on hot days:
Ozone damages trees and plants. It impairs plant growth, and makes them more easily harmed by insects and disease.
Ground-level ozone irritates the eyes, nose, throat, and respiratory system. It's especially bad for those with chronic heart and lung disease (like asthma, bronchitis, and emphysema), children and the elderly, as well as pregnant women.
Ozone aggressively attacks lung tissue and has harmful effects on peoples' health. You might think of it as sunburn on your lungs. Breathing ozone-containing smog can lead to several types of health problems.
Difficulty breathing and lung damage
If you suffer from asthma, being exposed to high levels of smog can trigger asthma attacks.
Coughing and throat/chest irritation
High levels of ozone can irritate your respiratory system. These types of mild symptoms usually only last for a short time after you've been exposed. However, if levels remain high, then ozone can continue to harm your lungs even after symptoms disappear.