Seattle’s forecast air quality data is the best resource for understanding short-term trends in air quality. What is the current air quality in Seattle? What is Seattle doing to improve air quality? When will the air quality improve in Seattle? Other days in Seattle tend to achieve “good” to “moderate” US AQI ratings. Seattle has mixed air pollution ratings. Seattle’s air quality index (AQI) consistently averages ratings categorized as “good.” The city misses the mark, however, when it comes to its number of unhealthy pollution days, or 24-hour spikes. In order to further drive air quality improvements in the future and meet federal attainment levels for 24-hour PM2.5 and ozone pollution, Seattle air quality policies must be multifaceted. While 92% of the global population is exposed to dangerous levels of air pollution, many places lack measurements to quantify its effects and allow communities to respond effectively. Seattle, Spokane, WA, and Coeur d’Alene, ID area tied for 14th worst particle pollution, experienced similar elevated PM2.5 levels as a result of wildfires. Seattle’s failing grade was a result of exceeding the allowable target of 3.2 unhealthy ozone days and 3.2 unhealthy PM2.5 days.

While August was the most polluted month in 2017 and 2018 as a result of wildfires, elevated PM2.5 levels throughout the winter months tended to be roughly 40 percent higher than in the summer months. Seattle aims to reach an electric vehicle market share of 30 percent for privately owned electric vehicles by 2030.2 This adoption goal is dependent on individual consumers, however, and may take longer than the proposed timeline. From a broader perspective, the 14.2 unhealthy pollution days represent just 4 percent of the year. On average, Seattle experiences 14.2 unhealthy pollution days a year, with 7 owing to high ozone and 7.2 owing to high PM2.5.1 The US Environmental Protection Agency (EPA) recommends no more than 3.2 unhealthy pollution days each year for each pollutant. Driving Seattle’s declining air quality is a combination of population growth, new industry and construction, the increased frequency and severity of wildfires, and EPA rollbacks on a variety of emission sources.

The city’s growing population will add new construction, increase strain on Seattle’s infrastructure, and increase the toll of residential daily emissions. A growing population and economy does not need to be a reason for more emissions, however. Seattle air quality is the total of constant daily emissions, weather patterns, and pollution events. Seattle PM2.5 pollution is often attributed to the large concentration of industrial facilities and seafaring ships in South Park and Georgetown.4 It may come as a surprise that a majority of emissions, instead, originate from the city’s motor vehicles. Such conditions may likely counter Seattle air pollution measures intended to reduce the prevalence of precursor pollutants in the air. Italy: DM 185/2003. Technical measures for reuse of wastewater (Issuing Institutions: Ministry of Environment, Ministry of Agriculture, Ministry of Public Health). Since 2016, all key measures for PM2.5 and ozone pollution have been on the rise. Shifting towards cleaner energy and more fuel-efficient and low-emission vehicles, clearing forest underbrush with prescribed fires, and further advancing limits on emission sources are all means that have the potential to again reduce Seattle air pollution levels within federal attainment levels.

Prior to the 2015 to 2017 monitoring period, Seattle had met federal attainment levels for the allowable number of “unhealthy” PM2.5 and ozone days. How is Seattle air quality? The American Lung Association (ALA) releases an annual air quality report card showing comparative pollution levels across US regions and counties. Schulte, Bret. “A World of Thirst.” Us News and World Report. In the 1900 World Exhibition in Paris, Rudolf Diesel demonstrated his engine that ran on peanut oil. Heavy duty trucks and other diesel engines are especially culpable. Stems that creep along the ground are called stolons, and stems that grow below ground are called rhizomes. If Phil emerges from his hibernation hole in the ground to see his shadow (yielded by a sunny day), that means six more weeks of winter. Others seem to depend more on rain and snow filtering miles beneath the ground for their water supply.