Precursor pollutants are largely emitted by vehicles and smoke stacks however, they can also travel hundreds of miles from neighboring cities when carried by wind. Ozone, a secondary pollutant, occurs in the atmosphere when high temperatures (over 84☏) and sunlight (UV radiation) causes pollutants, nitrogen oxides (NO x), and volatile organic compounds (VOCs) to react. While both pollutants share some of the same sources, such as motor vehicles and fossil fuel combustion at industrial complexes, power plants, and factories, they are also unique. Portland’s unhealthy air pollution is a combination of PM2.5 and ozone pollution, two of the most prevalent and dangerous pollutants in the US. Ozone tends to indicate warmer temperatures and increased vehicular traffic, such as during rush hour, though individual sources may vary. When Portland PM2.5 levels are exceedingly high, there is usually a fire burning nearby or domestic wood burning during a cool air inversion. The “main pollutant” indicates which of the six criteria pollutants is present at the riskiest levels (usually PM2.5 or ozone). Monitor Portland air pollution data at the top of this page to stay aware of pollution spikes and health advisories. Meanwhile, ozone, a secondary pollutant, only becomes problematic in the summer, when abundant sunshine and heat create ideal conditions for its formation. Fine particle pollution tends to rise in the winter months with increased household wood burning and pollution-trapping temperature inversions. In Portland, each season brings unique pollution challenges. This is a slip from Portland’s “A” rating in the 2014 to 2016 monitoring period, which experienced less than 1 unhealthy day a year. 1 Due to the frequency of these events, the American Lung Association (ALA) graded Portland a “C” for 24-hour PM2.5 and 24-hour ozone in their 2019 State of the Air report. In the most recent 3-year monitoring period spanning 2016 to 2018, Portland averaged roughly 3 unhealthy pollution days a year. The concerning trend coincides with a growing population and number of vehicles on the road, numerous EPA regulatory rollbacks, warming global temperatures, and more frequent and severe wildfires. Portland air quality has achieved a mean annual air quality index (AQI) rating of “good.” For the last two decades, Portland has achieved air pollution standards set by the Environmental Protection Agency (EPA) for all six criteria pollutants measured in real-time: PM2.5, PM10, ozone, carbon monoxide (CO), nitrogen dioxide (NO 2), and sulphur dioxide (SO 2).ĭespite this success, Portland’s air pollution levels have been climbing since 2016.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |