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PM 2.5 AQI of US monitors, calculated utilizing NowCast, courtesy US EPA PM2.5 AQI map, calculated utilizing NowCast, courtesy US EPA. The PM (particulate matter) NowCast is a weighted average of hourly air monitoring data used by the United States Environmental Protection Agency (USEPA) for real-time reporting of the Air Quality Index (AQI) for PM (PM 10 - particles less than 10 micrometers ...
An individual score (Individual Air Quality Index, IAQI) is calculated using breakpoint concentrations below, and using same piecewise linear function to calculate intermediate values as the US AQI scale. and The final AQI value can be calculated either per hour or per 24 hours and is the max of these six scores.
The Air Quality Index is a tool used by the Environmental Protection Agency (EPA) in order to communicate outdoor air quality. It’s a scale of 0 to 500, with the higher number indicating the air ...
The index and the air quality objectives were set in 1987; and pollutant levels are measured over varying periods, in μg/m 3. There are hourly, 24-hour and annual targets for sulfur dioxide and nitrogen dioxide, and 24-hour and annual targets for particulates.
24-hour Not to be exceeded more than once per year on average over 3 years 40 CFR 50.6: Fine particulate matter (PM 2.5) Primary 9.0 μg/m 3 (12 μg/m 3 prior to May 6, 2024) [25] annual Annual mean, averaged over 3 years 40 CFR 50.18: Secondary 15 μg/m 3: annual Annual mean, averaged over 3 years 40 CFR 50.7: Primary and Secondary 35 μg/m 3: ...
24/7 Help. For premium support please call: 800-290-4726 more ways to reach us. ... as judged by the EPA's Air Quality Index rating system. Moderate air quality is between 51 and 100, or in the ...
Since 1999, the EPA has used the air quality index (AQI) to communicate air pollution risk to the public, on a scale from 0 to 500, with six levels from Good to Hazardous. [10] (The previous version was the Pollutant Standards Index (PSI), which did not incorporate PM2.5 and ozone standards.)
In the United States, the EPA maintains a repository of air quality data through the Air Quality System (AQS), where it stores data from over 10,000 monitors. [23] The European Environment Agency collects its air quality data from 3,500 monitoring stations across the continent. [24]