# `aqi`

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The `aqi` crate provides functions for calculating the Air Quality
Index based on concentrations of particuate matter.

The AQI is defined for ozone (O₃), 1.0-2.5 micron particulate matter
(PM2.5), 2.5-10 micron particulate matter (PM10), carbon monoxide
(CO), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂).

The AQI helps make air quality more understandable to laypersons,
normalizing air quality on a scale from 0 to 500, with round-number
ranges that indicate qualities such as "Good", "Unhealthy", and
"Hazardous".

For further information, see [AQI basics][aqi-info] and [AQI techinical
assistance][aqi-detail].

Additionally, this library supports "adjusted" PM2.5 AQI values, using
the LRAPA, EPA and AQandU conversion formulas.

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[docs-url]: https://docs.rs/aqi
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[license-url]: https://github.com/kelnos/aqi-rs/blob/main/LICENSE
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[aqi-info]: https://www.airnow.gov/aqi/aqi-basics/
[aqi-detail]: https://www.airnow.gov/publications/air-quality-index/technical-assistance-document-for-reporting-the-daily-aqi/