How We Analyze Air Quality
We believe that air quality data should be historical, not just real-time. To understand the true health of a city, you need to look at its "Smoke Season" trends over a decade, not just today's forecast.
1. Data Sources
All historical data on this site is sourced directly from the US EPA Air Quality System (AQS). We aggregate daily summary files for PM2.5 (Particulate Matter < 2.5 microns) from 2014 to the present day.
2. Ranking Methodology
Most rankings focus on annual averages, which can be misleading. A city might have clean air for 11 months and catastrophic smoke for 1 month, resulting in a "Moderate" average.
Our rankings weigh Median Annual PM2.5 as the primary metric, filtered to exclude outliers. However, we heavily weight "Smoke Days" (AQI > 100) to identify seasonal risks.
3. Wildfire Smoke vs. Pollution
We distinguish between cities impacted by Wildfire Smoke (Western US, summer peaks) and those impacted by Industrial/Winter Pollution (Inversion layers). Our algorithms analyze the seasonality of pollution spikes to properly attribute the cause.
4. CADR Calculations
When recommending air purifiers, we use a strict standard of 4.8 Air Changes Per Hour (ACH). Most manufacturers market their coverage area based on 1 ACH (Dust/Pollen).
Worried about more than just smoke?
Air quality is just one factor. Check our sister site for a complete analysis of tornado, hurricane, and flood risks.
Visit DisasterCalculator.com →Have questions?
We are committed to transparency. If you spot an error in our data or modeling, please reach out.
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