Aurora vs Mecca: PM2.5 compared
Aurora and Mecca were both measured on only 2 days over the last year, too few to compare them (it takes 30).
Right now
Compare either city with another
Aurora
Side by side with Commerce City (the nearest), Gujranwala (the world's worst on 30 days).
Mecca
Side by side with Indio (the nearest), Hanford (United States's 2nd worst on 30 days), Gujranwala (the world's worst on 30 days).
The same rules as every SmogRank figure: reference monitors first, and a day counts with 18 measured hours. How we measure.
Updated 2026-10-08 20:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); Love My Air (City and County of Denver), no reuse terms published (why we use them).