Derry vs Letterkenny: PM2.5 compared

Derry and Letterkenny were both measured on only 16 days over the last year, too few to compare them (it takes 30).

Right now

Derry#738on the 24-hour board of 738, at 4 US AQI (0.8 µg/m³)

Letterkenny–not on the 24-hour board right now

Compare either city with another

Derry

Side by side with London (United Kingdom's worst on 30 days), Gujranwala (the world's worst on 30 days).

Letterkenny

Side by side with Edenderry (Ireland's 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).