SmogRank / London / Northampton
London vs Northampton: PM2.5 compared
Over the last year, Northampton's air was 18% more polluted than London's: PM2.5 averaged 11.9 µg/m³ against 10.1, on the 137 days both cities were measured. Northampton had the dirtier air on 109 of those days, London on 28. Northampton was over the WHO's daily guideline of 15 µg/m³ on 25 of them, London on 18.
Right now
The last year, day by day
Month by month
Year by year
| Year | London | Northampton | Days London was worse |
|---|---|---|---|
| 2026 so far | 54 | 58 | 15 |
| 2025 | 53 | 53 | 92 |
| 2024 | 39 | 46 | 11 |
Means in US AQI over the days both cities were measured that year; a year shows once they share 30 such days.
Each city's worst days
London
- 26 Jan 202610838.5 µg/m³
- 23 Mar 20269934.6 µg/m³
- 4 Mar 20269532.5 µg/m³
Northampton
- 26 Jan 202611340.4 µg/m³
- 9 Mar 202611039.3 µg/m³
- 3 Feb 20268929.3 µg/m³
Daily means in US AQI, with µg/m³ beside them, since the index stops at its top value, over the days both cities were measured in the last year. Each date opens that day's world board.
Compare either city with another
London
Side by side with Borehamwood (the nearest), Birmingham (United Kingdom's 2nd worst on 30 days), Gujranwala (the world's worst on 30 days).
Northampton
Side by side with Milton Keynes (the nearest), Gujranwala (the world's worst on 30 days).
Use this page
SmogRank, PM2.5 daily means compared, London and Northampton, 8 Oct 2025 – 7 Oct 2026, smogrank.com/compare/gb-london/gb-northampton (accessed 8 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
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).