SmogRank / London / Royal Leamington Spa

London vs Royal Leamington Spa: PM2.5 compared

Over the last year, London's air was 35% more polluted than Royal Leamington Spa's: PM2.5 averaged 9.7 µg/m³ against 7.2, on the 150 days both cities were measured. London had the dirtier air on 126 of those days, Royal Leamington Spa on 22. London was over the WHO's daily guideline of 15 µg/m³ on 16 of them, Royal Leamington Spa on 14.

Right now

London#546on the 24-hour board of 738, at 18 US AQI (3.3 µg/m³)
Royal Leamington Spa#470on the 24-hour board of 738, at 22 US AQI (4.0 µg/m³)

The last year, day by day

London
Royal Leamington Spa
Each city's daily mean from 8 Oct 2025 to 7 Oct 2026, one stripe a day, coloured by band. A blank stripe is a day without a daily mean.

Month by month

London, Nov 2025: 6.6 µg/m³Royal Leamington Spa, Nov 2025: 4.7 µg/m³Nov2025London, Dec 2025: 9.3 µg/m³Royal Leamington Spa, Dec 2025: 6.6 µg/m³DecLondon, Jan 2026: 10.3 µg/m³Royal Leamington Spa, Jan 2026: 7.7 µg/m³Jan2026London, Feb 2026: 8.9 µg/m³Royal Leamington Spa, Feb 2026: 7.2 µg/m³FebLondon, Mar 2026: 13.2 µg/m³Royal Leamington Spa, Mar 2026: 10.1 µg/m³MarAprMayJunJulAugSepOct
Monthly means in µg/m³ over the days both cities were measured. Solid: London. Faded: Royal Leamington Spa. A month shows once both share 10 such days. Dashed line: the WHO daily guideline, 15 µg/m³.

Year by year

YearLondonRoyal Leamington SpaDays both measuredDays London was worse
2026 so far54449277
20254835240209
20244436273226
20234937228196

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

Royal Leamington Spa

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).

Royal Leamington Spa

Side by side with Coventry (the nearest), Gujranwala (the world's worst on 30 days).

Use this page

SmogRank, PM2.5 daily means compared, London and Royal Leamington Spa, 8 Oct 2025 – 7 Oct 2026, smogrank.com/compare/gb-london/gb-royal-leamington-spa (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).