SmogRank / London / York

London vs York: PM2.5 compared

Over the last year, London's air was 17% more polluted than York's: PM2.5 averaged 9.7 µg/m³ against 8.3, on the 146 days both cities were measured. London had the dirtier air on 101 of those days, York on 42. London was over the WHO's daily guideline of 15 µg/m³ on 16 of them, York on 18.

Right now

London#546on the 24-hour board of 738, at 18 US AQI (3.3 µg/m³)

York#639on the 24-hour board of 738, at 14 US AQI (2.6 µg/m³)

The last year, day by day

London

York

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

Monthly means in µg/m³ over the days both cities were measured. Solid: London. Faded: York. A month shows once both share 10 such days. Dashed line: the WHO daily guideline, 15 µg/m³.

Year by year

Year	London	York	Days both measured	Days London was worse
2026 so far	54	52	88	57
2025	48	36	242	204
2024	45	38	265	193
2023	49	42	229	157

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
4 Mar 20269532.5 µg/m³
9 Mar 20269231.2 µg/m³

York

5 Mar 20269130.7 µg/m³
9 Mar 20268829.2 µg/m³
26 Jan 20268024.8 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).

York

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

Use this page

SmogRank, PM2.5 daily means compared, London and York, 8 Oct 2025 – 7 Oct 2026, smogrank.com/compare/gb-london/gb-york (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).