High pollution warning issued for London by City Hall

A high air pollution alert has been issued for London on Tuesday as temperatures are forecast to rise above 30C.

City Hall said strong sunshine and hot weather are expected to trigger high ozone levels, with airflow from mainland Europe likely to worsen the situation.

The forecast, produced by Imperial College London, prompted the mayor’s office to trigger the alert, which will be displayed on bus stop countdown boards, London Underground signs and sent to schools and borough councils.

Mete Coban, the deputy mayor for environment and energy, said London’s “toxic air” is linked to around 4,000 premature deaths in the capital each year.

“We are urging Londoners to look after themselves in this pollution alert during the hot weather, stop their engines idling, and refrain from burning wood or garden waste – all of which contribute to high levels of pollution,” he said.

High air pollution can particularly affect older people, young children, and those with existing heart and lung conditions.

The warning system was introduced by the mayor in 2016. It uses the government’s Daily Air Quality Index to determine when alerts are triggered.

The UK Health Security Agency, has issued heat health alerts, for all of England – beginning on Tuesday morning and lasting until Wednesday.

London is among the regions facing the hottest conditions with temperatures of up to 34C (93F) forecast, triggering an amber alert.

An air quality report, external published last year said high pollution episodes were now a “rare occurrence” in London.

It said between 2018 and 2023, 19 high pollution alerts were issued and 217 moderate pollution alerts, “enabling Londoners to increase their awareness of high pollution episodes and take precautionary action on these days”.