
London’s air pollution measured at strangely high levels this morning, leaving many to wonder why it has risen so dramatically.
Air quality levels measured at 7 in the Daily Air Quality Index, meaning dangerous particles remained low down, risking public health.
This is despite the city’s air pollution levels dramatically improving since the introduction and expansion of of Sadiq Khan’s Ultra Low Emission Zone.
So why was it so high this morning?
How high is the air pollution in London?
The city’s pollution levels were measuring at 7 in the Daily Air Quality Index this morning, with 1 being low and 10 being very high.
It is based on pollutants being concentrated over a specific time, and measures the risk to health alongside this .
This level naturally alarmed Londoners, as anything reading at 4 or more is considered to be harmful.
It comes as London’s pollution was declared to be markedly better since the Mayor introduced the Ultra Low Emission Zone.
Eleven boroughs saw reduced emissions, which included falls in nitrogen oxides, carbon dioxide and PM2.5 particulates.
And across the city, NO2 concentrations were nearly a third lower than compared with a scenario without any phases of Ulez.
Why is London’s air pollution so bad?
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Some have feared the air quality, which was worse over London and the rest of the south east of England, was due to the oil tanker explosion.
France was also experiencing high levels near the English Channel and around Lille.
But this is unlikely to be the cause. The general changing weather can cause pollution to be kept lower on the ground, raising the levels.
Imperial College said an ‘air feed from the near continent’ is bringing in pollution and is dueled by ‘poor dispersion’ once it arrives in the UK.
Dr Mark Miller, a Reader at the University of Edinburgh, told Metro: ‘An increase in wind and rain can help dissipate the particles which are in the air.
‘But a change in pressure can hold pollution lower to the ground, raising the levels.’
Dr Miller said this can have a serious impact on health, as there is ‘no such thing as safe levels of pollution’.
Those living nearby heavy traffic will be the worst affected, as particles produced from vehicles are ‘smaller and can enter the blood stream’.
What is being done to tackle air pollution?

The Ultra Low Emission Zone, which now covers all London boroughs, charges drivers running non-compliant vehicles to enter the city.
London is also transitioning to greener transport, including the use of electric buses and more EV charging points for motorists.
Taxis and private hire drivers are also being encouraged to invest in electric vehicles.
The easiest way for Londoners to check the air pollution is with a free report from addresspollution.org.
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