Heatwave hot sun. makes heat stroke, danger. Change, high.

Analysis: How the heatwave connects to poor air quality

Image credit: Dreamstime

By crunching data relating to London, E&T investigates the connection between high temperatures and poor air quality.

It's official, Brits have been experiencing the hottest days on record with temperatures climbing to around 39°C in southern and eastern England this week. 

While some may call this weather a boon there are perils, especially in cities, one of which is air pollution. Research suggests that as temperatures increase and heat and sunlight cook up a toxic cocktail of chemical elements in the air, pollution surges and air quality drops in tandem. Smog emerges out of ground-level ozone gas originating from a mix of nitrogen-oxide emissions.

The effect on humans is not to be underestimated, experts warn. People exposed to the smog could experience breathing difficulties and respiratory infections, especially those already suffering from respiratory or heart problems. In severe cases ozone exposure can effect pregnant women by bringing on premature labour, and can also effect cognitive development in very young children.

The UK National Health Service advises to open windows for ventilation only when it is cooler, to listen to alerts on the radio, social media and TV, and check up on friends, relatives and neighbours who may be less able to look after themselves. 

In larger urban areas such as London, with its 8.8 million inhabitants, the effect of heatwaves is particularly noticeable. 

Data from King's College London suggests that for the month of July each year from 2010 to 2018, particulate matter (PM10) as well as ozone levels slightly increased for London. Nitrogen oxides, nitric acid and ozone found to enter human lungs can be harmful to the delicate tissue found there after only brief exposure.

Heatwaves in London and the UK are not new. In big cities, research finds them to grow ever more prevalent and to have detrimental consequences. Asia, currently home to a fifth of the world’s population, and specifically in India, Pakistan and Bangladesh, heatwaves and other circumstances caused by climate change could render places uninhabitable, according to research from 2017.

Some Londoners may be luckier than others. During the July 2006 heatwave, those in the east of the city experienced lower top temperatures than the rest of the capital according to data published by the Greater London Authority. 

Heatwave visualisation 2006

Image credit: Ben Heubl, Greater London Authority

In 2018, E&T found that both ozone and nitric oxide levels (a molecule of nitrogen oxides) increased throughout the day

Despite the record high temperatures this week – the UK was not alone, Paris also reached a record 40.6°C and deemed it the hottest day – the latest measurements issued by the Department for Environment Food and Rural Affairs at the time of writing suggest that the majority of sites across the country bear only moderate air quality risk.  


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