Some UK cities have seen significant drops in air pollution as the shutdown to tackle the coronavirus pandemic disrupts work and travel, analysis suggests.
Assessment of data from roadside monitoring sites in York, Birmingham, Glasgow, London and Manchester has revealed reductions in key pollutants nitrogen dioxide and tiny particles known as “PM2.5”.
The analysis by scientists from the University of York of data from the London Air Quality Network and UK Automatic Urban and Rural Network showed the pollutants had fallen to levels lower than the average of the past five years.
Monitoring of European cities, many of which are in lockdown over the pandemic, by the European Environment Agency (EEA) also reveals large decreases in air pollution, particularly nitrogen dioxide.
The reduction in nitrogen dioxide in UK and European cities is likely to be caused by lower levels of traffic, experts said.
Sources of PM2.5 include road transport, industry and fuel burning.
Professor James Lee from the Department of Chemistry at York and the National Centre for Atmospheric Science (NCAS) said: “These are the two air pollutants that have the biggest health impacts on people.
“From our analysis, pollution levels are clearly lower than the average of the previous five years.
“I would expect them to drop even further over the coming weeks.
“We will continue to analyse the data and potentially take in more sites to build a bigger, more accurate picture of the situation.”
The data will need to be carefully analysed to pinpoint the exact cause of the decline, the scientists warn, as many things can affect air pollution, including local weather, new regulations and human activity.
Air pollution causes an estimated 40,000 early deaths in the UK each year.
It is linked to health problems including stroke, heart disease, lung cancer and disease, and respiratory diseases and infections, as well as stunting the growth of children’s lungs.
Experts have warned that the health benefits of reduced air pollution and lower exposure as people stay off the streets and in their homes in the shutdown may not offset mortality from Covid-19 and health problems caused by isolation.
Data from local monitoring stations analysed by the EEA reveals big drops in nitrogen dioxide in some cities across Europe.
In Milan, northern Italy, average concentrations of the pollutant over the past four weeks are at least 24% lower than over four weeks earlier this year.
Rome’s pollution levels over the past four weeks were 26-35 % lower than for the same weeks in 2019, the EEA said.
Cities in other European countries have also seen major reductions in nitrogen dioxide where lockdown measures have been implemented during the week of March 16-22.
Barcelona’s pollution levels fell 40% from one week to the next, and were down 55% compared to the same week in 2019, while Lisbon has seen a 41% drop in nitrogen dioxide week-on-week and is down 51% compared to the same week last year.
Hans Bruyninckx, EEA executive director, said: “The EEA’s data shows an accurate picture of the drop in air pollution, especially due to reduced traffic in cities.
“However, addressing long-term air quality problems requires ambitious policies and forward-looking investments.
“As such, the current crisis and its multiple impacts on our society work against what we are trying to achieve, which is a just and well-managed transition towards a resilient and sustainable society.”