Air pollution can come from a variety of sources, from energy production to agriculture, but the majority comes from road vehicles such as cars or vans.
Overall, transport accounts for nearly one-quarter of the UK’s overall emissions, and of those, at least 50 per cent comes from vehicles. This is because the UK has over 30 million cars on the road, and public transport options in outside urban areas are often limited, forcing people to drive their cars instead.
Many countries and cities across the world have significant car reduction policies that have benefited their overall air pollution levels. London’s own ULEZ has accounted for a 44 per cent reduction in roadside air pollution, according to research released by the London Assembly in 2020.
Air pollution is measured by how many micrograms of miniscule particles, called PM2.5, which are invisible to the naked eye and “small enough to pass through the lungs, into the bloodstream, and into your organs”, according to the British Lung Foundation.
How many countries have levels of air pollution over the World Health Organisation’s (WHO) recommended limits of five micrograms per year? And which country is leading the way in keeping its air pollution levels down?
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The Big Issue has used data from State of Global Air, which is a project that provides a report and interactive website analysing the trends in air quality for every country in the world. The report is produced by the Health Effects Institute and the Institute for Health Metrics and Evaluation.
It provides comprehensive and consistent air quality data for 2019, making it the best source to compare air pollution levels in different countries.
How much air pollution does the UK have?
According to State of Global Air, the UK had an average of 10.1 micrograms per cubic metre of PM2.5 in 2019 across the country.
This is twice the WHO recommended limit but many areas across the country average significantly higher levels.
A report published by climate organisation Friends of the Earth in October 2022 found 97 per cent of neighbourhoods in England and Wales are between one and two times more polluted than the WHO guidelines.
Friends of the Earth and other climate organisations have been calling for the government to lower air pollution in all areas of the UK to 10 micrograms of PM2.5 by 2030.
How much air pollution does the United States have?
Air pollution levels in the United States were lower than the UK’s in 2019, averaging 7.7 micrograms per cubic metre.
The Environmental Protection Agency (EPA) previously had targets of 12 micrograms across the country, but revised this in January 2023 as part of the Clean Air Act, lowering the target to between nine and 10 micrograms.
As the climate crisis continues, the US is experiencing more wildfires, extreme weather, and increased flooding. The Natural Resources Defence Council previously wrote progress has been made over air quality in recent years but climate change “will make it harder in the future to meet pollution standards”.
How much air pollution does Scandinavia have?
All Scandinavian countries (Sweden, Norway, and Denmark) have relatively low levels of air pollution, though all are higher than the WHO’s recommended limits.
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Denmark averaged 9.8 micrograms of PM2.5 per cubic metre in 2019, nearly twice the WHO limit. Air pollution in Denmark comes mainly from wood burning stoves and boilers, vehicles, ships, and energy production.
The country has continued to invest heavily in reducing emissions from all of those sources.
Norway averaged 6.6 micrograms of pollution per cubic metre in 2019, but the country is aiming to reduce this significantly by getting rid of fossil fuels. As part of the country’s Climate Act, the country hopes to reduce greenhouse gas emissions by 40 per cent by 2040.
Additionally, Norway’s capital city Oslo achieved the world’s highest concentration of electric cars in 2020 and is working to make all public transport fossil-free by 2025, further reducing the levels of air pollution from vehicles and transport.
Sweden has the lowest air pollution levels of all Scandinavian countries, tied for the world’s lowest air pollution levels. It averaged 5.6 micrograms of PM2.5 per cubic metre in 2019.
Though many might assume China is likely a major source of air pollution, it actually does not have the highest PM2.5 levels in the world.
China averaged 47.7 micrograms of PM2.5 per cubic metre in 2019, nearly 10 times the recommended limit set out by the WHO.
China has made significant progress in reducing air pollution in the last decade – in fact, air pollution in 2019 saw a 20 per cent decrease from PM2.5 levels in 2014.
But, findings from China’s national pollution research programme published in Reuters said air pollution standards need to be revised significantly.
The report urged the Chinese government to promote clean energy and reduce emissions from transport, as well as upgrading manufacturing processes and facilities to reduce pollution.
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The last recommendation is particularly important as some areas of the north have annual average levels of 200 micrograms due to the industries located there.
How much air pollution does Canada have?
According to State of Global Air, levels of PM2.5 averaged 7.1 micrograms per cubic metre in 2019 – slightly less than the U.S average but still 1.4 times higher than the WHO limit.
Canada’s government website states: “The quantity of emissions of many air pollutants has generally decreased in Canada in the past two decades.”
This reduction was achieved through major regulations to phase out energy from coal-production as well as strict guidelines for emissions from cars and trucks.
Which country has the highest air pollution levels?
India has the highest levels of air pollution, averaging 83 micrograms of PM2.5 per cubic metre in 2019.
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According to Bloomberg, over 90 per cent of India’s population lives in areas where pollution levels are significantly higher than the WHO guidelines – “coal-fired power plants, factories, and vehicles are among the major sources of pollution”.
Nearly 2 million people in India are estimated to have died in 2019 as a result of air pollution, Bloomberg reported, while in 2020, India had nine of the world’s 10 most polluted cities.
Those nine cities had average annual pollution levels at least 18 times higher than WHO recommended limits. Population sizes in each city range from 5,000 people to over 2 million people.
In comparison, London’s pollution levels were only 2.8 times higher than the recommended limit in 2019 with a population of close to nine million people.
Which country has the lowest air pollution levels?
Finland has the lowest air pollution levels. In 2017, Finland’s annual average of PM2.5 was 5.6 micrograms – only slightly higher than the WHO’s limit.
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Analysis published by WHO in 2018 found Finland had the cleanest air in the world due to its strong environmental regulations.
According to the official website for Finland, legislation has been introduced to curb emissions from large industrial facilities and they have “made progress in controlling emissions from agriculture, transport, and homes”.
But, it said there is “still a need to reduce airborne emissions of carbon dioxide, noise, and particles from traffic”.