A tale of three cities
A tale of three cities
The bad, the ugly and the good
We’ve been looking at air quality in London - big city that has poor air quality with similar challenges, and broadly similar levels of pollution. But are there any examples of cities who have got it right? And which cities have got it wrong? The IQAir website has a nice comparison tool. Alongside London, we picked two cities of (broadly) similar size and looked at the PM2.5 levels.
The IQAir website has data for 7323 global cites, and for comparison, London ranks 3457 out of 7323, sitting squarely in the middle of the pile. In 2022, the annual mean concentration of PM2.5 in London was 9.6µg/m³, nearly double the WHO target.
Lahore: struggling with severe pollution
For a truly terrifying level of air pollution, Lahore has it all. Lahore, the second-largest city in Pakistan, has been grappling with severe air pollution in recent years. According to IQAir, in 2022 it had an annual mean concentration of PM2.5 of nearly 100µg/m³, ranking it the most polluted city in the world.
Several factors contribute to Lahore's air quality challenges, including rapid urbanisation, industrial growth, and a high volume of vehicles on the roads. Additionally, seasonal agricultural burning in nearby regions and the use of low-quality fuels for heating and cooking contribute to the city's high levels of air pollution. As a result, residents of Lahore experience numerous health issues, such as respiratory illnesses, heart diseases, and premature deaths.
Sydney: costal city with cleaner air
Sydney, Australia's largest city, boasts a more favourable air quality scenario. Despite being a large global city with a population of 5.4 million people, Sydney ranks 7052 out of 7323 cities listed by IQAir. It managed to attain an annual mean concentration of PM2.5 of around 3.1µg/m³, which meets the WHO target of 5µg/m³. Go Sydney!
But how did they achieve this target? Natural factors such as geographical location and a coastal location that helps disperse pollutants all help, but a strict PM2.5 limit of 8µg/m³ and stringent emission controls contributes to lower levels. Sydney's urban planning focuses on green spaces, public transportation, and mixed-use development, helping to reduce pollution from traffic.
What next for London?
The Mayor of London has published plans for improving air quality, including introducing cleaner busses, improving the electric vehicle charging infrastructure and widening the Ultra Low Emission Zone (ULEZ). But can London do it alone? Analysis of PM2.5 data before and after COVID lockdowns showed that despite a 55% reduction in traffic, levels of PM2.5 actually increased, due to easterly winds and pollutants from Northern Europe. The Task Force for International Cooperation on Air Pollution (TFICAP) promotes international collaboration towards preventing and reducing air pollution to improve global air quality, and it is clear that global cooperation is needed to address air pollution for us all.