Air pollution kills millions each year, especially in the world’s biggest cities. But it can get better! Here’s how megacities around the world are already making their air cleaner and safer.
In this repository, you will find the methodology, data and code behind the story that came out of this analysis.
Story by Kira Schacht
Story links
The file Database.xslx contains the data our analysis is based on.
IQAir is a Swiss company that collects air quality data and also sells equipment such as air filters, masks, and monitors. We scraped their database of annual average PM 2.5 levels in more than 7,000 cities from 2017 to 2022. For quality control, we also interviewed CEO Frank Hammen about their data collection and analysis process. IQAir shared with us the number of measuring stations their annual averages are based on for 2021 and 2022.
Our analysis focused on the world's biggest cities, with populations of 5 million or even 10 million people. To filter for these cities, we used population data from the UN Department of Economic and Social Affairs: Dataset "Annual Population of Urban Agglomerations with 300,000 or More in 2018 (thousands)", projection for 2022.
Some complementary data for years prior to 2017 was taken from the WHO Ambient Air Quality Database 2022 when analyzing the air quality of cities in China.
- Rafay Alam, Environmental Lawyer, Pakistan
- Zoe Chafe, C40
- Sophie Gumy, Technical Officer at WHO's Department of Environment, Climate Change, and Health
- Frank Hammes, IQAir
- Bhavreen Kandhari, WarriorMoms
- Abid Omar, Pakistan Air Quality Initiative