Just before the 2008 Olympics, a machine on the roof of the US embassy in Beijing began to tweet air pollution measurements to the world. The numbers that appeared each hour were often shocking but they demonstrated the power of objective measurement. The resulting response has led to huge improvements in air quality for much of the vast Chinese population.
Globally, particle pollution contributed to an estimated 4.1 million early deaths in 2019, but 141 of the world’s 234 countries had no regular measurements. If you live in the US, Canada or western Europe, your average distance to a monitoring site is just over 20km (12 miles). This seems a long way to give an understanding of the air in your local street but in central Africa the average distance is more than 1,000km.
Satellite data can help but it is hard to resolve pollution in the lowest part of the atmosphere where we live. Computer models can combine satellite data with the location pollution sources and the sparse measurements, but this data is not good enough to tell us how air pollution changes day to day and in response to cleanup initiatives. There is an urgent need for more pollution measurements around the world.
