Half the world’s population subject to worsening air pollution levels

Researchers at the University of Exeter and the World Health Organisation (WHO) said the study shows that air pollution constitutes a major - and in many areas increasing - threat to public health.

Professor Gavin Shaddick, lead researcher, said, “While long-term policies to reduce air pollution have been shown to be effective in many regions, notably in Europe and the United States, there are still regions that have dangerously high levels of air pollution, some as much as five times greater than World Health Organisation guidelines, and in some countries air pollution is still increasing”.

The WHO has estimated that more than four million deaths annually can be attributed to outdoor air pollution. 

Air quality around the world improved dramatically during the coronavirus lockdown due to reduced industrial activity and the closure of businesses, with one estimate suggesting the shift saved 11,000 lives in Europe alone.

However, in May, following the broad reopening of the Chinese economy, air pollution levels shot back up in that country to those seen before the pandemic crisis began.

The researchers identified many major sources of fine particulate matter air pollution, including the inefficient use of energy by households, industry, the agriculture and transport sectors, and coal-fired power plants. In some regions, sand and desert dust, waste burning and deforestation are additional sources of air pollution.

Although air pollution affects high and low-income countries alike, low and middle-income countries experience the greatest burden, with the highest concentrations seen in Central, Eastern Southern and South-Eastern Asia.

For the study, the research team examined trends in global air quality between 2010 and 2016, against a backdrop of global efforts to reduce air pollution, both through short and long-term policies.

The team used ground monitoring data together with information from satellite retrievals of aerosol optical depth, chemical transport models and other sources to provide yearly air quality profiles for individual countries, regions and globally.

“Although precise quantification of the outcomes of specific policies is difficult, coupling the evidence for effective interventions with global, regional and local trends in air pollution can provide essential information for the evidence base that is key in informing and monitoring future policies,” Shaddick added.