North Africa, the Middle East and South Asia have the highest levels of antibiotic resistance, while Europe and North America have the lowest.
Almost half a million premature deaths in 2018 were linked to antibiotic resistance potentially resulting from air pollution, costing global economies an additional $395bn.
The study from researchers at Zhejiang University in China suggests that meeting World Health Organization (WHO) air quality guidelines by 2050 could reduce antibiotic resistance by 17 per cent and prevent 23 per cent of associated premature deaths, which would deliver annual economic savings of $640bn (£500bn).
Although the misuse and overuse of antibiotics are the main drivers of antibiotic resistance, evidence suggests that particulate matter PM2.5 can contain antibiotic-resistant bacteria and resistance genes, which may be transferred between environments and inhaled directly by humans.
The study indicates that increases in air pollution levels have coincided with larger increases in antibiotic resistance in more recent years.
Although air is recognised as a key vector for disseminating antibiotic resistance, there is limited data on how the genes that lead to this resistance are carried via air pollution. The researchers theorised that hospitals, farms and sewage-treatment facilities that emit and spread antibiotic-resistant particles through the air could be to blame.
Professor Hong Chen, lead author of the study, said: "Antibiotic resistance and air pollution are each in their own right among the greatest threats to global health. Until now, we didn't have a clear picture of the possible links between the two, but this work suggests the benefits of controlling air pollution could be two-fold: not only will it reduce the harmful effects of poor air quality, but it could also play a major role in combatting the rise and spread of antibiotic-resistant bacteria."
Until now, there was limited data on how much influence PM2.5 air pollution – which is made up of particles 30 times smaller than the width of a human hair – has on antibiotic resistance globally. Sources of PM2.5 include industrial processes, road transport and domestic coal and wood burning.
In total, data on more than 11.5 million test isolates were included in the analysis, covering nine bacterial pathogens and 43 types of antibiotics.
Data on antibiotic usage, sanitation services, economics, health spend, population, education, climate and air pollution were used to investigate the influence of these factors on levels of antibiotic resistance.
The findings indicate antibiotic resistance increases with PM2.5, with every 1 per cent rise in air pollution linked with increases in antibiotic resistance of between 0.5 and 1.9 per cent, depending on the pathogen.
The association has strengthened over time, with changes in PM2.5 levels leading to larger increases in antibiotic resistance in more recent years.
The highest levels of antibiotic resistance are found in North Africa, the Middle East and South Asia, while levels in Europe and North America are low. Due to their large populations, China and India are thought to be the countries where changes in PM2.5 have the greatest impact on premature death toll from antibiotic resistance.
The authors' modelling of possible future scenarios indicates that if there were no changes to current policies on air pollution, by 2050 levels of antibiotic resistance worldwide could increase by 17 per cent. The annual premature death toll linked to antibiotic resistance would rise to around 840,000, with the greatest increases in sub-Saharan Africa.
