Outdoor air pollution and respiratory health.

The need to address the impact of air pollution on health is reinforced by recent scientific evidence and the 2021 WHO Air Quality Guidelines (AQG). Air pollution is an avoidable risk factor causing a high burden for society with elevated deaths, health disorders, disabilities and huge socio-economic costs, especially in low- and middle-income countries. We have evaluated recent evidence from international reports, systematic reviews and official websites of international agencies. Growing evidence shows a causal relationship between air pollution exposure and acute lower respiratory infections, chronic obstructive pulmonary disease, asthma and lung cancer. Exposure to air pollution in both the short- and long-term has a serious impact on respiratory health. Harmful effects occur even at very low pollutant concentration levels, and there are no detectable thresholds below which exposure may be considered safe. The adverse respiratory health effects of air pollutants, even at low levels, are confirmed by recent epidemiological studies. Scientific respiratory societies and patient associations, along with other stakeholders in the health sector, should increase their engagement and advocacy to raise awareness of clean air policies and the latest WHO AQG.