In March 2019 researchers from the USA published their overview on air pollution and exposure levels and how this affects local policy actions. Measurement of air pollution levels has significantly improved recently which has led to a better awareness and improved local policy actions to reduce elevated air pollution levels and adverse health effects. Common outdoor air pollutants have been identified as being associated with an increased risk of cardiovascular and respiratory diseases, lung cancer, and premature death. Recent evidence also implicates air pollution with a range of medical conditions, including neurological diseases, cardiometabolic diseases, and renal disease. In 2010 Public Health England indicated that air pollution exposure in London had resulted in 41,404 life years lost. On a global basis, the World Health Organisation (WHO) has estimated that each year over 7 million premature deaths each year are due to the combined effects of indoor and outdoor air pollution. Overall, ischaemic heart disease and strokes account for 80% of the premature deaths attributed to air pollution, followed by chronic obstructive pulmonary disease or acute lower respiratory infections at 14%, and lung cancer at 6%. A recent study reported that 4.2 million deaths annually were attributable to particulate matter 2.5, making it the fifth-ranking mortality risk factor in 2015 globally.
Asthma is one of the most widespread health problems known to be worsened by air pollution, especially amongst children. In fact it has been estimated that the majority of childhood asthma is induced by the environment. In a study which looked at the association between asthma and air pollution experienced by inner-city children with asthma, the findings pinpointed the diesel-related fraction of particulate matter 2.5 as being most responsible for the increased risk of cough, wheeze, and total symptoms in the children living near roadways. This helped identify the particular diesel fuels that were most responsible and led to action by governments to reduce diesel traffic.
It has been estimated that approximately 90% of the world’s population is breathing in air that falls below the WHO air quality guidelines. In the USA for example more than 125 million people are estimated to live in communities with unhealthy air. It is now recognized that personal exposure to pollution can vary dramatically from street to street in a town or city, and that it can also vary at different times during a day. Even those who live next door to one another may have very different residential pollution exposures. Accordingly, the exposures and health implications of pollution may be very different for population groups living in close proximity to high levels of outdoor pollution.
Exercise is also an important factor to consider when assessing the effects of air pollution exposure, particularly if exercise is undertaken outdoors. During exercise, the increased breathing rate introduces more air pollution into the airways than at rest. This can lead to greater dosages of air pollution amongst exercising individuals, which should be taken into consideration when choosing where to exercise. Nevertheless, studies indicate that the benefits of exercise can outweigh the adverse effects of air pollution exposure. In particular, the potential health benefits of increased walking and increased cycling have been shown to outweigh the risks posed by increased inhalation of air pollution.
The first WHO Global Conference on Air Pollution and Health in Geneva, Switzerland (30 October–1 November 2018) highlighted the need to make commitments to air quality around the globe.
Caplin M et al. Advancing environmental exposure assessment science to benefit society. Nat Commun. 2019; 10: 1236.