Air pollution and disease burden
Authors: Shilu Tong
Journal: The Lancet Planetary Health (2019)

Air pollution represents a considerable threat to health worldwide.1Burnett R Chen H Szyszkowicz M et al.Global estimates of mortality associated with long-term exposure to outdoor fine particulate matter.Proc Natl Acad Sci USA. 2018; 115: 9592-9597Crossref PubMed Scopus (1018) Google Scholar, 2GBD 2015 Risk Factors CollaboratorsGlobal, regional, and national comparative risk assessment of 79 behavioural, environmental and occupational, and metabolic risks or clusters of risks, 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015.Lancet. 2016; 388: 1659-1724Summary Full Text Full Text PDF PubMed Scopus (2838) Google Scholar, 3Cohen AJ Brauer M Burnett R et al.Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: an analysis of data from the Global Burden of Diseases Study 2015.Lancet. 2017; 389: 1907-1918Summary Full Text Full Text PDF PubMed Scopus (3224) Google Scholar According to the 2015 Global Burden of Disease Study,3Cohen AJ Brauer M Burnett R et al.Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: an analysis of data from the Global Burden of Diseases Study 2015.Lancet. 2017; 389: 1907-1918Summary Full Text Full Text PDF PubMed Scopus (3224) Google Scholar exposure to outdoor fine particulate matter (PM)2·5 is the fifth leading risk factor for death worldwide, accounting for 4·2 million deaths and 103·1 million disability-adjusted life-years in 2015. Although air pollution is a universal issue, it is likely to cause the greatest harm in susceptible individuals who are exposed to high PM2·5 concentrations. People with chronic diseases (particularly cardiorespiratory illnesses), little social support, and poor access to medical services are most at risk from air pollution. China is the largest developing country in the world, with exceptional economic growth observed in the past four decades.4Economy watchChina Economy.http://www.economywatch.com/world_economy/china/Date: 2013Date accessed: November 25, 2018Google Scholar However, similar to other rapidly industrialising countries, air pollution, water contamination, and land degradation are serious environmental issues in China, and thus are the focus of a considerable amount of research and public attention.5Zhang K Dearing J Tong S Hughes T China's degraded environment enters a new normal.Trends Ecol Evol. 2016; 31: 175-177Summary Full Text Full Text PDF PubMed Scopus (28) Google Scholar To protect the environment and public health, policies have been established to tackle air pollution and other environmental problems. Since the implementation of the Ambient Air Quality Standards (GB 3095-2012), and the release and implementation of the Air Pollution Prevention and Control Action Plan,6The State Council of the People's Republic of ChinaThe Air Pollution Prevention and Control Action Plan.http://www.gov.cn/jrzg/2013-09/12/content_2486918.htmDate: 2013Google Scholar air quality in most regions of China has improved substantially. Previous studies7Madaniyazi L Nagashima T Guo Y et al.Projecting fine particulate matter-related mortality in east China.Environ Sci Technol. 2015; 49: 11141-11150Crossref PubMed Scopus (58) Google Scholar, 8Lelieveld J Evans J S Fnais M et al.The contribution of outdoor air pollution sources to premature mortality on a global scale.Nature. 2015; 525: 367-371Crossref PubMed Scopus (3221) Google Scholar, 9Di Q Wang Y Zanobetti A et al.Air pollution and mortality in the Medicare population.N Engl J Med. 2017; 376: 2513Crossref PubMed Scopus (781) Google Scholar have shown that air pollution is associated with increased morbidity and mortality, and some studies reported that reductions in air pollution have been associated with improvements in the health of the Chinese population. However, little data are available on the public health benefits of air pollution control measures and policies in developing countries. This issue is important since the disease burden associated with air pollution has increased in the past decade, especially in low-income and middle-income countries.3Cohen AJ Brauer M Burnett R et al.Estimates and 25-year trends of the global burden of disease attributable to ambient air pollution: an analysis of data from the Global Burden of Diseases Study 2015.Lancet. 2017; 389: 1907-1918Summary Full Text Full Text PDF PubMed Scopus (3224) Google Scholar The modelling study by Qing Wang and colleagues in The Lancet Planetary Health10Wang Q Wang J Zhou J Ban J Li T Estimation of PM2.5-associated disease burden in China in 2020 and 2030 using population and air quality scenarios: a modelling study.Lancet Planet Health. 2019; 3: 71-80Summary Full Text Full Text PDF PubMed Scopus (48) Google Scholar provides important information with regard to the health benefits of air quality improvements in China. The authors used county-level PM2·5 and mortality data to estimate PM2·5-associated disease burden in 2020 and 2030. Wang and colleagues reported that the projected health benefit of the Air Pollution Prevention and Control Action Plan is considerable, and could reduce the number of PM2·5-related premature deaths by 129 278 deaths (13·5%) in 2020 and by 217 988 deaths (22·8%) in 2030 compared with 2010. However, the health benefits resulting from air quality improvements would be offset by the effect of the population growth and ageing. Thus, to reduce future disease burden, the implementation of more stringent measures for air quality improvement and public health protection are needed in China. Concerted efforts are needed to cope with population growth and ageing. The authors estimated the future disease burden in China at the county level, with full coverage of the entire country for multiple scenarios. Future efforts should use the county-level age structure and the baseline mortality of diseases to project the health benefits associated with air quality improvements. As discussed by the authors, no data on future age structure (county or provincial level) or future baseline mortality (county or provincial level) of each disease were available, which is an important limitation of the study since baseline mortality is likely to decline over time and the pace of population ageing might vary between counties. The authors' assumption that for chronic obstructive pulmonary disease and lung cancer, the relative risk (RR) for the same exposure concentration of PM2·5 was the same for all adults might be incorrect. Previous studies11Zhang S Li G Tian L et al.Short-term exposure to air pollution and morbidity of COPD and asthma in East Asian area: a systematic review and meta-analysis.Environ Res. 2016; 148: 15-23Crossref PubMed Scopus (99) Google Scholar, 12Fougère B Landkocz Y Lepers C et al.Influence of aging in the modulation of epigenetic biomarkers of carcinogenesis after exposure to air pollution.Exp Gerontol. 2018; 110: 125-132Crossref PubMed Scopus (6) Google Scholar have shown that the associated with air pollution for chronic obstructive pulmonary disease and lung cancer varies with age, and these results are biologically plausible. Additionally, the difference in risk across age groups is exacerbated by the fact that the population is rapidly ageing in China, and the incidence of chronic obstructive pulmonary disease and lung cancer is likely to be higher in older populations (aged >55 years) than younger populations (aged <55 years). Thus, this modelling approach requires improvement for future projections. Quantifying and projecting the health benefits induced by air quality improvements is complex, and requires consideration of differences that might exist between counties as suggested by Wang and colleagues. An urgent need exists to identify the characteristics of future disease burden associated with air pollution, including the changing patterns of disease, spatial distributions, at-risk populations, most sensitive diseases, and the optimum model to use for such projections. This study highlights the need to formulate and implement more stringent environmental policies and public health measures in China to control air pollution in the future. These policy implications are applicable to other developing countries with similar levels of air pollution and similar population demographics. I declare no competing interests. Estimation of PM2·5-associated disease burden in China in 2020 and 2030 using population and air quality scenarios: a modelling studyTo reduce the future disease burden in China, targets that are stricter than the interim target and stringent policies to improve air quality and protect public health are needed, especially for at-risk population groups, such as older individuals (aged >55 years) and patients with cardiovascular diseases, particularly in regions with a high disease burden. Full-Text PDF Open Access