(added on 2017/11/24)
Toxic air 毒氣熏天
Ambient air pollution is emerging as one of the leading risk factors for ill health in the human population. The recent problem faced by people in India is particularly worrisome. In early November 2017, the Air Quality Index reached a historically high level, paralleling heavy smog in some cities. The Indian government had to close schools for 3 days in Delhi in their Capital region.
The map shows the distribution of particulate matter (PM) 2.5 over Indian subcontinent on 16 November 2017, and the disability-adjusted life-years (DALY, an index reflecting lost years of healthy life) of four selected diseases associated with air pollution in different states of India. As depicted by the coloured isolines of PM2.5 concentration, air pollution problem was more severe in the north-western part of India. As shown by graduated colours, the burden of three respiratory diseases, i.e. chronic obstructive pulmonary disease (COPD), tuberculosis and asthma, in north-western states of India was particularly higher. A higher burden of ischaemic heart disease was observed in south-western India, where PM 2.5 concentration level was moderate. Although both respiratory and cardiovascular diseases were associated with exposure to air pollutants, impact of air pollution on respiratory disease appears to be more direct.
The air pollutant data in the maps were obtained from the World Air Quality Index Website (http://aqicn.org/city/delhi/dtu/), whereas corresponding epidemiological data were extracted from an article published in Lancet.