An inter-sectoral management plan needed for addressing air pollution

A study done by researchers in IIT Delhi and University of Berkeley has projected the ambient PM2.5 exposure and premature mortality burden in India under climate change scenarios. The study titled "Ambient PM2.5 exposure and expected premature mortality to 2100 in India under climate change scenarios" was published recently in Nature Communications. Prof Sagnik Dey of the Center of Atmospheric Sciences, one of the authors of the research paper, talks about air pollution and its associated health burden in India.

How big is the air pollution problem in India?

Ambient PM2.5 exposure is more than double the Indian standard in the entire Indo-Gangetic Basin, thereby invalidating the myth that 'air pollution is only Delhi's problem' Statistics of 100+ Indian cities reveals that the pollution has been rising rapidly in the cities in the Indo-Gangetic Basin and central India. Most of these cities are second and third-tier cities without any pollution monitoring. Pollution emitted from large anthropogenic sources (70% of the country's population lives in this basin) is trapped in this basin by mountains in the north and south under favorable meteorology. Air quality management plan must be formulated for the entire region; otherwise only Delhi-centric plan would not be successful.

What is the impact on human health?

Short-term exposure to high pollution level leads to cardiopulmonary and cardio-vascular diseases. Several studies in the recent past in India have shown evidence. Chronic exposure to PM2.5 allows these fine particulates to deposit in our alveoli leading to development of chronic obstructive pulmonary disease (COPD), ischemic heart disease (IHD), stroke and lung cancer amongst adult population and acute lower respiratory infection (ALRI) amongst child population. This results in death earlier than the expected life expectancy (an Indian male is expected to live at least 66.9 years and a female 70.3 years). Epidemiologists have developed method to estimate this premature mortality burden, which depends on pollution level, age-specific population distribution, baseline mortality (i.e. number of deaths from a particular disease from all possible factors) and exposure-risk function (i.e. associated risk of premature death from air pollution). Household air pollution is even larger than the ambient air pollution in India and is associated with additional health burden.

How are the pollution and health burden projected to change in future under climate change?

We project the ambient PM2.5 exposure and premature mortality burden in India under climate change scenarios RCP4.5 (moderate climate change) and RCP8.5 (worst case scenario). Ambient PM2.5 exposure is expected to peak in 2030 and 2040 under the RCP4.5 and RCP8.5 scenario respectively. Premature mortality burden is expected to be 2.4-4% and 28.5-38.8% higher under RCP8.5 than under RCP4.5 scenario in 2031-2040 and 2091-2100 respectively. Projected meteorological changes induced by climate change are expected to facilitate dispersion of the pollutants in the warming world. Improved health conditions due to economic growth is expected to compensate the impact of changes in age-distributed population, that would result in a reduction in per capita health burden for all combined scenarios except the scenario where the world remains fragmented in dealing with climate change.