The Health Burden of Air Pollution
“Outdoor air pollution is the second leading risk factor for mortality in India. Nearly one million lives are lost prematurely in India to air pollution,” said Dr. Alexandra Karambelas, Postdoctoral Research Fellow, The Earth Institute, Columbia University. She was speaking at a public lecture organized by Columbia Global Centers | Mumbai in May, which drew linkages between energy emissions, air quality and health outcomes and emphasized the need for better monitoring of air quality in India in order to draw up appropriate mitigation strategies.
Particulate matter (PM) refers to all solid and liquid particles suspended in the air. Particulates less than 2.5 microns in diameter are mostly from combustion processes, whereas larger particulates are often from natural sources like dust and sea salt. These particulates are considered hazardous since they can stay suspended in the air longer than other pollutants and can penetrate our lungs and bloodstream unfiltered. "Liquids and solids of 2.5 microns (PM 2.5) and lesser in diameter are a major driver of air pollution in India,” informed Dr. Karambelas. “The source contribution to PM 2.5 varies between cities, between urban and rural regions, and undergoes seasonal fluctuations. The firecrackers during the festival of Diwali, for example, make it a high pollution period,” she explained.
Emissions have been increasing in India due to industrial growth, population explosion, urbanization, and motorization. The country lacks robust emission inventories and data management mechanisms to scientifically study pollution and its causes in a manner that could inform prevention and mitigation efforts. Data and high-resolution images required to capture such variations in pollution levels aren’t available for many parts of India, particularly for rural areas. Although scientists can model projections for these unmonitored pockets, poor quality data hampers the quality of projections as well.
Dr. Karambelas has developed a high resolution inventory of emissions over northern India, particularly the Indo-Gangetic Plain, to investigate which specific urban and rural activities were responsible for emitting corresponding pollutants in the air. Her findings, when juxtaposed with the Global Burden of Disease study, showed the burden of premature deaths in urban and rural areas. According to her, “Premature deaths among adults due to air pollution in both urban and rural areas are nearly similar - 5.6 deaths per 10,000 deaths in urban areas annually versus 6.4 deaths per 10,000 deaths in rural areas.” But air pollution in cities often grabs more attention, as rural air pollution caused by indoor smoke is not as visible.
Dr. Karambelas’ findings illustrate how reducing emissions from certain sectors mitigates the impact of air pollution. The lecture was organized as part of the Center’s ongoing efforts to create a network of inter-disciplinary experts to investigate the science of air pollution, to stimulate collective and evidence-based action to tackle the worsening air quality across the country. Better data and more robust monitoring mechanisms are the need of the hour.