Cross country study finds link between air pollution and Covid-19

Areas with poor air quality and higher emissions of particulate matter (PM) 2

Areas with poor air quality and higher emissions of particulate matter (PM) 2.5 are more likely to have Covid-19 infections and related deaths, according to a joint study by four institutes across the country. This is the first time that a pan-India study has found a direct correlation between air pollution and Covid-19.

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Statistical analysis established that there was a significant correlation between Covid-19 cases and PM2.5 concentrations in all states in India, with a correlation coefficient of 0.66. The correlation coefficient for PM2.5 concentrations and deaths resulting from Covid-19 was 0.61. In statistics, a correlation coefficient above 0.5 means the two data sets have a compelling correlation to each other.

The study titled ‘Establishing a link between fine particulate matter (PM2.5) zones and Covid-19 over India’ based on anthropogenic emission sources and air quality data was published in the peer-reviewed journal Urban Climate on June 10. The study was conducted by scientists from Utkal University, Bhubaneswar; Indian Institute of Tropical Meteorology (IITM), Pune, Department of Earth and Atmospheric Sciences, National Institute of Technology Rourkela; School of Earth, Ocean and Climate Sciences, Indian Institute of Technology, Bhubaneswar. It was partially funded by the Ministry of Earth Sciences, the Government of India.

The study involves three kinds of data sets—National Emission Inventory (NEI) of PM2.5 for 2019, developed by the scientists; a number of Covid-19 positive case and corresponding death as of November 5, 2020, adopted from the government of India website and air quality index data (in-situ observations) collected for 16 stations across the country. The scientists divided specific areas into different hotspot zones across India. From 36 states, 16 districts were picked for the study, including Mumbai and Pune.

Maharashtra recorded the second-highest emission load- 828.3 Gigagram per year (Gg/Yr) of PM2.5, after Uttar Pradesh which recorded 1138.08 Gg/year, according to the National Emission Inventory developed by the scientists. ‘Between March and November 2020, Maharashtra recorded 17.19 lakhCovid-19 cases, which was the highest in the country.

“However it is important to note that in terms of PM2.5 emission per person, Maharashtra is ahead of Uttar Pradesh,” said Sahu.

Among the 16 cities captured in the study, Mumbai and Pune recorded the third and fourth highest ‘bad air quality days’ respectively. For Mumbai, out of a total of 165 bad air quality days, 22 were very poor. Pune recorded a total of 117 bad air quality days. Parallelly, Mumbai recorded 2.64 lakh Covid-19 cases and 10,445 deaths during the period studied, which was the highest in the country while Pune recorded 3.38 lakh Covid-19 cases and 7,060 deaths. The transport and industrial sector was the major PM2.5 contributor in Maharashtra and correlated with a rise in Covid-19 cases.

“What is worrying is that there is evidence that the novel coronavirus sticks to fine particles like PM2.5 allowing them to move from one part to another by making the airborne transmission of Covid-19 more effective. Through our analysis, it has become clear that rising pollution load is becoming more of a catalyst to aggravate the Covid-19 cases,” said Sahu, adding that polluted hotspots are also triggering long-term effects and more studies are needed to understand this.

Apart from Mumbai and Pune, the study also found that two other hotspots -Nagpur and Chandrapur - in Maharashtra witnessed high pollution as well as higher Covid-19 cases and casualties. Gufran Beig, senior scientist and founder project director, System of Air Quality Weather Forecasting and Research (SAFAR) and co-author of the paper said that at hotspots within Maharashtra exposure to daily air pollution can make a person’s lungs weak.

“When human-induced emissions are added combined with the double impact of the Covid-19 virus, the damage to lungs will be much faster and worsen health conditions,” said Beig.

The study found that all the districts where cases of Covid-19 crossed 20,000 recorded emissions more than 200 Gg/yr of PM2.5. “It confirms that sources of the tiny particle are fossil fuel and mostly dominated in developed and urban places,” said the study.

Sahu said the study results will help slow down the spread of the virus by providing more preventive steps and resources in areas with high pollution levels for present situations as well as for future possibilities. Among solutions, the study highlighted that there was a need to adopt cleaner technology, better transport emission norms like Bharat Stage (BS) VI at the earliest, and ensure better coal technology like ultra-supercritical power plants to reduce particulate emissions.

Ashok A Shingare, member secretary, Maharashtra Pollution Control Board, who was not a part of the study said, “By and large we are aware that if there are more pollutants in the air, there is a predominance of more pneumatic diseases in those regions. Considering the Covid-19 impacts the pulmonary system, there has to be and is a clear correlation for health ailments emerging out of both air pollution and Covid-19. Keeping the transport sector as the major source of air pollution in Mumbai and Pune, we have leapfrogged from BS-4 to BS-6 but implementation and adoption of these new vehicles are lacking. There is a need for building more awareness and to keep economics in mind for faster adoption of BS 6.”