Virus could cling to air pollutants

Updated on Apr 26, 2020 04:14 AM IST
India has among the highest particulate matter (PM) concentrations globally.
The highest number of Covid-19 cases were recorded in Lombardy and Po Valley in northern Italy, an area also characterised by high concentrations of particulate matter (PM).(Reuters file photo)
The highest number of Covid-19 cases were recorded in Lombardy and Po Valley in northern Italy, an area also characterised by high concentrations of particulate matter (PM).(Reuters file photo)
Hindustan Times, New Delhi | ByJayashree Nandi & Anonna Dutt

SARS-CoV-2, the virus that causes Covid-19, can cling to air pollutants, tests conducted in Italy have found -- a finding which, if validated, should cause concern in India, especially Delhi, where air pollution is a recurring problem, although both the researchers themselves and experts said it remains to be see if the virus remains viable and virulent on these particles.

Preliminary findings from the study suggest that if weather conditions are stable and concentrations of particulate matter (PM) are high, the virus could create clusters with PM.

There is no reason to panic yet because no assessments have been conducted on the viability of SARS-CoV- 2 when absorbed on PM.

The yet-to-be-peer-reviewed test results published in Medrxiv — a website on health research papers — says it needs to be studied what average PM concentrations are required for a potential “boost effect” to the outbreak. The study led by the University of Bologna and University of Trieste was conducted by collecting PM10 (coarse, respiratory pollution particles) from Bergamo in Italy’s Lombardy region.

The highest number of Covid-19 cases were recorded in Lombardy and Po Valley in northern Italy, an area also characterised by high concentrations of PM. Data available till April 12 shows about 30% of Covid-19 positive people live in Lombardy, according to the paper.

The research team conducted their studies on 34 PM10 samples from an industrial area in Bergamo collected with air samplers over a period of three weeks from February 21 to March 13. The study found several samples tested positive for SARS-CoV-2 gene markers.

India has among the highest PM concentrations globally. The Indian Council for Medical Research (ICMR) under the Union ministry of health released a report in December 2018 which concluded that one in eight deaths in India in 2017 were due to air pollution.

Professor Kalpana Balakrishnan, who was one of the lead authors of the ICMR study and director, department of environment health engineering, Sri Ramachandra Medical College and Research Institute in Chennai, said: “It is well known that viruses and bacteria can be components of PM. They were detected along with PM fraction during measles, H1N1, and viral haemorrhagic fever outbreaks. An article in BMJ has also captured this. In fact, it has also been seen that during seasonal peaks of the outbreak, the virus or bacteria is found more in the PM component. But I will not attach much importance to it as of now because we don’t know if the virus on the PM remains viable. Is it virulent?”

She added that she was “more concerned about long-term PM exposure leading to population level vulnerability to Covid-19 health outcomes”. “Long-term exposure causes cardio-respiratory issues which can make people very vulnerable,” she said.

The findings of ICMR published in The Lancet Planetary Health also found that air pollution lowers life expectancy by 1.7 years on average in India. India’s average annual PM 2.5 concentration was more than 80 micrograms per cubic metres in 2018, eight times the World Health Organization guideline for annual average PM2.5, according to a study by IIT-Delhi.

Prolonged exposure to air pollution leads to a chronic inflammatory response even among the young and healthy which makes people living in polluted areas more susceptible to developing chronic respiratory conditions. This is borne out by the high Covid-19-related death rates in northern Italy compared to the rest of the country, scientists said in a paper published in The Journal of Environmental Pollution on April 4.

The aerosolised virus can put health workers at risk. Manufacturers of protective garments for health care workers say that increase in humidity and pollution levels can mean that the Covid-19 virus stays suspended in aerosolised state. “The health ministry demands that the PPE kits be fluid-resistant with seam-sealing because earlier it was thought that the virus can only be transmitted through droplets. Seam-sealing is of no use against the aerosolised virus unless the material for the coverall is viral-resistant. Currently, the manufacturers are using laminates to make the non-woven material fluid-resistant, but these laminates are also porous and can allow particles less than the size of 2.5 micrometer to pass through; the size of the coronavirus is between 60 and 140 nanometer,” said Sanjiv Relhan, chairman, Preventive Wear Manufacturers Association of India.

“The study found evidence of Covid-19 on particulate matter. However, we cannot draw parallel with India or any other country, since the longevity of the virus on PM may vary with temperature and humidity. Unless such relation is established, it is practically difficult to model for Indian condition. Nonetheless the study implies that risk is greater for airborne transmission in polluted places, a theory proven true in USA, Italy, UK so far (based on studies reported),” said Sagnik Dey, associate professor and air quality expert at IIT Delhi.

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