9.8 million globally, 2 million in India die due to air pollution annually

Guwahati, April 18: Air pollution has become a major cause of concern all over the world and annually around 9.8 million people die because of it, said noted microbiologist and CEO of the Centre for Study on Environmental Microbiology, Dr Sukumar Debnath.

In an interview with The Assam Tribune, Dr Debnath, a former microbiologist of Tocklai Tea Research Institute (TTRI), said that rainfall can only give temporary relief from air pollution.

The following are the excerpts from the interview:

Assam Tribune: How do you see the increasing pollution level in Guwahati city?

Debnath: Air pollution is a global problem and 9.8 million people die every year globally. In India, about 2 million people die annually. Pollution has two components - abiotic (chemical compounds and various gases) and biotic. Biotic components are fungal spores, bacteria, pollen grains, leaf hair lichen fragments, algal cell, animal hair, etc. Not much research data is available in this regard.

As we now know pollution is measured by AQI, air quality index value where several components are considered (PM2.5, PM10, carbon dioxide, methane, carbon monoxide, ozone, nitrogen dioxide, ammonia, sulphur dioxide and lead). In urban areas, vehicular exhausts get mixed up with pollutants in air and make a complex mixture of partially combusted hydrocarbons. To calculate AQI, at least three pollutants are taken including PM2.5 and PM10u. If the AQI is below 50, it is good, between 51 and 100 it is satisfactory, 101 to 200 is moderate, between 201 and 300 is poor, 301 to 400 is very poor and 401 to 500 is severe.

The AQI of Guwahati is manifold higher than the recommended value, particularly PM2.5.

AT: Is lack of rainfall one of the reasons for the deterioration of the air quality?

Debnath: Rainfall provides temporary relief to polluted areas. Pollutants as we know have independent origins. For example, CO2 originates from industrial smoke, fuel burning, forest fire, etc. Vehicular traffic smoke may have complex aromatic compounds, including some with carcinogenic properties. Rainfall clears our sky, takes down larger particles and precipitates smaller particles attached to vegetation and becomes a source for soil moisture.

AT: Are construction activities like construction of bridges linked to deterioration of air quality?

Debnath: Construction activities like felling of trees, soil disturbances, demolition and disposal of building materials generate enormous quantity of fine soil particle, which finally contributes to PM10 and PM2.5. In urban areas, vehicular exhausts mix up with soil particles in air and aggravate the situation.

AT: What will be your suggestion to the authorities and common people to improve air quality?

Debnath: We are aware that the Government of India is gathering data and monitoring air pollution. Unless you monitor you cannot improve. Several major initiatives have been taken to deal with the issue.

Persons with pre-existing respiratory ailments should avoid visiting highly polluted areas to avoid exposure to allergenic pollens and fungus spores and use masks while outdoors. People should also inform authorities about wild-fires, plant avenue trees after consultation with botanist, and plant trees in vacant places as exposed soil emits higher CO2 from soil. Green plants will absorb CO2 from soil and retain it as cellulose biomass.

AT: How is climate change and increase in pollution level affecting the tea industry? Will the production and quality of tea deteriorate due to these issues?

Debnath: Plants and microorganisms respond to air pollution. Deposition of air pollutants on living leaves of plants may alter plant physiology and lowers immunity to fight diseases. In such cases, the role of entophytic microbes in stimulating plant growth promotion will become relevant. Some existing pathogenic microbes or insects may become more powerful and cause serious infections.

The impact of climate change on tea in North East India is evidenced by decreasing rainfall, irregular distribution, and high temperatures exceeding 35 degrees Centigrade at times or more.

Shade trees however provide necessary organic matter by way of leaf fall and also cut sunshine to a great extent. As warming trend is polarized, areas of higher latitude will experience greater impact of temperature. Pests and disease organisms will also migrate from tropical areas to polar regions. Future tea cultivation will be dependent on science-based precision agriculture and greater reliance on new elite cultivars resistant to pests and diseases.