City air quality dips, breathe carefully

Air pollution worries are back in Delhi. Since the scary smog of November last year, which was attributed to the winter season and crop burning in adjoining states, certain areas in the city have recorded an alarming level of fine particulate matter (particles less than 2.5 micrometers) recently.

These particles, 100 times thinner than human hair, are made of toxic compounds and heavy metals produced by automobiles, burning of plants and processing metals. They stick to the inner passages of lungs and cause respiratory problems.

While the World Health Organisation puts the safe level of Particulate Matter 2.5 (PM2.5) at 20 mg/cubic metre of air, it was recorded at 565 mg/cu m in Delhi a week back. This is just second to Beijing’s 755 mg/cu m which is the worst recorded level of PM2.5 in the world.

The question arises that inspite of measures being taken by the government, including the landmark conversion of commercial vehicles to CNG in 2000, why is the air quality of Delhi deteriorating? Where are we failing?

Professor Mukesh Khare of IIT Delhi, a specialist in air pollution modelling and member of the eight-member govt. committee on smog prevention, says, “CNG conversion was no doubt a good move. As a result, we don’t see solid carbon particles, in the form of soot, in Delhi’s air today.

However, every fuel has its own characteristics and associated problems. CNG, which burns at a high temperature, produces copious amounts of Nitrogen Oxides. NO2 combines with other pollutants in the air to create aerosols which constitute PM2.5.”

“CNG is a better fuel than diesel, but I would recommend a multi-fuel policy nation-wide. We should use a range of eco-friendly fluels like biodiesel, high-octane petrol, electric fuel as well as CNG to prevent the concentration of any one harmful fuel combustion product.”

Anumita Roychowdhury, research at Centre for Science and Environment, adds, “A process we call ‘tyre emission’ also contributes to particulate matter production considerably. Indian roads are made of bitumen which, when rubbed by automobile tyres, produce carbon pollutants. Many countries have started adding polymers to bitumen. It binds bitumen to concrete so strongly that any amount of friction with tyres does not produce pollutants.”

“Further, there should be stringent guidelines on construction work. Construction sites produce a lot of particulate matter which is harmful for health. Simple sprinkling of water and keeping silt mounds covered can prevent their dispersion in the air.”

When Metrolife contacted Dr MP George, scientist with the Delhi Pollution Control Committee, he told us, “The figure of 565 mg/cu m PM 2.5 was only recorded at a few locations in Delhi for a few hours, so it is not as hazardous as it sounds.”

“However, some steps can definitely be taken to reduce air pollution in Delhi, the most important of which is reducing the number of vehicles on roads. Taxation and parking policies can be made more stringent to disincentivise keeping personal vehicles. Simultaneously, the public transport system should be strengthened so that people don’t feel the need to buy cars. That will be the final solution to controlling
pollution.”   

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