Nanoparticles pose mega risk to Delhi

Nagpur: As winter and along with it the season of deteriorating air quality approaches, air quality monitoring data has revealed rise in levels of nanoparticles in Delhi’s air.

According to climate researchers, nanoparticles are minuscule particles measuring between 10 to 1000 nanometres (nm) in diameter, making them invisible to the naked eye. Believed to be more dangerous to human health, these toxic particles are 600 times smaller than a human hair strand and can penetrate deep into the lungs, bloodstream, and the brain.

The air quality research was conducted on Bawana road in the northwest part of the national capital, which connects Delhi to Rohtak in Haryana. The monitoring location is surrounded by educational institutions, households, and commercial areas where the dominant source of pollution is vehicles. Apart from transport, other pollution sources included biomass burning, fuel used for residential heating in winter and fireworks etc.

The research was carried out by Rajeev Kumar Mishra, assistant professor at department of environmental engineering, Delhi Technological University; S Ramachandran from the Physical Research Laboratory, Ahmedabad; and Kanagaraj Rajagopal, a research scholar from Advanced Air and Acoustics Research Laboratory, Delhi Technological University.

Bawana road, which has a vehicular density of around 1,300 per hour, and an average of 40,000 vehicles per day, was divided into two periods during the research. The first period was from April 1, 2021 to June 30, 2021, while the second was from October 3, 2021 to November 30, 2021.

Researchers found that nanoparticles directly related to vehicular exhausts were found more in the roadside areas. “When the wind speed is high, they get dispersed to the surrounding regions of the road, which may increase the exposure to the residents living nearby,” they stated.

Highlighting that the ultra-fine particles can contribute up to 90% to the total nanoparticle concentrations in urban areas, Mishra said, “For a city like Delhi, residential zones adjacent to roads are more exposed. People working near the road, such as police personnel, street vendors, drivers, motorcyclists, delivery personnel, and the urban poor living around it are more susceptible.”

Researchers further revealed that during the first period, which also saw Covid lockdown, the recorded vehicle fleet was 49% lower than the normal period. Due to this, the nanoparticle concentration was lower by 31% (from the baseline) due to restrictions on vehicular movement and other anthropogenic sources.

Similarly, in the second phase which was post Diwali, the concentration of particles went up by 35%. “This happened mainly due to vehicular and firecracker emissions,” said Rajagopal.

The nanoparticle concentration was found to be more during peak hours, which is nearly twice when compared to non-peak hours. Researchers suggested policy building in accordance with the concentration of the particles. “The quantitative outcomes of this study can be used to estimate human health impacts, develop policies and standards, initiate mitigation measures for pollution events with implications to climate change, and help move towards a sustainable future,” added Mishra.

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