Indian Scientists Establish ‘Toxicity Benchmark’ for PM2.5 Pollution

Synopsis

Researchers at Bose Institute have established that PM2.5 pollution becomes significantly more toxic when levels exceed 70 micrograms per cubic metre. Their findings stress the need for effective policies to control air quality in Kolkata.

Key Takeaways

PM2.5 toxicity increases drastically above 70 µg/m³.
The study highlights a non-linear relationship between pollution load and toxicity.
Biomass burning is a major contributor to PM2.5 toxicity.
NCAP aims for a 40% reduction in particulate matter by 2026.
Kolkata is identified as a non-attainment city.

New Delhi, April 11 (NationPress) Researchers from the Bose Institute, an independent research facility under the Department of Science and Technology, have demonstrated that the toxicity level of PM2.5 sees a significant increase when pollution levels reach approximately 70 micrograms per cubic metre.

The toxicity benchmark suggests that "strategies, policies, and control measures must be implemented to maintain PM2.5 pollution below this threshold of around 70 micrograms per cubic metre, as exceeding this level leads to a rapid escalation in toxicity that becomes difficult to manage," according to the researchers.

PM2.5, or particulate matter with a diameter of 2.5 micrometres or less, is a major air pollutant that poses severe health risks, including respiratory and cardiovascular issues, and serves as a critical indicator of air quality.

The study, led by Prof. Abhijit Chatterjee, concentrated on the toxicity of atmospheric aerosols in Kolkata's air.

The researchers investigated how toxicity levels change with rising aerosol pollution and examined the oxidative potential of ultrafine aerosols (PM2.5), or the ability to produce reactive oxygen species (ROS) that enter human lung cells through inhalation.

The increased presence of reactive oxidative species hampers the effectiveness of natural antioxidants in human cells, resulting in oxidative stress.

The findings, published in the journal Science of The Total Environment, revealed a non-linear correlation between PM2.5 pollution levels and their toxicity (OP).

“Until PM2.5 pollution reaches around 70 micrograms per cubic metre, toxicity levels remain stable. As PM2.5 levels rise, the OP values experience a spike until they hit about 130 micrograms per cubic metre. Beyond this, OP values show little change,” the research team noted in their publication.

Moreover, the researchers identified biomass and solid waste burning as the primary source of PM2.5 contributing to increased toxicity in Kolkata's ultrafine aerosols.

“Although the National Clean Air Programme (NCAP) has successfully mitigated various air pollution sources such as road dust, construction debris, and vehicular emissions, biomass/solid waste burning remains poorly controlled. Emissions from this source are exacerbating toxicity levels,” the researchers emphasized.

The NCAP was initiated in 2019 by the Ministry of Environment, Forest and Climate Change (MoEFCC) to address air pollution across the nation.

This program aims to reduce particulate matter by 40% by 2026 relative to 2017, implementing strategies and action plans for 131 non-attainment cities in India that fail to meet the National Ambient Air Quality Standards. Kolkata is one of these identified cities.