Indian researchers introduce 'toxicity standard' of PM2.5 pollution

IANS April 11, 2025 220 views

Indian researchers from the Bose Institute have discovered a critical threshold in PM2.5 pollution that dramatically increases its toxicity. The study reveals that when pollution reaches around 70 micrograms per cubic metre, the health risks escalate rapidly. Biomass and solid waste burning emerge as primary contributors to this toxic particulate matter. The findings underscore the urgent need for targeted air quality management strategies in urban environments.

"With the increase in PM2.5, the OP values show a jump and sudden rise" - Bose Institute Research Team
New Delhi, April 11: Researchers at the Bose Institute, an autonomous research institute under the Department of Science and Technology, showed that the toxicity value of PM2.5 experiences a sudden jump when the pollution reaches around 70 micrograms per cubic metre.

Key Points

1

Pollution toxicity jumps dramatically at 70 micrograms per cubic metre

2

Biomass burning key source of toxic PM2.5

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Study reveals non-linear relationship between pollution and health risks

The toxicity standard implies that “policies, strategies and control measures should be taken to keep PM2.5 pollution within this limit of around 70 micrograms per cubic metre, because once the PM2.5 load exceeds this value, the toxicity starts to increase rapidly and goes beyond control,” said the researchers.

PM 2.5, or particulate matter with a diameter of 2.5 micrometres or smaller, is a significant air pollutant posing serious health risks, including respiratory and cardiovascular problems, and is a key indicator of air quality.

The study, led by Prof. Abhijit Chatterjee, focussed on the toxicity of atmospheric aerosols over the atmosphere of Kolkata.

The researchers explored how the degree of the toxicity changes with the increase in total aerosol pollution load and have studied the oxidative potential of ultrafine aerosols (PM2.5) or the potential of forming the reactive oxygen species (ROS) that are introduced to the human lung cells via inhalation of particles.

The enhanced presence of the reactive oxidative species makes the natural antioxidants of human cells incapable of counteracting, leading to oxidative stress in cells.

The study, published in the journal Science of The Total Environment, showed that there is a non-linear relationship between the PM2.5 pollution load and its toxicity (OP).

“Up to the PM2.5 pollution load of around 70 micrograms per cubic metre, the toxicity remains unchanged. With the increase in PM2.5, the OP values show a jump and sudden rise till the PM2.5 pollution reaches around 130 micrograms per cubic metre. With the further increase in PM2.5 load exceeding 130 micrograms per cubic metre, OP values do not change much,” the team explained in the paper.

Further, the researchers found that biomass/solid waste burning is the key source of PM2.5 that is enhancing the toxicity of ultrafine aerosols over Kolkata.

“While the National Clean Air Programme (NCAP) has been effective in reducing and curbing various air pollution sources like road dust, constructional/demolition dust, vehicular exhaust, industrial emissions, etc. However, biomass/solid waste burning could not be kept under good control. The particles emitted from this particular source are accelerating the toxicity,” the researchers said.

NCAP was launched in 2019 by the Ministry of Environment, Forest and Climate Change (MoEFCC) to combat air pollution in the country.

The programme is focused on the reduction of particulate matter by 40 per cent by 2026 with respect to 2017 through strategies and action plans for 131 non-attainment cities (not attaining the National Ambient Air Quality Standard of India) in India for different states. Kolkata has been identified as one of such cities in India.

Reader Comments

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Priya K.
This is such important research! As someone with asthma in Delhi, I can literally feel the difference when PM2.5 crosses 70. Hope policymakers take note and implement stricter controls on biomass burning. 🌱
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Rahul S.
Interesting study but I wish they had included more cities beyond Kolkata. The toxicity threshold might vary regionally based on pollution sources. Still, a good starting point for air quality standards.
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Ananya P.
The NCAP program needs to focus more on rural areas where biomass burning is common. Urban pollution gets attention but rural air quality affects everyone downwind. Great to see Indian researchers leading this important work!
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Sanjay M.
As a doctor, I see the health impacts daily. This research gives us concrete numbers to advocate for better policies. That toxicity jump at 70μg/m³ explains why emergency visits spike during bad air days.
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Neha T.
While the science is solid, I'm concerned about implementation. We have good research and programs like NCAP, but enforcement remains weak. How do we ensure these findings actually lead to cleaner air? 🤔

We welcome thoughtful discussions from our readers. Please keep comments respectful and on-topic.

Tags:
Air Pollution PM2.5 Bose Institute Kolkata Environmental Research Abhijit Chatterjee NCAP
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