Centre for Air Pollution Studies

The fifth India Clean Air Summit (ICAS) — the Center for Study of Science, Technology and Policy’s flagship event on air pollution — will be held from 22–24 August in Bengaluru. This year’s summit promises to be just as (if not more) informative, insightful, and engaging as the previous ones.

Jharkhand is a mineral-rich state in India. Its cities have access to various solid fuels and proximity to several heavy industries. These factors, along with the movement of traffic (public and goods), contribute to air pollution in the state.

In 2019, the Ministry of Environment, Forest, and Climate Change (MoEFCC) under the Government of India launched the National Clean Air Programme (NCAP), which proposes strategies to reduce air pollution in several cities in India. In Jharkhand, only Dhanbad, a non-attainment city, and Ranchi and Jamshedpur, million-plus cities, are under the purview of NCAP. However, considering the importance of mitigating air pollution in several cities in the state, the government has identified multiple cities, including Ramgarh, to generate evidence on air pollution.

Featuring “green growth” as one of its seven priorities, Union Budget 2023-24 announced some encouraging initiatives towards meeting its environmental targets. While many of these would indirectly aid air pollution control – a critical component of green growth – comprehensive proactive steps to tackle the rising air pollution were given a miss.

In this study, we combined state-of-the-art data modelling techniques (machine learning [ML] methods) and data from state-of-the-art low-cost particulate matter (PM) sensors (LCSs) to improve the accuracy of LCS-measured PM2.5 (PM with aerodynamic diameter less than 2.5 microns) mass concentrations. We collocated nine LCSs and a reference PM2.5 instrument for 9 months, covering all local seasons, in Bengaluru, India. Using the collocation data, we evaluated the performance of the LCSs and trained around 170 ML models to reduce the observed bias in the LCS-measured PM2.5.

To effectively manage air pollution, we need to measure it accurately and at high spatial resolution. However, maintaining a dense network of regulatory instruments is financially and technically burdensome for low- and middle-income countries. A hybrid approach that combines non-conventional, less expensive, short-term stationary, and mobile deployments may be a cost-effective solution. In the city of Bengaluru, India, we adopted such a hybrid measurement approach to generate high spatial resolution air pollution maps.

Low-cost sensors (LCSs) have revolutionized the air pollution monitoring landscape. However, the sensitivities of particulate matter (PM) LCS measurements to various particle microphysical properties and meteorological aspects warrant an accuracy investigation. We investigated the inter- and intracity variations in the accuracy of LCS-measured PM2.5 across geographically and demographically distinct Indian cities.

Atleast 9 million people die annually from air pollution-related complications, according to a recent study by The Lancet Commission on pollution and health. Meanwhile, the alarming increase in carbon dioxide and other greenhouse gas emissions, due to human activities, is escalating the climate crisis. Putting a number on deaths attributable to climate change is complex, but there’s no denying this: we are at crisis point and it is likely to get worse before (and if) it gets better.