5 months ago
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Chennai has emerged arsenic 1 of India’s better-performing cities connected good particulate pollution, adjacent arsenic dust-related contamination continues to airs a challenge, according to a caller appraisal by the Health Effects Institute (HEI) connected changes successful municipality aerial prime since the motorboat of the National Clean Air Programme (NCAP).
Analysing real-time aerial prime information from 2017 to 2024, the study recovered astatine slightest 1 monitoring presumption successful Chennai, Kodungaiyur, recorded the lowest yearly mean PM2.5 level successful the state successful 2024, astatine 12.6 micrograms per cubic metre, good beneath the nationalist modular of 40 µg/m³. Several different locations successful the metropolis besides reported PM2.5 levels beneath 20 µg/m³.
However, the representation is little encouraging erstwhile it comes to PM10, which denote the coarser particles mostly linked to roadworthy dust, operation enactment and ungraded re-suspension.
Across the country, much than 90% of monitoring stations breached the PM10 modular successful 2024. Chennai was nary exception, though immoderate neighbourhoods performed notably amended than most. The Velachery residential area, for instance, recorded an yearly PM10 mean of 47 µg/m³, placing it among a tiny fig of locations nationwide that met the modular of 60 µg/m³.
The Delhi-NCR portion continues to predominate the database of the astir polluted locations for some PM10 and PM2.5, with yearly PM10 levels crossing 250 µg/m³ astatine aggregate stations. Cities specified arsenic Patna, Ghaziabad and parts of Punjab and Haryana besides reported persistently precocious contamination levels.
Coastal cities similar Chennai and Mumbai, by comparison, showed little PM2.5 concentrations — a signifier the study links partially to meteorological factors specified arsenic oversea breeze.
The study besides cautions against relying solely connected city-wide averages. Even successful cities similar Chennai, which person aggregate monitoring stations, contamination trends tin alteration sharply from 1 neighbourhood to another.
Environmental wellness researcher Vishvaja Sambath said that aggregated information risks obscuring section hotspots and uneven exposure. “It masks the existent occupation of pollution. We request to look astatine much granular data,” she added.
Significantly, the study noted that PM2.5 is not included successful the revised NCAP target. This is simply a occupation arsenic determination are capable grounds that prolonged vulnerability to good particulate substance causes superior chronic issues, said Ms. Sambath.
S. M. Shiv Nagendra of the Department of Civil Engineering, IIT Madras, said information from monitoring stations cannot beryllium treated arsenic typical of an full city, arsenic each presumption measures aerial prime lone wrong a radius of a fewer 100 metres.
Mr. Nagendra pointed retired the Environmental Protection Agency recommends 1 monitoring presumption for each 5 lakh people. He besides noted that monitoring stations should beryllium strategically located to seizure source-specific emissions, specified arsenic vehicular contamination successful high-traffic areas and emissions circumstantial to concern zones.
