Chennai air quality slips to 'poor' levels, smoggy conditions to prevail

Highest pollution levels were recorded in Manali, where PM 2.5 levels touched 334 µg/m3 and were recorded to be 321 µg/m3 in Velachery.
Chennai city witnessed heavy smog on Monday. (Photo | Debadatta Mallick, EPS)
Chennai city witnessed heavy smog on Monday. (Photo | Debadatta Mallick, EPS)

CHENNAI: Chennai air quality on Monday has deteriorated dramatically under smoggy weather conditions. At 8 pm, the Air Quality Index (AQI) for the city peaked to 270 enough to cause breathing discomfort to most people on prolonged exposure.

The continuous ambient air quality monitoring systems of Central Pollution Control Board (CPCB) has continuously flagged 'yellow alert', a colour code, for most part of Monday indicating 'poor' air quality.

The monitoring station in Velachery residential area showed PM 2.5 concentration spiked as high as 321 µg/m3 (micrograms per cubic meter) and the 24-hour average being 256. Highest pollution levels were recorded in Manali, where PM 2.5 levels touched 334. PM 2.5 is a tiny particulate matter of diameter 2.5 or less than 2.5 microns that can enter deep into the lungs. The National Ambient Air Quality (NAAQ) standard for PM 2.5 is 60 µg/m3.

"The reason for sudden spike is pollution levels can be attributed to lack of wind, anti-cyclonic circulation in upper air and dry weather conditions in southern peninsula, all of which is blocking the pollutants to disperse. The current wind pattern of north easterly is bringing industrial emissions from Ennore directly into the city and there is pollution from vehicles, construction activity and road dust. All these pollutants circulate at surface level and when sea breeze brings moisture, the combination will trigger smog like condition," said N Puviarasan of Regional Meteorological Centre.

The met official said smoggy conditions would prevails for few more days until rainfall activity picks up pace again. To a query, the official dismissed the possibility of Delhi pollution pushed along the East Coast and deteriorate Chennai air quality. "This is purely a local phenomenon."

When contacted, Tamil Nadu Pollution Control Board (TNPCB) chairman AV Venkatachalam said the air quality has deteriorated during late evening hours. "As per our data, the air quality during the day was moderate and high pollution levels were recorded only during late evening hours. The board is contemplating asking industries in Ennore and other areas to reduce the emissions for next few days."

Pollution levels in Chennai (Parameter: PM 2.5)

StationMinimum Average  Maximum
Manali 176   295 334
Alandur Bus Depot 19250317
Velachery residential area  175256321

Good (0-50) Satisfactory (51-100) Moderately polluted (101-200) Poor
(201-300) Very poor (301-400) Severe (> 401)

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