Patna’s air quality remains ‘very poor’

PATNA: The Air Quality Index (AQI) of Patna remains “very poor”.
The AQI of Patna as per the daily bulletin issued by the Central Pollution Control Board (CPCB) dropped from 398 on Monday to 366 on Tuesday but it continued to remain in the “very poor” category. The CPCB states prolonged exposure to “very poor” AQI can lead to respiratory disorders.
The AQI is an assessment of the air quality taking into account eight pollutants: PM2.5 (particulate matter less than 10 micron), PM10 (particulate matter less than 10 micron), nitrogen oxides, sulphur dioxide, ozone, carbon monoxide, ammonia and lead.
On November 21, the AQI of Patna at 423 was the highest in the country. It dropped to 370 on November 22, but again surged to 373 on November 23 and plunged to 347 on November 24.
PM2.5 has been found to be the biggest contributor to the high AQI in Patna. The average level of PM2.5 in the air at Patna on Tuesday was around 219.01 micrograms per cubic metre, over two times the corresponding daily permissible limit of 100 micrograms per cubic metre.
Experts said despite more than double of the prescribed limit of PM2.5, the AQI did not witness a steep surge owing to comparatively higher wind speed. A Patna Meteorological Centre official said easterly wind was blowing at an average speed of 10-12kmph on Tuesday, which led to dispersal of particulate matter.
However, the AQI may rise if the wind speed reduces as easterly winds are moist and heavy, and prevent the particulate matter to escape in the upper level of atmosphere.