Pollution: Chandigarh AQI slips to ‘moderate’ level
Dushyant Singh Pundir
Chandigarh, October 9
In recent days, the air quality in the city has witnessed a concerning deterioration with the Air Quality Index (AQI) slipping to the “moderate” level due to changing weather and vehicular emissions.
According to the Central Pollution Control Board, the AQI shot up to 140 in the city around 9 pm.
An official of the Chandigarh Pollution Control Committee said the AQI was recorded at 124 on October 8, 130 on October 7, 128 on October 6, 119 on October 5, 115 on October 4, 105 on October 3, 109 on October 2, and 104 on October 1.
Barring a few days in the month, the average AQI in September remained “satisfactory”, he said. Since the beginning of the month, the AQI remained at the “satisfactory” level in the city. The minimum temperature of the city also dropped from 23° Celsius recorded on September 24 to 19.4° Celsius on October 5.
The city’s declining AQI could be chiefly attributed to vehicular pollution and recent climatic shifts. As temperatures dropped slightly in the past few days, these conditions exacerbated the problem, said Dr Ravindra Khaiwal, a distinguished Professor of Environment Health from the Department of Community Medicine, PGIMER, who recently secured the top position in the Atmospheric Science category of the 2023 Global Scientist List released by Stanford University.
He highlighted the significance of the atmospheric boundary layer, a crucial component in understanding air quality. With the onset of wintry conditions, this layer has descended to a lower altitude, measuring between 7 km and 8 km above the Earth’s surface, compared to its usual height of 10 km to 12 km. This change, which depends on local meteorological factors, has a direct and immediate effect on the AQI.
Addressing another critical concern, Dr Khaiwal emphasised the burning of crop stubble in the neighbouring states of Haryana and Punjab had a relatively minimal impact on the city’s air quality. He pointed out that stubble burning only becomes a significant concern when prevailing winds carry the pollutants towards the city.
He said stubble burning would only make an impact in the city when prevailing winds were blowing towards the city, he said. Meanwhile, 23 farm fires were reported in Punjab and 31 in Haryana today against 131 and 97, respectively, yesterday, he added.
An increase in the AQI causes breathing discomfort to most people on prolonged exposure. — TNS
Atmospheric boundary layer
Dr Ravindra Khaiwal, Professor of Environment Health, PGI, says with the onset of wintry conditions, the atmospheric boundary layer has descended to a lower altitude, between 7 km and 8 km above the Earth’s surface, compared to its usual height of 10 km to 12 km. This change, which depends on local meteorological factors, has a direct and immediate effect on the AQI.
Minimal impact of stubble burning
Dr Khaiwal says the burning of crop stubble in the neighbouring states has a relatively minimal impact on the city’s air quality. It only becomes a significant concern when winds carry the pollutants towards the city.
