Abstract Number: 1214 Working Group: Air Quality in Megacities: from Sources to Control
Abstract Deteriorating urban air quality in Delhi and National Capital region (NCR) is one of the prime topics of discussion. There are many distinctive features of Delhi which impact air pollution like uncontrolled sources of pollution in its surrounding perimeter (where city regulations do not apply, and where they apply, are not followed stringently), a number of unregulated and unaccounted sources within the city, unfavourable geographic location and regional meteorology, with windy and dusty conditions during summer and foggy weather with limited ventilation and mixing during winter. At the onset of winter, during the Months of October-November every year, a thick blanket of smoke and fog covers the northern states including Delhi. Hazy weather is witnessed during these winter months which may have been caused by pollution emissions during Diwali celebrations period and smoke generated from burning of agriculture stubble during a few overlapping or subsequent weeks. However, there has been no conclusive study available that adequately determines the dynamics and movement of the pollutants that come towards Delhi due to burning of stubble (paddy crop) residue in states like Punjab and Haryana.
Agricultural stubble burning emits significant quantity of air pollutants like NOx, SO2, CO, NH3 and particulate matter. The current study is trying to evaluate the contribution of pollution from the stubble burning in the states of Haryana and Punjab in the air quality of Delhi and NCR. Ambient air quality monitoring with respect to major air pollutants, viz. PM10, PM2.5, SO2 and NO2 is carried out during the stubble burning period in Punjab and Haryana States. Chemical profiling is also done under the studyA total of seven sites were selected for ambient air quality monitoring, two in Punjab: Patiala and Sangrur; two in Haryana State: Karnal and Rohtak; and three in Delhi: Pitampura, Sarojini Nagar and Nariana. Twelve hours sampling is done, twice a day, from 8am to 8pm and 8pm to 8 am.
Episodic days are also monitored during these two months. High pollution loading was observed during the month of November. It is also observed that, in general, the monitored sites breach the National Ambient Air Quality Standards (NAAQS), set at 100 µg/m3 and 60 µg/m3 for PM10 and PM2.5 respectively, even during the normal days and are much higher during the episodic days. During the analysis, it was also observed that local sources around monitoring station influences the air quality significantly. The meteorological parameters are monitored in Ludhiana (Punjab), Rohtak (Haryana) and Nariana (Delhi). Winds are mostly observed in calm condition during the study period. This may be indicating towards a very low possibility of movement of long transport of pollution and more contribution of local sources in pollution level. The current study comprising of weather monitoring, ambient air quality monitoring, chemical characterisation and source profiling, reveals interesting facts about the correlation between Delhi’s pollution level and stubble burning in the states of Haryana and Punjab and the same is discussed in the detailed paper.