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Title:	Results: Diwali 2021 Air Quality Monitoring on IISER Mohali Campus
Authors:	Sinha, V.
Issue Date:	5-Nov-2021
Publisher:	IISER-M
Description:	In case you are interested to know about the Air Quality during Diwali last night (04.11.2021-05.11.2021) and its comparison relative to previous years, please read further to know about the results. Background Intro for Interpretation: Due to the sulphur content in the firecrackers, gaseous sulphur dioxide in ambient air is considered a very good tracer for fire cracker emissions. PM2.5 is the mass concentration of all aerosol particles with aerodynamic equivalent diameter upto 2.5 micron , and of concern from health perspective and is the criteria pollutant that is frequently in exceedance of the national air quality standards. Fire crackers also emit very high amounts of PM2.5. For those who would like more background info on basics of air pollution and ambient air quality over our region you may listen to the following public lecture available on IISER Mohali's youtube channel courtesy Outreach IISER Mohali: https://www.youtube.com/watch?v=KI29iTev-Ng. Now to the results (attached herewith as pdf) many of you have been keenly awaiting: 1)The first figure in the attached pdf provides a summary comparison of the peak 15 min average mass concentrations (PM2.5) and mixing ratios (Sulphur dioxide) observed during Diwali 2021 relative to the average of the peak 15 min average values observed in the previous 9 years (2012-2020). 2) The second figure in the attached pdf shows the data at a temporal resolution of 15 minutes, from 17:45 on 04.11.2021 till 2 am on 05.11.2021. For your easy reference the respective National Ambient Air Quality Standard (NAAQS) (24 h average concentration exposure standard value for PM2.5 and SO2 which should not be exceeded) are shown as red traces. The summary is that 2021 Diwali night was characterized by much better air quality relative to the past years despite the air masses arriving mainly from the tri-city urban areas and low wind speeds which favour accumulation of pollutants near place of emission ( < 1.5 m/s in general but also dipped to 0.5 m/s aorudn 10 pm). While the permissible timing for fire cracker bursting (8 to 10 pm per Mohali admin communication) was not strictly adhered to, the highest intensity of the activity based on SO2 was between 8-10 pm. Around 10 pm you see an increase in PM2.5 but not SO2, because of dip in wind speed (plummeted to 0.5 m/s) AND because removal of SO2 from gas phase is more rapid than that of PM2.5 , the latter of which also has many more strong sources including biomass burning. So kudos to all who did not add to the pollution through fire cracker emissions, in particular many young campus residents (they may want to show the plots to their class teachers:). Finally, I would like to thank all the past and current students who keep/have kept the IISER Atmospheric Chemistry facility (which sits on CAF roof top) running 24/7 since Aug 2011 and make sharing of these results possible with all of you. The past and present institutional support is also gratefully acknowledged. It is worth mentioning that every additional year we still have working instruments, can be counted as a great blessing because we are way past the normal shelf life of these instruments and it takes alot of effort to keep them going. For this year's Diwali monitoring data,please also join me in specifically thanking our students namely Muhammed Shabin, Raj Singh, Savita Datta, Pooja, Anita Sharma, Sneha Saha, Jaswinder Singh and Anik Das who ensured that all instruments worked without issues/downtime by skipping some of their sleep and festivity time during Diwali. The overall uncertainty for the Sulphur dioxide measurements is less than 6% of the measured value whereas for PM 10 measurements it is less than 8% of the measured value.
URI:	https://www.youtube.com/watch?v=KI29iTev-Ng http://hdl.handle.net/123456789/3961
Appears in Collections:	Public Lectures

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