title: Large inter annual variation in air quality during the annual festival 'Diwali' in an Indian megacity.
abstract: A network of air quality and weather monitoring stations was established under the System of Air Quality Forecasting and Research (SAFAR) project in Delhi. We report observations of ozone (O3), nitrogen oxides (NOx), carbon monoxide (CO) and particulate matter (PM2.5 and PM10) before, during and after the Diwali in two consecutive years, i.e., November 2010 and October 2011. The Diwali days are characterised by large firework displays throughout India. The observations show that the background concentrations of particulate matter are between 5 and 10 times the permissible limits in Europe and the United States. During the Diwali-2010, the highest observed PM10 and PM2.5 mass concentration is as high as 2070µg/m3 and 1620μg/m(3), respectively (24hr mean), which was about 20 and 27 times to National Ambient Air Quality Standards (NAAQS). For Diwali-2011, the increase in PM10 and PM2.5 mass concentrations was much less with their peaks of 600 and of 390μg/m(3) respectively, as compared to the background concentrations. Contrary to previous reports, firework display was not found to strongly influence the NOx, and O3 mixing ratios, with the increase within the observed variability in the background. CO mixing ratios showed an increase. We show that the large difference in 2010 and 2011 pollutant concentrations is controlled by weather parameters.
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India.
authors.forename: Neha
authors.initials: N
authors.lastname: Parkhi
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India. Electronic address: chate@tropmet.res.in.
authors.forename: Dilip
authors.initials: D
authors.lastname: Chate
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India.
authors.forename: Sachin D
authors.initials: SD
authors.lastname: Ghude
authors.affiliation: India Meteorological Department New Delhi, India.
authors.forename: Sunil
authors.initials: S
authors.lastname: Peshin
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India.
authors.forename: Anoop
authors.initials: A
authors.lastname: Mahajan
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India.
authors.forename: Reka
authors.initials: R
authors.lastname: Srinivas
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India.
authors.forename: Divya
authors.initials: D
authors.lastname: Surendran
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India.
authors.forename: Kaushar
authors.initials: K
authors.lastname: Ali
authors.affiliation: India Meteorological Department New Delhi, India.
authors.forename: Siddhartha
authors.initials: S
authors.lastname: Singh
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India.
authors.forename: Hanumant
authors.initials: H
authors.lastname: Trimbake
authors.affiliation: Indian Institute of Tropical Meteorology, Pashan, Pune, India.
authors.forename: Gufran
authors.initials: G
authors.lastname: Beig
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D000397:Air Pollution / Q000706:statistics & numerical data; D002248:Carbon Monoxide / Q000032:analysis; D004784:Environmental Monitoring; D006693:Holidays; D007194:India; D009589:Nitrogen Oxides / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D002248:Carbon Monoxide
keywords: Air quality; Diwali; Fireworks; Particulate pollution; System of Air Quality Forecasting and Research (SAFAR); Trace gases