title: Seasonal variability of ambient NH3, NO, NO2 and SO2 over Delhi.
abstract: We present the diurnal and seasonal variability of ambient NH3, NO, NO2 and SO2 over Delhi, India. Ambient NH3, NO and NO2 were measured continuously during winter, summer and autumn seasons using NH3- and NOx-analyzer, which operates by chemiluminescence method with a higher estimation efficiency (> 90%) than the chemical trap method (reproducibility 4.7%). Prominent diurnal, day-to-day and seasonal variations of ambient mixing ratio of NH3, NO, NO2 and SO2 were observed during the study period. Seasonal variation with higher mixing ratio in winter was observed for all measured trace gases except NO. Day-night variation of all measured trace gases observed was higher in winter in comparison with summer. Late morning increase in NO2 mixing ratio might be attributed to conversion of NO to NO2 with the interaction of O3.
authors.affiliation: Radio and Atmospheric Sciences Division, National Physical Laboratory, Council of Scientific and Industrial Research, Dr KS Krishnan Road, New Delhi-ll0 012, India. sudhir@nplindia.ernet.in
authors.forename: S K
authors.initials: SK
authors.lastname: Sharma
authors.forename: A
authors.initials: A
authors.lastname: Datta
authors.forename: T
authors.initials: T
authors.lastname: Saud
authors.forename: M
authors.initials: M
authors.lastname: Saxena
authors.forename: T K
authors.initials: TK
authors.lastname: Mandal
authors.forename: Y N
authors.initials: YN
authors.lastname: Ahammed
authors.forename: B C
authors.initials: BC
authors.lastname: Arya
mesh_terms: D000641:Ammonia / Q000032:analysis*; D004784:Environmental Monitoring; D007194:India; D049449:Luminescence; D009569:Nitric Oxide / Q000032:analysis*; D009585:Nitrogen Dioxide / Q000032:analysis*; D012621:Seasons; D013458:Sulfur Dioxide / Q000032:analysis*
chemical_list: D013458:Sulfur Dioxide; D009569:Nitric Oxide; D000641:Ammonia; D009585:Nitrogen Dioxide