title: Temporal variability of benzene concentration in the ambient air of Delhi: a comparative assessment of pre- and post-CNG periods.
abstract: CNG (compressed natural gas) was fully implemented in public transport system in Delhi in December 2002. The study assesses the benzene concentration trends at two busy traffic intersections and a background site in Delhi, India. Monitoring was done for two different time periods viz; in the year 2001-2002 (pre-CNG) and two winter months (January and February) of the year 2007 (post-CNG) to assess the impact of various policy measures adopted by the government of Delhi to improve the air quality in the city. Annual average benzene concentration for the pre-CNG period was found to be 86.47+/-53.24 microg m(-3). Average benzene concentrations for the winter months (January-February) of pre- and post-CNG periods were 116.32+/-51.65 microg m(-3) and 187.49+/-22.50 microg m(-3), respectively. Enhanced values could be solely attributed to the increase in the vehicular population from 3.5 million in the year 2001-2002 to approximately 5.1 millions in the year 2007.
authors: School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India. psk@mail.jnu.ac.in
authors: P S
authors: PS
authors: Khillare
authors: Raza Rafiqul
authors: RR
authors: Hoque
authors: Vijay
authors: V
authors: Shridhar
authors: Tripti
authors: T
authors: Agarwal
authors: S
authors: S
authors: Balachandran
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001554:Benzene / Q000032:analysis*; D004784:Environmental Monitoring; D005579:Fossil Fuels; D007194:India; D012621:Seasons; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D005579:Fossil Fuels; D001335:Vehicle Emissions; D001554:Benzene