246 | Page MEASUREMENT AND ANALYSIS OF AMBIENT AIR QUALITY IN A COMMERCIAL AREA -A CASE STUDY OF GORAKHPUR CITY Punya Prateek Chauhan 1 , Dr.A.K. Mishra 2 1 PG Scholer ,Civil Engg. Department M.M.M University of Technology Gorakhpur (U.P.), (India) 2 Assistant Professor ,Civil Engineering Department, M.M.M. University of Technology Gorakhpur- (U.P), (India) ABSTRACT Present study deals with assessment of the ambient air quality in Gorakhpur city employing air quality index. 24 hour average concentration of three major pollutants SO 2 , NO2 and PM 10 were monitored for the year 2015 in a commercial area near Jalkal Bhawan in Gorakhpur city. Measurement of the pollutants were carried out from January 2015 to December 2015. Air Quality Index was calculated by IND-AQI procedure. Maximum monthly average concentration of PM 10 , SO 2 ,NO 2 were 243.1, 23.6 and 49.8 was observed in February, September and April respectively. The annual average concentration of SO 2 was found below the prescribed limit given by CPCB, and NO 2 was found slightly above than the maximum limit but PM 10 was always found more than prescribed limit given by CPCB. The overall AQI was found to fall under the category moderate and monthly average concentration of No 2 is greater than SO 2. Keyword: Air Quality Index, PM 10 , SO 2 , NO 2, IND-AQI (break point concentration). I. INTRODUCTION Air pollution is actually the addition of any harmful substance to the atmosphere which causes the damaging of environment, human health and quality of life. Air pollution is mixture of various gases, particulate matter, aerosol, water vapour which is emitted by natural and anthropogenic source (Shivangi Nigam 2015). Air pollution increases with the increase in residential, commercial and industrial development of an area.. The growth of population, industry and number of vehicles and improper implementation of stringent emission standards make the problem of air pollution still worse (Ravikumar, 2014).Increasing rate of emission of Air pollutant is a serious matter of concern for government. For management of air pollution Central Pollution Control Board is executing a nation-wide programme of ambient air quality monitoring known as National Air Quality Monitoring Programme (NAMP). The network consists of three hundred and forty two (342) operating stations covering one hundred and twenty seven (127) cities/towns in twenty six (26) states and four (4) Union Territories of the country (CPCB 2009). Air pollution has emerged as a major challenge, particularly in urban areas. The problem becomes more complex due to the multiplicity and complexity of the air polluting source mix (e.g., industries, automobiles,