[Gohain*, 5.(3): April, 2016] ISSN: 2277-9655 (I2OR), Publication Impact Factor: 3.785 http: // www.ijesrt.com © International Journal of Engineering Sciences & Research Technology [436] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY ANALYSIS OF AMBIENT AIR QUALITY IN GUWAHATI CITY – A CASE STUDY Mitali Gohain * , Dr. Kalyan Kalita * Dept. of Mechanical Engg., Regional Institute of Science and Technology, Meghalaya, India Dept of Mechanical Engg, Assam Engineering College, Guwahati, Assam, India DOI: 10.5281/zenodo.49747 ABSTRACT This study reports the analysis of the ambient air quality at six different locations in Guwahati city. It investigates the concentration of the pollutants - Suspended Particulate Matter (SPM), Respirable Suspended Particulate Matter (RSPM), Nitrogen Dioxide (NO 2 ) and Sulphur Dioxide (SO 2 ) for the months of April, May and June 2014. Six sampling sites (Industrial, Residential and Urban) were selected on the basis of different parameters like population density, meterological data etc. The sites selected were Bamunimaidam, Khanapara, Boragaon, Jalukbari, Santipur and Ulubari. The Air Quality Index (AQI) was calculated using Indian Air Quality Index (IND-AQI) procedure. It revealed that SPM and RSPM are mainly responsible for polluting the environment at different locations in Guwahati city. The concentration of gaseous pollutants namely SO 2 and NO 2 were under the permissible limits as per National Ambient Air Quality Standards (NAAQS), Central Pollution Control Board (CPCB) while the concentration of particulate pollutants (SPM and RSPM/PM10) were higher than the permissible limits as per CPCB. KEYWORDS: Ambient air quality, Air Quality Index, SO 2 , NO 2 , SPM, Guwahati . INTRODUCTION Air pollution is considered to be primarily an urban problem in Guwahati city as the rate of urbanization increases. Growing air pollution has emerged as a serious concern in the city with vehicular emission and dust contributing a major share of the deteriorating air quality. In rural areas, air quality is considered to have been negatively affected with areas adjacent to industrial estates or isolated industrial plants set up outside city limits. The notion of maintaining good air quality has been the focus of attention among concerned stakeholders in Guwahati. The Pollution Control Board, Assam (PCBA) has been monitoring the city’s ambient air quality under the National Air Quality Monitoring Programme (NAMP) and has recorded high levels of air pollution in all its monitoring stations in the city. Under N.A.M.P., four air pollutants namely, Sulphur Dioxide (SO 2 ), Nitrogen dioxide (NO 2 ), Suspended Particulate Matter (SPM) and Respirable Suspended Particulate Matter (RSPM/PM 10 ) have been identified for regular monitoring at all the locations. The monitoring of pollutants is carried out for 16 hours (4-hourly sampling for gaseous pollutants i.e. SO 2 and NO 2 and 8-hourly sampling for particulate matter i.e. SPM and RSPM) on all working days of a week. The problem of air pollution in the Guwahati city is mainly because of vehicles and small and medium-scale industries. With more and more people these days purchasing private vehicles, the energy consumption (fossil fuel) and SO X , NO X emissions have increased tremendously. According to reports, more than 400,000 vehicles ply on Guwahati's roads every day and approximately 70% of these vehicles don't have emission clearance certificates. So majority of the vehicles plying on Guwahati roads could be emitting excessive amounts of toxic pollutants. The