J. Environ. Res. Develop. Journal of Environmental Research And Development Vol. 7 No. 1A, July-September 2012 484 *Author for correspondence A FUZZY INFERENCE SYSTEM FOR AIR QUALITY IN USING MATLAB, CHENNAI, INDIA Kumaravel R.* 1 and Vallinayagam V. 1. SRM University, Career Development Centre, Kattankulathur, Chennai (INDIA) 2. Department of Mathematics, St.Joseph’s College of Engineering, Chennai (INDIA) Received April 25, 2012 Accepted August 05, 2012 ABSTRACT Air quality is an important issue of relevance in the context of present times. The proposed model is designed to predict Air Quality Index (AQI) for Chennai in Tamil Nadu, India. A Fuzzy Inference System (FIS) simplifies and speed up the computation of AQI as compared to the currently existing standards. In this paper, the proposed model is compared with Indian Air Quality Index (IAQI) and it is found that the designed model results in accurate prediction. The earth’s atmosphere is a mixture of gases and particulate-phase substances. The most abundant of these, Nitrogen(N 2 ) and Oxygen(O 2 ), comprise approximately 78% and 21% respectively, of atmosphere mass and volume. Air quality can be defined qualitively. It is poor when cause a reduction in visibility, soil building surfaces and damage materials, damage crops and other plants, cause adverse health effects. It is deemed good when the sky appears clean and no adverse environmental effects are evident. Key Words : Air Quality Index (AGI), Fuzzy logic, Fuzzy Inference System (FES), MATLAB INTROUDCTION The atmosphere that surrounds the plant earth is one of the factors that makes our plant hospitable towards life. The average human makes use of about 30 pounds of air each day, using it to oxidize food for energy and warmth. A number of trace gases make up the remaining 1% average concentration 1 in Table 1. Table 1 : Percentage and volume with different gases Gases Percentage of volume Nitrogen 78.03 Oxygen 20.99 Argon 0.94 Carbon di oxide 0.03 Balance* 0.01 *Includes hydrogen, helium , neon, krypton, xenon and vari- ous pollutants Contamination or pollution of the atmosphere occurs as a consequences of natural process as well as human activity ( the letter are called anthropogenic). Anthropogenic air pollution as been continues to be viewed as a serious environmental and public health problem. Its seriousness lies in the fact that elevated pollutant levels are produced in environments where harm to human health 2 and welfare is more likely. The quality of air is our communities, country side and even remote locations changes form hour to hour, day to day and over longer time scales. Air quality 3 can be defined qualitively. It is poor when cause a reduction in visibility, soil building surfaces and damage materials, damage crops and other plants, cause adverse health effects. It is deemed good when the sky appears clean and no adverse environmental effects are evident. The AQI is used to report daily air qualities in metropolitan areas for four pollutions O 3 ,PM(PM 10 and PM 2.5 ), CO, SO 2 and NO 2 . Chennai, the fourth largest city in India, capital of the state Tamil Nadu and is located on the eastern sea- coast of the sub-continent at an latitude 3 of 13’04" North and a longitude of 80’15" East. It is located at the center of an extensive network of surface, sea and air transportation facilities serving South India and is well connected to the