BS-III Diesel Vehicles in Imphal, India: An Emission Perspective

Air pollution is an inevitable factor in the modern era. Substances, in the form of particles or gases, which are subtended in the air and causing harm to the environment and living organisms both directly and indirectly, are termed as pollutants, and these pollutants lead to air pollution. The origin of air pollution is not restricted to only man made, but it may also be from natural causes like eruption of volcanoes or by forest fire. There are two divisions of air pollutants-primary and secondary. Primary pollutants are those which are emitted directly from a source like exhaust of automobile, industries, burning of fossil fuels. Some of them include hydrocarbons (HC), carbon dioxide (CO2), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen oxide (NOx), particulate matter. A secondary pollutant is a product of reaction among the primary pollutants or with water vapor and sunlight, and examples are sulfuric acid, ozone, peroxy-acyl-nitrate (PAN). The pollutants in the air cause severe adverse effect on the human health also, like asthma, bronchitis, and even lung cancer. Thus, it is important to measure, control, and check the pollution of air from time to time. The authors in this paper have attempted to study the emission characteristics of BS-III commercial diesel auto rickshaws operating in the city of Imphal, Manipur, India. A mobile flue gas analyzer (MFGA) was used for recording the data. The oxygen percentage in the exhaust ranged from 16.6 to 21.3% (vol.). The ambient temperature during recording of data varied from 24.8 to 27 degrees C. Higher NOx values in some of the engine indicate that the engine has high combustion, which is due to improper cooling of the engine. Low CO2 was observed in some vehicles which indicate that the engine has incomplete combustion.