Controlling toxic air pollutants in Indian metros in the new millennium

The current set of diesel vehicles on Indian roads emits inordinate amounts of particulate matter, NOX, and sulphur dioxide. Of highest concern are the fine, respirable particles of sizes 10 and 2.5 microns (PM 10 and PM 2.5) which are highly carcinogenic and carry toxic heavy metals with them. It is time to set standards to particularly address PM 10 and PM 2.5 emissions. The answer may lie in control technologies such as particulate traps, oxidation catalysts, and NOX catalytic controls. Further, given the poor maintenance of vehicles in India, there is a tendency to pollute more as they get older. One solution could be in mandatory periodic fitness certification for all such vehicles. This paper attempts to highlight developments taking place around the world concerning the influence of various additives on the emission behavior and characteristics of the vehicles.