Vehicular Pollution

Means of transportation are an important infrastructural facility. These play a very important role in the overall development of a country. Availability, intensity, frequency, efficiency and cost of means of transportation are considered as index of development. But as the number of vehicles are increasing rapidly, it has slowly but surely started hindering our atmospheric purity  with the vehicular and noise pollution. Vehicular Pollution is mainly an urban problem.  In the modern age of industrialization and technological advancement, the menace of vehicular Pollution is increasing day by day. Vehicular exhaust, a by-product of fuel combustion contains potentially lethal chemical compounds such as carbon monoxide (CO), oxides of nitrogen, oxides of Sulphur and unburnt hydrocarbons.  

                                
                                Source: Statistical Abstract of Punjab, 2000   
 
In Punjab, The total vehicle population has increased  16 times between 1975-76 to  1999-2000 out of which the maximum increase has been observed in population of 2/3 wheelers. The trend is shown in the graph. The vehicle( type) wise increase in the population of different vehicles in the state is shown in the table below. So, we can see that there is tremendous increase in the number of  small vehicles like 2 and 3 wheelers in the last decade  in the state. Correspondingly, the road length in the state has also increased from 25705 km in 1975-76 to 44063 km in 1999-2000.

                                  Increase in Vehicular Population in Punjab

                                                                         Source: Statistical Abstract of Punjab, 2000 

This increase in vehicular Population is itself an indicator of increase in vehicular Pollution over the years in the state. Besides increase in the number of vehicles the poor maintenance of vehicles is major reason for the high vehicular emissions, Majority of the three-wheelers, fitted with diesel engines, use diesel and kerosene as fuel, which causes lot of pollution in the State. The Petrol driven vehicles commonly emit carbon monoxide un burnt hydrocarbons, Nitrogen oxides and particulates containing lead as exhaust emissions or through crankcase and fuel evaporation loss.  Since about 25% o 40% of fuel is exhausted with being burnt, 2 wheelers are main contributors of un burnt hydrocarbons in air.  As per a  Green Ratings  study by  CSE( Centre for Science and Environment) with the support of the UNDP and the Indian Union Ministry of Environment and Forests (MOEF) , the carbon monoxide and hydrocarbons plus nitrogen oxides emitted by two stroke two-wheeler engines (even with catalytic converter) were 23 per cent and 38 per cent higher respectively than their 4-stroke equivalents without catalytic converter. A comparative study of the impact of fuels on emissions involving three diesel mass transport vehicles (MTVs) and two CNG-fueled MTVs showed that CNG was far better in terms of tailpipe emissions, having five times lower particulate matter and overall 73 per cent lower emissions than the diesel vehicles.  

Diesel engines are much less polluting than petrol engines. Both types of engines are not very efficient converters of fuel energy. However, diesel types, with a conversion efficiency of around 30%, must be more efficient and use less fuel than petrol types with a 15-20% conversion efficiency. Both types of engines have incomplete combustion of fuel.  So, the major pollutant is CO, amounting to 91% by weight of all vehicle emissions.  Traffic management and road conditions is another important reasons for high  vehicular emissions. Further, the  State  roads have to cater to manually driven carts, slow moving cycles and rickshaws, speeding two and four wheelers and heavily loaded buses and trucks. The roads are thus congested   resulting in  slow movement of traffic and traffic jams. Hence vehicles are not driven at optimum speed to give maximum fuel efficiency and low emissions. Survey Conducted by Indian Institute of Petroleum(IIP), Dehradun on emissions from Indian vehicles have shown that the average mass emissions from Indian cars measured by IIP were CO: 26.28 gms/km, HC:4.61gms/km and NO_x :2.71 gms/km. These are higher than the world and nationals standards. Further only 45% of intercity buses, 36% of state buses and 10% of trucks meet the emission norms.