proposed integrated complex for delhi judicial academy

Rapid Environmental Impact Assessment (REIA) Study for Proposed Integrated Complex for Delhi Judicial Academy,
National Law School, and National Institute for Mediation & Conciliation at Dwarka, New Delhi
Despite the phenomenal growth in vehicular population, the levels of Nitrogen Dioxide have
remained more or less constant, this can be attributed to the phasing out of old commercial vehicles
and implementation of Euro-I and subsequently Euro-II norms for petrol and diesel driven private
vehicles.
The main fuels used in vehicles are petrol, diesel and CNG Gas. The main pollutants that come out
from the exhaust tail of vehicular engines are:
- Carbon dioxide
- Carbon monoxides
- Oxides of Nitrogen
- Oxides of Sulphur
- Hydrocarbon, and
- Particulate Matter
In addition to above pollutants, unburnt products like aldehydes, formaldehydes, acrolein,
acetaldehyde and smoke would also be emitted from petrol and diesel operated vehicles. The
concentration of these pollutants in the engine exhaust varies with the type of engine namely, spark
ignition (petrol engine) or compression ignition (diesel engine) two stroke or four stroke engines;
and also mode of engine operation. Table 4.2 gives the emission factor of various major pollutants
from petrol (SI), diesel (CI) and CNG engines.
Diesel exhaust concentration of hydrocarbons is more than that of SI engine exhaust. Carbon
monoxide concentrations in diesel engine exhaust is negligible to that of SI engines. Concentration
of oxides of nitrogen is more in diesel exhaust. Thus diesel engine exhaust contains lower
concentrations of harmful pollutants like hydrocarbons, carbon monoxide and therefore, it is less
hazardous. Table 4.3 summarises the comparative emissions from CNG and Diesel engines. From
this table it could be concluded that CO, NOx and PM are about 45 to 300% higher in diesel
vehicles than CNG vehicles.
Sulphur Dioxide
The oxides of sulphur (SOx) occur in ambient air to a large extent as primary specific pollutants in
the form of sulphur dioxide (SO2) and sulphur trioxide(SO3) under ambient conditions. It has been
observed that the percentage of SO2 existing in ambient air may be more than 95 percent, while the
remaining 5 per cent or less of SOx may be in the form of sulphur trioxide. The major atmospheric
man-made sources of SO2 are burning of fossil fuels in stationary combustion and industrial
processes, viz. petroleum, chemical, metallurgical and mineral industries, domestic emissions and
fires, while the natural sources are volcanoes, geothermal activity, bacterial decomposition of
organic matter, forest fires, etc. These sources are described in the Figure 4.3.
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