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
The record shows that over the last few years, the levels of SO 2 have drastically come down
in the ambient air of Delhi. Annual mean SO 2 levels were observed as 18.03 µg/m 3 , 14.1 µg/m 3 ,
11.3 µg/m 3 in the year 2000, 2001 and 2002 respectively. SO 2 levels decreased by 21.8 % & 19.6
% in the year 2001 & 2002 respectively. The annual mean SO 2 levels in Delhi satisfy the annual
average of National Ambient Air quality Standards for residential areas, which is 60 µg/m 3 .
Nitrogen Dioxide
The nitrogen oxides exist in ambient air in various forms viz. nitrous oxide (N2O), nitric oxide
(NO), nitrogen dioxide (NO2), nitrogen trioxide (NO3), nitrogen tetroxide (N2O4) and nitrogen
sesquioxide (N2O5). However, only nitric oxide and nitrogen dioxide that exist freely in air are
important as air pollutants. Generally, the atmospheric concentration of nitric oxide and nitrogen
dioxide are clubbed together and reported as oxides of nitrogen (NOx). The nitric oxide (NO) in
ambient environment is less stable and rapidly gets converted to nitrogen dioxide. The nitrogen
dioxide is considered to be important from the view point of pollution and smog formation,
primarily because of its photo-dissipation effect into ozone and oxidation products of hydrocarbons,
wherever the unburnt hydrocarbon exists in atmospheric air. Sources of oxides of nitrogen are
presented in Figure 4.4.
The figure shows the annual average values of NO2 observed during last six years. Despite, an
increase in the number of vehicles from 1997 to 2002, the NO2 levels have shown an increase from
41.7 to 47.2 µg / m 3 which is not very significant. The annual mean of NO2 levels in Delhi is well
within the annual average of National Ambient Air Quality Standards for residential areas, which is
60 µg/ m 3 .
Suspended Particulate Matter (SPM)
The airborne particles or particulate matter (PM) can be solid or comprising liquid droplets of
diameter ranging between 0.002 to 500 micron having a life time in suspension varying from few
seconds to several months. The suspended particulate matter (SPM) are the particles/aerosols
having diameter less than 100 micron that tend to remain suspended in the atmosphere for a long
period of time. The particles may be directly emitted into the atmosphere. The sources of PM, SPM
and RSPM/PM10 are given in Figure 4.5.
The figure shows that SPM levels have increased from 363 to 456 µg/ m 3 between 1997 to 2002.
But, SPM levels reduced by 11.4% in the year 2001 and increased again to 19.4 % in the year 2002.
This could be attributed to the adverse meteorological conditions in 2002.
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