lR;eso t;rs - Ministry of Environment and Forests

3
Concentration (µg/m )
3
Concentration (µg/m )
70
60
50
40
30
20
10
0
60
50
40
30
20
10
0
Figure 2.2.6: Trends in Annual Average Concentration of NO in Residential Areas of
2
Delhi, Mumbai, Chennai and Kolkata
1995
1996
1997
1998
1998
1999
1999
Delhi
Source: Central Pollution Control Board, 2008
2000
2001
2002
2003
2004
2005
2006
2007
Year
Res. Area NAAQS
2000
Chennai
2001
2002
Year
2003
2004
Res. Area NAAQS
2005
2006
2007
3
Concentration (µg/m )
3
Concentration (µg/m )
90
75
60
45
30
15
0
80
70
60
50
40
30
20
10
0
1999
2002
2000
2003
2001
Mumbai
2002
Year
Kolkata
Remark: Data for 2007 for Chennai, Kolkata and Mumbai is the average of data available as on date
It is well-known that particulate matter less than 2.5 micron (PM
2.5) is the most harmful particle as it reaches the alveolar region
(i.e. blood and gas exchange region) of the respiratory tract,
causing various respiratory and cardiovascular ailments. It has
also been established that fine particles are more prone to get
enriched with toxic and carcinogenic substances than the coarse
particles.
Recognizing its importance, CPCB has initiated the monitoring
of PM in some major cities.
2.5
Particulate matter with size less than 2.5 micrometre (PM 2.5)
was
measured at BSZ Marg (ITO), New Delhi using continuous
analyzers (Figure 2.2.8). The annual average concentration of
3
PM was found to be 102 ìg/m during 2007. The monthly
2.5
3
average concentration of PM 2.5 varied from 34 ìg/m to
26
State Of Environment Report-2009
2004
Year
2003
2005
2004
Res. Area NAAQS
Res. Area NAAQS
2005
2006
2006
2007
2007
3
198 ìg/m , change in climatic conditions being a decisive factor.
Presence of lesser volume of troposphere in the winter season,
aided easy mixing resulting in higher concentrations. Similarly,
lower concentrations were observed in monsoon months as
particulate matter is washed out due to wet deposition.
NOISE POLLUTION
Of late, noise has been recognized as a pollutant which until
recently was considered only a nuisance. The Central Pollution
Control Board (CPCB) notified the ambient noise standards, in
1987 under section 20 of the Air (Prevention and Control of
Pollution) Act, 1981. The noise standards specify 55 dB (A) and
45 dB (A) as limits for day and night time, respectively, for
residential areas; 75 dB (A) and 70 dB (A) in the day and night