 |
5.0 RESULTS & DISCUSSION
5.1 Particulate PAH at 6 NAAQM stations :
Particulate PAH are being monitored at 6 NAAQM stations in Delhi on monthly basis since year 1993. 15 PAH compounds measured, using GC-FID technique in CPCB laboratory, are : Naphthalene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benzo(a)anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(e)pyrene, Benzo(a)pyrene, Perylene, Indeno(cd)pyrene, Dibenzo(ah)anthracene, Benzo(ghi)perylene.
The summary of the data i.e. location wise annual trend of TPAH conc. with minimum & maximum values of TPAH (particulate phase) measured at 6 NAAQM stations namely Siri Fort, Ashok Vihar, Janak Puri, Nizamuddin, Shahdara, Sahazada Bagh during the study period 1993-2000 are given in Table-17.
Monthly & seasonal variations in TPAH conc. during the study period (1993-2000) are shown in Table –18 and Figure:2 - 4. Year wise annual mean TPAH conc. ranges between 18 ng/m3 (during 1999) and 38 ng/m3 (during year 1997). PAHs levels were slowly increasing from year 1993 till 1997 & thereafter going down year after year , which may be due to improvement in fuel quality, phasing out of old vehicles & stricter emission norms (Euro I & II) vis a vis improvement in engine technology. Season wise higher TPAH levels have been observed during winter season ranging between 22 and 44 ng/m3 (except during monsoon 1997 i.e. 53 ng/m3). Monsoon & Summer (ranging between 8 and 24 ng/m3) have recorded comparatively low TPAH levels , which may be due to washout during rainy season & photolysis during sunlight in Summer season.
Annual mean concentration of individual PAH compounds are given in Table -19 and Figure - 6. Maximum annual mean concentration was found during 1997 for Indeno(cd)pyrene (8.4 ng/m3) followed by Benzo(b+k)fluoranthane (6.3ng/m3) & Benzo(e)pyrene (5.4 ng/m3). Benzo(ghi)perylene was also found higher (4.0 ng/m3) during 1998. For rest of compounds concentration was observed below 4.0 ng/m3 during whole study period. Location wise annual mean concentration profile of Benzo(a)pyrene during 1993-2001 is given in Figure- 5. Naphthalene was not detected due to its high volatility.
Table –17 Total PAHs Concentrations (ng/m3) in Delhi|
Year |
Locations |
Minimum |
Maximum |
Average |
Std.Dev. |
|
1993 |
Siri Fort |
22.7 |
34.6 |
28.1 |
4.6 |
|
|
Ashok Vihar |
2.9 |
35.7 |
14.1 |
12.6 |
|
|
Nizzamuddin |
11.3 |
32.4 |
21.0 |
9.1 |
|
|
Janak Puri |
6.6 |
25.8 |
16.3 |
9.2 |
|
|
Shahdra |
9.7 |
42.4 |
23.2 |
12.7 |
|
|
Shazada Bagh |
20.0 |
41.6 |
30.9 |
10.2 |
|
|
Average 1993 |
12.2
|
35.4
|
22.3
|
9.7
|
|
1994 |
Siri Fort |
13.5 |
30.2 |
22.5 |
6.0 |
|
|
Ashok Vihar |
5.1 |
58.0 |
27.2 |
17.2 |
|
|
Nizzamuddin |
7.8 |
49.6 |
29.8 |
14.0 |
|
|
Janak Puri |
6.1 |
39.7 |
20.1 |
12.5 |
|
|
Shahdra |
3.0 |
56.3 |
29.2 |
18.4 |
|
|
Shazada Bagh |
8.6 |
49.9 |
28.6 |
15 |
|
|
Average 1994 |
7.4 |
47.3 |
26.2 |
13.9 |
|
1995 |
Siri Fort |
9.1 |
31.7 |
19.3 |
8.0 |
|
|
Ashok Vihar |
5.1 |
47.6 |
25.2 |
14.3 |
|
|
Nizzamuddin |
13.4 |
30.8 |
20.8 |
6.3 |
|
|
Janak Puri |
8.0 |
40.9 |
24.0 |
12.0 |
|
|
Shahdra |
9.2 |
56.0 |
30.2 |
16.1 |
|
|
Shazada Bagh |
8.7 |
60.2 |
36.5 |
18.6 |
|
|
Average 1995 |
8.9 |
44.5 |
26.0 |
12.5 |
|
1996 |
Siri Fort |
7.4 |
31.7 |
18.0 |
8.0 |
|
|
Ashok Vihar |
8.0 |
47.6 |
26.6 |
14.1 |
|
|
Nizzamuddin |
12.9 |
60.3 |
33.2 |
17.4 |
|
|
Janak Puri |
5.9 |
43.5 |
22.7 |
12.4 |
|
|
Shahdra |
13.3 |
75.2 |
41.1 |
18.5 |
|
|
Shazada Bagh |
13.0 |
56.8 |
36.0 |
16.2 |
|
|
Average 1996 |
10.1 |
52.5 |
29.6 |
14.4 |
|
1997 |
Siri Fort |
7.7 |
49.6 |
23.9 |
14.0 |
|
|
Ashok Vihar |
10.2 |
52.2 |
34.6 |
15.1 |
|
|
Nizzamuddin |
10.8 |
49.8 |
31.5 |
15.0 |
|
|
Janak Puri |
5.0 |
60.3 |
29.3 |
17.5 |
|
|
Shahdra |
26.7 |
94.8 |
50.8 |
23.0 |
|
|
Shazada Bagh |
14.7 |
93.1 |
51.3 |
28.6 |
|
|
Average 1997 |
12.5 |
66.6 |
36.9 |
18.9 |
|
1998 |
Siri Fort |
8.5 |
46.2 |
22.0 |
13.0 |
|
|
Ashok Vihar |
6.4 |
44.1 |
22.2 |
11.3 |
|
|
Nizzamuddin |
5.8 |
61.8 |
25.0 |
15.0 |
|
|
Janak Puri |
8.2 |
70.0 |
25.8 |
18.4 |
|
|
Shahdra |
14.6 |
82.9 |
40.3 |
20.9 |
|
|
Shazada Bagh |
11.4 |
79.5 |
35.4 |
21.6 |
|
|
Average 1998 |
9.2 |
64.1 |
28.4 |
16.7 |
|
1999 |
Siri Fort |
2.5 |
18.5 |
9.0 |
4.5 |
|
|
Ashok Vihar |
4.1 |
44.0 |
17.2 |
11.2 |
|
|
Nizzamuddin |
6.6 |
35.7 |
18.7 |
7.0 |
|
|
Janak Puri |
4.1 |
58.7 |
16.3 |
14.7 |
|
|
Shahdra |
6.2 |
41.6 |
19.9 |
10.1 |
|
|
Shazada Bagh |
10.5 |
52.5 |
25.9 |
12.0 |
|
|
Average 1999 |
5.7 |
41.8 |
17.8 |
10.0 |
|
2000 |
Siri Fort |
6.1 |
27.2 |
15.2 |
6.5 |
|
|
Ashok Vihar |
6.4 |
35.9 |
19.4 |
9.5 |
|
|
Nizzamuddin |
13.4 |
30.8 |
20.8 |
6.3 |
|
|
Janak Puri |
8.5 |
53.3 |
17.1 |
13.2 |
|
|
Shahdra |
6.3 |
49.6 |
25.9 |
15.5 |
|
|
Shazada Bagh |
5.2 |
43.5 |
23.6 |
14 |
|
|
Average 2000 |
7.7 |
40.1 |
20.3 |
10.8 |
Table – 18 : Total Polycyclic Aromatic Hydrocarbons ( ng / m3 ) in Ambient Air in Delhi.
|
Period |
Year 1993 |
Year 1994 |
Year 1995 |
Year 1996 |
Year 1997 |
Year 1998 |
Year 1999 |
Year 2000 |
|
Jan |
- |
40 |
46 |
42 |
30 |
64 |
19 |
21 |
|
Feb |
- |
32 |
37 |
35 |
31 |
48 |
19 |
28 |
|
Mar |
- |
- |
24 |
26 |
29 |
34 |
15 |
29 |
|
Apr |
- |
- |
16 |
17 |
13 |
24 |
13 |
14 |
|
May |
- |
8 |
7 |
10 |
14 |
25 |
16 |
14 |
|
Jun |
- |
- |
11 |
14 |
17 |
12 |
11 |
9 |
|
Jul |
13 |
- |
15 |
17 |
58 |
13 |
15 |
18 |
|
Aug |
13 |
12 |
19 |
22 |
51 |
13 |
16 |
11 |
|
Sep |
22 |
14 |
27 |
31 |
49 |
19 |
17 |
15 |
|
Oct |
19 |
22 |
39 |
42 |
58 |
26 |
26 |
23 |
|
Nov |
33 |
26 |
45 |
48 |
49 |
33 |
26 |
39 |
|
Dec |
33 |
39 |
48 |
51 |
54 |
35 |
22 |
25 |
|
|
||||||||
|
Minimum |
12 |
7 |
7 |
10 |
11 |
9 |
6 |
9 |
|
Maximum |
35 |
40 |
50 |
53 |
69 |
64 |
42 |
39 |
|
Average |
22 |
24 |
28 |
30 |
38 |
29 |
18 |
21 |
|
Std. |
10 |
13 |
15 |
14 |
20 |
17 |
10 |
9 |
|
Monsoon |
16 |
13 |
20 |
23 |
53 |
15 |
16 |
15 |
|
Winter |
28 |
32 |
43 |
44 |
44 |
41 |
22 |
27 |
|
Summer |
- |
8 |
14 |
17 |
18 |
24 |
14 |
17 |
Figure – 2: Total Polycyclic Aromatic Hydrocarbons in Ambient Air in Delhi.
Figure – 3: Annual Trend of Total Polycyclic Aromatic Hydrocarbons
in Ambient Air in Delhi (1993-2000)
 |
Table- 19 : Annual Average Values (ng/m3 ) of PAHs
Compounds in Ambient Air in Delhi
|
Polycyclic Aromatic Hydrocarbons (PAHs) |
Year 1993 |
Year 1994 |
Year 1995 |
Year 1996 |
Year 1997 |
Year 1998 |
Year 1999 |
Year 2000 |
|
Phenenthrene |
0.5 |
0.7 |
0.6 |
0.9 |
0.9 |
0.6 |
0.5 |
0.2 |
|
Anthracene |
0.7 |
1.1 |
0.6 |
0.8 |
1.4 |
0.2 |
0.3 |
0.5 |
|
Fluoranthene |
1.0 |
1.1 |
0.6 |
1.9 |
1.6 |
1.6 |
1.1 |
0.9 |
|
Pyrene |
1.0 |
2.1 |
1.7 |
2.0 |
2.9 |
1.8 |
1.3 |
0.7 |
|
Benzo(A)Anthracene |
2.3 |
2.6 |
3.1 |
3.1 |
3.7 |
2.3 |
1.8 |
1.1 |
|
Chrysene+ Tp |
1.6 |
2.1 |
2.6 |
2.7 |
2.8 |
3.5 |
1.9 |
2.1 |
|
Benzo(B+K)Fluroanthene |
2.9 |
2.7 |
3.4 |
3.6 |
6.3 |
2.6 |
1.0 |
3.5 |
|
Benzo (E) Pyrene |
2.6 |
2.7 |
3.4 |
2.9 |
5.4 |
3.8 |
2.2 |
2.8 |
|
Benzo(A)Pyrene |
2.0 |
2.7 |
3.4 |
2.5 |
2.3 |
3.5 |
1.9 |
2.8 |
|
Perylene |
1.6 |
2.3 |
1.9 |
3.0 |
3.0 |
2.1 |
1.4 |
2.5 |
|
Indeno(Cd) Pyrene |
1.9 |
1.8 |
2.4 |
3.0 |
8.4 |
0.9 |
1.0 |
2.7 |
|
Dibenzo(Ah) Anthracene |
2.1 |
2.2 |
2.1 |
1.7 |
1.7 |
1.8 |
1.3 |
2.6 |
|
Benzo(Ghi) Perylene |
2.1 |
2.4 |
2.5 |
2.2 |
2.2 |
4.0 |
2.2 |
2.4 |
Figure –6: Annual Average Individual Polycyclic Aromatic Hydrocarbons
in Ambient Air in Delhi
5.2 Particulate (Total & Respirable) PAH Monitoring at ITO :
PAHs are being measured both suspended Particulate matter as well as respirable fraction at ITO since 1998.results of TPAH concentration at ITO during 1998-2000 are given in Table – 20 on monthly basis.
Monthly maximum total SPM laden TPAH was observed during December 1999 (118ng/m3) while minimum value was observed during June 1998 (14ng/m3).
Maximum respirable particulate laden TPAH was observed during December 1999 (77ng/m3) while minimum values was observed during August 1998 as well as August 2000 (i.e. 6.8 ng/m3 both).
Maximum seasonal concentration of total SPM laden TPAH was observed during winter ranging between 35ng/m3 (during 1998) and 64 ng/m3 (during 1999), which may be because of inversion condition in winter, while monsoon and summer recorded lower values of TPAH which may be because of wash out during monsoon and photolysis during summer season.
Respirable SPM laden fraction as percentage of total SPM leaden TPAH was observed 56, 66 & 54 % during 2000, 1999 & 1998 respectively with overall average of 60 % approximately.
PAHs concentration in TSPM & respirable SPM fraction have been shown in Figure- 7 for different month & season during for the year 2000.
Table –20 Total PAH Conc. (ngm./m3) at AMS II, ITO Intersection (BSZ MARG)TrafficIntersection During Year 1999- 2000
|
Period |
Year 2000 |
Year 1999 |
Year 1998 |
|||
|
TPAH (SPM) |
TPAH (RSPM) |
TPAH (SPM) |
TPAH (RSPM) |
TPAH (SPM) |
TPAH (RSPM) |
|
|
JAN |
38.2 |
25.3 |
28.7 |
26.4 |
56.9 |
- |
|
FEB |
68.6 |
51.4 |
26.4 |
15.5 |
44.2 |
- |
|
MAR |
51.4 |
29.9 |
26.9 |
18.8 |
22.2 |
- |
|
APR |
24.5 |
10.4 |
25.7 |
21.0 |
29.1 |
- |
|
MAY |
18.5 |
16.9 |
17.6 |
9.9 |
21.3 |
17.2 |
|
JUN |
18.7 |
11.7 |
23.5 |
7.4 |
14.0 |
9.0 |
|
JUL |
45.3 |
12.4 |
32.0 |
10.5 |
16.1 |
12.0 |
|
AUG |
24.0 |
6.8 |
19.1 |
13.6 |
14.5 |
6.8 |
|
SEP |
14.9 |
8.5 |
47.6 |
16.4 |
15.6 |
13.5 |
|
OCT |
54.1 |
24.5 |
73.0 |
67.0 |
20.5 |
13.0 |
|
NOV |
81.2 |
50.8 |
73.0 |
59.0 |
25.6 |
20.5 |
|
DEC |
32.2 |
14.4 |
118.0 |
77.0 |
27.5 |
20.4 |
|
AVERAGE |
39.3 |
21.9 |
43 |
28.5 |
26 |
14.0 |
|
MINIMUM |
14.9 |
6.8 |
17.6 |
7.4 |
14.0 |
6.8 |
|
MAXIMUM |
81.2 |
51.4 |
118.0 |
77.0 |
56.9 |
20.5 |
|
MONSOON |
28 |
9 |
33 |
14 |
15 |
11 |
|
WINTER |
55 |
33 |
64 |
49.0 |
35 |
18.0 |
|
SUMMER |
28 |
17 |
23 |
14 |
22 |
13 |
Figure -7 : Total PAHs Concentration at AMSII, I.T.O. ( B.S.Z. Marg) Delhi
During 1998-2000.
5.3 Polycyclic Aromatic Hydrocarbon at Selected Locations including Traffic
Intersections in Delhi:
Polycyclic Aromatic Hydrocarbon (PAH) have been monitored at selected locations in Delhi constituting traffic intersections Madhuban Chowk, Rohini (T), Dhaula Kuan (T), All Indisia Institute of Medical Sciences (T) ITO Intersection (T), petrol pumps (P), residential areas (R) and industrial area (I) namely Ashok Vihar (R), Siri Fort (R), Jawarlal Nehru University (R), Janpath (P), G.T. Road, Shahdara (P), Preet Vihar (P), Malka Ganj (P), Town Hall (C), and Moti Nagar (I). 15 PAH compounds have been monitored namely Naphthalene, Phenanthrene, Anthracene, Fluoranthene, Pyrene, Benzo(a)Anthracene, Chrysene, Benzo(b)fluoranthene, Benzo(k)fluoranthene, Benzo(e)pyrene, Benzo(a) pyrene, Perylene, Indeno(cd)pyrene, Dibenzo(ah)anthracene, ,Benzo(ghi)perylene. SPM and RSPM laden PAH’s concentration (total PAH) during April – May, 2000 have been shown in Figure-8 and 9.
Following observations have been drawn based on these values.
(1) Highest TPAH (both SPM and RSPM laden) levels were observed at Dhaula Kuan, i.e. 75 & 67 ng/m3 respectively.
(2) Least SPM laden TPAH levels was observed at JNU, i.e. 18.0 ng /m3 ..
(3) Least RSPM laden TPAH levels was observed at Ashok Vihar, i.e. 6 ng /m3s
(4) Average SPM laden TPAHs level for traffic intersections, petrol pumps, residential, commercial & industrial locations have been calculated 53, 28, 30, 43 and 46 nag/m3 respectively.
(5) Average RSPM laden TPAHs level for traffic intersections,
petrol pumps, residential, commercial & industrial locations have
been calculated 44, 18, 10, 28 and 41 nag/m3 respectively.
(6) RSPM laden TPAH accounts for 83%, 64%, 33%, 65% and 89% of SPM laden TPAH.
