Effects of unregulated anthropogenic activities on mixing ratios of volatile organic air pollutants—A case study

Figures & data

Figure 1. Sampling sites in Kolkata metropolitan area.

Table 1. Description of the sites: Extensive study

Category	Site Name	Description
Industrial area	Baithak-khana	Surrounding area is mixture of small-scale industries and commercial places, mainly paper industry, very congested with narrow busy lane. Vegetation is very poor, and the site is about 200 m away from the main road. There is a very busy railway station in the vicinity of the sampling site.
	Kashipur	Mainly industrial area with few residential places. Vegetation is poor. Close to the main road with very high traffic congestion.
	Behala	Adjacent area is surrounded by small-scale industries, such as PVC pipe and polypropylene, paint, and engineering works. Vegetation in surrounding area is fair, and the site is quite away from the main road.
Petrol pump vicinity	Beleghata	This area is mainly residential with some commercial activities. Traffic congestion is less, with good amount of vegetation. There is a major petrol pump in the vicinity of this site.
	Bosepukur	The site is near a residential area with some shops, schools, and restaurants. Traffic congestion is moderate. The vegetation is moderate at the site. There is a major petrol pump in the vicinity of this site.
	Theatre Road	The neighboring is commercial area containing offices, shopping mall, restaurants, and small shops. Vegetation is moderate, and the traffic congestion is high. There is a major petrol pump in the vicinity of this site.
Residential	Alipur	This area is purely residential and quite away from the main road. There is very good vegetation around the site.
	Dunlop	The surrounding area is purely residential with minor commercial activity and is quite away from the main road. There is fair vegetation surround the site.
	Entally	The surrounding area is a mixture of residential and commercial places and is away from the main road. The traffic pressure on street near the site is moderate with poor vegetation.

Figure 2. The variation in contribution of different carbonyl VOC species towards total ambient concentration in (a) pre-festival season and (b) post-festival season.

Figure 3. Diurnal variation of ambient total carbonyl levels in pre- and post-festival season in different sites of Kolkata City.

Figure 4. Variation in ozone forming potential of ambient total carbonyls as estimated during pre- and post-festival season.

Figure 5. Comparison of ambient concentrations of (a) carbonyls and (b) noncarbonyl VOCs obtained during the intensive study depicting the effect of event of Diwali.

Table 2. Principal component analysis for comparison of source contribution towards the ambient level of oxygenated and nonoxygenated VOCs during intensive study

	16 October, 2009						17 October, 2009
	Component						Component
Compound	PCv	PCf	PCc	PCph	PCoth1	PCoth2	PCv	PCf	PCD	PCc	PCph	PCoth1&2
Formaldehyde				.59							.97
Acetaldehyde				.96							.75
Acetone		.79		.50					.92
Propanal		.89						.96
Crotonaldehyde			.80							.84
Butanal		.89						.91
Benzaldehyde					.89				.76
Isovaleraldehyde						.74			.66			.58
Valeraldehydes			.80						.76
o-Tolualdehyde			.90					−.63	.58
m&p-Tolualdehyde	.55				.65							.91
Hexanal				.76							.92
Dimethylbenzaldehyde		.63		.51		.54				.69		.50
Chloroform	.95						.96
Toluene	.88						.96
Ethylbenzene	.89						.97
m&p-Xylene	.92						.98
o-Xylene	.91						.77
Styrene	.87						.95
Propylbenzene	.99						.81
1,2,4-Trimethylbenzene	.87						.41			.80
1,3,5-Trimethylbenzene	.95						.65			.57
Naphthalene			.65				.76
Eigenvalue	8.79	4.07	3.42	2.29	1.55	1.19	7.91	4.94	3.35	2.79	1.92	1.09
% of variance explained	38.23	17.70	14.87	9.94	6.73	5.18	34.40	21.46	14.56	12.14	8.34	4.73

Notes: The reported values represent the VARIMAX-rotated principal component loadings. Only components with eigenvalues greater than unity were retained. Only fact loadings greater than 0.5 were listed.