Voc/sub s/ in urban atmosphere of lahore-pakistan

Most of the South Asian cities like Lahore, Karachi, New Delhi, Khatmandho, Dhaka, are facing deteriorating situation of ambient air quality with ever increasing levels of air pollutants especially toxics like VOC/sub s/ (Volatile Organic Compounds). This study was designed to assess current situation for VOC/sub s/ compounds such as Benzene, Toluene, Ethyl benzene, o-Xylene, and m+p Xylene in the ambient air and understanding of their emission sources. The selected sites were hotspots of sources like Transport, Industry, and Residential sectors. Online measurements were undertaken during February, 2006 using VOC Analyzer. The measured levels of VOC/sub s/ were found slightly higher in industrial site like, Kotlakhpat Ind. Area (Benzene; 0.8-40.3 micro g/ m/sup 3/, Ethyl Benzene;I.2-50.6 micro g/m/sup 3/) than other sites while levels at sites representative of traffic sectors like, Chowk Yateem Khana, Azadi Chowk, Ichra, varies as (Benzene; 1-7 .1 micro g /m/sup 3/), (Benzene; 1-7.4 micro g /m/sup 3/), (Benzene; 3.2-9.0 micro g / m/sup 3/, Ethyl Benzene; 3-8 micro g /m/sup 3/, and Xylene (m+p); 0-1.3 micro g/m/sup 3/), respectively. Only benzene was major pollutant at residential or in urban background sites like Model Town, Airport, UET (University of Engineering and Technology), SRDC which varies from 0.6-7.2 micro g/m/sup 3/. The measured levels were well within guideline values of New Zealand, UK, WHO and USEPA, etc. Although the current levels were well within guidelines limits of most of international agencies but if the usage of benzene in gasoline remained increasing with this trend, the air quality conditions would be worsened in the city in near future. Therefore, some mitigating steps like reduction of benzene contents in gasoline, enhancing vehicular engine burning efficiency, and adopting Euro emission standards for vehicular, etc. should be adopted. (author)