NO2 MONITORING ALONG NATIONAL HIGHWAY OF NORTHERN PUNJAB USING CAR MAX-DOAS INSTRUMENT

Abstract

Air quality is an important environmental concern worldwide. National Environmental quality standards are implemented by regulatory authorities to improve the air quality on the bases of emission levels. US EPA defines 6 criteria air pollutants for the assessment of Air quality; Nitrogen Dioxide (NO2) is one of them. The sources of NO2 include emission from vehicles, power plants, lightening, soil emission etc. This study presents result of car MAX-DOAS field campaigns (2014-2015) conducted along national highways of Punjab. Main objectives of the field campaigns were to monitor NO2 concentration level within and around major cities, and to identify the sources of NO2 emissions. Result showed that the concentration of NO2 varies in these cities e.g. 75×1015 molecules/cm2 in Rawalpindi, 65×1015 molecules/cm2 in Lahore and exceed the Pakistan National Environmental Quality Standards of 42.5 ppb. Furthermore, car MAX-DOAS results were compared with OMI observations. Result showed that OMI observations are largely underestimated especially over the urban centers of Punjab.