A study of CO2 and related trace gases using a laser-based technique at an urban site in western India

Continuous measurements of surface-level carbon dioxide (CO<inf>2</inf>) along with its co-emitted carbon monoxide (CO) and methane (CH<inf>4</inf>) are being made at Ahmedabad using a laser-based cavity ring down spectrometer, which offers much longer path length for accurate and fast measurements of these species simultaneously. The average data during November 2013 show large variability in all the three species. These measurements also show significant diurnal variations with maximum in CO being relatively the shortest-lived species in this set of gases. The correlations and slopes among them have been used to identify potential emission sources.