Measurement of carbon dioxide concentration in the surface air of Pantnagar, Uttarakhand

128-131The rising concentrations of green house gases and their ill effects have become a matter of concern for the whole globe. Carbon dioxide (CO2)is considered as the most important greenhouse gas due to its highest contribution in global warming. To predict the magnitude of climatechange in near future along with its possible effects, it is necessary to have the authentic information about the present concentration of carbondioxide concentration in the ambient air. Therefore, continuous measurement of carbon dioxide concentration from ambient air was carried outat the roof top of Agrometeorology Department, Pantnagar at one minute interval between 9.00 AM to 4.00 PM with the help of an Infraredgas analyzer (IRGA). Thereafter, per minute concentration of CO2 was averaged for 30 minutes duration. The instrument was calibrated atregular intervals with the 780 ppm standard CO2 gas. During the period of study the overall average CO2 concentration of the ambient air wasfound to be 340.32 ppm. However, monthly average values varied in the range of 331.89 ppm (August) to 355.46 ppm (September). Basedon the whole five months period of observation, monthly maximum CO2 concentration was found in the range of 368 ppm to 404 ppm, however monthly minimum CO2 concentration varied between 314 and 324 ppm. The highest CO2 concentration i.e. 404 ppm was recordedin a day of December and the minimum value of CO2 (314 ppm) was observed in a day of month August 2007. A polynomial relationship wasalso observed for the varying CO2 concentration with time of observation for the whole study period. It may be appropriate to mention herethat there was a decrease in the concentration of CO2 between 12-2 PM. The possible reasons might be the accelerated photosynthesis ratedue to higher intensity of solar radiation at that time as well as higher air temperature. However, it is difficult to predict the exact trend andrate of increase or decrease in CO2concentration at the site. Therefore, the present study is continuously going on as per schedule to providea definite and better trend scenario for the CO2 concentration