Comparison of sample collection in canisters to online sampling in atmospheric analysis

The core objective of this study was to collect air samples in balloons, their analysis and result comparison with simultaneous online sampling with lab equipment as well as with 4 types of semiconductor based gas sensors (NO, NO2, CO, CO2) produced by Alphasense. For accurate measurement it is important to collect air samples correctly and thus, it is necessary that air flow rate does not vary significantly throughout sampling time. In the experiment we used piece of gas chromatography capillary column for air flow restriction, which is an innovative method. The study was conducted in the laboratory where air pollution is less variable. Our sample results have been compared to online data which was constantly measured. After studying the fill rate of the air sampling balloon, we selected the period of time when the filling rate was constant. The use of gas chromatography capillary is simple and available. The study was conducted with 30 cm capillaries with 30 minutes of sampling time interval in an open window laboratory and compared the obtained results with online data. Following research equipment was used during our studies: ECO Physics NOx Analyzer CLD 780 TR to measure nitrogen oxides with O3 Chemiluminescence. Methane (CH4) and Carbon oxides (CO, CO2) were measured by PICARRO G2401 CRDS analyzer based on cavity ringdown spectroscopy.