Determination of the relative contribution of volatile organic compounds (VOCs) to particulate organic carbon levels in the atmospheric sampling

Within the scope of the thesis study, two equivalent PM2.5 samplers were designed and developed to eliminate sampling errors in the results of atmospheric particulate organic carbon (OC) and particulate polycyclic aromatic hydrocarbons (PAH) caused by volatile organic compounds (VOC) and gas phase PAH compounds. The ratios of elemental carbon (EC) measured in samples obtained from parallel C and UC samplers (ECc/ECuc) were found to be 1.02 ± 0.085 (median: 1,000). It was understood that the developed devices have a mass loss of less than 10% due to the denuders they contain in their sampling air-path. It was concluded that if impregnated denuder is not used, the results of atmospheric particle OC concentrations will be reported with higher values due to pozitive errors of 53.2 ± 7.23% (median: 52.00%) on average. It was observed that the total error (net error) was still positive, but decreased to an average of 35.1 ± 16.8% (median: 31.0%) after including the negative errors quantified from the backup filter into the calculation. In cases where denuders were not used in the sampling, it was observed that the results with positive errors of 41.0 ± 14.6% (median: 33.8%) on average would be obtained for the total PAHs. Ozone induced negative interference was the highest in ACY (28%), followed by FLA (20%), PHE (18%), and15% for NP and BghiP compounds, relative to their medians. While no ozone effect was seen in PYR and CHR compounds and negative errors of 10% or less were found in all other individual PAH compounds. In terms of total PAH compounds, it was observed that atmospheric ozone caused negative errors at an average of 8% (median: 6.0%) during the study and the temperature in the sampling environment did not affect the positive error result which was calculated from the PAHs in the samples of C and UC samplers. However, it was observed that the OC values measured in the backup filters of the C and UC samplers increase in direct proportion to the ambient temperature, and the relative humidity in the ambient atmosphere did not have a significant effect on the OC results. It has been determined that increases in ambient temperatures in the sampling environment cause PAH losses from primary and backup filters, while increases in ambient humidity contribute positively but at low levels to PAH retention capacity in primary and backup filters.