Simultaneous determination of atmospheric sulfur and nitrogen oxides using a battery-operated portable filter pack sampler

We developed a method to analyze atmospheric SO, (particulate SO42- + gaseous SO2) and NOx (NO + NO2) simultaneously using a battery-operated portable filter pack sampler. NOx determination using a filter pack method is new. SO2 and NOx were collected on a Na2CO3 filter and PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-3-oxide-1-oxyl) + TEA (triethanolamine) filters (6 piled sheets), respectively. Aqueous solutions were then used to extract pollutants trapped by the filters and the resulting extracts were pre-cleaned (e.g. elimination of PTIO) and analyzed for sulfate and nitrite by ion chromatography. Recoveries Of SO2 and NOx from standard pollutant gases and consistency of the field data with those from other instrumental methods were examined to evaluate our method. SO, and NO, could be analyzed accurately with determination limits of 0.2 ppbv and 1.0 ppbv (as daily average concentrations), respectively. The sampler can determine SOx and NOx concentrations at mountainous or remote sites without needing an electric power supply.