Comparison of ambient particulate mass and water-soluble ionic concentrations by dichotomous and denuder samplers with mass concentrations of EPA monitoring stations in southern Taiwan

Three stations were selected to determine the concentrations of ambient particulate matter (PM) for comparison with monitoring data of the Taiwan Environmental Protection Agency (TEPA). A dichotomous sampler was equipped with quartz fiber filters to take PM2.5 and PM2-5-10, and a denuder sampler was equipped with a Teflon filter PM2.5. PM10 and PM2.5 mass concentrations were compared to the TEPA data, and the difference of the principal water-soluble inorganic ions in PM was determined using the dichotomous and denuder sampler systems. Results indicated that the PM10 concentration at the TEPA monitoring station was 2-15% higher than the dichotomous sampler. PM2.5 concentrations of the TEPA monitoring station were 9-16% higher than the dichotomous sampler and less than 10% higher for the denuder sampler. Volatile ionic species such as nitrate, ammonium, and chloride ions in the dichotomous sampler were lower than in the denuder sampler with Teflon filters, and the average content ratio of the dichotomous and denuder samplers was 0.53 for chloride ions, 0.61 for nitrate, 0.66 for ammonium, 0.88 for sulfate, 1.08 for sodium, 0.99 for potassium, 0.92 for magnesium and 1.13 for calcium. Therefore, artifact effects for ionic species and mass concentration should be considered in the use of a dichotomous sampler with a quartz filter