LAUSR

Abstract Passive samplers based on molecular diffusion are used to measure many organic and inorganic gaseous species in the atmosphere. In this study, the permeation resistance of two types of polytetrafluoroethylene membrane filters (TA300 and PF100, the same manufacturer but different membrane thicknesses) was evaluated and 0.2% NaCl-impregnated and polyamide filters (Nylasorb and Magna, different manufacturers) were compared as adsorbents for nitric acid (HNO3). As a reference, an annular denuder coated with NaCl was used for measuring HNO3 concentration. Based on the observed data and effective sampling area of the passive sampler, the sampling velocity (SV) was estimated and compared with reported values from other studies. The NaCl-impregnated filter had a slightly higher SV than the nylon (polyamide) filters. The SV for the thinner permeation filter, with a larger porosity (TA300) was much higher than the less porous filter (PF100). According to these results, the SV for a HNO3 passive sampler can be adjusted by selecting appropriate permeation filters according to the potential concentration at the sampling site and the maintenance schedule of the sampler.