Simultaneous Measurement of Nitric Acid, Sulfur Dioxide and Ammonia in Air using a Passive Sampling Polyamide Filter

Abstract

Ambient acidic and basic gases were sampled by the use of proposed passive sampler which was composed of polyamide filter wrapping with poly-tetra-fluoro-ethylene (PTFE) sheet. The trapped gases were extracted with pure water and simultaneously determined by ion chromatography. Nitric acid (HNO₃), sulfur dioxide (SO₂) and ammonia (NH₃) were cumulatively collected within 10 weeks, but hydrochloric acid (HCl) was not cumulative especially in summer. The collected amount of HNO₃, SO₂, and NH₃were determined with 4.8-8.3%, 2.7-4.7%, and 4.0-6.2% relative standard deviation, respectively, at atmospheric levels for 14-70 days. The average sampling rates were estimated 185-238 m/day for HNO₃, 29-78 m/day for SO₂and 31-82 m/day for NH₃.