Measurement of Nitric Acid in Smog

Open Access
Publisher Website
Google Scholar
Abstract
The formation of nitric acid (HONO2) in the polluted atmosphere has been monitored using a newly developed analyzer. The analytical method, the operation and performance of the analyzer and some results of recent applications are described. The analysis consists of sample conditioning in combination with a Mast micro-coulomb detection cell adapted for sensing acids rather than oxi-dants. Results of calibration and interference testing are presented. The sensitivity of the instrument to HONO2 is about 2 ppb. Application of the analyzer for smog chamber and atmospheric studies is demonstrated. In simulated smog experiments with synthetic auto exhaust, the pattern of HONO2 formation parallels that of ozone formation. A similar formation pattern was observed during ambient sampling. Evidence is presented which suggest that these reactions, may both contribute to HONO2 formation in smog, but the relative importance of the two is yet uncertain. Atmospheric sampling in the Los Angeles area indicated 24 hour average HONO2 concentrations of about 3 ppb and 1 hour average maximum concentrations of about 10 ppb.

This publication has 0 references indexed in Scilit: