Determinación de acido nítrico y nitratos en partículas atmosféricas

Abstract

Gaseous and particulate nitrates were simultaneously sampled at the Metropolitan University facilities North of Mexico City. The technique applied was the Denuder Difference Experiment (D.D.E.) which is relatively simple and avoids losses of particulate nitra te caused by sampling artifacts. Values for samples collected over 7 h were in the range of 1.81- 14.17 mg/m3 for total nitrates. A modification of the analytical method for determining nitric acid and particulate nitrate concentrations was developed. The filter extractions were made following the method published by Shaw et al., and the final analysis was modified employing the reduction-diazotization method from the Texas Air Control Board.