COMPARISON OF 6 DENUDER METHODS AND A FILTER PACK FOR THE COLLECTION OF AMBIENT HNO3(G), HNO2(G), AND SO2(G) IN THE 1985 NSMC STUDY

The concentration of HNO//3(g), HNO//2(g), particle nitrate and particle nitrite have been determined using annular denuders (AD), nylon denuders (ND), short nylon denuders (SD), tungstic acid denuders (TD), cylindrical carbonate denuders (CD), a filter pack (FP), and a denuder difference method (DD) in field tests during the 1985 NSMCS. Concentrations of SO//2(g) and particle sulfate were measured by the annular denuder (AD) and cylindrical carbonate denuder (CD) systems. The results of linear regression comparison of various collection methods for total nitrate, HNO//3(g), and results calculated as the denuder difference between nitrate and nitrite collected on the FP sampler and on the filter pack after the AD are presented. The results obtained for the nitrogenous species studied are also correlated with other atmospheric parameters which might be related to the formation of HNO//3(g) and/or HNO//2(g) in the atmosphere. Concentrations of SO//2(g) measured by the annular denuder (AD) are compared to values determined by flame photometry.