Development and Optimization of a Sampling and Analytical Method to Measure Hexavalent Chromium in Ambient Air

Abstract

The overall goal of this study was to develop a sensitive and reliable method for the measurement of ambient airborne hexavalent chromium [Cr(VI)] by systematically evaluating and optimizing the sampling, sample processing and analytical processes. This method can also simultaneously quantify the inter-conversion rates between Cr(VI) and trivalent chromium [Cr(III)] and the recovery rate of Cr(VI). The specific aims of this study are: 1) to optimize the (IC/ICPMS) method for Cr(VI) analysis, e.g., lower the detection limit to the one in a million risk level i.e., 0.083 ng/m3; 2) to reduce the Cr(VI) background level on the blank filter; 3) to determine the recovery and conversion rate of Cr(VI) and Cr(III) during sampling, storage and extraction; 4) to characterize the factors that have been suggested to potentially affect the stability of Cr(VI), i.e., particle types, relative humidity (RH), temperature (T), ozone (O3 ), sulfur dioxide (SO2 ) and nitrogen dioxide (NO2 ) in ambient air; and 5) to evaluate the developed method in the field during summer and winter seasons.