MAX-DOAS Network-Measurement of NO2, HCHO and SO2 during the NEAQS-ITCT 2004 Campaign

From July 1st through August 15th the New England Air Quality Study Intercontinental Transport and Chemical Transformation (NEAQS-ITCT) 2004 Campaign took place. As a part of it we performed measurements with Multiple Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) at six different sites (MIT Cambridge, Thompson Farm (UNH), URI Narragansett, NL Brookhaven, Harvard Forest (Harvard University) and Pinnacle State Park (UAlbany)) and on the research vessel Ron Brown to derive slant column densities of NO₂, HCHO and SO₂. Such a comprehensive network of kindred and continuous measurements was assembled for the first time. Thereby scattered sun light was measured at several elevation angles (Multiple Axis). This setup allows to gain information on the vertical distribution of atmospheric trace gases. We present the first results of these MAX-DOAS measurements and show an overview of the regional and temporal variations of the trace gases over the north-eastern States, which have often been called the tailpipe of the USA.