A FEASIBILTY STUDY OF THE MARGA TOOL AS AN AEROSOL ANALYZER

Abstract: An aerosol’s chemical composition is one of the key parameters defining its physical behavior, particularly with regard to the properties important for climate impact. To address this issue of gas to aerosol formation there is a need for in-situ measurements of fine aerosol and trace gases. For this study, in-situ compositional data for aerosol and trace gases were collected from June to September 2005. The aerosol microphysical measurements were obtained using a Climet Instruments CI-500. The atmospheric chemical components were measure using an instrument called the Monitoring Instrument for Aerosol and Gas (MARGA). Thermo Environmental analyzers where used to measure sulfur dioxide and nitrogen dioxide levels. In this study, daytime data with high and low RH restraints were analyzed to find consistencies with respect to accepted behavior for gas – aerosol formation. The back ground levels were found to be constant for both regimes under review, 3.0mg/m3 for sulphate, 0.3mg/m3 for nitrate and 1.3mg/m3 for ammonium. We can see the nearby morning traffic which produce NOx that in turn causes an increase in nitrate from 6:00 am to 8:00 am or 9:00 am, this is seen to a much greater extent at the higher RH. We see the build up of sulphate due to photochemical production with ranges 3 – 13 mg/m3. Table 2 shows the temperature range for Figure 1 as 24.9-28.5oC and Figure 2 as 22.8-27.4oC and the average of both sets is 26oC. The daily average concentration for SO4, NO3, and NH4 is higher for figure 1 for the RH> 90 % atmosphere. With th