Year-long Measurements of Aerosol Composition and Size Distributions at the ASCENT- Rubidoux Site

ROYA BAHREINI, Bradley Ries, Yumeng Cui, Erin Bowey, Sean Raffuse, Sabrina Westgate, Armistead G. Russell, Ann M. Dillner, Nga Lee Ng, University of California, Riverside

     Abstract Number: 231
     Working Group: Coast to Coast Campaigns on Aerosols, Clouds, Chemistry, and Air Quality

Abstract
Through the Atmospheric Science and Chemistry mEasurement NeTwork (ASCENT), funded by the National Science Foundation, 12 sites have been established across the United States to provide comprehensive, high time-resolution measurements of aerosol composition and size distributions. One of the sites is located in Rubidoux, CA which is downwind of major urban and industrial sources in the Los Angeles Basin. In addition to the main ASCENT instrumentation, namely an Aerosol Chemical Speciation Monitor (ACSM, PM_2.5, Aerodyne Research Inc.), an aethalometer (AE33, PM_2.5, Magee Scientific), an XRF-based trace metal monitor (Xact-625i, PM_2.5, Sailbri Cooper, Inc.), and a scanning mobility particle sizer (SMPS 3839W89, TSI, Inc.), we have installed a Modulair-PM sensor (QuantAQ) to obtain fast measurements of PM₁ and PM_2.5 mass concentrations. Furthermore, the South Coast Air Quality Management District provides online measurements of several air pollutants (including PM_2.5 mass concentration, O₃, CO, SO₂, NO₂, and total NMHC) and collects 24-hr integrated PM_2.5 filters (once every 3rd or 6th day) for offline chemical analysis. Here we report on the first set of long-term comparisons between the data collected through ASCENT and those available externally to demonstrate the performance of ASCENT instruments at this site. Furthermore, we present diurnal and seasonal trends of aerosol composition and size distributions and highlight the main differences observed under specific conditions (e.g., 4th of July fireworks, wintertime inversions, and summertime high-ozone alert days).