Preliminary Results from the ASCENT Network: Aerosol Composition and Concentration at Cheeka Peak Observatory

OLIVIA HAKAN, Philip Rund, Olga Garmash, Odelle Hadley, Courtney Winck, Nga Lee Ng, Ann Dillner, Roya Bahreini, Armistead G. Russell, Joel A. Thornton, University of Washington

     Abstract Number: 716
     Working Group: Aerosols Spanning Spatial Scales: Measurement Networks to Models and Satellites

Abstract
The Atmospheric Science and Chemistry mEasurement NeTwork (ASCENT) is a recently developed network that measures aerosol concentration and composition across the US. The 12 ASCENT sites continuously monitor aerosol concentration and speciation in near real time. Each site has been equipped with an aerosol chemical speciation monitor (ACSM), an aethalometer (AE33), a Xact multi-metals monitor (Xact625i), and a size mobility particle scanner (SMPS). These instruments measure non-refractive mass loading and composition, light-absorbing particle concentration, metal concentrations of 46 different species, and the total particle concentration and size distribution, respectively. The University of Washington’s field site, Cheeka Peak Observatory, is located on the Olympic Peninsula, roughly 75 miles from the nearest city of Port Angeles and less than 5 miles from the pacific ocean. In this poster, we show preliminary results from six months of combined sampling. Over this period, particle size distributions measured by the SMPS have exhibited a number-weighted median particle diameter of 66 nm and an average total particle number concentration of 830 particles/cm3 (ranging from <100 to >4440 particles/cm3). The AE33 has measured an average of 0.03 μg/m3 of black carbon, with values ranging from 0 - 1.2 μg/m3. And the ACSM has shown that non-refractory fine mode particle mass at the CPO field site is primarily dominated by organic and sulfate aerosol species with mean speciated mass concentrations of 0.03 (chloride), 0.05 (ammonia), 0.03 (nitrate), 0.24 (sulfate), and 0.22 (organic) μg/m3. This data set also includes episodic organic aerosols from smoke and forestry-related practices, new particle formation from both marine and terrestrial sources, and evidence of heavy metals from maritime vessel traffic.