Source Apportionment of Aerosols at ASCENT Network Site Cheeka Peak Observatory

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

     Abstract Number: 405
     Working Group: Coast to Coast Campaigns on Aerosols, Clouds, Chemistry, and Air Quality

Abstract
The Atmospheric Science and Chemistry mEasurement NeTwork (ASCENT) is a recently developed network with 12 measurement locations across the US. Each site has been equipped with an aerosol chemical speciation monitor (ACSM), an aethalometer (AE33), an Xact multi-metals monitor (Xact625i), and a scanning mobility particle sizer (SMPS) to measure aerosol concentration and composition in near-real time. These instruments measure non-refractive mass loading and composition, light-absorbing particle concentration, metal and element concentrations of 46 different species, and the total particle concentration and size distribution, respectively. Cheeka Peak Observatory is located on the Olympic Peninsula, roughly 75 miles from the nearest city, Port Angeles, and less than 5 miles from the Pacific Ocean. We analyze results from the first year of all four instruments sampling, including source apportionment from the Xact and ACSM using Non-Negative Matrix Factorization (NNMF) and comparison to data from the co-located IMPROVE and NCore networks. Based on measurements from the Xact, the metals and elements at CPO are dominated by terrestrial and marine sources: chlorine (98.2 ng/m3), aluminum (83.7 ng/m3), sulfur (56.3 ng/m3), potassium (8.3 ng/m3), and silicon (6.4 ng/m3), are, on average the most abundant species measured at the site. The ACSM reports speciated non-refractory PM2.5 mass to be mostly organic aerosol with an average of 1.21 μg/m3, followed by sulfate 0.38 μg/m3, nitrate 0.076 μg/m3, ammonium 0.073 μg/m3, and then chloride 0.025 μg/m3. In this data set, we have observed episodic organic aerosol from wildfire smoke and forestry-related practices, particle growth events, and evidence of rare heavy metals from maritime vessel traffic.