AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Background PM2.5 Source Apportionment at Cheeka Peak Atmospheric Observatory in the Olympic Mountain Range
ODELLE HADLEY, Olympic Region Clean Air Agency
Abstract Number: 142 Working Group: Source Apportionment
Abstract This study used the Environmental Protection Agency’s positive matrix factorization model (EPA PMF5.0) to identify five primary source factors comprising the ambient PM2.5 concentrations at Cheeka Peak Atmospheric Observatory (CPO), Neah Bay WA in 2011, 2012, and 2013. Cheeka Peak is home to both an IMPROVE (Interagency Monitoring for Protected Visual Environments) and an Ncore trace gas monitoring site. The first factor, identified as marine traffic residual fuel oil (RFO), was the highest contributor to PM2.5 in late summer months. Over the 3-year analysis, the RFO total concentration and percent contribution to PM2.5 steadily declined. This may be attributed to regulations restricting the sulfur content of ship fuel implemented in June 2012. In winter, biomass combustion (BMC) and sea salt were the highest contributors to PM2.5 observed at CPO. BMC accounts for a large percent of the particulate pollution when winds are easterly. Sea salt is the dominant winter factor when winds blow from the west. Trace carbon monoxide (CO) and reactive nitrogen species (NOy) are most strongly correlated with the BMC factor. While CO is a major pollutant emitted during biomass combustion, the correlation with NOy is likely due to a shared source region, i.e. urban and suburban centers. The fourth factor was identified as aged crustal material, or dust, and was the least significant. In all three years, dust peaked in the spring and was associated exclusively with north-easterly winds. The last factor was identified as aged sea salt mixed with nitrate and sulfate. It did not exhibit a strong seasonal cycle and was not specifically associated with a particular wind direction.