Weekday/weekend differences in gasoline related hydrocarbons at coastal PAMS sites due to recreational boating

Analysis of PAMS (Photochemical Assessment Monitoring Stations) data at several coastal sites reveals large weekday/weekend differences in gasoline related hydrocarbons. Elevated concentrations of gasoline related constituents, including alkanes, alkenes, and aromatics, are observed on weekends at the PAMS monitors at Sherwood Island State Park in Westport, CT and at Newbury, MA. An analysis of the ratio of the concentrations of 2,3-dimethylbutane to 2,2-dimethylbutane indicates these compounds are freshly emitted, and an investigation in conjunction with wind data shows that the elevated concentrations are associated primarily with onshore winds. These elevated concentrations are most likely due to weekend recreational boating.