Nonmethane hydrocarbon and oxy hydrocarbon measurements during the 2002 New England Air Quality Study

摘要: [1] Nonmethane hydrocarbons (NMHCs) and oxy (oxy HCs) were measured aboard the National Oceanic Atmospheric Administration research vessel Ronald H. Brown during New England Air Quality Study from 13 July to 10 August 2002 by an online dual gas chromatographic instrument with two separate analytical columns equipped, respectively, flame ionization mass spectrometer detectors. Measurements, taken each half hour, included C2 C10 alkanes, C5 alkenes, alcohols ketones, C6 C9 aromatics, biogenic volatile compounds including six monoterpenes, isoprene its immediate oxidation products methacrolein methylvinylketone. All have been categorized their contribution OH loss rate calculated for 298K 1 atm. Large temporal variability was observed all compounds. Airflow Providence, Rhode Island/Boston, Massachusetts, urban corridor northeast Hampshire coast usually heavily laden NMHCs HCs of anthropogenic origin. Comparison specific compound ratios automotive tunnel studies suggested that these predominantly mobile source emissions. When such flow occurred daylight hours, plumes accompanied increases in ozone 80 120 ppbv range. About equally as often, much less chemically mature NMHC encountered near coast. Ozone titrated out latter plumes, unusually high mixing C4 alkenes partly gasoline vapor release rather than In coastal region explored, spite large input periods offshore flow, frequently dominated During cleaner marine air inflow reaction methane HCs, acetone, formaldehyde, acetaldehyde.