Keywords: air quality, air pollution, hydrocarbons, isoprene, ozone production, pollutant emissions, North Carolina, ozone control, nonmethane hydrocarbons, NMHCs, volatile organic compounds, VOCs
Vertical distribution of VOCs and ozone observed in suburban North Carolina
As a continuing effort by the State of North Carolina to develop a State Implementation Plan for ozone control in the Raleigh Metropolitan Statistical Area, vertical measurements of C2–C10 hydrocarbons and ozone are made on a 610 meter multi-communications tower. Results signify that both long-range transport from fossil fuel combustion, petroleum exploration, petroleum refineries, and geogenic natural gas and local emissions from surface coating and paper production are the major sources of anthropogenic organic compounds at this location. Vertical distributions of various compounds are examined with respect to the relative abundance as well as reactivity to study the role of NMHCs in ozone production. When the concentrations of NMHCs are lower than some threshold value (60 ppbC), ozone concentrations increase with the increase of NMHC concentrations; but when NMHC concentrations are higher than 60 ppbC, ozone concentrations decrease with increase of NMHC concentrations.