This work presents measurements of sulfur dioxide (SO<inf>2</inf>) emission fluxes from point sources using airborne near-ultraviolet (UV) spectroscopy. A Czerny-Turner spectrograph has been optimized to measure SO<inf>2</inf> and the oxygen collision complex (O<inf>4</inf>) in the wavelength region of 286-408 nm from an aircraft platform. The spectrograph was deployed aboard the NOAA WP-3D Orion aircraft during the New England Air Quality Study during the summer of 2004. The spectrograph has zenith and nadir field of views, allowing for measurements of pollution plumes when the aircraft is in or above the planetary boundary layer. The near-UV spectra are analyzed using the differential optical absorption spectroscopy (DOAS) method to retrieve SO<inf>2</inf> and O<inf>4</inf> difterential slant column densities (DSCDs). The SO<inf>2</inf> DSCDs are used to identify point source plumes and are converted to vertical column densities (VCDs), which are needed to calculate emissions of SO<inf>2</inf> from point sources. The conversion to VCDs requires knowledge of the photon optical path length or the air mass factor (AMF). We present a novel approach to calculate the AMF using observations of the absorption of solar radiation by O<inf>4</inf>. The SO<inf>2</inf> VCDs, wind speed and direction, and aircraft speed are then used to obtain emission fluxes from power plants. The measured SO<inf>2</inf> power plant emission fluxes are compared to the reported emissions from the power plants. The measured and reported SO<inf>2</inf> emission fluxes are in good agreement. Copyright 2008 by the American Geophysical Union.