Articles | Volume 8, issue 11
Research article
10 Nov 2015
Research article |  | 10 Nov 2015

High-resolution measurements from the airborne Atmospheric Nitrogen Dioxide Imager (ANDI)

J. P. Lawrence, J. S. Anand, J. D. Vande Hey, J. White, R. R. Leigh, P. S. Monks, and R. J. Leigh

Abstract. Nitrogen dioxide is both a primary pollutant with direct health effects and a key precursor of the secondary pollutant ozone. This paper reports on the development, characterisation and test flight of the Atmospheric Nitrogen Dioxide Imager (ANDI) remote sensing system. The ANDI system includes an imaging UV/Vis grating spectrometer able to capture scattered sunlight spectra for the determination of tropospheric nitrogen dioxide (NO2) concentrations by way of DOAS slant column density and vertical column density measurements. Results are shown for an ANDI test flight over Leicester City in the UK on a cloud-free winter day in February 2013. Retrieved NO2 columns gridded to a surface resolution of 80 m × 20 m revealed hotspots in a series of locations around Leicester City, including road junctions, the train station, major car parks, areas of heavy industry, a nearby airport (East Midlands) and a power station (Ratcliffe-on-Soar). In the city centre the dominant source of NO2 emissions was identified as road traffic, contributing to a background concentration as well as producing localised hotspots. Quantitative analysis revealed a significant urban increment over the city centre which increased throughout the flight.

Short summary
An airborne spectrometer was used to produce a high spatial resolution (80 x 20 m) map of nitrogen dioxide over Leicester City (UK) and the surrounding countryside. Clear local hotspots due to traffic, industrial activity and power generation are observable, as are comparative reductions over parks and rural areas. A positive temporal gradient was also observed over the 2-hour flight, possibly indicating traffic build-up over time.