We report airborne differential optical absorption spectroscopy (DOAS) measurements of aerosol extinction and NO<sub>2</sub> tropospheric profiles performed off the North coast of Norway in April 2008. The DOAS instrument was installed on the Safire ATR-42 aircraft during the POLARCAT-France spring campaign and recorded scattered light spectra in near-limb geometry using a scanning telescope. We use O<sub>4</sub> slant column measurements to derive the aerosol extinction at 360 nm. Regularization is based on the maximum a posteriori solution, for which we compare a linear and a logarithmic approach. The latter inherently constrains the solution to positive values and yields aerosol extinction profiles more consistent with independently measured size distributions. Two soundings are presented, performed on 8 April 2008 above 71° N, 22° E and on 9 April 2008 above 70° N, 17.8° E. The first profile shows aerosol extinction and NO<sub>2</sub> in the marine boundary layer with respective values of 0.04±0.005 km<sup>−1</sup> and 1.9±0.3 × 10<sup>9</sup> molec cm<sup>−3</sup>. A second extinction layer of 0.01±0.003 km<sup>−1</sup> is found at 4 km altitude. During the second sounding, clouds prevented us to retrieve profile parts under 3 km altitude but a layer with enhanced extinction (0.025±0.005 km<sup>−1</sup>) and NO<sub>2</sub> (1.95±0.2 × 10<sup>9</sup> molec cm<sup>−3</sup>) is clearly detected at 4 km altitude. <br><br> From CO and ozone in-situ measurements complemented by back-trajectories, we interpret the measurements in the free troposphere as, for the first sounding, a mix between stratospheric and polluted air from Northern Europe and for the second sounding, polluted air from Central Europe containing NO<sub>2</sub>. Considering the boundary layer measurements of the first flight, modeled source regions indicate closer sources, especially the Kola Peninsula smelters, which can explain the NO<sub>2</sub> enhancement not correlated with a CO increase at the same altitude.