We present a spectral imager capable of measuring the 2-D distribution of NO2
above well-delimited emission sources (power plant, city, etc.) with an unprecedent spatiotemporal resolution. Tests at a coal-fired power plant demonstrated its capability to observe dynamic processes such as the conversion from NO to NO2
in the early plume. Potential applications are pollution sources monitoring, reactive plume chemistry models validation, ships and volcanic emissions tracking, etc.