As underlined by the latest report (IPCC, 2013) as well as the numerous reports on air quality, atmospheric nanoparticles, mainly dielectric, have an effect on climate and public health, which still needs to be quantitatively evaluated. One of the main uncertainties is relative to the organic aerosol (carbon, Diesel soot particles), which efficiently absorbs light. In this context, the Optics, Environment, Remote Sensing group of the iLM developed a new methodology allowing remote detection of absorbing nanoparticles in the atmosphere.

To discriminate between absorbing and purely scattering particles, the authors exploited Kirchhoff’s fundamental law, associated with Planck‘s radiation emitted by dielectric absorbing nanoparticles in the atmosphere, after their incandescence induced by laser (LII). By setting the formalism associated with lidar remote sensing of incandescent absorbing particles, then by a numerical simulation, the authors identified the optical requirements allowing to observe Planck’s radiation in the atmosphere with the iLM lidar instrument.