This work shows the possibility to measure scattered light from particles, which are exposed to miniscule laser intensities, with the help of a very sensitive single-photon measurement technique. The advantages for subsequently designed sensors can be found in explosive prevention, avoiding product damage and improved user safety. Measurement systems to examine suspensions and aerosols are described. Laser output is less than 5 mu W. The measurements start at 200 nm particle diameter and are carried out in a 90 degrees arrangement as a worst-case scenario for scattering intensities.