Abstract: Method for determining polycyclic aromatic hydrocarbon (PAH) concentration in a solid state sample. The method includes exposing the sample to diffuse reflectance infrared spectroscopy, recording at least one spectroscopic parameter of infrared diffuse reflection of the sample, which is a signal obtained at one or more frequencies within a range of frequencies (+/?10 cm?1) selected from the group consisting of 3000-3100 cm?1, 740, 777, 814, 842, 1430, 1510, 1600, 4055-4056, 4642-4646, 5924, and 5951-5953 cm?1, and performing data analysis by correlating the at least one spectroscopic parameter with variables of a trained multivariate calibration model related to PAH concentrations, thereby determining PAH concentrations in the sample.