Retrieval of NO2 density using diffused solar radiation from buildings

A proposed method for monitoring near ground NO2 density using diffused radiation from buildings is based on two assumptions: 1) the refractive index of the buildings is of a low frequency compared to the wavelength; and 2) for a given narrow range of distances, the horizon distribution of NO2 is approximately uniform. Based on these two assumptions, the NO2 density of Chengdu was calculated, the results of which are very close to the corresponding data from the atmospheric monitoring site, proving the method is feasible.