The intensity change of the image quality (IQ) can reflect the photography condition change of a CCD camera. A novel air quality evaluation method

which only uses the surveillance image

is presented in this paper. First

different IQ metrics

i.e. the noise brightness ratio

the contrast level and the blur level

are employed to evaluate the IQ. Then we use them to build different time series data. After that we utilize a Gompertz type diffusion process (GTDP) of stochastic growth and the detrend fluctuation analysis (DFA) method to analyze and fit the trend of these series above. Finally

we can use the parameters of the GTDP model and the DFA model to evaluate and classify the IQ change level of different atmospheres. Some experiment data

which are captured in a solar day and a misty day

are utilized to verify the validity of our method.