The higher the content of dissociating silica dioxide concentration in dust ,the greater damage is. In the process of measurement, when the change of temperature and humidity in the laboratory doesn't accord with the standard, it will directly influence on measurement data.The data of dust dissociating silica dioxide concentration were measured using infrared spectrophotometry and Fourier transform infrared spectrometer. The qualitative and quantitative analysis was carried out on the material using the physical phenomenon of selective absorption of light and the record of 12.5μm （800 cm-1） absorbance spectrum peak value was calcuated. The results showed that when the temperature and humidity in the laboratory didn＇t accord with the standard, the wave number, absorbance value, peak position, peak intensity and peak shape were changing in the experiment,so the data of dissociating silica dioxide concentration was higher. In order to reduce the measuring errors, air conditioners and dehumidifier equipments should be used, lab environment temperature should be controled within 18 ~ 24 ℃ and the relative humidity was less 50 % RH.