Abstract:
Vegetation can intercept and absorb particulate matter, sulfur dioxide and nitrogen oxides in the atmosphere, which plays a role in the purification of atmospheric pollution. However, it releases a large number of volatile organic compounds, which can promote the formation of photochemical smog pollution. Taking Gansu Province as an example, vegetation cover index (NDVI) and tropospheric formaldehyde (HCHO) column concentrations from 2008 to 2016 were interpreted by means of satellite data inversion, and the relationship between them and the influencing factors were discussed. The results show that:(1) The spatial distribution gradient of the NDVI in Gansu Province decreases from southeast to northwest from 2008 to 2016. The interannual dynamics are not significant but the seasonal dynamics are significant, which are similar to the temporal-spatial distribution and dynamics of HCHO column concentration. (2) The annual NDVI value varies from 0.22 to 0.25, while the HCHO column value ranges from 7×10
15 to 11×10
15 molec/cm
2, respectively, there is a significant positive correlation between them, and the correlation coefficient is 0.63. (3) The distribution of NDVI and HCHO in Gansu Province is not only related to meteorological factors such as radiation, temperature and precipitation, but also similar to the distribution characteristics of human footprint in the central part of Gansu Province. Researches have shown that the human footprint index in Central Gansu Province is high, HCHO is mainly derived from human activities, while the human footprint index in western and southern Gansu Province is low, and HCHO is mainly derived from natural emissions.