Abstract: The atmospheric environmental capacity refers to the atmospheric environment pollution of a kind of pollutants. Simply speaking, it refers to a pollutant carrying capacity which a regional environment can accept. Environmental capacity is the basis to confirm the index of the pollutant discharge capacity. It will ensure the realization of environmental protection which means that the discharging capacity is smaller than environmental capacity. The Lanzhou New District of 806 km2 area will be located in the Qinwangchuan basin between Gaolan County and Yongdeng County. It is one of major projects which are supported by the State Council of China, the provincial party committee and the government of Gansu Province. The study and the checking of the atmospheric environmental capacity are the precondition and base of atmospheric pollution total amount control. The accurate calculation of atmospheric environmental capacity can provide scientific basis for the regional atmospheric pollution control and environmental planning. At the same time, the limited resources can also be fully utilized, and then promote the scientificity and systematization of the environmental management. After summarizing and analyzing some domestic and overseas studies on the atmospheric environmental capacity calculating methods, A value method, which is the simplest mode, is adopted in this paper to account the atmospheric environmental capacity in Lanzhou. The SO₂, PM₁₀ and NO₂ are selected as the influence factors. By using the observation data in Zhongchuan airport station from 2008 to 2010, A value method was adopted to count the atmospheric environmental capacity in Lanzhou New District. In the process of calculating the atmospheric environmental capacity, the transportation and diffusion, dry deposition, wet deposition and chemical transformation courses were considered in this thesis. Thus the model can reflect the transference and transformation of atmospheric environmental pollutants, and the dynamic changing process as well. The calculating results of environmental capacity can reflect the actual atmospheric environmental capacity in Lanzhou New District. Also the results acquired in this paper can provide the scientific references for the atmospheric pollution control in Lanzhou New District exactly. The A value in the different seasons is calculated in this paper with the observation data. The results are as follows: the A value is 2.55×10⁴ km²/a to 10.52×10⁴ km²/a. The biggest A value is in April and the smallest is in December. The weighted average A value in a year is 5.42×10⁴ km²/a. The SO₂ sensitizes to wet deposition, PM₁₀ sensitizes to dry deposition. Nevertheless, the transportation and diffusion of every pollutant occupy the main position of the atmospheric environmental capacity. Especially the transportation and diffusion of PM₁₀ and NO₂ are more than 90%, so their dynamic changing process can be neglected when the atmospheric environmental capacity is calculated. The results indicate that the atmospheric environmental capacity of the SO₂ is 15.03×10⁴ t, the PM₁₀ is 18.03×10⁴ t, and the NO₂ is 15.16×10⁴ t.

Key words: Lanzhou New District, atmospheric environmental capacity, characteristic analysis