Atmospheric Environmental Capacity And Its Limit To Urban Growth With A Case Study Of Wuxi City

With the growing economy, China’s urbanization has improved continuously. Wuxi, as an important city in Yangtze River Delta region, has also experienced rapid industrialization and urbanization process in recent years. With the growing scale in urban areas, Wuxi, in recent years, has been compromised as a representative to the fog and haze air pollution incidents. Air quality and the health of residents suffer from threats. Thus there is an urgent need for research on the control city scale based on environmental capacity.Currently, researches on the scale of urban population and economies are mostly among the field of urban planning. However, such a research, in the view point of environmental science, is mainly in the urban population and economic threshold analysis based on water environmental capacity. Therefore, how to reasonably determine the scale of urban development by using the atmospheric environmental capacity is an important issue which policymakers are facing.To solve this scientific question, we provide a way to calculate the threshold of city scale based on constrains of atmospheric environmental capacity.1. After analysis on the current situation of Wuxi’s atmospheric environment, we choose the atmospheric pollutants types as the study object. We calculate the atmospheric environmental capacity in Wuxi by the A-P value method.2. We set three scenarios (high, middle and low) of the atmospheric emission intensity between2010and2020and predict, in various scenarios, the atmospheric emission intensity of Wuxi in2020. Furthermore, we calculate the GDP and the population threshold of Wuxi in2020.3. We analyze, in constrain of atmospheric environmental capacity, the correspondence between emissions intensity reduction and GDP growth rate between2010and2020in Wuxi, and obtain the correspondence formulas.It is shown that the environmental capacity of SO2, NO2, PM10are8.51,5.68,9.93(104t/a). According to the total emissions in2010, there was a surplus of atmospheric environment capacity in Wuxi. According to the Cannikin Law, under the three scenarios, the GDP threshold would be16145,9116,5309(108Yuan/a); the population threshold would be10.09,5.7,3.32million. The correspondence formulas of the emissions intensity reduction and the GDP growth rate are as follows: SO2emission intensity decrease rate≥(GDP growth rate-0.083)/(GDP growth rate+1) NO2emission intensity decrease rate≥(GDP growth rate-0.042)/(GDP growth rate+1) Particulate emission intensity decrease rate≥(GDP growth rate-0.01)/(GDP growth rate+1)It is shown that in constrain of atmospheric environmental capacity, atmospheric particulate matter emission intensity would have the greatest restriction and NO2would have the least restriction on Wuxi’s city scale between2010and2020.