基于微观模拟的企业排污强度差异及区域特征

Micro-simulation of Firms' Heterogeneity on Pollution Intensity and Regional Characteristics

同一工业行业内的企业存在排污强度个体差异,从数量有限的企业环境统计数据得出行业平均排污强度,并用其代表该行业在区域层面的经济-环境水平,会带来一定偏差.因此以嵌入环境消耗投入的生产函数为基础,建立了企业运营决策的微观模拟模型,从机制上描述企业排污强度的差异.以2005年德阳市机械制造行业为案例,对模型的相关参数进行了率定,使其较好地描述了2005年环境统计口径内各企业的COD排放强度.模型的计算结果表明,由环境统计口径内企业计算的区域平均COD排放强度(万元固定资产排放0.002 6 t,万元工业产值排放0.001 5 t)小于由区域内全部企业计算的区域平均COD排放强度(万元固定资产排放0.003 0 t,万元工业产值排放0.002 3 t),市域内6个县级行政区的排污强度也体现出了明显差异.以上的排污强度区域特征主要源自行业内部结构(企业的规模分布,技术分布),及其空间差异.

In the same industrial sector, heterogeneity of pollution intensity exists among finns. There are some errors if using sector＇s average pollution intensity, which are calculated by limited number of firms in environmental statistic database to represent the sector＇ s regional economic-environmental status. Based on the production function which includes environmental depletion as input, a micro-simulation model on finns＇ operational decision making is proposed. Then the heterogeneity of firms＇ pollution intensity can be mechanically described. Taking the mechanical manufacturing sector in Deyang city, 2005 as the case, the model＇s parameters were estimated. And the actual COD emission intensities of environmental statistic firms can be properly matched by the simulation. The model＇ s results also show that the regional average COD emission intensity calculated by the environmental statistic firms （0.002 6 t per 10 000 yuan fixed asset, 0.001 5 t per 10 000 yuan production value） is lower than the regional average intensity calculated by all the firms in the region （0.003 0 t per 10 000 yuan fixed asset, 0.002 3 t per 10 000 yuan production value）. The difference among average intensities in the six counties is significant as well. These regional characteristics of pollution intensity attribute to the sector＇s inner-structure （firms＇ scale distribution, technology distribution） and its spatial deviation.