At present, there is no unified method in all countries. Generally, the comprehensive index method is used to evaluate the current environmental quality, that is, to calculate the environmental quality value (or environmental quality index). Firstly, environmental quality indicators and evaluation criteria are selected, then the environmental quality values of each sub-index are calculated, and finally the comprehensive environmental quality values are calculated. This method is comprehensive, simple and practical. The general formula of calculation is: the general formula of calculation

Where p is the comprehensive environmental quality value of N pollutants in environmental elements; Ki is the weight coefficient of I pollutant; Ci is the measured concentration of I pollutant; ? Si is the evaluation standard of I pollutant; E is the total environmental quality; General formula for calculating environmental quality weight system with Qj as J environmental factor

Number; Pj is the comprehensive environmental quality value of J environmental factors. The evaluation standard generally adopts various pollutant discharge standards or allowable concentrations stipulated by the state; According to the theory of environmental chemistry, the pollution property right coefficient is obtained through simulation test; The weight coefficient of environmental factors is determined by the proximity between factors (media) and human intake. The greater the environmental quality value, the worse the environmental quality.