通过对各个等级的空气质量进行频数统计，作为模糊评价的评价因素，再根据侧重点与需要对各项因素设定不同的权重，通过matlab编程实现对不同地区的空气质量的等级评价。(Through frequency statistics for each grade of the air quality, as the fuzzy appraisal factors, according to the focus and need to set different weights for each factor