range from moderately polluted to highly polluted (Figure
5(b)). Although differences exist between PLI and PN, the
two have similar distributions, both showing high values
among aluminum plants in Lanzhou, coal-fired power plants
in Xigu, Yanerwan, the building materials market and leather
factory, and low values in Anning District. Nemerow Index
shows that high values are also distributed in Shuishang
Park and Panhandle, which are located near the materials
market-West Station-Xiaoxihu Park-Chengguan Bridge. These
results indicate that the areas which are strongly impacted
by human activities, such as industry and vehicles, all face
serious pollution problems.