The cities with high concentration of particulate are mainly located in Xinjiang, Qinghai, Gansu, Shanxi, Inner Mongolia, Shaanxi, Ningxia and Hebei.

• 颗粒物浓度高的城市主要分布在新疆、青海、甘肃、山西、内蒙古、陕西、宁夏、河北等省区。