The factors of urban pollution are mainly amog (smoke and dust in air), fine sand flying up in air and secondary dust (ground dust), as well as dispersion of solid waste and sewage irrigation.

• 该市地处西北黄土高原西部,是黄河河谷盆地型城市,其城市污染代表了黄土高原干旱、半干旱条件下污染特征。