Bioassays on the skin, subcutaneous tissue, cervix, and trachea of experimental animals have shown that particulate matter of urban air can be carcinogenic in the intact animal.

• 对实验动物的皮肤、皮下组织、颈和气管的生物鉴定表明，城市空气中的颗粒物质对健康动物可能是致癌的。