Fog is thickened and acidified when the air is filled with sulfur-laden soot particles produced by the burning of coal. Dense acid fogs that killed thousands of people in London up to 1956 led to legislation that prohibited coal burning in cities.
- thicken [ˈθikən] v. 使变厚，使变浓
- acidify [əˈsidifai] v.酸化
- sulfur-laden [sulfur-ˈleidn] adj. 含有硫黄的
- soot particle [sut - ˈpɑ:tikl] n. 煤烟颗粒
- coal [kəul] n.煤
- dense [dens] adj. (烟、雾等)浓密的
- acid fog [ˈæsid - fɔg] n. 酸雾
- legislation [ˌledʒisˈleiʃən] n. 法规、法案，立法
- prohibit [prəˈhibit] v.禁止
