短语词组短语dustiness index 含尘指数dustiness degree 含尘度seam dustiness 煤层含尘量permissible dustiness 允许含尘量dustiness s 含尘量air dustiness 空气污染度dustiness of the air 空气污染度degree of dustiness 含尘度maximum permissible dustiness 最大允许含尘量 返回 dustiness