矿井瓦斯，有毒气体矿井中有时污染空气的恶臭气体或有毒气体 Foul or poisonous gas that sometimes pollutes the air in coal mines.
现代城市是由大得怕人的大厦和充斥着难闻的汽油味，煤灰和有毒气体和又阴暗又狭窄的街道所组成。 The modern city consists of monstrous edifices and of dark narrow streets full of petrol fumes, coal dust, and toxic gases.
