Because while icons like the Empire State  Building and the Brooklyn Bridge were built using Pittsburgh steel, its mills were  responsible for a huge decline in air quality, giving it another less desirable  nickname - the 'Smoky City'.

因为虽然像帝国大厦和布鲁克林大桥这样的标志性建筑是使用匹兹堡钢铁建造的，但它的钢厂造成了空气质量的大幅下降， 给它带来了另一个不太受欢迎的绰号——“大烟城” 。