Some cities are known for their cleanliness, and some are notorious for smog and poor air quality. It’s a fact of the carbon-burning world we live in, coupled with the geographical features of the places we occupy. In Los Angeles, the surrounding mountains keep emissions inside the valley, making its air the most polluted in the nation. In Miami, fresh ocean air is constantly pushed into the city, giving it some of the best quality air in the nation.
Source: These are the most polluted neighborhoods in your city