Many Americans seem to believe that in the "Good-Old-Days" before the automobile, American cities were paradises of clean air and little noise. This belief is especially promoted by environmentalists, who seem to know little of history, or science, for that matter.
By the turn of the century, urban Americans were drowning in pollution. Tons of it. Besides smoke from factories, wood and coal fires, and the general lack of sewage, there were 150,000 horses in New York City alone, each one producing an average of 22 pounds of manure a day. (3,300,000 pounds a day - 1650 tons)
The stench was appalling, and at its worst, a serious health hazard. Manure bred lots of flies, and flies spread cholera, typhoid fever, and dysentery. When it was dry, manure turned to dust that spread throughout the city, covering clothes and furniture. When it rained, the streets turned into cesspools. It was impossible to walk about the city without tracking manure, and whatever it contained, home with you.
In the 18th century Benjamin Franklin had lamented the "thundering of coaches, chariots, chaises, waggons, drays and the whole fraternity of noise" in Philadelphia. As the cities grew, it only became worse. Iron wheels and horseshoes on cobblestones made a constant din, and noise was blamed for creating a variety of nervous disorders.
In the early 20th century automobiles began to appear on the highways and streets of America, competing for space with horses, wagons, coaches and carriages. Magazine articles began to appear urging the banning of horses. Automobiles were promoted as being cleaner, quieter, cheaper, and faster. Today our air and water is cleaner than it has been at any time since humanity first began to gather together in cities.