Today the word downtown can conjure up many different mental images. It is easy to imagine downtown as a place of tall buildings, traffic congestion, many pedestrians, and a plethora of entertainment options. It is good to keep in mind that downtown may not have always meant this.
Chicago's downtown, in the earlier industrial era, was a gritty and polluted place. The buildings downtown as well as the outlying factories ran their boilers with coal, which plumed out and formed clouds that blocked the sun and caused serious health hazards as well as being a foul smelling dirty mess.
The working-class populations that settled the adjacent residential
the most immediate effects, but prevailing winds from
the southwest carried noxious stenches into the prestigious
close to downtown Chicago. Citizen complaints prompted
a more vigorous enforcement of public health laws after 1860, the effect of which was to push the offending industries beyond the city limits into new industrial suburbs.
One of the many factors that coincides with the redevelopment of cities and the urban core is the reduction of pollution. Manufacturing has gotten cleaner, has relocated out of city centers, or out of the country entirely. Better technology has allowed coal fired boilers to be replaced with cleaner alternatives like natural gas. So downtown living has become a more attractive idea with the reduction or elimination of pollution from the city core.