What efforts have been made, especially by the EPA ,to improve air quality?

The EPA (Environmental Protection Agency) has many
guidelines set in place the control the use of dangerous air contaminants such as
asbestos, aerosols, carbon monoxide, chlorofluorocarbons, mercury, etc. It also
discusses in great detail ground level ozone which is of particular concern, especially
in the summer time when the temperature rises.

Ozone can be
either good or bad. When it is low it is considered bad ozone. This bad ozone is caused
by poor vehicle exhaust, gasoline vapors, pollutants from industry, etc. The EPA has
guidelines that must be lawfully followed to help protect the environment from these
dangerous pollutants. For example, some areas require that people take their vehicles in
for emissions tests. Industry is also heavily fined for breaking rules set in place by
the EPA.