Environmental Protection Agency

The Environmental Protection Agency (EPA) is the federal agency in charge of protecting the environment and controlling pollution. The following viewpoint is a summary of the EPA’s National Air Quality and Emissions Trends Report of 1996. According to the EPA’s report, emission levels for most air pollutants declined during the 1990s. These levels of air pollutants decreased even though the U.S. population, economy, and the number of vehicle miles traveled all increased. The EPA has reduced some air pollutant standards even further, which the organization claims will lead to lower levels of pollution.

As you read, consider the following questions:

1. What is the only air pollutant whose emission level has increased since 1970, according to the EPA?
2. What would account for a difference in the percent change in ambient concentrations of an air pollutant...