News release: “After a careful review of the science, the U.S. Environmental Protection Agency (EPA) is affirming the current national air quality standards for carbon monoxide (CO). The science shows that the current standards protect public health, including those who are most susceptible, and the environment. Since 1980, levels of CO in the air have fallen by 80 percent, mostly as a result of motor vehicle emissions controls. CO is a colorless, odorless gas emitted from combustion processes. Nationally, and particularly in urban areas, the majority of CO emissions come from motor vehicles. CO can cause harmful health effects by reducing oxygen delivery to the body’s organs (like the heart and brain) and tissues. To ensure people are protected from unhealthy concentrations of CO and to develop better information about CO and its health impacts, EPA is revising the air monitoring requirements. The changes will require a more focused monitoring network with CO monitors placed near roads in 52 urban areas with populations of 1 million or more.”