Mark Henle/The Republic

Anyone who lives in metro Phoenix has seen the brown cloud that drapes the horizon on a still day.

The pollution is more than what can be seen. Valley air carries bits of dirt, toxic metals, ammonia from farm fertilizer, ozone that irritates nasal tissues. Freeways spew a mix of exhaust and dust, putting anyone who lives nearby at an increased risk.

A day with bad air takes its toll first on those who are already ill. A heavily polluted day sends children to emergency rooms. People with respiratory problems are forced indoors. But a lifetime with bad air takes a toll on each one of us. People who live in bad air live shorter lives.

Government plans typically focus only on narrow parts of the problem  so overall solutions continue to fall short. The Valley sprawls with little regard for how growth has affected air quality  so each day, traffic rolls on as 300,000 people or more live their lives in the danger zone.

The biggest problem may be the most obvious: No one who lives in the Valley can escape the air we breathe.