Photo by The Maricopa County Air Quality Department

Afternoon winds are more variable but frequently occur from the west. When this is the case, air that was blown out of Phoenix in the morning is pushed back in the afternoon – and we breathe a double dose of pollutants, from both our morning and our evening commutes.

Because many air pollutants are invisible, clear air doesn’t necessarily equate to healthy air. But common sense dictates – and science supports – that when the brown cloud is hanging over the Valley, the air is bad for us in all kinds of ways. For example, combustion sources create invisible as well as visible pollutants (and motor vehicles also kick up PM10 pollution in the form of road dust). The same weather patterns that keep visible pollutants over the city keep invisible ones there as well.

A Silent Killer

What are the consequences of breathing in the brown cloud? Significant. The toxic cocktail of pollutants in our air affects us in multiple ways.

Let’s take particulate matter, first. According to the American Lung Association’s State of the Air 2007 report, exposure to particulate pollution is killing us – and not just slowly. Even short-term exposure to particulate pollution is linked to increased mortality from respiratory and cardiovascular diseases, especially among children and the elderly. High particulate pollution is directly linked to greater infant mortality, more heart attacks and more hospitalizations for conditions such as strokes. “Unfortunately, particle pollution does not just make people die a few days earlier than they might otherwise; these are deaths that would not have occurred if the air was cleaner,” the report states.

Long-term exposure to particulate pollution kills, too. Breathing particulate pollution day in and day out puts us at increased risk for lung cancer and cardiovascular disease. The effects of living with particulate pollution are similar to smoking: According to a 2005 review of existing research, the body responds to particulate matter much as it does to cigarette smoke. Even if you’re healthy now, expect the effects to catch up with you – chronic exposure to particulate pollution will shorten your life by one to three years.

Ozone pollution also is taking years off our lives. As with particulate pollution, high levels of ozone are associated with greater mortality in people with heart failure, pulmonary congestion or lung disease. Even in relatively healthy people, exposure to ozone can trigger some immediate adverse effects: shortness of breath, wheezing and coughing, and increased susceptibility to respiratory infections. Chronic exposure can cause pulmonary inflammation and increased asthma attacks.

According to the governor’s office, in 2005, Arizonans spent 23,000 patient days – more than 60 years – in the hospital for asthma. Air pollution is especially problematic for asthma sufferers. Heightened and more frequent asthma attacks triggered by air pollution are the primary cause of school absences among children in Arizona. In 2005, more than 2,500 Arizona children under the age of 15 were hospitalized for asthma.

“Just living here and breathing the air, you’re probably taking one percent off your lifespan,” says Sandy Bahr, conservation outreach director for the Sierra Club. “It’s just criminal that we have to tell our children to play inside because the air is so bad.”

A Hazy Situation

Just how bad is bad?

Ozone and particulates are the biggest offenders in Maricopa County. The American Lung Association’s State of the Air 2007 report gave the county an “F” grade for ozone pollution and a “D” grade for particle pollution. (Most other counties in Arizona received an “A” or “B” on the same scale.)

According to the Sierra Club, in 2005, Maricopa County exceeded the federal health standard for ozone 30 times. And “all of the recent research indicates that the levels established by the EPA (Environmental Protection Agency) are not protective enough of public health,” Bahr says.

Ozone is formed when sunlight reacts with volatile organic compounds emitted from vehicles and other sources. So unlike the brown cloud, which is seen more frequently in the fall and winter, ozone is at its worst during the long, sunny days of summer.

However, PM10 pollution – from construction activities, vehicular travel, agriculture and other sources – is Maricopa County’s biggest challenge. In 2005, the Phoenix area exceeded the federal health standard for particulates 20 times; in 2006, it exceeded it 23 times. Because Maricopa County failed to meet PM10 standards by its deadline of December 31, 2006, we now have a federal obligation to cut particulate emissions by 5 percent per year until we’re in compliance. If we fail, we could lose up to $1 billion in federal highway funding – a threat that has finally spurred our traditionally recalcitrant legislature into action.