Dear EarthTalk: I know of issues associated with the Earth’s ozone layer, but what is "ground level ozone" and why is that a problem?
—D. Goetz, Palm Beach, FL
Ozone (O3) is a colorless gas formed when three atoms of oxygen bond together. About 90 percent of the Earth’s ozone forms naturally in the stratosphere, dozens of miles above ground. It forms the protective layer that shields us from overexposure to the sun’s radiation, and is therefore considered "good" ozone.
The rest of the ozone found on Earth occurs at ground level, and forms when nitrous oxides and various "volatile organic compounds" (VOCs)—originating with car exhaust, industrial emissions, chemicals and gasoline vapors, as well as some natural sources—bond together in the presence of sunlight.
Ground level ozone, or "bad" ozone, is a key component of smog, which wreaks havoc on human health and the environment, especially in urban areas. The U.S. Environmental Protection Agency (EPA) reports that exposure to even relatively low concentrations of ground-level ozone for extended periods (several hours) can significantly reduce lung function and cause respiratory inflammation in normal, healthy people. Symptoms can include chest pain, coughing, nausea and congestion. For people with asthma and other respiratory illnesses, exercising in ozone-rich air can be deadly. Repeated exposure to high levels of ozone for several months or more can produce permanent structural damage in the lungs.
Beyond its effects on our health, the EPA estimates that pollution from ground-level ozone is responsible for nearly $2 billion in agricultural crop yield losses in the U.S. alone each year. The pervasive gas has also been shown to damage forests in California and the eastern U.S. and to contribute to global warming.
Under the mandate of the Clean Air Act, the EPA is charged with monitoring and limiting the amount of ground-level ozone in urban areas, and issuing warnings when smog levels are above its standard of 0.12 parts per million. But new studies indicate that ground-level ozone causes adverse health effects at even lower concentrations. And, according to the EPA, even rural areas suffer increased ozone levels, because wind carries ozone and the pollutants that form it hundreds of miles away from their original sources. As a result, the EPA is reviewing whether revisions to ozone standards and policies are warranted.
High concentrations of ground-level ozone are not as common in Canada, but three urban regions—British Columbia’s Lower Fraser Valley, the Windsor-Québec City Corridor and the Southern Atlantic Region that includes New Brunswick and Nova Scotia—do suffer several "bad air days" each year. The Canadian government, through its own Clean Air Act, has even stricter standards for exposure to ground-level ozone than in the U.S., though enforcement is not as big a priority given the smaller scope of the problem there.
To help minimize ground-level ozone, avoid car trips and the use of power lawn equipment during especially hot or windless days. Paints and solvents, most which off-gas VOCs that create ozone and form smog, are also best to steer clear of with hot summer temperatures coming on strong. Those concerned about their respiratory health should follow local weather sources, most which post smog alerts.
Dear EarthTalk: Are there organizations that specifically address the environmental challenges faced by poor and minority communities?
—Bill Macomber, Ann Arbor, MI
When sociologist Robert Bullard began uncovering the proximity of hazardous waste sites to minority neighborhoods across the American South during the course of his graduate research in the 1980s, the "environmental justice" movement was born. In the intervening two decades, environmental and human rights advocates around the U.S. and the world have launched thousands of nonprofit community groups to battle so-called "environmental racism"—whereby otherwise distressed and poor minority communities are disproportionately exposed to the brunt of industrial pollution in their own backyards.
Environmental justice is fundamentally a local issue, but several national groups have devoted considerable resources to righting wrongs and helping communities defend their rights to clean air and water. Perhaps the best known is the Center for Health, Environment and Justice (CHEJ), founded by Lois Gibbs, the mom-turned-activist who in the early 1980s got authorities to shut down and remediate the Love Canal district of Niagara, New York, where buried industrial waste was causing serious health problems. CHEJ has since fought alongside thousands of communities to get toxic sites cleaned up and obtain restitution.
In other ongoing efforts, Environmental Defense’s "Living Cities" program pairs teams of scientists, lawyers and economists with local groups working to resolve environmental health issues in minority population centers. And the Natural Resources Defense Council (NRDC) conducts studies, produces reports and policy analyses and mounts campaigns and lawsuits on various environmental justice issues, with a recent focus on helping the victims of Hurricane Katrina. Another big player is the Earthjustice Legal Defense Fund, a nonprofit public interest law firm that has championed several high-profile environmental justice cases since it began as the Sierra Club Legal Defense Fund in 1971. Protecting farm worker communities from dangerous pesticides is a current focus area.
Those with environmental justice issues needing attention can contact one of these groups or a regional one that can help size up potential toxic threats and provide assistance on what to do. The Southwest Network for Environmental and Economic Justice, the New York City Environmental Justice Alliance, the Environmental Law and Policy Center of the Midwest and the San Francisco Urban Institute are all great resources, as are Robert Bullard’s Environmental Justice Resource Center, based at Clark Atlanta University, and the Environmental Research Foundation, located in New Jersey.
The U.S. Environmental Protection Agency (EPA) has also begun to take these issues seriously and in 1992 created its Office of Environmental Justice to integrate environmental justice into EPA policies and programs. Community groups can apply for EPA grants, and an EPA internship program places students directly into communities to assist local groups in addressing local environmental and public health issues.
CONTACTS: CHEJ; Earthjustice; Southwest Network for Environmental and Economic Justice; San Francisco Urban Institute; Environmental Law and Policy Center; New York City Environmental Justice Alliance; Environmental Justice Resource Center; Environmental Research Foundation