Searing Heat Leaves US Cloaked in Smog
Hot weather across America acts like a pot lid, making it hard for pollutants to escape.
From Lansing, Mich., to Laredo, Texas, Americans are lamenting the dramatic reemergence of an unsightly side effect of the country's soaring temperatures: smog.
In southern California, officials are finishing a tried-and-true, late-night setup with a punch line of their own: It was so hot that (drum roll, please) the area suffered six times as many Stage 1 smog alerts as last year, breaking a six-year streak of increasingly cleaner air.
"We just got a major wake-up call," says Linda Waade, executive director of a watchdog group known as Coalition for Clean Air. A Stage 1 alert is considered unhealthy for the entire population, as opposed to lower designations, which are considered warnings to just children, the elderly, and those with respiratory ailments. "As much progress as we've made in recent years by cutting emissions from cars, buses, factories, this shows we still have a ways to go in cleaning up the dirtiest air in America," she says.
Besides the visual gauze that is obscuring landscapes from here to the Ozarks, another air-quality issue is being driven home by the heat: increased ozone levels. Across the South, the summer is shaping up as the worst season in a decade.
In May, Florida had a full week of unhealthy ozone levels, followed by forest fires that have contributed to bad air through midsummer.
Charlotte, N.C.; Fayetteville, Ark.; and Raleigh, N.C., have reported 26 bad ozone days between them, while Great Smoky Mountains National Park has blamed Tennessee cities for smog that has drifted over its trails. Alabama, Georgia, Louisiana, and Oklahoma have also reported an increase in ozone, and are being closely monitored by the US EPA.
Both smog and ozone are created by the mixture of emissions of hydrocarbons from cars, buses, and factories with volatile organic compounds such as the vapor of oil paints.
The formation is made stronger by heat and sunlight. High pressure weather systems have lingered at high altitude over the Pacific, Gulf of Mexico, and Rocky Mountains. Acting like a pot lid, the dense bodies of air make it harder for pollutants to escape by reinforcing what scientists call the "natural inversion layer" - the warm air that hangs over city and valley geographical basins.
The ozone situation would be worse and more extensive if it weren't for high winds - courtesy of a high pressure front circling over New Mexico - that have accompanied the heat across the mammoth state of Texas. But the winds bring other annoyances - drier landscapes, dust, and fire warnings.
"Even though we have had a record heat wave, the prevailing winds have kept ozone levels down across Texas," says Dave Bary, regional EPA spokesman for Texas, New Mexico, Oklahoma, Arkansas, and Louisiana. One paradox of the intense heat, he says, is that people remain inside and use more electricity and air conditioning. That behavior creates more demand for power from coal-fired utility companies, which in turn spew more pollutants into the air.
The atmospheric conditions that have created the current heat wave are an anomaly created in the aftermath of El Nio, experts say, as a series of dry conditions have created the driest April-to-June period in 104 years in Florida, Texas, New Mexico, and Louisiana. Although this particular heat wave is not evidence of global warming, they say, it is an extreme occurrence that will become more frequent in coming years.
"One year might be a little warmer and the next a little colder, but the trend behind them both is a gradual warming in which we can expect more of this," says Alan Robock, a climatologist at Rutgers University who tracks regional and global weather patterns.
Both President Clinton and Vice President Al Gore have seized on the summer heat wave to spotlight dangers of global warming, the gradual increase in temperatures generated by the greenhouse effect. For each of the first six months of 1998, the mean global temperature was warmer than the same months of 1997.
Such trends are spotlighting moves by officials across the South and Los Angeles to both raise consciousness of such dangers and increase local laws. Yesterday, officials of the California Air Resources Board (CARB) held hearings to propose new regulations strengthening auto-emission standards on minivans, light trucks and sport-utility vehicles.
But reducing car emissions is difficult in the car-loving South, according to Michael Rodgers, director of the Georgia Tech Air Quality Laboratory. He says a major difference between the South and other parts of the US is land-use patterns.
"Most of the cities in the South got their major growth in population post-World War II, which means that Atlanta, Nashville [Tenn.], or Charlotte all grew up when most people had automobiles," he says. The result is that the core of many Northern and Midwestern cities is compact whereas a larger proportion of Southern cities live a suburban lifestyle.
Therefore, say many organizations concerned about ozone and managing land use in the future will be key.
"Transportation money is being withheld by the federal government because our transportation planners can't figure out how keep the region growing and still maintain air quality standards," says Jeane Pierce, Voluntary Ozone Program coordinator for Georgia. Alabama, South Carolina, and other states have voluntary ozone action programs like Georgia's, which encourage citizens to carpool, telecommute, or use mass transit on "ozone alert" days.
* Tabatha Yeatts contributed to this article from Atlanta.