Ozone

Smog and soot levels have dropped significantly in Southern California over the last decade, but the Los Angeles region still has the highest levels of ozone nationwide, violating federal health standards an average of 137 days a year. The city ranks second in the country, behind Bakersfield, for the highest year-round levels of toxic particles or soot, and fourth in the nation for the number of short-term spikes in soot pollution. The rankings, part of the annual "State of the Air" report by the American Lung Assn., are based on federal and state data, which show that more than 90% of Californians live in counties with unhealthful air. Unlike parts of the East and Midwest, where coal-fired power plants are a primary source of toxic pollution, Southern California's chemical stew is the product of tailpipe emissions from cars and diesel pollution from trucks, trains and ships linked to the ports of Los Angeles and Long Beach.

"Potiche" is a glossy throwback made with a modern eye, an old-fashioned romantic fantasy starring Catherine Deneuve and Gerard Depardieu that's been knowingly updated with tart, contemporary touches. The updater is François Ozon, who's been down this road before. Though the French writer-director is mostly known for such serious dramas as "Swimming Pool" and "Time to Leave," he did another glossy confection, "8 Women," which also starred Deneuve. What Ozon has done is freely adapt a 1980 mainstream "theatre de boulevard" play by Pierre Barillet and Jean-Pierre Grédy (whose work also inspired the Goldie Hawn-starring "Cactus Flower")

Ozone generators are often used in hotel rooms, cars and private homes to get rid of the smell of cigarette smoke, but new evidence suggests that this cure may be worse than the disease. Researchers at the Univeristy of California's Lawrence Berkeley National Laboratory have found that ozone combines with nicotine and other components of cigarette smoke to produce chemicals that are a greater asthma hazard than the original smoke. In particular, the chemicals combine to form ultrafine aerosols that can carry dangerous chemicals deep into the lungs, where they trigger the development of asthma.

People who live in excessively smoggy areas tend to have higher rates of heart disease, according to several studies. New research shows just how certain components of smog destroy cells in the heart. In research presented Wednesday, scientists exposed rats to ozone — a major component of smog when it forms near the ground from hydrocarbons — for various periods of time. The found that, compared to unexposed rats, the hearts of the rats exposed to ozone had increased levels of tumor necrosis factor-alpha, which is a marker for inflammation.

California strawberry farmers may soon have a new pesticide to use on their fields. The state's Department of Pesticide Regulation is recommending approving use of the soil fumigant methyl iodide. However, scientists say that methyl iodide is very toxic and can cause cancer, brain damage and miscarriages. An independent panel of scientists, invited to review the health FOR THE RECORD: Pesticide: An article in Monday's Health section on the debate over a pesticide that may be approved for use on strawberry crops said that molecular biologist Edward Loechler works at Brandeis University.

Kudzu, a fast-growing and invasive Asian vine introduced in the American South several decades ago, has now blanketed more than 7 million acres of the region, making it sometimes seem more common than the hallmark azaleas, dogwoods and peach trees. Now there's evidence that the plant also increases air pollution. A paper published Monday in the Proceedings of the National Academy of Sciences reported a link between kudzu and the production of ozone, the colorless and odorless gas that is the main component of smog.

Metropolitan Los Angeles, extending to Riverside and Long Beach, remains the smoggiest city in the United States, with an average of more than 140 days a year of dangerous ozone levels, the American Lung Assn. reported Wednesday in its annual assessment. All of the nation's 10 smoggiest counties are in California, with San Bernardino, Riverside, Kern, Tulare and Los Angeles leading the pack. And the state's cities and counties, with their ports, refineries, power plants and crowded freeways, rank near the top for particle pollution.

Ozone from Asia is wafting across the Pacific on springtime winds and boosting the amount of the smog-producing chemical found in the skies above the western United States, researchers said in a study released Wednesday. The new study, published in the journal Nature, explores a phenomenon that has puzzled scientists in the past decade: Ground-level ozone has dropped in cities thanks to tighter pollution controls; but it has risen in rural areas in the western U.S., where there is little industry or automobile traffic.

The Environmental Protection Agency proposed the nation's strictest-ever smog limits Thursday, a move that could put large parts of California and other states in violation of federal air quality regulations. The EPA proposed allowing a ground-level ozone concentration of between 60 and 70 parts per billion, down from the 75-ppb standard adopted under President George W. Bush in 2008. That means cracking down further on the emissions from cars, trucks, power plants, factories and landfills.