1. AIR POLLUTION:
Ozone to blame for reduced crop yields, tree damage

Browning on potato leaves shows evidence of exposure to high concentrations of ozone. Photo courtesy of USDA.

Ground-level ozone is a huge health concern, sending thousands of people each year to hospital emergency rooms. But a growing number of scientists and advocates are focusing on ozone's damaging environmental impacts, as evidence mounts that ozone is harming some of the nation's most prized forests and economically important crops.

Ozone is damaging ponderosa pine seedlings in California's San Bernardino Mountains and stunting the growth of yellow poplars in the Great Smoky Mountains National Park in Tennessee. It is dramatically reducing crop yields, with researchers at Princeton University estimating ozone is to blame for 90 percent of all crop losses caused by air pollution.

And it is harming wildlife. Researchers at the University of Virginia have found that air pollution, particularly ozone, significantly reduces a flower's aroma, making the flower difficult for bees to find and pollinate, making it harder for bees to feed. Go to story #1