The Air Up There
Although the environmental control systems in commercial aircraft restrict the spread of germs and other airborne pathogens, airlines could reduce the risk of disease transmission further by recirculating the air more often, says Mark A. Gendreau, lead author of a new study published this month in the medical journal Lancet.
Currently, the vast majority of airlines vent old air from the cabin, filter it and mix it with some portion of fresh air before returning it to the cabin. Gendreau points out that a properly functioning ventilation system on an aircraft will remove 63 percent of airborne organisms during each air exchange. One study from a previous inflight tuberculosis incident found that the risk of fellow passengers being exposed could have been cut by half if the ventilation rate had been doubled.
There are no federal regulations concerning how often airlines must recirculate the air. Typically, air is recirculated anywhere from five to 15 times an hour, Gendreau said in an interview. Even under most current conditions, a passenger is not likely to be infected by another's airborne germs unless they sit within two rows of each other for more than eight hours, he said. However, he noted that passengers as far as five rows from SARS carriers contacted the disease -- so clearly, the science is inexact.
"The point of the paper is that if airlines increased air exchanges, particularly if there was a known outbreak of disease somewhere in the world, that might decrease the risk of transmission," said Gendreau.
Air circulation in plane cabins is "a hot topic in Congress," said Gendreau. Tightening regulations, he said, is critical during an era of emergent disease and extensive world travel. "Although the risk of disease transmission on planes is relatively low, the SARS outbreak shows how quickly a pandemic can spread."
Just You and the Trees
The nearly 400 members of the Coalition of National Park Service Retirees have spent a combined total of 11,000 years in America's national parks. Recently, they jointly came up with their 10 favorite less-traveled spots among the vast system's 388 parks and historic sites.
Each pick comes with a poetic description of one or more retirees' experiences at the spot. Writing about the view from a boat in Crater Lake National Park in Oregon one moonless night, a retiree described seeing "the Milky Way reflected in this six-mile-diameter natural mirror."
For sheer wildness, retired park supervisors recommend Arrigetch Peaks in the Gates of the Arctic National Park and Preserve in Alaska. For the finest coral reefs: Dry Tortugas National Park in Florida.