A recent study shows that air and noise pollution at Yellowstone National Park declined to a level well below the Occupational Safety and Health Administration exposure limits for employees after new snowmobile limits went into effect.
Researchers say further study is needed before a direct correlation can be made between the decreasing levels and new snowmobiling rules. The study, commissioned by the National Parks Service, is one of several that will be taken into account when long-range winter use plans are developed.
The study focused on the west entrance that's considered the park's busiest for snowmobile traffic and the warming hut near the headwaters of the Madison River during the extended Martin Luther King Jr. and President's Day holiday weekends. Also involved in the study was exposure at a Mammoth Hot Springs maintenance shop in February.
Yellowstone planner Kevin Schneider said the findings show that the restrictions, including the type of snowmobiles allowed, are having an effect, although the limit of 720 sleds was never reached last season. The study's authors said that pollution exposure could increase if the daily limits are reached.
More research will be done this winter, and Terry Spear, the study's lead author and head of the Safety, Health and Industrial Hygiene Department at Montana Tech in Butte, says this winter's focus will be the sources of the noise.
More info:
www.nps.gov/yell