Recent data from the City of Aspen show November of 2009’s high temperature at about seven degrees warmer than the historic average. In recent years, November in Aspen has been warming faster than any other month.
November temperatures have been warming at the rate of six degrees per decade for the high temperatures and four degrees per decade for the low temperatures.
“That is why scientists focus on longer-term trends to evaluate climate,” explained Kim Peterson, Aspen’s global warming program manager. “Short-term changes from month to month are much more variable.”
November’s temperatures were a concern for snowmaking, since November is a key month for making snow. This November did not have any days with below-zero temperatures, although December has already broken some records for cold temperatures.
Particulate air pollution levels (PM-10), on the other hand, were close to average for November. November is usually a month with low pollution levels, because there is less traffic. “Almost all PM-10 on high pollution days comes from traffic,” said Aspen’s Environmental Health Director Lee Cassin.
Another factor keeping PM-10 levels down may have been the low precipitation. “This November had the second-lowest precipitation of any November in the last ten years, so streets would not have gotten as much sand and dirt tracked out as usual,” Cassin said. The average PM-10 level in November was 18.4 millionths of a gram of PM-10 in each cubic meter of air, compared to a federal standard of 50.
The City of Aspen has several programs designed to reduce both PM-10 and greenhouse gas emissions, from the in-town and valley mass transit systems, HOV lanes, paid parking (revenues paying for transit), rebates for free home energy audits, and the ability to buy Canary Tags to offset greenhouse gas emissions that cannot be avoided.
For more information on air quality in Aspen, visit www.aspenpitkin.com/Departments/Environmental-Health. For information on Aspen’s global warming programs, go to www.aspenpitkin.com/Departments/Canary-Initiative/.