Science and Public Policy
In general, most scientists prefer to do their experiments in a sealed laboratory where they can isolate their subjects from external influences. There is good reason for doing so as this allows scientists to test their theories without worrying if their results are actually due to another cause. However, too many scientists assume that their subjects laboratory behavior, under artificial conditions, equates to the real-world behavior under actual conditions.

For decades, scientists have assumed that most trees absorbed pollution and some folks have made decisions based upon this information. For example, Canada has asked for a "pollution credit" for its large forests under the convoluted Kyoto climate change accord. However, some scientists recently measured the amount of pollution absorbed by pine trees under more realistic conditions and found that when exposed to ultraviolet light (like that generated by the sun), pine trees actually create air pollution.

This new information should be a warning that while laboratory tests are very useful, realistic tests are also needed before any policy decisions are made upon their results.