Investigation by U.S. EPA showed that indoor environment has become one of top four major factors affecting the human health, and 40% of the disease incidence were caused by the indoor pollution.

• 美国环保署组织的调查表明 ,室内环境问题已成为影响人类健康的 4个主要环境因素之一 ,4 0%25的发病率是由室内环境差引起。