二手烟与儿童智力
根据美国NIH 2005年一月发表的文章，通过对全国范围内的4,399个6-16岁儿童所作的调查，发现在经过吸入了5天的二手烟后，这些儿童的考试成绩（特别是数学成绩）明显低于正常水平，证明了二手烟与儿童智力及理解能力降低之间的直接关系。
Second Hand Smoke and the Brain
Children who are exposed to even extremely low levels of tobacco smoke in the last 5 days score lower on standardized tests. Their performance on math tests is significantly lower, but lower still on reading tests. Their short-term memory scores appear to be unaffected. These startling results come from an analysis of 4,399 children 6 to 16 years old published in the January 2005 Environmental Health Perspectives (the NIH journal on environmental health).
Exposure to smoke was strongly associated with decreased cognitive ability. This held true even after adjusting for gender, race, region, poverty, parent education, parent marital status, and blood tests for iron and lead. The level of tobacco smoke exposure was measured by blood tests as well as by asking questions. The greater the exposure, the poorer the children performed on intelligence tests, but the biggest drops in scores happened at the lowest levels of exposure. There is no safe level of smoke exposure for their developing brains. Any tobacco smoke that children can smell appears to be enough to affect their intelligence. Alan Greene MD FAAP January 28, 2005