ADHD finked to Air Pollutants

　　Children have an increased of attention problems seen as early as grade school. If their noses inhaled ( 吸入) a certain type of air pollution when they were pregnant. That's the finding of a new study, released when things aren't burned completely, this pollution is known as polycyclic aromatic hydrocarbons of PAHs.

　　The biggest sources of these PAHs: the bruning of fossile fuels, wood and trash. Frederica Perera works at Columbia University's Mailman School of public Health is Ne York City. She and her team studied the xposure to air pollution of 233 nonsmoking pregant women in New York City.

　　Because burning tobacco can spew (排放) PAHs into the air and lungs. Perera's team focused on nonsmokers.

　　The researchers investigated signs of attention problems in those children, now age 9. They asked each child's mother a series of questions. These included wahtever her child had problems doing things that needed sustained(长期的 )mental effort, such as homework or games with friends.

　　The scientists also asked if the kids had trouble following instructions or made grequent, careless mistakes. All of these can be sumptoms of a disorder called Attention Deficit Hyperactiviety Disorder, or ADHD. About one in U.S. children has ADHD. Among the women stueied traffic and home heating were the primary sources of air pollution exposure. Perera and her team suspect.

　　Some of these women had low levels of PAHs in their bolld. Others had ghigh levels. Those with high levels were five times as likely to have dhilren who showed attention problems by age 9. The new findings were published November 5 in the journal PLOS ONE.

　　16. Perera and her team chose nonsmiking pregnant women all over America.

　　A. Right

　　B. Wrong

　　C. Not mentioned

　　17. The main purpose of the research was to find out how exposure to PAHs played a role in harming the subjects' physical health.

　　A. Right

　　B. Wrong

　　C. Not mentioned

　　18. Nonsmoking mothers were selected because the effect of smoking on PAHs was unclear.

　　A. Right

　　B. Wrong

　　C. Not mentioned

　　19. The blood of each woman was tested once a month during pregnancy.

　　A. Right

　　B. Wrong

　　C. Not mentioned

　　20. Kids with ADHD commonly fail in school.

　　A. Right

　　B. Wrong

　　C. Not mentioned

　　21. The women with high levels of PAHs in their blood were more likely to have kids with ADHD.

　　A. Right

　　B. Wrong

　　C. Not mentioned

　　22. Traffic and home heating were considered to be the biggest sources of PAHs for the subjects in the research.

　　A..Right

　　B. Wrong

　　D. Not mentioned