What does the passage say about the secondhand smoke?

Scientific evidence has been building about the dangers to people who do not smoke from those who do. Now the top doctor in the United States says the evidence cannot be argued: secondhand tobacco smoke is a serious public health risk.
   Recently Surgeon General Richard Carmona released the government’s largest report ever on secondhand smoke. For example, it says nonsmokers increase their risk of lung cancer by up to thirty percent if they live with a smoker.
   He noted the added dangers faced by children who have to breathe secondhand smoke. These children are at increased risk for sudden infant death syndrome, severe breathing problems and ear infections. The report says smoking by parents also slows lung growth in their children.
   Scientists have estimated that secondhand smoke kills about fifty thousand adults in the United States each year.
   The report says separating smokers from nonsmokers or trying to clean the air in buildings is not enough protection. Doctor Carmona noted the progress in establishing smoke-free public places in the United States. Blood tests show that Americans are being exposed to secondhand smoke in fewer numbers and at lower levels since the late 1980s.