Each year the evidence grows that people who breathe someone else's cigarette smoke can receive the same unhealthy effects as the person who smokes. Passive smoke is cigarette, cigar, or pipe smoke inhaled by nonsmokers. It is also smoke that remains in a closed environment after the smoker is through smoking. Passive smoke includes mainstream smoke, what a smoker blows off, as well as sidestream smoke, what comes from burning tobacco.

Passive smoke contains large amounts of the same harmful ingredients as the smoke inhaled into a smoker's lungs. However, mainstream smoke may contain less nicotine and tar than sidestream smoke. This may be because sidestream smoke is hotter than mainstream smoke and has not been filtered through the cigarette.

A smoke-filled room may have levels of carbon monoxide and other pollutants as high as those that occur during an air pollution emergency. A nonsmoker could inhale enough nicotine and carbon monoxide in an hour to have the same effect as having smoked a whole cigarette.

Passive smoke causes eye irritation, headaches, and coughing. It causes more frequent ear infections, asthma attacks, and other respiratory problems, and aggravates existing heart and lung diseases, including lung cancer. Lengthy exposure to these conditions can result in the same kinds of health problems that the smoker may experience. Consider these facts:

• New studies indicate that passive smoke not only makes existing heart disease worse; it can actually cause it.
  
• Nonsmokers who live with smokers have a higher risk of dying from heart disease than do nonsmokers.
  
• An estimated 37,000 people die annually from heart disease directly caused by passive smoke.
  
• At least 3,700 people die annually from lung cancer and 12,000 from other forms of cancer because of exposure to others' smoke.