DEAR DOCTOR K: My husband smokes. Is secondhand smoke really as dangerous for me as I’ve heard?

DEAR READER: More than a thousand studies show beyond the shadow of a doubt that secondhand smoke can be very bad for you – bad for adults, and even worse for kids.

You don’t take as much smoke into your lungs when you live with a smoker than if you are a smoker. But you take in more than enough to threaten your health.

Whether it’s smoke from a cigarette, cigar or pipe, secondhand smoke is a dangerous mixture of freshly burned tobacco and exhaled smoke that contains hundreds of chemicals. These include formaldehyde, benzene, carbon monoxide, ammonia, arsenic and lead. Some are known to cause cancer; others are highly poisonous to cells all over the body.

That sounds like it should have negative effects on your health, and it does. The U.S. Surgeon General estimates the following risks to nonsmokers from exposure to secondhand smoke at home or work. Secondhand smoke:

• increases their risk of heart disease by 25 percent to 30 percent;

• increases their risk of lung cancer by 20 percent to 30 percent;

• causes asthma or triggers asthma attacks;

• is responsible for 50,000 deaths each year in the United States – more people than are killed in automobile accidents.

The best thing you can do – for your health as well as your husband’s – is to persuade him to quit smoking. If your husband can’t or won’t quit, ask him to smoke outside or just in one room that no one else uses.

Don’t be lulled into a false sense of security by air cleaners or air filters. They can’t eliminate the hazards of secondhand smoke. And don’t assume the dangers of secondhand smoke disappear once the smoke clears. Nicotine in smoke residue clings to walls, carpets, clothing and other surfaces. It can react with a common indoor air pollutant to form cancer-causing compounds that can persist for months.