Do you live with or spend time with someone who smokes? If so, you may be exposed to secondhand smoke — even if you don’t smoke yourself.
“Secondhand smoke contains harmful chemicals from burning tobacco products, like cigarettes, cigars and pipes,” said Archan Shah, MD, a pulmonologist with Banner MD Anderson Cancer Center. “When you inhale it, you’re breathing in the same dangerous toxins as the person smoking.”
Secondhand smoke is also known as passive smoking or environmental tobacco smoke and it’s not safe for anyone.
Read on to learn how secondhand smoke affects your body, where you might be exposed to it and how to reduce the risk for yourself and your loved ones.
What is secondhand smoke?
Secondhand smoke is a combination of:
- Mainstream smoke: The smoke exhaled by a person who smokes
- Sidestream smoke: The smoke that comes directly from a burning cigarette, cigar or pipe
“Sidestream smoke is also dangerous,” Dr. Shah said. “There is no safe level of secondhand smoke exposure. Toxins such as benzene, toluene, cadmium and others are found in smoke from nicotine-containing products.”
When exposed, even for a short time, those chemicals enter your lungs, bloodstream and organs. That’s why health experts agree: There’s no safe level of exposure.
Even if you haven’t smoked a day in your life, exposure to secondhand smoke can lead to serious illness.
Health risks of secondhand smoke for adults
Secondhand smoke affects nearly every organ in your body. It can:
- Increase the risk of lung cancer
- Damage the lining of blood vessels
- Raise the risk of heart attack, stroke, high blood pressure and other chronic diseases
- Trigger asthma attacks or worsen chronic obstructive pulmonary disease (COPD) symptoms
- Lower your immune system’s ability to fight infections
“Cigarette smoke has more than 7,000 chemicals, some of which are known to cause cancer,” Dr. Shah said. “Smoking is directly responsible for about 90% of lung cancer deaths and 80% of COPD deaths.”
More than 7,300 lung cancer deaths and 33,000 heart disease deaths occur each year among adults who smoke.
Health risks of secondhand smoke for children
Children are especially vulnerable to environmental tobacco smoke because their lungs and immune systems are still developing. They also breathe faster than adults, which means they take in more air and more harmful chemicals with each breath.
Breathing in secondhand smoke can lead to:
- More frequent and severe asthma attacks
- Bronchitis and pneumonia
- Middle ear infections
- Respiratory infections
- Slower lung growth and function
- Increased risk of SIDS (sudden infant death syndrome)
Babies exposed during pregnancy are also at higher risk for low birth weight, preterm delivery and developmental problems.
“Children have no control over their environment,” Dr. Shah said. “It’s up to us as adults to ensure they’re safe from harmful smoke in the home, the car and other places.”
Thirdhand smoke: What you can’t see still matters
You may think that once the smoke clears, the danger is gone. But that’s not the case.
Thirdhand smoke refers to the toxic residue left behind after smoking. It settles on walls, floors, furniture, clothing, toys and even your skin and hair.
“Young children are especially at risk because they spend time crawling on floors, putting things in their mouths and touching surfaces where residue builds up,” Dr. Shah said. “Pets can also be affected.”
To protect your household:
- Wash clothing, bedding and soft toys regularly
- Clean or replace curtains, rugs and upholstery
- Vacuum with a HEPA filter
- Wipe down hard surfaces with vinegar or other non-toxic cleaners
- Repaint or replace materials in heavily smoked-in areas
When moving into a new home or apartment, ask about its smoking history. Thirdhand smoke can remain long after a smoker moves out.
How to protect yourself and your family
Whether you smoke or not, there are simple steps you can take to reduce exposure and protect your loved ones.
If you don’t smoke:
- Make your home and car completely smoke-free
- Ask visitors to step away from doors or windows if they smoke
- Avoid restaurants, hotels and public spaces that allow smoking
- Talk to your children about why smoking is harmful
- Support friends and family members who are trying to quit
If you smoke:
- Quitting smoking is one of the most important steps you can take to protect your health and your family.
“Quitting smoking is hard, but it’s one of the most important things you can do for your health and your family’s health,” Dr. Shah said. “Every day you reduce exposure to tobacco smoke is a step toward better health.”
If you’re not ready to quit yet, reduce the risks by:
- Only smoking outside, away from doors and windows
- Never smoking in the house or car, even when others aren’t present
- Changing your clothes and washing your hands after smoking
- Not smoking around children, even outdoors
When to talk to your health care provider
If you’ve been exposed to secondhand smoke regularly – especially over many years – talk to your health care provider. Even if you feel fine, your provider can help you understand your risks and recommend next steps.
“Lung cancer screening isn’t typically recommended based solely on secondhand smoke exposure,” Dr. Shah said. “But based on your personal health history, your health care provider may recommend screening tests or other follow-up care.”
Lung cancer screening, which usually includes a low-dose CT scan, can detect cancer early when it’s most treatable.
Speak to your provider if you experience symptoms like:
- A cough that doesn’t go away
- Wheezing or shortness of breath
- Chest pain
- Unexplained fatigue
- Coughing up blood
While these symptoms don’t always mean cancer, they shouldn’t be ignored.
Bottom line
Secondhand smoke is a serious health risk, but it is preventable. By choosing smoke-free environments, supporting loved ones who want to quit and staying informed, you can protect your health and your family's health.
Need help quitting?
Need help quitting or understanding lung health risks? Banner MD Anderson Cancer Center offers support programs and screening services to help you take the next step.
