Reviewed by: HU Medical Review Board | Last reviewed: June 2023

Tobacco smoke is a strong asthma trigger. This is true of both firsthand smoke (when you yourself are smoking) and secondhand smoke (when people are smoking around you).1

Both types of smoke irritate the airways. This can lead to airway narrowing and asthma symptoms. Secondhand smoke is especially harmful for children with asthma. It increases the risk of asthma attacks and stays in the hospital.1

Quitting smoking is the best way to reduce exposure to smoke. It can improve symptoms and lung function for you and your children. Reducing secondhand smoke exposure is also important, especially in children. Talk to your doctor about ways to quit smoking and reduce exposure to smoke.1,2

How does smoking affect asthma?

Smoke from cigars, cigarettes, and pipes is harmful to your body in many ways. Tobacco smoke contains at least 7,000 different chemicals. Over 250 of these are harmful or toxic. About 70 of them can cause cancer.3

Tobacco smoke causes damage to your airways and cells deep in the lungs. For example, it harms hairlike structures in the airway that sweep away dust and mucus. Smoke also causes the lungs to make more mucus. This causes irritating substances to build up in the airways.1

About 20 percent of people with asthma smoke. Tobacco smoke is a potent asthma trigger. It can cause inflammation and structural changes to the airways. This can make airways even more sensitive. Smoking increases the risk of developing asthma and can worsen existing asthma. Among people with asthma, people who smoke:3-6

  • Have more severe symptoms and asthma attacks
  • Have more unscheduled doctor visits and hospital admissions
  • Have worse quality of life
  • Have worse lung function
  • Do not respond as well to inhaled corticosteroids (drugs used to control asthma)

How does secondhand smoke affect asthma?

Secondhand smoke is also called passive smoke. It includes smoke from burning tobacco (called sidestream smoke) and smoke exhaled by a smoker (mainstream smoke). Sidestream smoke contains higher amounts of toxic compounds than mainstream smoke.7

Exposure to secondhand smoke is linked to many poor health outcomes. It decreases lung function and increases airway inflammation. Children are most vulnerable because their lungs are still developing. Exposure to secondhand smoke may cause childhood asthma.1,4,7,8

There is a clear link between secondhand smoke and worse asthma outcomes in children. Studies have shown that:1,4,7,8

  • Infants whose mothers smoked during pregnancy have increased airway sensitivity and worse lung function
  • Older children whose parents smoke get more bronchitis and pneumonia
  • Children exposed to secondhand smoke wheeze and cough more
  • More than half of children in the United States with asthma are exposed to secondhand smoke
  • Children with asthma exposed to secondhand smoke have more frequent asthma attacks
  • Almost half of children who go to the emergency room for asthma live with smokers
  • Secondhand smoke exposure causes over 200,000 asthma attacks among children every year

How do e-cigarettes and vapes affect asthma?

Electronic cigarettes (e-cigarettes) and vapes are the most common nicotine products used by adolescents. Inhaled vapor is produced by heating a liquid that contains nicotine, flavoring, and other chemicals.9

E-cigarettes contain fewer toxic chemicals than cigarette smoke. But the inhaled vapor can still be harmful, especially for people with asthma. Studies have shown that current e-cigarette use is linked to asthma symptoms. More research is needed on the effects of e-cigarette use in asthma.10-12

E-cigarette use is also linked to other tobacco smoke exposures. Almost 3 out of 4 e-cigarette users are past cigarette smokers. E-cigarette users may also use cigarettes or marijuana. This makes it hard to study the effects of e-cigarette use separately.9-11

How can I reduce exposure to smoke?

The best thing to do is to quit smoking. Quitting smoking can reduce the frequency and severity of your symptoms. It can also help keep your children healthy. Quitting smoking can reduce their risk of asthma symptoms. Compared to current smokers, former smokers:2,13

  • Have fewer asthma attacks and a higher quality of life
  • Have better lung function and asthma control
  • Are less sensitive to triggers
  • Need less rescue medicine and inhaled corticosteroids
  • Respond better to medicine
  • Have a lower risk of other chronic conditions, such as heart disease and cancer

Quitting smoking is not always easy. Many programs, methods, and therapies can help you quit. Talk to your doctor about the right methods for you. Cutting back on how much you smoke can help. But it does not help by much.1,13

It is important to avoid any exposure to secondhand smoke. Reducing secondhand smoke exposure for children with asthma can improve their symptoms. Some ways to reduce smoke exposure include:1,8

  • Not allowing smoking in your home or car
  • Not allowing caregivers or anyone to smoke around you or your child
  • Ensuring that no one at your child’s school or daycare smokes
  • Avoiding public places that allow smoking

By providing your email address, you are agreeing to our privacy policy.