People with asthma may wonder how smoking conventional cigarettes or using electronic cigarettes can affect the condition.

Cigarette smoke can trigger asthma symptoms. Despite this, in the United States, 21 percent of people who have asthma currently smoke, compared with 16.8 percent of people who do not have asthma.

This article discusses how smoke, secondhand smoke, and electronic cigarette (e-cigarette) vapor affect people with asthma. It also explores how people can reduce their exposure to asthma triggers.

How are asthma and smoking linked?

Smoking cigarette being held in person's hand linked to asthma
Smoking can aggravate the symptoms of asthma.

Smoking is harmful for everyone, but it is particularly harmful for people with asthma. Both smoke and secondhand smoke may trigger asthma symptoms.

Tobacco smoke is an irritant. It contains over 7,000 chemicals, at least 69 of which can cause cancer.

Smoke can aggravate asthma because:

  • Smoke particles cause the airways to swell and become narrow.
  • When smoke reaches the lungs, it triggers mucus production.
  • Smoke can damage the cilia, which are tiny hairs in the throat that normally sweep away mucus.

When a person with asthma inhales smoke or secondhand smoke, they may notice some respiratory or asthma symptoms. The result is often swollen, narrow airways filled with mucus.

This may trigger an asthma attack and cause the following symptoms:

  • coughing
  • wheezing
  • shortness of breath
  • chest tightness

Secondhand smoke refers to that exhaled by someone who smokes mixed with smoke from the end of a lit cigarette or cigar. The smoke from the end of a lit cigarette or cigar may contain more harmful substances than firsthand smoke.

Both firsthand and secondhand smoke are harmful to a person’s health.

E-cigarettes and asthma

Some people may turn to e-cigarettes as a way to stop smoking. However, the debate about whether e-cigarettes are any less harmful is ongoing.

Research into the link between e-cigarette vapor and asthma is also ongoing. Initial studies suggest that vapor may be less toxic than tobacco smoke. However, it is unlikely to be healthful for people with asthma.

A 2016 report by the U.S. Department of Health and Human Services looked into the effects of vaping on health. The report notes that e-cigarette vapor is not harmless “water vapor,” as many people believe.

The propylene glycol and vegetable glycerin present in e-liquid may be safe when people eat them in foods, but they produce substances that may be toxic when turned into vapor.

E-cigarette vapor contains a number of chemicals and volatile organic compounds. It follows that inhaling e-cigarette vapor may irritate a person’s airways.

A 2017 review paper concluded that chemicals in e-cigarette vapor, such as propylene glycol and vegetable glycerin, could induce respiratory effects not usually observed in people who smoke cigarettes.

Another study suggests that high school students who used e-cigarettes had a higher risk of asthma, and they were more likely to have taken days off school due to severe asthma symptoms.

Tips to reduce smoke exposure

Man smoking cigarette while driving car
A person should avoid smoking in a car if someone with asthma will use that car.

Quitting smoking is the most beneficial way to reduce smoke exposure. A doctor can offer support and advice on how to quit smoking.

While quitting, using nicotine replacement aids such as gum or patches may help. Since it is not possible to inhale these, they are less likely to trigger asthma symptoms than using e-cigarettes.

To avoid secondhand smoke exposure, make sure anyone who smokes does not do so:

  • in the house
  • in the car
  • around children or other adults

In addition, people should:

  • avoid venues that allow smoking
  • choose schools with a smoke-free campus policy

It is important to teach children why and how to avoid secondhand smoke. These lessons are more likely to have an effect when caregivers themselves do not smoke.

Other health risks of secondhand smoke

Secondhand smoke is not just harmful for people with asthma. There are many other risks associated with secondhand smoke.

The Centers for Disease Control and Prevention (CDC) estimate that since 1964, 2.5 million adults who did not smoke have died because they breathed secondhand smoke.

All levels of secondhand smoke exposure have health risks for both adults and children, as discussed below.

Secondhand smoke and health problems in adults

Exposure to secondhand smoke negatively impacts adult health in a number of ways. It increases the risk of:

Secondhand smoke exposure may also be linked to other cancers, including:

Secondhand smoke and health problems in children

Second-hand smoke may cause ear infections.
Secondhand smoke may cause ear infections in children.

As well as triggering asthma attacks, secondhand smoke can cause children to get sick more often.

Secondhand smoke may increase the risk of the following health problems in children:

Secondhand smoke exposure is also linked to sudden infant death syndrome. This occurs when an otherwise healthy infant suddenly dies without a clear cause or explanation.

More research is needed, but secondhand smoke may also be linked to childhood:

Smoking during pregnancy harms a baby. Babies of mothers who smoke during pregnancy are more likely to:

  • have respiratory problems
  • develop asthma
  • have a low weight at birth
  • be born prematurely
  • be born with birth defects

The CDC report that since 1964, 100,000 babies have died from complications as a result of exposure to chemicals present in tobacco smoke.


Smoke and secondhand smoke contain a number of irritants that can aggravate a person’s airways. Both are common asthma triggers. They may cause an asthma attack, leading to breathing difficulties.

Research into the link between e-cigarette vapor and asthma is ongoing. However, as vapor contains chemicals, it follows that it is likely to irritate a person’s throat and may trigger asthma.

When quitting smoking, noninhalable nicotine replacements such as gum or patches may be more suitable for people with asthma. This is because they are less likely to irritate the throat.

Secondhand smoke causes many other health problems for children and adults exposed to it. Reducing secondhand smoke exposure using the strategies explored above is the best way to avoid its negative health effects.