• Second-hand smoke is a trigger for people with asthma.
  • People who smoke and who have asthma have worse asthma control and faster loss of lung function.
  • Women who smoke during pregnancy are harming the development of their baby’s lungs.
  • If you have asthma, avoid smoky places whenever possible.

People with asthma have sensitive airways inside their lungs. Certain ‘triggers’ can make these airways narrow.

If you have asthma, smoking can lead to more asthma symptoms, more frequent and more severe asthma attacks, worse asthma control and less benefit from some asthma medications. It can also restrict your level of activity and reduce your quality of life.

Smoking also damages your airways, leading to inflammation and faster loss of lung function. (Lung function is a measure of the amount of air that you can breathe in and out of your lungs, and how hard and fast you can breathe out.)

Stopping smoking may reduce asthma symptoms and use of asthma medication within a few months.

Smoking causes damage to airways

Your lungs are lined by tiny hairs called cilia. These move in a wave-like motion to sweep dust, pollens and other irritants out of your lungs. Cigarette smoke damages these tiny hairs.

This means your lungs will be less able to clean themselves, which can lead to mucus and toxic substances collecting in the lungs, increasing the risk of lung infection. Smoking can also damage the small airways and air sacs within the lungs, causing lung disease including emphysema.

As lung disease slowly worsens over time, it can limit airflow, causing shortness of breath. Quitting smoking reduces your risk of developing lung disease, and slows down any worsening of lung disease if you already have it.

Asthma and passive smoking

Breathing in other people’s cigarette smoke can be harmful to people with asthma, especially children. Second-hand cigarette smoke can: 

  • trigger an asthma attack 
  • increase the frequency of asthma attacks
  • increase your need for asthma medication
  • make your airways more sensitive to other triggers like pollen
  • reduce your lung function.

Smoking during pregnancy affects your baby’s health

If a woman smokes when she is pregnant, the chemicals in the cigarette smoke are passed to the developing baby through the umbilical cord. The baby’s lungs can be affected, which increases the baby’s risk of having weaker lungs and developing wheezing symptoms early in life.

Smoking during pregnancy also causes many other problems, such as low birth weight and premature labour, and increases the risk of fetal death and stillbirth.

Second-hand smoke can cause asthma in children

Children exposed to second-hand smoke are more likely to develop asthma in childhood. Children with asthma who live in a smoky environment have more severe symptoms, suffer more frequent asthma attacks and are more likely to use asthma medications. 

Children of people who smoke are more likely to develop chest infections and other illnesses. Viral chest infections in infancy increase the risk of developing asthma in childhood, especially among infants who are sensitised to allergens. 

In Victoria, it is illegal to smoke in cars carrying children who are under 18 years of age.

Asthma and smoking – reducing risk

You can reduce the risk of worsening your asthma by avoiding cigarette smoke. Some suggestions include: 

  • Quit smoking.
  • Make your home completely smoke free – ask guests not to smoke in your house.
  • Avoid smoky places, such as outdoor areas of pubs, bars and cafes.

If you wish to use nicotine replacement therapy or quitting medications to stop smoking, talk to your doctor or pharmacist about which products are suitable for you. Use of e-cigarettes to quit smoking is not recommended as they have not been approved by the Therapeutic Goods Administration  (TGA) and they contain many chemicals that are potentially toxic.

Asthma and smoking – when you can’t avoid smoky places

If you can’t always keep away from smoky places, it is important to manage your asthma on a daily basis. If you need to take your reliever medication more than two times a week (excluding ‘before exercise’ medication), visit your doctor. Your asthma management plan might need to be adjusted. 

Remember to take your reliever medication with you when you visit a smoky place.

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Managing asthma

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This page has been produced in consultation with and approved by: Quit

Last updated: April 2019

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