You can be exposed to secondhand smoke, also known as secondhand smoke, in two ways. These are:
- regular smoke, which is the smoke a person exhales while smoking
- sidestream smoke, the smoke produced by burning objects, such as the end of a cigarette
Both types of secondhand smoke can cause negative health effects because they contain harmful chemicals, such as:
- toxic metals, such as cadmium
- dangerous gases, such as 1,3-butadiene
- other carcinogens (carcinogens), such as benzo(a)pyrene and formaldehyde
According to experts, cigarette smoke can harm almost every organ in the body and is the leading preventable cause of illness and death in the United States.
You can be at risk for the negative effects of cigarette smoke even if you don’t smoke yourself.
According to the National Cancer Institute, secondhand smoke can have immediate and long-term effects on cardiovascular health. It can increase the risk of heart disease by about 25-30% and may also increase the risk of:
Passive smoking can also increase the risk of stroke by 20-30%.
Adults exposed to secondhand smoke have a 20-30% higher risk of developing lung cancer, according to the Centers for Disease Control and Prevention (CDC).
The CDC notes that even brief exposure can cause damage to the body’s cells and lead to cancerous changes.
Pregnancy and reproductive complications
Secondhand smoke can negatively affect pregnant people and fetuses. Negative effects can be:
- premature birth
- placental abruptions
- previous placenta
- fertility problems
- in fetuses and neonates:
- lower birth weight
- growth disturbances
- cleft lip and palate development
- higher risk of death
The CDC estimates that exposure to secondhand smoke causes about 41,000 deaths among adults in the United States each year.
Many of these deaths are due to heart disease or lung cancer.
However, there are ways to avoid secondhand smoke and manage your risk.
Other secondhand smoke effects
Other possible secondary smoke effects include:
- chronic obstructive pulmonary disease (COPD)
- other types of cancer, such as mouth, colon and breast cancer
- decreased immune function and increased infections
- slow healing
Secondhand smoke in children and babies
Young people in particular are at risk of experiencing the risks of secondhand smoke. They may also be at risk of additional effects, such as:
Try not to panic if you are exposed to smoke
If you or someone you care for has been exposed to limited amounts of smoke, it does not always mean you will have serious complications.
While short-term exposure can still have effects, complications are more likely with long-term exposure to high doses.
If you are concerned about smoking and your health, your doctor will be able to monitor your condition and recommend any necessary treatment.
How to avoid secondhand smoke
Certain precautions can help you avoid secondhand smoke while living with people who smoke and when in public places.
Ways to avoid exposure to secondhand smoke include:
- only visit places where smoking is prohibited, if your state still allows smoking in public places
- the use of smoke-free restaurants, rental cars and hotels
- distance yourself from others who smoke
- not allowing people to smoke indoors, such as in your home or car, even with the windows open
- advocate for a smoke-free workplace
- ensure that places where people you care for spend time are smoke-free, such as nurseries and care homes
- teaching children to avoid smoke
- quit smoking, if you smoke, to protect others
- while quitting, reducing tobacco or nicotine use with non-smoking methods, such as nicotine patches, and aiming to reduce their use altogether
Contact your doctor immediately if you develop symptoms of illness after passive smoking.
Read more tips to quit smoking.
Some popular methods do not stop secondhand smoke exposure
The following methods do not completely stop exposure to secondhand smoke:
- open windows and use ventilation or air purifiers
- restrict smoking to specific rooms, even with the door closed
- restrict smoking to certain times of the day
Smoke can linger in rooms for hours.
No amount of secondhand smoke is without risk — even small amounts of secondhand smoke can be harmful. This also applies to secondhand smoke that you cannot see or smell.
Thirdhand smoke is the contamination and residue left behind after secondhand smoke has dissipated.
Early research and animal research suggest that thirdhand smoke may cause health effects such as:
- respiratory infections and other lung conditions, such as fibrosis
- slow wound healing
- metabolic syndrome
- reduced immunity
- behavioral disorders
However, this relationship is not fully understood. Researchers don’t yet know what levels of exposure may have effects.
Thorough cleaning by washing walls and ceilings with detergent, vacuuming with a HEPA filter, and washing fabrics can help remove third-hand residue.
Exposure to cannabis smoke
Other substances, including cannabis, can also cause health effects from secondhand smoke.
Although less research has been done on the long-term effects of secondhand exposure to cannabis smoke, it contains many of the same harmful chemicals as tobacco smoke. This includes toxic and carcinogenic chemicals such as cadmium, lead and acetaldehyde.
The American Lung Association also suggests that exposure to secondary cannabis smoke produced longer-lasting effects on blood vessel function in some cases than tobacco smoke.
Read more about how cannabis can affect your health.
While electronic cigarettes such as vapes and pods do not produce smoke, they can expose people to other harmful aerosols. This can lead to:
- oral lesions and tooth fractures due to electronic cigarette explosions
- serious lung and respiratory diseases
- heart and vascular disease
- DNA damage
Learn more about how vaping affects your health.
Frequently Asked Questions
Adithya Cattamanchi, MD, has reviewed the following FAQs.
Can you fail a drug test by secondhand smoke?
A 2014 study notes that, while very rare, extreme second-hand cannabis exposure can cause a positive urine drug test. Extreme exposure included being in a very small, enclosed space with a lot of smoke.
However, in less extreme circumstances, exposure to secondhand cannabis did not have enough of an effect to influence a drug test.
Can Smoking Cause Chest Pain?
Smoking can cause chest pain. Exposure to secondhand smoke can also cause inflammation and respiratory effects that lead to chest pain.
Secondhand smoke can cause harmful health effects in any amount. These secondhand smoking effects include an increased risk of cancer, cardiovascular disease, and reproductive complications.
Fetuses, infants and children can also be particularly susceptible to secondhand smoke. They are at risk of additional complications, such as respiratory and developmental disorders. Passive smoking also poses a risk of premature death.
Exposure to secondhand smoke can be prevented with measures such as banning smoking in your home and avoiding smoking in public.
Talk to your doctor if you have any concerns about smoking and your health.