Smoking at UNB

Second & third-hand smoke

Second-hand smoke: also called environmental tobacco smoke, is considered highly toxic. It includes smoke from a cigarette (side stream smoke), smoke exhaled by a smoker (mainstream smoke), as well as smoke from pipes, cigars or marijuana.

Two-thirds of the smoke produced by tobacco spreads into the ambient air. Anyone within close range of an active smoker cannot help but breathe in this tobacco smoke, and therefore becomes a passive smoker.

Third-hand smoke: is residual nicotine and other chemicals left on indoor surfaces by tobacco smoke. Third-hand smoke clings to clothes, furniture, drapes, walls, bedding, carpets, dust, vehicles and other surfaces long after smoking has stopped. The residue from third-hand smoke builds up on surfaces over time. Third-hand smoke can't be eliminated by airing out rooms, opening windows, using fans or air conditioners, or confining smoking to only certain areas of a home.

Second-hand smoke exposure

Once inhaled, smoke causes the release of the many different chemicals in one’s body, disrupting the mechanism in the lungs that would normally protect it from injury brought about by tobacco smoke. As a result, second-hand smokers experience nasal congestion, have inflamed airways and tend to cough a lot. Second-hand smoke is also known to damage the walls of the air sacs (alveoli), which eventually impairs the ability of the lungs to supply oxygen to the blood.

There is no safe threshold for second-hand smoke exposure.

Short term second-hand smoke exposure may cause relatively minor problems like:

  • Irritating the eyes, nose and throat
  • Causing headaches, dizziness and nausea
  • Causing physical reactions that have been linked to heart attack and stroke such as increased heart rate, decreased oxygen supply to the heart and constriction of blood vessels - which increases blood pressure and makes the heart work harder.

Long-term exposure can:

  • Aggravate the symptoms and speed up the progression of lung disease
  • Reduce the level of protective or good cholesterol in the blood
  • Increase the risk of respiratory infections such as a cold, flu, bronchitis (acute bronchitis), and pneumonia
  • Cause Chronic Obstructive Pulmonary Disease (COPD)
  • Increase the risk of lung cancer and has been linked to cancer of the blood (leukemia), breast, cervix, thyroid, and lymph glands

More recent studies have also linked second-hand smoke to nasal sinus cancer.


Second-hand smoke is especially harmful to young children who, because they breathe faster than adults, are prone to inhale more smoke relative to their size.

In nursing infants and children of parents who smoke, second-hand smoke produces the following effects:

  • Doubles the risk of SIDS (crib death)
  • Exacerbates inflammatory bowel disease
  • Increases the risk of ear infections, and respiratory tract disorders such as: bronchiolitis, pneumonia, tonsillitis, and asthma
  • Increases the risk ear infections, and respiratory tract disorders such as: bronchiolitis, pneumonia, tonsillitis, and asthma

More information about smoking and pregnancy.


Second-hand smoke also affects the health of household pets. Their fur coat traps the smoke particles which the animals then absorb when they groom themselves. Second-hand smoke may cause leukemia in cats and increases the risk of cancer in dogs.


Tobacco smoke is the main source of indoor pollution and the easiest to eliminate completely by forbidding anyone from smoking in the house. Opening a window, smoking in another room, or using air purifiers or ventilation systems offers no protection against second-hand smoke.

After the cigarette is extinguished, the second-hand smoke remains in the environment. It settles on food, clothing skin, carpets, curtains in the air etc., and re-mains there for days or weeks.

Ways to eliminate second-hand smoke include:

  • No smoking inside
  • Creation of closed smoking rooms with independent ventilation
  • Smoking cessation programs for those who want to quit
  • Public education exposing the hazards of second-hand smoke
  • Make your home and car smoke-free

Did you know?

  • There is no safe level of exposure to second-hand smoke. It is hazardous for everyone, especially for children.
  • Second-hand smoke has been confirmed as a cancer-causing substance.
  • Second-hand smoke contains over 4,000 chemicals. More than 70 of these are known to cause, initiate or promote cancer and are called “carcinogens”.
  • The toxic and cancer-causing chemicals found in second-hand smoke include arsenic, carbon monoxide, ammonia, formaldehyde, cyanide, and benzene, just to name a few.
  • Nicotine, carcinogens and toxic chemicals found in tobacco smoke are inhaled when people breathe second-hand smoke and reach every organ in the body.
  • The majority of the smoke from a lit cigarette is not inhaled by the smoker, but enters the air around the smoker. As a result, the majority of nicotine and tar enters the air from the burning cigarette as second-hand smoke.
  • The concentration of many cancer-causing and toxic chemicals can be higher in second-hand smoke than in the smoke inhaled by smokers.
  • Smoking in an enclosed space such as a car greatly increases the concentration of harmful chemicals produced by second-hand smoke.
  • All forms of smoke are harmful. Numerous toxic chemicals are formed during combustion so that many of the chemicals created when tobacco burns are also created when other plants burn.

Second-hand smoking myths

The truth: Second-hand smoke is airborne and spreads from one room to another even if the door of the smoking area is closed.

In addition, toxic chemicals from second-hand tobacco smoke remain in rugs, curtains, clothes, food, furniture, skin, hair and other materials in the house long after the cigarette is extinguished.

The only way to protect non-smokers from indoor exposure to second-hand smoke, is to completely eliminate indoor smoking.


The truth: You may think that opening a window or turning on a fan clears the smoke from a room or your car, but that is not the case.

Extensive studies have shown that there is no level or type of ventilation that eliminates the harmful effects of second-hand smoke.

Opening a car or room window may cause the smoke to be blown back into the car or room.


The truth: Many parents think that it's all right to smoke in their car or home when their children aren't around. What they may not know is that second-hand smoke lingers long after they finish a cigarette.

Researchers found that second-hand smoke remains in contaminated dust and surfaces, even if smoking took place days, weeks or months earlier.

Since children crawl on carpeting, lie on the floor and sofas or place items in their mouths, they are exposed to more second-hand smoke deposits on surfaces than adults.


The truth: Air fresheners only mask the smell of the smoke but do not reduce the harm of second-hand smoke in any way. The truth is that even air filters (air purifiers) make little difference.

Second-hand smoke is composed of both particles and gases. Most air filters are designed to remove large particles in the air, but they do not remove the smaller particles and gases that are contained in second-hand smoke.

Conventional air cleaners cannot remove all the poisons, toxins, gases and particles found in second-hand smoke. Exposure to second-hand smoke cannot be controlled by air cleaning or air exchange.


The truth: Even if you ban smoking inside your house but continue to smoke outside, it can still affect others. While smoking outside reduces exposure, it does not completely protect others, especially infants and children, because of tobacco smoke residues and toxins that may be brought inside on clothes, skin and hair.

If you are smoking outside, it is important to be several metres away from any doorway, window, or vents so the smoke does not drift inside the house.

You should also stay several metres away from other people when you smoke outdoors, as outdoor exposure can be harmful when smoking in close proximity to other people.


Source: Canadian Lung Association BREATHE, Goverment of Canada