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Irritants: Cigarette Smoke, Pollutants, Perfumes, Cleaning Products and More


“Irritant” is a broad category that includes things such as cigarette smoke, pollutants, strong perfumes, cleaning products, paint fumes, dust, and exhaust fumes. Irritants are different from allergens because they do not set off the immune system. Irritants damage the lining of the airways, which triggers asthma symptoms.1

People living in North America spend nearly 90% of their time indoors.2 The indoor air in homes and workplaces may contain a number of irritants. Studies have shown that repeated exposure to low level irritants can cause or aggravate asthma.1 One-time exposure to high levels of an irritant can also cause breathing problems.1

Irritants in the home

Irritants in the home come from unvented gas stoves, wood-burning stoves or fireplaces, space heaters, cleaning agents, perfumes, dry-cleaned clothing, and tobacco products.3,4 Newly constructed or renovated homes contain irritants from flooring and carpets, particle board, wall coverings, and painting.3 Inside moisture may also cause carpeting and vinyl floors to release irritating chemicals.4 Common irritants in the home are listed in Table 1.2,3

Table 1. Common irritants in the home and their sources

Nitrogen dioxide (NO2)
Unvented stoves, space heaters, poorly vented furnaces and fireplaces
Plywood, particle board, fiberboard, paints, varnishes, floor finishes, new furniture, cigarette smoke
Volatile organic compounds (VOCs)
Dry-cleaned clothing, room deodorizers, cleaning sprays, wet paint, new carpet, cigarette smoke

Dales R, et al. CMAJ. 2008;179:147-152; National Heart, Lung, and Blood Institute. Expert panel report 3 (EPR-3): Guidelines for the diagnosis and management of asthma – Full Report 2007. Accessed 11/12/14 at:

Nitrogen dioxide irritates the eyes, nose, throat, and airways.5 Brief exposure to high levels of nitrogen dioxide has been linked with airway reactions and asthma attacks.4 Low-level exposure has been linked to increased airway sensitivity in people with asthma and an increased risk of colds in young children.5

Formaldehyde and asthma have been linked in several studies, but the exact effects are unknown.4,6 Formaldehyde may cause burning or tingling in the eyes, nose, and throat, chest tightness, wheezing, and nose bleeds.5 One study showed that breathing in formaldehyde did not affect lung function directly, but it did make people react more strongly to dust mite allergens.4 Other studies have shown that formaldehyde increase the risk of developing asthma.6

Volatile organic compounds (VOCs) irritate the eyes and upper respiratory tract, causing runny and stuffy nose, rash, itching, headache, nausea, vomiting, and shortness of breath.5 VOCs in the home increase the risk of developing asthma 1.6-fold.7 However, in people who already have asthma, it is not known whether VOCs cause asthma attacks.4

How many homes have irritants? How common are sensitivities?

More than half of the homes in the United States have a gas stove, which produces nitrogen dioxide and other irritants.8 Children living in multi-family housing who are exposed to gas stoves are 2.3 times more likely to wheeze than children without a gas stove.8 They are 4.3 times more likely to have chest tightness.

About 10% to 20% of the general US population is hypersensitive to formaldehyde.5 All homes have some amount of formaldehyde.9 The levels of indoor formaldehyde have gone down since the US banned the use of formaldehyde insulation in the early 1980s. Traditionally constructed stand-alone homes have lower levels than manufactured homes.

VOC levels are 2 to 5 times higher inside than outside.10

What can I do to reduce my exposure to irritants at home?

  • Use ventilation when cooking with a gas stove.11
  • Open the flue when using the fireplace.10
  • Do not use room deodorizers, perfumes, and strong smelling chemical sprays.2
  • Choose solid hardwood flooring and furniture.2
  • Increase ventilation in the home.2
  • Wait a few days to bring recently dry-cleaned clothing into the house.2
  • Do not allow smoking in the home.
  • Follow the instructions for using cleaners, paints, paint strippers, and similar products safely.10
  • Buy only what you need when it comes to paint, kerosene, etc.10 Discard any left over products safely.
  • Do not idle the car in the garage.10
  • Use air conditioners and dehumidifiers to reduce indoor humidity.

Workplace Irritants

Irritant-induced asthma is a type of work-related asthma. Common workplace irritants are listed in the Table 2.12 People who are regularly exposed to these irritants on the job have a higher risk of asthma, such as cleaners, nurses, textile workers, hog farmers, poultry workers, and people who work in aluminum smelters.1 Another term for irritant-induced asthma is “reactive airways dysfunction syndrome,” which is a severe form.1

Table 2. Common Workplace Irritants

Metam Sodium
Calcium Oxide
Spray paint
Sulphur dioxide
Cleaning agents
Swine confinement facilities
Construction dusts
Tobacco smoke
Diesel exhaust
Uranium hexaflouride
Dinitrogen tetraoxide
Welding fumes
Farming barn dusts
World Trade Center exposure

Tarlo SM. Curr Allergy Asthma Rep. 2014;14:406.

In some cases, there is a clear relationship between exposure to high levels of an irritant and asthma symptoms. Examples are accidental chlorine spills or fire smoke inhalation.13 Another example is the dust left by the collapse of the World Trade Center. About 16% of workers exposed developed irritant-induced asthma.1

However, low-level exposure to irritants is common in many jobs.14 It can be difficult to identify which irritants are causing respiratory symptoms. Safety Data Sheets have information about the risks and safe handling of chemical products. The Safety Data Sheets will state whether a chemical is known to irritate the airways. These documents may be helpful in identifying potential workplace irritants.

How common is workplace exposure to irritants?

Work-related asthma has been well studied, but most of the research has been done on allergens (“sensitizing agents”) in the workplace. It is estimated that work-related asthma accounts for 9% to 25% of adult asthma cases.13,15

Much less is known about the frequency of irritant-induced asthma. One recent study from Estonia showed that 17.4% of workers were exposed to low or moderate levels of irritants.16 In this study, professional cleaners were twice as likely to have asthma as people working administrative or service jobs.14

What can I do to reduce my exposure to irritants at work?

Steps to reduce your exposure to workplace irritants could include:13

  • Switching tasks or jobs
  • Improving workplace ventilation
  • Use of a fitted respirator
  • Closing off the source of the irritant

Procedures should be in place to minimize exposure in the case of accidents. These measures may include:1,12

  • Worker education on best safety practices
  • Good procedures for containment and ventilation
  • Plans for evacuating workers
Written by: Sarah O'Brien | Last Reviewed: May 2016.
  1. Tarlo SM, Lemiere C. Occupational asthma. N Engl J Med. 2014;370:640-649.
  2. Dales R, Liu L, Wheeler AJ, Gilbert NL. Quality of indoor residential air and health. CMAJ. 2008;179:147-152.
  3. National Heart, Lung, and Blood Institute. Expert panel report 3 (EPR-3): Guidelines for the diagnosis and management of asthma - Full Report 2007. Accessed 11/12/14 at:
  4. Kanchongkittiphon W, Mendell MJ, Gaffin JM, Wang G, Phipatanakul W. Indoor environmental exposures and exacerbation of asthma: An update to the 2000 review by the Institute of Medicine. Environ Health Perspect. 2014 Oct 10.
  5. Environmental Protection Agency. Indoor air pollution. Accessed 1/19/15 at:
  6. McGwin G, Lienert J, Kennedy JI. Formaldehyde exposure and asthma in children: a systematic review. Environ Health Perspect. 2010;118:313-317.
  7. Arif AA, Shah SM. Association between personal exposure to volatile organic compounds and asthma among US adult population. Int Arch Occup Environ Health. 2007;80:711-719.
  8. Belanger K, Gent JF, Triche EW, et al. Association of indoor nitrogen dioxide exposure with respiratory symptoms in children with asthma. Am J Respir Crit Care Med. 2006;173:297-303.
  9. Centers for Disease Control and Prevention. Formaldehyde exposure in homes: A reference for state officials to use in decision-making. March 2008. Accessed 1/19/15 at:
  10. Environmental Protection Agency. An Introduction to Indoor Air Quality (IAQ). Accessed 1/19/15 at:
  11. Kile ML, Coker ES, Smit E, et al. A cross-sectional study of the association between ventilation of gas stoves and chronic respiratory illness in U.S. children enrolled in NHANESIII. Environ Health. 2014;13:71.
  12. Tarlo SM. Irritant-induced asthma in the workplace. Curr Allergy Asthma Rep. 2014;14:406.
  13. Tarlo SM, Balmes J, Balkissoon R, et al. Diagnosis and management of work-related asthma: American College Of Chest Physicians Consensus Statement. Chest. 2008;134(3 Suppl):1S-41S.
  14. Casas L, Nemery B. Irritants and asthma. Eur Respir J. 2014;44:562-564.
  15. Centers for Disease Control and Prevention (CDC). Work-related asthma—38 states and District of Columbia, 2006-2009. MMWR Morb Mortal Wkly Rep. 2012;61:375-378.
  16. Dumas O, Laurent E, Bousquet J, et al. Occupational irritants and asthma: an Estonian cross-sectional study of 34,000 adults. Eur Respir J. 2014;44:647-656.