Asthma Irritants: Smoke, Pollutants, Perfumes, and More

Reviewed by: HU Medical Review Board | Last reviewed: June 2023

Substances in the air can irritate the airways for people with asthma. These irritants can trigger asthma symptoms. This is sometimes called irritant-induced asthma. Irritants do not cause an allergic reaction.1

Examples of irritants include smoke, air pollutants, and odors. Indoor air in homes and workplaces often contains irritants, too. Talk to your doctor to identify what irritants trigger your symptoms. Reducing your exposure may lower your risk of an asthma attack.1

Why do irritants trigger asthma symptoms?

Irritants cause asthma symptoms differently than allergens. Allergens cause the body to release a chemical, immunoglobulin E (IgE). This leads to an immune response that causes airway inflammation and narrowing.2

Irritants do not trigger an IgE response. We do not know how irritants cause asthma symptoms. They may affect nonimmune cells in the airway. This leads to inflammation and airway changes such as bronchospasm. For people with asthma with sensitive airways, this causes symptoms.3,4

Your risk of experiencing asthma symptoms because of an irritant depends on:4,5

  • How much of the irritant you are exposed to
  • How long you are exposed to the irritant
  • The type of irritant
  • Whether you smoke cigarettes or have in the past
  • Genetic risk factors
  • Other factors that are personal to you

What are common asthma irritants?

Cigarette smoke

Cigarette smoke is a strong asthma irritant. It can trigger symptoms whether you are the person smoking or someone else is smoking around you (secondhand smoke). Cigarette smoke contains thousands of chemicals. Many of these chemicals cause airway inflammation. Cigarette smoke can cause permanent changes to the structure of the airway. This can make the airway more sensitive.6,7

People with asthma should avoid smoking and being around smoke. Cigarette smoke affects health outcomes for people with asthma. For example, children exposed to secondhand smoke have a higher risk of worse symptoms. People who have asthma and smoke:8,9

  • Are more likely to have asthma attacks
  • Do not respond as well to inhaled corticosteroids
  • Are more likely to have to go into the hospital
  • Have a higher risk of developing chronic obstructive pulmonary disease (COPD)

Other indoor and outdoor pollutants

Gases and particles in indoor and outdoor air can be asthma irritants. These pollutants can irritate airways and cause asthma attacks. Cigarette smoke is the most irritating pollutant. But other air pollutants are also common. These include:1,8

  • Volatile organic compounds (VOCs) from cleaning sprays, paint, and certain furniture
  • Nitrogen dioxide and particulate matter from unvented stoves, space heaters, furnaces, and car engines
  • Formaldehyde from plywood, paints, and new furniture
  • Ozone from fossil fuel combustion, gasoline vapor, vehicle exhaust, and solvents
  • Carbon monoxide from fossil fuel combustion
  • Sulfur dioxide from the combustion of coal and oil

Exposure to these pollutants affects lung function in children and adults. This increases the risk of asthma attacks and hospital admissions. It also makes asthma symptoms harder to control.8

Workplace exposures

Irritants in the workplace can trigger asthma. Hundreds of workplace substances can trigger asthma. Common workplace irritants include:10

  • Gases and fumes (chlorine, sulfur dioxide, smoke, exhaust)
  • Cleaning agents (bleach, ammonia, detergents)
  • Proteins found in animal and plant substances
  • Chemicals (paints, varnishes, adhesives, insulation, solvents)
  • Dusts (bacterial dust, grains, textiles)
  • Metals (platinum, chromium, nickel sulfate)

Low exposure to these irritants is common in many jobs. For example, work settings where you may be exposed to irritants include:10

  • Factories and manufacturing plants
  • Restaurants and bakeries
  • Farms
  • Repair shops and service stations
  • Healthcare facilities
  • Retail stores
  • Hair salons

Odors and fragrances

People with asthma may be sensitive to odors and fragrances. Strong scents can trigger a reaction that leads to airway narrowing. Some odors and fragrances that may trigger asthma include:11,12

  • Dry-cleaned clothing
  • Cleaning products
  • Perfumes
  • Scented detergents
  • Deodorants
  • Holiday-related scents

How can I reduce exposure to asthma irritants?

Taking your asthma medicine can reduce symptoms caused by irritants. Asthma medicines reduce airway inflammation and sensitivity. This can make you react less to irritants.4,9

You can also reduce symptoms by reducing exposure. Talk to your doctor about identifying irritants that cause symptoms. Depending on your triggers, you can reduce exposure at home by:6,8,10

  • Asking family and friends not to smoke near you or in your home
  • Increasing ventilation when cooking
  • Using nonpolluting heating and cooking sources
  • HEPA air filter
  • Using a meter to test indoor air quality
  • Using fragrance-free cleaning products

You can also reduce your exposure at work by:6,8,10

  • Asking your employer to modify your job to reduce exposure
  • Talking to your employer about improving ventilation
  • Wearing a face mask while working

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