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Triggers of WRA

Work related asthma triggers are things that irritate your lungs and make your asthma worse. Allergens and irritants are two different types of triggers. Allergens cause allergic reactions while irritants make your asthma symptoms worse by irritating your airways (breathing tubes).

Some of the common work-related asthma triggers are listed below.

Common Triggers at Home or Work

  • Animals
  • Chemicals including cleaning products, paints, and solvents
  • Dust; second-hand smoke; gases, fumes, odours or smoke, and perfume
  • Very cold; hot, humid, polluted, or smoggy outdoor or indoor air
  • Exercise and strong emotions including stress

Common Allergens at Work or Home

Allergens cause allergic reactions. The allergens below could also occur at home:
Animals (occupation example: laboratory settings)

  • Dust mites (occupation example: domestic cleaners)
  • Fungal spores (occupation example: working in classroom settings)

Common Triggers that are Not Allergens

  • Irritants – triggers that do not cause an allergic reaction but make your asthma worse by irritating your airways. examples include dusts, smoke, fumes and sprays (e.g. industrial sources, second-hand smoke, and cleaning products in buildings)
  • Weather (e.g. temperature or humidity extremes, smog)
  • Exercise and emotion
  • Viral or other respiratory infections related to work that can make your asthma worse (e.g. health-care workers or teachers)

Specific Work Allergens

Specific work allergens and sensitizers are usually considered causes of occupational asthma. In some cases, people who already have asthma may become allergic or sensitized to things at work that they would not usually come across outside the workplace. For example, a baker who has had asthma since childhood becomes allergic to the flour at work. Some specialists and compensation boards would consider this as occupational asthma, while others would consider this as work-exacerbated asthma.

Mixed Exposures

Mixed exposures of common allergens and irritants. For example, cleaners exposed to dust mites, animals, fungal spores and also cleaning products.


Work Exacerbated Asthma Triggers and Jobs

Industries with a higher risk of work-exacerbated asthma

  • Services industry (cleaners, restaurants industry, fire fighters)
  • Wholesale and retail trade (manufacturing of plastics, furnishings, electronics)
  • Public administration (like a government office job)
  • Transportation and public utilities (like a bus driver or a city electrical worker)

Common Triggers

  • Mineral and inorganic dusts
  • Sprays
  • Fumes and gases (e.g. construction dust, paint fumes, cleaning triggers, irritant chemicals such as acids)

Specific WEA Triggers and Jobs

TriggersRelevant Jobs and Workplaces
Renovation dust in offices
Mining, animal care workers changing cages (also can cause occupational asthma)
Bakeries - flour dust (also can cause occupational asthma)
Farms - grain dust (also can cause occupational asthma)
Fumes and Vapours
Medical radiation technologists (non-digital)
Cleaning products in various settings, such as carpet cleaning
Cleaning, general office cleaning
Laboratory workers
Health-care workers (cleaning products, construction/renovation dust, moulds, paint fumes, chemicals, second hand smoke, carpet glue fumes, ammonia products, other chemicals)
Swimming teachers (pools)
Paint fumes in industry or in renovation of offices
Diesel exhaust fumes in shipping areas of industries, and in workers on highways, toll booths, and tunnels
Ozone - some swimming pools, bottling plants, photocopy machines, some paper mills
Ammonia - farming environments such as barns
Sulphur dioxide or hydrogen sulphide - paper mills
Chlorine or chlorones - paper mills, cleaning
Cold Environment
Outdoors in winter (snow removal, police controlling traffic, skaters, skating teachers)
Refrigeration settings (restaurant storage, etc.)
Firefighters and other emergency workers
Industrial settings (accidental fires)
Second-hand cigarette smoke (should not be an exposure at work now)
Farm workers, animal feed workers, laboratory, animal workers
Workers exposed to metal working fluids
Humidity and HeatIndustrial settings
Strenuous Exercise
Emergency response workers
Professional athletes or physical education teachers

Occupational Asthma (OA) Triggers and Jobs

TriggersRelevant Jobs and Workplaces
Flour, amylase and other enzymesBakers
Animal proteins
Laboratory workers
Animal researchers
Plant proteins
Greenhouse workers
Grain handlers
Western red cedar workers
Social workers
Laboratory workers (working with insects)
Hydro-electric workers (caddis flies)
Grain handlers, bakers
Enzymes such as protease, amylase and lipase
Detergent formulators
Laboratory workers
Pharmaceutical workers
Surgical instrument cleaners
Moulds and fungi
Contaminated offices and other work buildings
Cheese making
Crab, prawn, shellfish and other fish proteins
Seafood (crab, snow crab, prawn) workers
Fish processing plants
Psyllium, natural rubber latex, detergent enzymes
Hospital and geriatric department nurses
Other health-care workers
Pharmacists, pharmaceutical manufacturing (psyllium)
Polyurethane, adhesives, paint workers
Spray painters
Foundry workers
Soldering flux (colophony)Electronic workers
PlatinumJewellery, alloy and catalyst makers
Chromium, cobaltAlloy, catalyst, refinery workers
Phthalic anhydride, trimellitc anhydride (used in epoxy resins)
Plastics industry
Dye makers
Insecticide makers
Organic chemical manufacture
Foam workers
Latex makers
Gum Arabic
Printing industry
Nickel sulfate, chromiumMetal plating
Reactive dyesPrinting, fabrics
Glutaraldehyde, methacrylates, antibiotics and other medications
Hospital instrument cleaners
Pharmaceutical workers
Red cedar (plicatic acid) and other wood dustsWoodworkers, furniture makers
Persulfates, indirect exposure to methyl and ethyl acrylates (artificial nails)