What might trigger acute asthma attacks?

• Exertion.
  
  
• Cold.
  
  
• Smoke.
  
  
• Air pollution including exposure to certain chemicals. An example is isocynates which are used in some painting and plastics industries.
  
  
• Airway infection.
  
  
• Allergies, eg to pollens, house dust mites, domestic animals (especially cats), aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen.