Get Help

Call the Lung Health Line


Our certified respiratory
educators are ready to take your questions
(M-F 8:30am-4:30pm)


Pollen Grain

The pollen grain carries the male reproductive part of a plant to the female seed for the purpose of growing a new plant. Wind-pollinated plants are of most concern since their pollen grains are carried by the wind and easily inhaled into the nose and lungs where they can cause an allergic reaction.

A chart depicting how allergy triggers vary with the seasons. House dust is a trigger year-round. Tree pollen is worst from March to May, peaking in April. Grass pollen peeks in June. Ragweed peaks in August and September. Mould is a concern from spring through fall.

Tree pollen: high levels in spring

Grass pollen: high levels in early summer

Ragweed: high levels late summer until the first frost

How to reduce exposure to pollen

  • Keep your home and car windows closed when pollen levels are high—use an air conditioner if needed
  • Stay indoors when pollen levels are high—pollen levels are highest on sunny, dry, windy days
  • Replace any ventilation air filters regularly
  • If possible, avoid or reduce activities such as cutting grass
  • After being outdoors for a period of time, consider changing clothes and showering to wash off the pollen
  • Check pollen reports at weather.ca


Back to Causes of Asthma