Common Spring Tree Pollen Allergies in Vancouver

Unfortunately, Vancouver has one of the longest allergy seasons in Canada due to the combination of the city’s mild weather and rising spring temperatures due to global warming. The city also has a high concentration of trees, much higher than many other cities in Canada. Also, because most of the trees in Vancouver have been planted, the trees are mostly male trees in order to avoid cleanup of seeds and fruit; yet it is also only the male trees that produce pollen. Female trees, on the other hand, which are scarce in Vancouver, don’t produce pollen, and instead trap and remove pollen from the air and turn it into seed.

Alder trees, which are one of the most common causes of tree pollen allergies in Vancouver, thrive in warmer temperatures, thus alder tree pollen allergies will only increase and worsen with our unnaturally warm global warming spring weather. The highest pollen allergy counts usually start in mid to late February and last until mid-June. People who are allergic to alder pollen may also have cross-allergies to peaches, hazelnuts, cherries, almonds, parsley, apples and pears.

Birch trees are another common cause of pollen allergies in Vancouver. Birch pollen is also more likely than many other types of tree pollen to bring on asthmatic symptoms. The highest pollen count for birch trees usually starts in mid-March to early April and end in early to late May.  People who are allergic to birch pollen may also have cross-allergies to apples, pears, cherries, apricots, plums, peaches, kiwis, potatoes, carrots, celery, hazelnuts, almonds, walnuts, peanuts and soy.

Climate change will certainly cause tree pollen allergies to worsen in the future. According to scientific research, increasing levels of carbon dioxide (the main cause of global warming) increases the growth rate of plants as well as the amount and potency of plant/tree pollen. Due to rising temperatures, a longer spring means an extended growing season, and thus pollen will be circulating in the air for an extended amount of time. Also, living in polluted urban areas such as Vancouver makes hay fever symptoms worse because smog traps pollen, preventing it from circulating into the upper atmosphere. It has been very well documented that pollen allergies are a lot more common in polluted urban areas. Urban pollution has also been shown to increase  the toxicity of pollens by weakening the surface structure of the grains and by allowing the release of allergen proteins.

Recently, sublingual immunotherapy (SLIT) for all types of allergies including pollen allergies has become a trend. The allergist gives the patient a small dose of the allergen under the tongue to boost tolerance to the substance.  According to a 2009 World Allergy Organization (WAO) paper, SLIT is widely accepted and used in European, South American, and Asian countries as well as in Australia and is gaining interest from allergists in the United States and Canada.