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Climate Change and Allergies


It is well known that periodic climate changes (called phenology) especially precipitation and temperature are important predictors of tree and grass pollen production.   While there is much “science” and plenty of controversy over the issue of “global warming,” with climate changes come potential impacts relevant to allergy sufferers.

Correlation between air temperature and allergenic pollen

With warmer spring temperatures comes:

  • Increased amounts (concentration) of pollen
  • Longer pollination seasons have been recorded for trees, grasses and weeds
  • Earlier flowering of birch trees

Effect of climate change on allergic diseases

  • Increased allergen exposure and long distance transport of wind-borne pollen could generate increased symptoms to various plant species not commonly or currently present in sufficient quantities to produce symptoms.
  • Potential for increased algae blooms from the oceans to act as adjuvants (immune system stimulants) to increase the allergic potential of common airborne allergens

Allergic rhinitis:

  • Has increased in the U.S. from 10% in 1970 to 30% of the population in 2000.  Whether this increase has anything to do with climate change is not proven.
  • Increased humidity:  associated with an 8 to 15 fold increase in eosinophil influx into nasal tissues.  Eosinophils are the white blood cell that is responsible for nasal inflammation in allergic rhinitis.   This effect may be more relevant for those people living on the shorelines where higher humidity is found.


  • While there are many triggers for asthma, climate changes that increase the amount of pollen or duration of a pollen season may impact those patients with pollen as a trigger.
  • Air pollutants including ozone, nitrogen dioxides, particulate matter (PM) and diesel particles can not only aggravate existing asthma, but potentially induce asthma, especially in children.

Insect Allergy:  With increases in annual and winter temperatures, the geographic distribution of stinging insects (yellow jackets) has expanded northward.  For example, in Alaska, 3 independent patient databases compared temperature changes with insect sting reactions in each region.  There was a significant increase in patients seeking care for insect reactions in each database.

The most recent report on Global Climate Change was just released and can be found at:  This is from the United Nations panel and the first part of its much-anticipated 6-year update on the state of climate change. This is the report by the Intergovernmental Panel on Climate Change (IPCC).  Happy reading!

While the debate rages on regarding global warming, rest assured, that at Family Allergy & Asthma Care of Montana, we are here to provide individualized, state-of-the-art care regardless of the weather!

This information is solely for informational purposes and not intended as a substitute for consultation with a medical professional. 

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