Allergen Update
Halifax, Nova Scotia
Predominant pollen:
The tree pollen seasons can fluctuate from year to year by as much as two to three weeks at this site due to the effect of weather. The pollen seasons described here try to cover the time when each can occur.
Acer sp.- Maple has a short season in April lasting about one week. The main season can start late April and last until mid-May.
Alnus sp.- Alder season is highly affected by weather. Pollination occurs from late March to mid-June. The highest pollen counts are observed from April to early June.
Betula sp.- Birch can reach very high counts and the season can begin from early to late May and can end from late May to mid-June. This group is very affected by weather conditions. The birch look-a-likes' season lasts approximately three weeks and can occur from May to late June.
Pinaceae group- The season for the pine, spruces and firs can start from the second week of May to early June and end from early June to mid-July. The pollen season fluctuates from year to year due to the influence of the weather.
Cupressaceae group- The cedars, junipers, and yews produce low to moderate counts, with the occasional high count, throughout the pollen season. The season can vary a great deal and can start late March and end late June. The highest counts occur from early April to early May.
Fraxinus sp.- The ash pollen season lasts approximately one month and can occur from late April to mid-June. Some high counts are observed. The start and end of the season can vary by two weeks depending on weather.
Populus sp.- The poplar and aspen season can occur from April to mid-May, and the start and end of pollination can vary by as much as two to three weeks from year to year. The amount of pollen in the air may not be high enough to cause allergic reactions except in individuals who are highly sensitized.
Ulmus sp.- The elm season is very sporadic and occurs in late April to early May. The counts vary depending on where the sampler is located. Elms are considered highly allergenic. The elm season can strongly be affected by weather conditions.
Quercus sp.- Oak is an important allergen and there are two seasons: a very short one, occuring late April to early May, and the main season, which has some high counts, lasts one to two weeks and occurs between late May to mid-June.
Gramineae- The season with the highest counts occurs from mid-June to mid-July . Low counts are observed starting mid-May to late September.
Ambrosia sp.- Ragweed counts are always low but may be high enough to cause allergic reaction to individuals who are highly sensitized. The season is early August to the end of September.
Plantago sp.- The plantains produce low counts from late June to late September. May cause allergic reactions in individuals who are highly sensitized.
Predominant Spores:
Diatrypaceae sp.- Counts fluctuate throughout the whole counting season. The counts are particularly high in the spring and fall. Season continues well into October.
Erysephe sp. (Oospora sp.)- The powdery mildews occur from July and well into October.
Boletus sp.- Very high counts are observed. Season is from August to late October.
Coprinus sp.- The counts are significant but not as high as Ganoderma or Cladosporium. The season is from August and well into October. Considered an important allergen.
Ganoderma sp.- Very high counts are observed. The main season is mid-June to well into October. Considered an important allergen.
Uredinales sp.- Rusts are not found in very high numbers and the season is August to mid-October.
Ustilaginales- The smuts occur mostly from June to mid-October.
Alternaria sp.- Moderate counts are observed in August and September. May play a significant role in allergies in highly sensitized individuals.
Botrytis sp.- Moderate and high counts are observed from late May to mid-October. Could play a significant role in causing allergic reactions.
Aspergillus sp. & Penicillium sp.- They occur throughout the counting season but the highest counts are from July to well into late fall.
Cladosporium sp.- This is the most prominant spore for the whole season. The highest counts occur from late March to late fall. Could cause allergic reactions in sensitized individuals.
Fusarium sp.- Very sporadic counts are observed throughout the whole counting season. The season is from the end of March to mid-October.
Epicoccum sp.- Does not reach really high numbers but may cause reactions in highly sensitized individuals. The main season is from approximately mid-June to late September.
Helicomyces sp.- Sporadic throughout the whole season but the highest counts are observed from the end of May to the end of September.
Last Updated: 07-March-2006
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