Predominant Pollen and Spores

Calgary (West), Alberta

Tree pollen and spore seasons fluctuate from year to year by as much as two to four weeks at this site due to the effect of weather. The pollen and spore seasons described here are generalizations as to when pollination/sporulation occurs.

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Predominant Pollen for Calgary (West), Alberta

Due to extreme variations in the weather at this site, the tree pollen season fluctuates significantly from year to year. The pollen seasons described here try to cover the time when each can occur.

Alder (Alnus sp.)

Alder season starts from early March to early April and ends from late June to mid-July. The counts vary from low to moderate due to the number of species present.

Amaranthaceae & Chenopodiaceae

This group of weeds are similar microscopically and are not differentiated. They include some weeds, which are considered allergenic. Occasional moderate counts are observed. The season can start mid-June and end early October. At these levels they may be of no significance depending on species present and the sensitization of individuals.

Ash (Fraxinus sp.)

Ash pollination season is short and can start from late April to early May and end late May to mid-June. Some very high counts are observed. The pollen season and levels can vary a great deal which is partially due to weather. Considered to be allergenic only in highly sensitized individuals.

Birch (Betula sp.)

Birch season can start from late April to early May and end early to mid-June. The counts can reach high levels, depending on the year. Some years only low and moderate counts are observed. The seasonal fluctuations are partially attributable to weather.

Cedars, Junipers and Yew (Cupressaceae family)

Cedars, junipers and yews produce some moderate counts from mid-April to mid-May. The season starts early to late March and ends late July. Can cause allergic reactions in individuals who are highly sensitized.

Elm (Ulmus sp.)

Elm are important allergens. The season can start between late March to early May and can end late April to late May. The seasons can vary not only in when they occur but the amount fo pollen produced from year to year. This is probably mostly due to the effect of weather. The counts are low to moderate and can create allergic reactions.

Grasses (Gramineae family)

Grasses produce significant counts, from low to high range, from late May to early October with the most significant counts occuring in June and July.

Maple and Box Elder (Acer sp.)

Maple season varies from year to year slightly due to weather. Significant counts are observed from the end of April to the end of May. The season can start from the second week of April to early May and end late May to mid-June. The amount of pollen from the maples varies from one part of the City to the other. The counts at this site can get high compared to the other site.

Mugwort (Artemisia sp.)

Mugwort season is from late July to early October with low and the occasional moderate counts observed. Can be significant in causing allergic reactions.

Nettles (Urticaceae sp.)

Nettles and parietaria season can start from mid to late June and ends late August. The counts are usually low with the occasional moderate counts. Due to their small size they are considered important allergens.

Oak (Quercus sp.)

Oaks flower for a short period, with low counts and the season generally occurs in the month of May. Two seasons are possible with the second one occuring from mid-May to early June. Oaks can be highly allergenic.

Pine, fir and spruce (Pinaceae family)

Very high counts are observed for spruce, fir and pine trees from late May to late July. The pollen season can occur between early May to the end of July. The season varies from year to year due to weather.

Plantains (Plantago sp.)

Plantains pollinate from early June to mid-September. The counts are in the low range but may cause allergic reaction in highly sensitized individuals.

Poplar, cottonwood and aspen (Populus sp.)

Poplar, cottonwood and aspen season can start from mid-March to mid-April and end mid to late May. Some of the counts are very high and may cause allergic reactions.

Ragweed (Ambrosia sp.)

Ragweed season is from the mid-August to mid-September with only very sporadic low counts observed.

Sagebrush (Artemisia sp.)

Sagebrush season is from late July to early October with low and the occasional moderate counts observed. Can be significant in causing allergic reactions.

Willow (Salix sp.)

Willows pollen season can start from mid-April to the second week of May and end late May to mid-June. The season usually lasts at least a month and can be sporadic. There is some variation in the season from year to year and low to moderate counts are observed.

 

Predominant Spores for Calgary (West), Alberta

Spore seasons fluctuate from year to year by as much as two to four weeks at this site due to the effect of weather. Spores described here are generalizations as to when sporulation occurs.

Alternaria sp.

Alternaria counts are in the low to moderate ranges and some species are known to cause allergic reactions. The season is from mid-April to mid-October.

Aspergillus sp.

Aspergillus spores are found throughout the whole counting season and are probably present in significant numbers beyond that. The counts are significant from March to late fall.

Boletus sp.

Boletus season is very sporadic with some high counts observed. It may be of significance in causing allergic reactions. The season is from late June to the end of September.

Botrytis sp.

Botrytis may be a significant allergen, with low to moderate counts. The season is June to the end of September.

Cladosporium sp.

Some species of Cladosporium are known to cause allergic reactions. The most abundant spore found throughout the whole season. This spore exists all year round but very high counts are known to occur from March to well into late fall.

Coprinus sp.

Coprinus mushroom produces moderate and high counts from late May to early October. It is considered an important allergen.

Diatrypaceae sp.

The counts for Diatrypaceae are sporadic throughout the whole counting season. Very high counts can be observed from late March to mid-October. They are not known to cause allergic reactions.

Drechslera sp.

The counts for Drechslera are mostly in the low range with some moderate counts in July and August. This is a summer and fall spore, June to September. There are other related genera, which are also found in air samples, that can cause respiratory problems. One example is Bipolaris sp.

Epicoccum sp.

Some species of Epicoccum are known to cause allergic reactions. The season is from late May to the end of September with only low counts. May not be a significant allergen at these levels.

Erysiphe (Oospora) sp

Erysiphe, also known as Powdery mildew, season runs from May to mid-October. The counts are mostly in the low and moderate ranges with some high counts observed. May not be significant in causing allergic reactions.

Ganoderma sp.

Ganoderma also known as bracket fungus can produce high counts from mid-June to the end of September. It is considered an important allergen.

Helicomyces sp.

Helicomyces season is very sporadic from May to the end of September producing low to high counts.

Leptosphaeria sp.

Leptosphaeria season starts in May and runs through to the end of September. The counts vary from day to day, which is probably due to the effect of weather. Very high counts are observed from July to early October. They could cause allergic reactions.

Myxomycetes

Moderate counts are observed from April to mid-October. Allergenic properties are not well known.

Penicillium sp.

Penicillium spores are found throughout the whole counting season and are probably present in significant numbers beyond that. The counts are significant from March to late fall.

Uredinales sp.

Uredinales aka rusts do occur in very high numbers but not enough is known about their significance in causing allergic reactions at these levels. The season is from early June to mid-October. The counts are mostly low to moderate with some in the very high range.

Ustilaginales sp.

Allergenic properties of Ustilaginales also know as smuts are unknown. The season is from June to mid-October with some very high counts from July to the end of September.

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