Pollen grains are dust-sized particles produced by many trees and plants as they bloom and reproduce. Wind-pollinated plants manufacture pollen in vast quantities and rely on the wind to transport the pollen to the female parts of other plants of the same species for sexual reproduction.

Fungal, or mould, spores are small, seed-like bodies often produced by fungi and algae. The amount of airborne pollen varies according to the pollinating season and to the weather, while fungal spore levels are present year-round, but again vary in abundance.

15% of Canadians are affected by sensitivities to pollen or fungal spores. Allergic rhinitis or hay fever is an allergic reaction caused by pollen from trees, grasses, or weeds. Symptoms include watery or itching eyes, sneezing, runny nose, or swelling of the mucous membranes.

Pollen and spore counts and forecasts provide allergy sufferers with local information so that they can minimize their exposure to these allergens. A volumetric trap is used to sample the air on a twenty-four hour basis. The amount and types of pollen and spores captured are tabulated and pollen and spore frequencies are calculated. Weather forecasts are then used to make predictions of the next day’s pollen and spore levels.

Pollen counts are usually highest between 5 a.m. and 10 p.m., while higher levels of spores are frequently counted at night. Counts are also higher in sunny weather and after a rainfall, but they are low in rainy weather.

To return to the Pollen and Spore Count and Experimental Forecast Service home page, please click here.

This service is provided by Saint Mary's University, with the help of  the Lung Association of Nova Scotia and Environment Canada.