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General
What is a pollen count?
The pollen count is the number of pollen grains per cubic metre
(m3) of air, recorded over 24 hours. The results are sometimes stated as low, moderate, high or very high.
These can be explained a follows :
When are the pollen counts highest?
The pollen count will be at its highest on a perfect summer
day; clear sky, no rain and gentle breezes. The factors which
influence the pollen counts can be explained as follows:
· Amount of sunlight
Higher counts are found on sunny days as pollen spreads and
transfers from one flower to another, while the lower counts
are associated with overcast and cloudy days.
· Wind Effects
Higher counts are produced when winds are light, below
Force 4.
· Time of the day
Counts are usually lower early in the day. The peak level
is reached in the late afternoon and evening, while there
are morning peaks also. Lowest levels are usually around midday.
· Location
Pollen counts in rural grassy areas are much higher than urban
areas. However, research has shown that a higher percentage
of children in urban areas suffer from hayfever than in rural
areas. This is thought to be due to increased traffic pollution.
· Time of the year
Flowers produce most pollen in the summer months. Pollen counts
reach the highest in the months of June and July. In March
to May, the temperatures are usually quite low resulting in
low counts.
· Rainfall
Rain will wash the pollen out of the air, especially rain in the early morning.
When do different pollens cause Hayfever?
references
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Health Tip Group > Hayfever
| | Health Tip Name | Full Details | | Hayfever | more > | | Additional Information on Pollen | more > | | Hayfever and Exams | more > |
Health Tip Group > Allergy
| | Health Tip Name | Full Details | | Hayfever | more > | | Asthma Severity linked to Fungal Spores Aug 2002 | more > | | Hives | more > | | Additional Information on Pollen | more > | | Asthma & Pets | more > |
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