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Allergens > Airborne allergens
Pollen seasons
Pollen production does not occur all year round and therefore people allergic to only one type of pollen experience symptoms for a limited period of time during the year. For each specific plant pollination occurs in the same period every year. Usually, temperate regions the pollen season is opened by trees in late winter to early spring followed by grasses from mid spring to mid summer and then ended by weeds from late summer to mid autumn. However, in hot and humid regions, pollen emission can happen all year long
Tip: If you experience persistent symptoms (all year round) it may be because you are allergic to an allergen present all year long (=perennial allergen) but also because you might be allergic to different kind of pollens which are present in successive seasons during the year.
Even though pollination period is the same every year for a certain plant, some years the concentration of the pollen in the air is very high while in other years the air concentration is much lower (obviously these variations make your disease to be more or less severe in different years). These differences in concentration occur due to the fact that production of pollen as well as its release into the air can be influenced by a series of factors:
Even though pollination period is the same every year for a certain plant, some years the concentration of the pollen in the air is very high while in other years the air concentration is much lower (obviously these variations make your disease to be more or less severe in different years). These differences in concentration occur due to the fact that production of pollen as well as its release into the air can be influenced by a series of factors:
  • Weather conditions: in the colder years plants pollination is usually delayed, the quantity of pollen is lower and the pollen season is shorter than in the warmer years. This means that the symptoms may occur later than usual and be milder. In the warmer years the opposite happens, pollination is usually prompted by the favourable conditions and also pollen production is higher. In these years people allergic to pollen experience symptoms worse than usual.
  • Geographical location: pollination of the same plant occurs earlier in the southern (warmer) regions then in the northern (colder) ones. For example, there is a difference of several weeks between the beginnings of birch pollen season in the south of Europe compared to Scandinavia (Northern Europe). This can have an impact on allergic persons travelling between two regions.
  • Altitude: pollen season tends to start later and to be shorter in the areas located at high altitude. This is why mountain resorts an ideal holiday location for patients allergic to pollens
  • Atmospheric conditions: pollen counts are lower during the wet rainy days; on the contrary hot dry summer days stimulate pollen production.     
Tip: Hot, dry windy days are the most dangerous. Pollen production is favoured by hot temperatures while wind increases its dispersion, accentuating thus the risk of coming in contact with it and therefore the risk of developing symptoms.
  • Time of the day: pollen is released in the air by most plants in the early morning hours (from 4-9 am). Consequently in the countryside the highest pollen counts are generally recorded in the morning. In big cities the opposite can be noticed with higher pollen counts in the afternoon (the difference in timing arising from the time required by the pollen to be transported from the rural areas).     
What kind of allergic diseases can be caused by pollens?
Of all airborne allergens pollens are probably the largest ones (though still invisible to our naked eye). Therefore when inhaled, pollen grains are primarily retained in the nose, with only a small amount reaching the bronchi. As a consequence pollen is mainly causing allergic rhinitis and also allergic conjunctivitis (pollen landing on the eye lining). Asthma too can be caused by pollen. Asthma attacks occur very often during severe allergic rhinitis attacks when due to nasal blockage people then to breathe much more on the mouth, allowing thus pollen to get straight in the bronchi.
How to reduce pollen exposure?

After you have found out what pollen is, you would understand why pollen is one of the allergens most difficult to avoid. Complete avoidance is in all cases impossible. However, following the advices listed bellow may help in reducing the exposure to pollen and consequently the severity of your symptoms.

Tip: avoiding pollens can help to reduce the severity of symptoms you experience but it will not make them disappear completely. For a proper control of your symptoms you have to follow accurately the treatment recommended by your doctor.
DO…
  • Take note of the regional pollen forecast
  • Stay indoor during the hot, windy days
  • As much as possible keep closed the windows an doors of house (use air conditioning systems for refreshing and cooling the air in the house)
  • Vacuum frequently to remove pollen from carpets and furniture
  • Plan your holiday during the height of the pollen season
  • For holidays choose a location in an area with low pollen counts like high mountainous regions or the seaside
  • Before the start of the pollen    
DON’T…

During the days with high pollen forecast:

  • Don’t walk in the fields and meadows
  • Don’t practice outdoor sports
  • Don’t perform any kind of outdoor activities 
  • Don’t sleep with the bedroom windows open during the night, especially during the early morning hours
  • Don’t keep your car windows open when you drive, especially when passing through meadows and forests in blossom
  • Don’t dry your washings outdoors