In different parts of Spain pollination varies in species and seasons, which influences the allergies of its population.
- In the plateau the main allergy-causing pollens are grass and olive pollens, which pollinate mainly in May and June. Olive trees also belong to the family of ash, privet and linden trees. Patients living at the foot of the mountains of Madrid (Guadarrama…), where there is a lot of ash, come to the allergist’s office because they suffer from allergy in February-March or January-February-March, when the ash pollinates and the privet extends to July.
- Another important pollen in Madrid, Barcelona and in cities surrounded by housing developments, is the Arizona cypress, which is used as a hedge and pollinates mainly from mid-January to mid-March, sometimes also in December.
Of course, those who are allergic to the arizonica pollen are also allergic to pollens of the same family (other cypresses, junipers…). - The shade plane tree is an ornamental tree that is planted on the sidewalks of towns and cities and pollinates at the end of March and beginning of April.
In general and except for the olive tree, most trees pollinate between January and April, grasses and olive trees in May-June, weeds pollinate in summer (salsola in some areas of Castilla La Mancha, Aragon) or summer and autumn (chenopodium, parietaria, mugwort, rumex in Levante), although in practice many pollen have symptoms almost all year round.
How pollen allergy occurs
The pollens that produce allergy are very small, anemophilous (airborne), weigh very little and are carried by the wind over long distances (50 km or more), so on windy days the symptoms worsen, as well as on sunny days, since in general plants need a certain amount of sun and heat to pollinate (except the arizonica which does so in the middle of winter and in cold weather). Therefore, the patient does not need to live in the field to suffer the symptoms, although in the field it may be worse.
The pollen in the air is not visible to the naked eye, they are not those white particles released by trees in spring. It can be seen on a surface (typically on cars): when there is a lot of pollen, a very fine yellow dust is visible.
Rainy days improve the symptoms, because the rain sediments the pollens on the ground, as long as the rain is long enough, since short storms with a lot of wind and little rain will worsen the symptoms.
On the plateau the spring is very short, passing quickly from winter to summer, so the pollination of grasses is done in a short time and in an “explosive” way, reaching high concentrations of pollen in the air. On the coast the climate is milder and pollination is longer, reaching much lower grass pollen concentrations. Thus, if the patient who is allergic to grass pollens travels to the coast during the pollination season, he/she will notice a great improvement in his/her symptoms.
Measures to take during the pollination season for allergy sufferers
- In general, it can be said that it is practically impossible to avoid pollens unless you take draconian measures. Undoubtedly, during the allergy season, exposure to the open air should be avoided as much as possible, especially in the countryside (or under shady plane trees in cities).
- There are air purifying devices that quickly clean the inside of the house of pollen and other particles, the useful ones are those with special electronic filters called “HEPA” (high efficiency particulate arresting).
- The windows of your house will remain closed except for a couple of hours a day for ventilation. The bedroom windows should remain closed and the bedroom should be ventilated through the door to prevent pollen from entering and settling in the bedroom. There are also anti-pollen gauze that are placed on the windows.
- During the months of pollination, outdoor activities should be limited as much as possible, especially trips to the countryside, as well as activities by bicycle or motorcycle.
- If you travel by car, you should close the windows and put the air in closed circuit. Many cars are already equipped with special filters for pollens.
- Dark glasses sometimes improve allergic conjunctivitis somewhat, as well as special masks for pollens are available.
- When dusting, use a damp cloth. During this time of year, one of the components of house dust are the pollens that settle on the floor.
Pollination: when is there more pollen in the air?
The timing of pollination varies with latitude and altitude, the higher the latitude (the farther north) and altitude, the later the pollination and the farther south the earlier.
The patient should be informed before traveling to another place about the pollen calendar: In Madrid, grasses pollinate in May and June (especially from San Isidro to San Antonio, from May 15 to June 14), although if the weather is good, they can also pollinate earlier or, if it rains a lot in May, they can be delayed.