There are those who are notoriously hypersensitive to pollen and those who instead become so in large cities, due to the high levels of particular pollutants in the air. Of the 10 million Italians allergic to pollen, as many as 1 out of 3 may not really be allergic or rather would show all the classic symptoms – rhinitis, cough and asthma – but only because of environmental pollution. A German study, conducted by the Max Planck Institute for Chemistry in Mainz and the University Medical Center of the Johannes Gutenberg University, published in the journal ‘Frontier Allergy’, demonstrated that pollen ‘captures’ and ‘transports’ some well-known pollutants such as ozone, nitrogen dioxide (No2) and particulates, to then release them into the respiratory tract, intensifying the manifestations of hypersensitivity to allergens in those who suffer from them and triggering rhinitis, cough and asthma in non-allergic subjects.
To take stock of the aggressive combination, between pollen and polluting particles, the experts of the Italian Society of Aerobiology, Medicine and the Environment (Siama) who, like every year on the first day of spring, organize the National Pollen Day, now in its 16th edition. A seminar on environmental monitoring and the prevention of allergy and pollen risks will take place tomorrow in the Chamber, with the sponsorship of the Italian Society of Allergy, Asthma and Clinical Immunology (Siaaic) and will be attended, among others, by the Deputy Minister of the Environment Vannia Gava, the head of the Pollnet network, the Higher Institute for Environmental Research and Protection (Ispra) and Enea.
“The prevalence and severity of allergic diseases triggered by airborne plant pollen and other allergens are increasing worldwide – explains Vincenzo Patella, president of the Italian Society of Aerobiology, Medicine and the Environment (Siama) and UOC director of Internal Medicine Salerno Health Authority – Until now it had been assumed that this continuous increase recorded in recent decades was due to the combination of genetic predisposition and climatic anomalies, with warmer winters which tend to favor an increasingly abundant and lasting pollen load for early blooms”.
Not only. “The excessive exposure of allergens to some atmospheric pollutants which, in recent years, have reached high concentrations – observes the expert – would also play a decisive role in this ‘allergy epidemic’. nitrogen and particulate matter, components of the summer smog created by traffic, can alter the pollen’s allergenic and inflammatory potential: in fact, the pollutants enter the pollen and, once they reach the respiratory tract, are then released, thus enhancing, on the one hand, the symptoms of allergic patient, and on the other by triggering allergic-like reactions – he comments – in people who have always shown a fairly high threshold of sensitization to pollen”. Basically, ‘polluted’ pollen would trigger allergic reactions even in people who aren’t actually allergic.
“The German study published in the journal ‘Frontier Allergy’, with laboratory experiments showed that pollens from polluted areas are covered with harmful substances that alter their allergenic content and can strengthen their effect, causing more easily allergic reactions even in who does not suffer from it – comments Mario Di Gioacchino, president of the Italian Society of Allergy, Asthma and Clinical Immunology (Siaaic) – If nitrogen oxides and ozone reach high concentrations, they alter the protein components of pollen grains to such an extent as to non-allergic subjects symptoms such as rhinitis and cough.The German study shows, in particular, that some pollens, such as those of grasses, trigger the hyperactivation of Toll-like receptor 4 (Tlr4), cell receptors that activate the allergic reaction of the immune system, even in those who do not suffer from allergies”.
Climate and smog, according to Siama data, would also be responsible for the record pollen concentration values, well above the average, recorded this year in Italy. “In our country there are very different areas from the point of view of climate and vegetation – explains Patella – but the year we are living in is one of those that leave their mark because we have gone from concentrations of 200 total pollen per cubic meter to average in the peak days of 5 years ago to the current 2,000, 10 times more. This obliges us to improve the collection of this data. Furthermore, we ask the legislator to better regulate the toxicity thresholds of the individual pollen species – he underlines – by comparing them with the data from the smog stations. In this way we could facilitate prevention campaigns on air quality much more readily than in the past”.
“It becomes essential to study and deal with allergic disease – urge Patella and Di Gioacchino – also in the light of environmental problems, which can aggravate or even trigger it. To improve air quality, it is therefore important that public administrations not only adopt policies to reduce the rate of the main air pollutants, but also measures to contain the load of allergenic pollens.This can occur with the design of public gardens especially in metropolitan areas with non-allergenic species, such as jasmine, camellia and heather, in place of already existing dead plants anemophilous that entrust the propagation of pollen to the wind, such as birches, cypresses and olive trees”.
These are the recommendations of the experts for those who do not suffer from allergies: use of hypersaline nasal washes; use of artificial tears; comb your hair in the bathroom and not in the bedroom to prevent the pillow from collecting pollen through the hair; if symptoms worsen, consult a specialist before resorting to antihistamines and corticosteroids.