There are those who are notoriously allergic to pollen, and those who become so in large cities with high levels of specific pollutants in the air. As a result, of the 10 million Italians who are allergic to pollen, up to one-third may not be, or may manifest all of the classic symptoms - rhinitis, cough, and asthma - but only due to environmental pollution. A German study published in the journal Frontier Allergy by the Max Planck Institute for Chemistry in Mainz and the University Medical Center of the Johannes Gutenberg University found that pollen "captures" and "transports" some known air pollutants, such as ozone, nitrogen dioxide (NO2), and particulate matter, and then releases them into the respiratory tract, exacerbating hypersensitivity to allergens and triggering rhinitis, cough and asthma in non-allergic subjects " According to Vincenzo Patella, president of SIAMA and director of the Internal Medicine Unit of Salerno Health Company, "the prevalence and severity of allergic diseases caused by plant pollen carried by the air and other allergens are increasing all over the world. Until now, we had assumed that the continuous rise in allergic diseases observed in recent decades was due to a combination of genetic predisposition and climatic anomalies such as warmer winters, which favor an increasingly abundant and long-lasting pollen load for early blooms ". "Excessive exposure of allergens to some air pollutants, which have only recently reached high concentrations, would also play a decisive role in this 'allergy epidemic," according to the expert." Ozone, nitrogen dioxide, and particulate matter, components of the summer smog created by traffic, can alter the allergenic and inflammatory potential of pollen: the pollutants enter the pollen and once they reach the respiratory tract, they are then released, thereby enhancing, on the one hand, the symptoms of the allergic patient and, on the other hand, triggering allergic-like reactions in individuals who have always exhibited a relatively high threshold of sensitization to pollen ". In essence, "polluted" pollen would cause allergic reactions in people who are not allergic to it.