## 5 Discussion
In addition, establishing a system for measuring pollen's allergenic potential that can assess the increased allergenicity of pollen affected by pollution, could be considered a new indicator of health risks for citizens in urban areas [12]. This is consistent with the results obtained in this study, which show that both types of variables influence the pathologies considered. In addition, the interaction between pollutants and pollen grains [20] can increase the allergenicity of the latter. It could be stated that the solution to this problem lies in three measures: the adequate planning and management of green areas in cities, using a careful selection, particularly of anemophilous pollination flora species; the increasing control of air pollution; and the management of adequate epidemiological surveillance. Work [29], carried out in Korea, includes the same pollutants as the present study, except PM\({}_{2.5}\), as well as pollen data from trees and herbaceous plants in the two periods of the year, spring and autumn, when pollen concentrations are highest, and also comments on the relevance of climate change in terms of being the cause of the increase in the number of pollutants present in the atmosphere, as well as the expansion of allergens. With the increase in the mean annual temperature, the flowering stage of plants is anticipated to expand, which may lead to an increase in the concentration of pollen in the atmosphere and an increase in the number of people exposed to it, and, consequently, an increase in the prevalence rates of allergic diseases, allergic rhinitis, asthma, atopic dermatitis, and allergic conjunctivitis [29; 30]. However, in some of the models obtained in this work, it can be observed that the effects of the variables do not always increase the effects on the pathologies, as is the case of O\({}_{3}\) and PM\({}_{10}\) in some models for allergic rhinitis or, to a lesser extent, PM\({}_{10}\) in those for conjunctivitis (Appendix B). On the other hand, atmospheric pollutants wherein climate alterations have originated can cause a deformation of the epidermis, which affects the immune response, and which, with their binding to pollen grains, can increase the chances of inducing allergic diseases [29]. In the same study [29], there is a generally significant relationship between air pollutants, pollen levels, and the number of patients seen in outpatient clinics in Korea for allergic diseases in both spring and autumn. Particularly significant is the relationship between NO\({}_{2}\) and the three pathologies analyzed (allergic rhinitis, asthma, and atopic dermatitis) in spring and SO\({}_{2}\) (with a high positive association) with the three pathologiesin autumn. In addition, a highly significant relationship was obtained between allergic rhinitis and PM\({}_{10}\), NO\({}_{2}\), SO\({}_{2}\), O\({}_{3}\), and CO, as well as with the so-called tree and herbaceous pollen risk index, both in spring and autumn. Likewise, there is a significant association between the emergence of patients with allergic rhinitis and the concentration levels of pollen and pollutants PM\({}_{10}\), NO, SO\({}_{2}\), and CO [29]. These results agree with those obtained in the present study for allergic rhinitis, where PM\({}_{10}\) particles and O\({}_{3}\) are the pollutants most often involved in the calculated models, with NO\({}_{2}\), SO\({}_{2}\), and CO in fifth place. Japan stands out worldwide, together with Africa and Latin America, as one of the geographical areas with the highest prevalence rates for rhinoconjunctivitis, according to research conducted by the ISAAC (International Study of Asthma and Allergies in Childhood) between 1993 and 2003 [31]. There has, indeed, been an increase in the prevalence of this pathology worldwide in recent decades. Moreover, there are variations within the same country and its different regions, which can be caused by different factors: ethnicity, related to the types of allergens, and in terms of environmental risk factors, among which is atmospheric pollution.