Toledo and Climate Change: 30 Years of Clinical Aerobiology in the Center of Spain

Abstract

The incidence of allergic diseases has increased notably in recent years. The reasons for this increase include air pollution, diet, and infectious factors. This study aims to analyze the interactions between aeroallergens, environmental pollutants, and meteorological factors and their impact on allergenic sensitization in Toledo, Spain. An aerobiological study was conducted over the past 30 years (1994–2023) using a Burkard collector and the SEAIC (Spanish Society of Allergology and Clinical Immunology) methodology. Meteorological data were obtained from the State Meteorological Agency (AEMET) and pollutant data were acquired from the Castilla-La Mancha Air Quality Monitoring Network. Patients presenting with seasonal allergic symptoms at the University Hospital of Toledo were selected for skin testing with various types of airborne pollen. A total of twenty pollen taxa were identified in the Toledo atmosphere, as follows: Cupressaceae (26.53%); Olea europaea (21.62%); Quercus (21.12%); Poaceae (10.30%); Urticaceae (2.58%); Plantago (2.48%); Platanus (2.00%); Amaranthaceae (1.72%); Rumex (1.68%); and Morus, Pistacia, Populus, Artemisia, Fraxinus, Alnus, Carex, and Ericaceae (less than 1% each). The average temperature increased by 1.2 °C, while the level of precipitation remained stable. Among all pollutants, only a moderate increase in ozone levels was observed; however, the concentrations of particulate matter and nitrogen oxides decreased. The prevalence of pollen sensitization in allergic patients ranged from 8% for Pinus nigra to 84% for Phleum pratense. In conclusion, the rise in temperature due to climate change, coupled with high concentrations of pollutants such as ozone, can result in increased concentrations of the main types of wind-borne pollen. Thus, this can lead to a greater sensitivity to pollen and, consequently, more people becoming allergic to pollen.