Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 12 3 2013 09 15 220 227 EN María Morales Suárez-Varela Unit of Public Health, Hygiene, and Environmental Care, Department of Preventive Medicine, University of Valencia, Valencia, Spain AND CIBER Epidemiology and Public Health (CIBERESP), Spain AND Center for Public Health Research (CSISP), Valencia, Spain Amparo Gallardo-Juan Section of Radiology, General Hospital, Valencia. Spain Luís García-Marcos Pediatric Respiratory Medicine and Allergy Units, 'Virgen de la Arrixaca' University Children's Hospital, University of Murcia, Spain Natalia Gimeno-Clemente Unit of Public Health, Hygiene, and Environmental Care, Department of Preventive Medicine, University of Valencia, Valencia, Spain AND CIBER Epidemiology and Public Health (CIBERESP), Spain AND Center for Public Health Research (CSISP), Valencia, Spain Angel López Silvarrey-Varela Foundation María José Jove, A Coruña, Spain Iñaqui Miner-Canflanca Department of Paediatrics, Hospital de Donostia, San Sebastián, Spain José Batlles-Garrido Department of Paediatrics, Hospital Torrecárdenas, Almería, Spain Alfredo Blanco-Quiros Department of Paediatrics, University of Valladolid, Valladolid, Spain Rosa María Busquets-Monge Department of Paediatrics, Hospital del Mar, Barcelona, Spain Begoña Domínguez-Aurrecoechea Health Centre of Otero, Oviedo, Spain Alberto Arnedo-Pena Section of Epidemiology, Centre of Public Health, Regional Ministry of Health, Castellón, Spain Carlos González-Díaz Unit of Paediatric Allergy, Department of Paediatrics, Hospital of Basurto, Bilbao, Spain Inés Aguinaga-Ontoso Department of Health Sciences, Public University of Navarra, Navarra, Spain Antonio Martínez-Gimeno Department of Pediatrics, "Santa Lucía" University Hospital, Cartagena, Spain Agustín Llopis-González Unit of Public Health, Hygiene, and Environmental Care, Department of Preventive Medicine, University of Valencia, Valencia, Spain AND CIBER Epidemiology and Public Health (CIBERESP), Spain AND Center for Public Health Research (CSISP), Valencia, Spain 2015 10 16 Atopic Eczema (AE) is a chronic inflammatory skin disease that affects children and adults, and alters quality of life with a high morbidity rate and severe economic burden. The objective of the present work was to analyse specific atmospheric pollutants (O3, NO, PM10 and SO2) affecting the prevalence of diagnosed AE and its symptoms among 6-7-year-old schoolchildren. The participants included 21311 schoolchildren aged 6-7 years from 8 Spanish regions, whose parents completed the ISAAC Phase III questionnaire to ascertain AE diagnosis and symptoms. The mean levels (µg/m3) of O3, NO, PM10 (particles 10 micrometers or less in diameter) and SO2 were determined in each geographical area participating in this study.  According  to  these  mean  levels, three  levels of  exposure  to  each  pollutant  were considered: level 1 (percentiles 0-25); level 2 (percentiles 26-74); level 3 (percentiles 75-100). Exposure to O3  was associated with increased prevalence of rashes (exposure level 2, Odds Ratio (OR): 1.22, 95% Confidence Interval (95%CI): 1.02-1.45; level 3 OR:  1.33, 95%CI:1.10-1.61) and diagnosed AE (level 2, OR: 1.27, 95%CI: 1.17-1.39; level 3 OR: 1.27, 95%CI:1.15-1.41). An association was found between the level of NO and a drop in the prevalence of diagnosed AE (exposure level 2, OR: 0.88, 95%CI: 0.81-0.95; level 3 OR: 0.85, 95%CI:0.74-0.97). There was also an association between the highest exposure level to PM10 and a reduced prevalence of rashes (level 3 OR: 0.42, 95%CI: 0.22-0.81) and diagnosed AE (level 3OR: 0.53, 95%CI: 0.38-0.75). Future studies into exposure to  O3   and its relationship with allergic diseases may be conducted in order to prevent this association. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/509 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/509/529