The new World Health Organization guidelines recommend studies with simultaneous exposure to multiple air pollutants. The main objective has been to analyze the strength of the association between different concentrations of PM10 and NO2 and the exacerbation of chronic respiratory diseases (ECRD), specifically asthma and chronic obstructive pulmonary disease.Retrospective cross-sectional study. The population analyzed were adults treated in an urgent and primary health care center on certain lag+1 days in 2019. Three indices have been developed (1: high levels of PM10 and NO2; 2: high level of PM10 and low level of NO2, and 3: low levels of PM10 and NO2) and a logistic regression model for each of them, with ECRD as the outcome variable, and the progressive addition of adjustment variables (sex, age, tobacco, Charlson index, season, precipitation, wind and temperature).Four hundred and sixty-one people were analyzed, 17 with ECRD. Models 1 and 2 presented very similar values in the adjusted OR (4.28 [95% CI 1.05-17]), R2 (0.88) and the area under the ROC curve (>0.72). In both of them the significance was maintained after including the adjustment variables, while model 3 only allowed the addition of precipitation. The inclusion of the Charlson index and the tobacco consumption in the 3 models implied the loss of statistical significance of the PM10/NO2 combination regarding ECRD.High levels of PM10 are related to ECRD and have a greater impact than NO2, with tobacco use and comorbidities being the main precipitants of ECRD.