[Particulate matter PM₁₀, NO₂ and exacerbations of chronic respiratory diseases]

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.