Respiratory symptoms in Ecuadorian workers associated with informal labor and cantonal satellite pollution metrics

Introduction: Evidence on the association between ambient pollution and occupational hazards in Ecuador remains limited. This cross-sectional study evaluated the association between working conditions, satellite-derived ambient pollutants, geographic factors, and respiratory symptoms. Methods: We analyzed 1,807 workers across four sectors. Respiratory symptoms (ECRHS) were cross-referenced with Sentinel-5P telemetry, utilizing z-score standardized environmental variables and selecting optimal spatial/temporal concentration percentiles (p25, p50, p75, and p95) via the Akaike Information Criterion (AIC) for each outcome. Multivariable penalized logistic regression (Firth's method) identified factors associated with respiratory symptoms. Results: Informal employment showed the strongest association with respiratory symptoms, including asthma (aOR 12.56; 95% CI: 5.09-32.87), wheezing (aOR 6.78; 95% CI: 1.83-27.89), chronic cough (aOR 4.14; 95% CI: 2.26-7.74), and chronic phlegm (aOR 2.53; 95% CI: 1.39-4.67). Direct workplace chemical inhalation, compounded by a complete lack of risk awareness, was associated with significantly higher odds for asthma, wheezing, and chronic cough. Geospatially, after controlling for canton-level altitude-which acted as an independent protective factor against asthma (aOR 0.78; 95% CI: 0.66-0.93)-nitrogen dioxide (NO2) and sulfur dioxide (SO2) emerged as the primary independent environmental predictors for chronic phlegm and cough, while ozone lost statistical significance. Discussion/conclusion: Informal employment and unprotected chemical inhalation are strongly associated with respiratory symptoms, frequently exceeding the risks observed in traditional high-exposure sectors. Furthermore, regional atmospheric pollution showed a significant statistical association with chronic respiratory outcomes at the cantonal level. Integrating high-resolution aerospace monitoring into occupational health surveillance represents a potential strategy to address these overlapping structural vulnerabilities; however, causal inference remains limited by the cross-sectional design.