ObjectiveTo evaluate if extensive use of tear gas during the Chilean social uprising of 2019 was associated with a higher frequency of respiratory emergencies and bronchial diseases in a residential vulnerable population.DesignObservational, longitudinal, repeated measures study.SettingsSix healthcare centres (one emergency department and five urgent care centres) in the city of Concepcion, Chile during 2018 and 2019.ParticipantsThis study was conducted on daily respiratory emergencies and diagnosis. Daily frequency of urgency and emergency visits are administrative data, publicly available and previously de-identified.Primary and secondary outcome measuresAbsolute and relative frequency of daily respiratory emergencies in infants and older adults. A secondary outcome was the relative frequency of bronchial diseases (International Classification of Diseases 10th Revision, ICD-10: J20-J21; J40-J46) in both age groups. We finally measured the rate ratio (RR) of bronchial diseases above the daily grand mean, since the number of visits with these diagnoses in several days was zero. Tear gas exposure was assessed as the uprising period. Models were adjusted by weather and air pollution information.ResultsPercentage of respiratory emergencies during the uprising rose by 1.34percentage points (95% CI 1.26 to 1.43) in infants and 1.44percentage points (95% CI 1.34 to 1.55) in older adults. In infants, the emergency department experienced a larger increment in respiratory emergencies (6.89percentage points; 95% CI 1.58 to 2.28) than the urgent care centres (1.67percentage points; 95% CI 1.46 to 1.90). The RR of bronchial diseases above the daily grand mean during the uprising period was 1.34 in infants (95% CI 1.15 to 1.56) and 1.50 in older adults (95% CI 1.28 to 1.75).ConclusionsThe massive use of tear gas increases the frequency and probability of respiratory emergencies and particularly bronchial diseases in the vulnerable population; we recommend revising public policy to restrict its use.