Short-term effects of air pollutants on hospital admissions for acute bronchitis in children: a multi-city time-series study in Southwest China

Background: Few studies have investigated the effects of air pollutants on children with acute bronchitis. This study aimed to explore the acute effects of four air pollutants [fine particulate matter (PM_2.5), inhalable particulate matter (PM₁₀), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂)] on the daily number of children admitted to the hospital for acute bronchitis in Sichuan Province, China.

Methods: The 49,975 records of hospitalized children with acute bronchitis from medical institutions in nine cities/prefectures, Sichuan Province, China, as well as the simultaneous meteorological data and air pollution data from 183 monitoring sites, were collected from 1 January 2017 to 31 December 2018. A generalized additive model was adopted to analyze the exposure-response and lag effects of hospitalizations of children with acute bronchitis to air pollutants. Stratified analyses were conducted based on sex, age, and season.

Results: The single-pollutant model showed that a 10 µg/m³ increase at lag07 of PM_2.5, PM₁₀, SO₂, and NO₂ corresponded to an increase of 1.23% [95% confidence interval (CI) 0.21-2.26%], 1.33% (95% CI 0.62-2.05%), 23.52% (95% CI 11.52-36.81%), and 12.47% (95% CI 8.46-16.64%) in daily hospitalizations for children with acute bronchitis, respectively. Children aged 0-2 were more prone to PM_2.5 (P < 0.05). Interestingly, the effects were stronger in the warm season than in transition seasons and the cool season for PM_2.5 and PM₁₀ (P < 0.05).

Conclusion: The higher daily average concentrations of four pollutants in Sichuan Province can result in an increased number of children hospitalized for acute bronchitis.