Acute effects of ambient air pollution on hospital outpatients with chronic pharyngitis in Xinxiang, China

We present results on a time-series study that analyzed the acute effects of six criteria air pollutants on hospital outpatient with chronic pharyngitis (CP) in Xinxiang, China. Data on the concentration of air pollutants and CP outpatient records were collected daily in Xinxiang, China, from January 1, 2015 to December 31, 2018. This study identified 62,823 outpatients with CP. The annual average concentrations of PM 2.5 , PM 10 , SO 2 , NO 2 , CO, and O 3 are 75.7, 132.1, 33.2, 48.4, 1377, and 59.4 μg/m 3 , respectively. Further, a 10 μg/m 3 increment in the concentration of PM 10 , SO 2 , NO 2 , and CO corresponds to an increase of 0.28% (95% confidence interval (CI): 0.03–0.53%), 1.10% (95% CI: 0.09–2.11%), 1.82% (95% CI: 0.84–2.80%), and 0.03% (95% CI: 0.01–0.06%) in daily CP hospital outpatients, respectively. Furthermore, results indicated that outpatients under the age of 15 are more susceptible to the air pollutants, excluding O 3 . Meanwhile, males might be more susceptible, and effect estimates appear slightly stronger in the cool season. Therefore, we should implement effective measures to manage air pollutants and reinforce protection of the high-risk population.