Association between atmospheric particulate matters and outpatient visits for respiratory disorders in Jiaxing City of Zhejiang Province from 2019 to 2021： a time series analysis

Objective To explore the effect of exposure to atmospheric particulate matters on the outpatient visits of respiratory disorders in Jiaxing City，Zhejiang Province.

Methods Daily air pollutant monitoring data，meteorological data and outpatient visits of respiratory disorders in Jiaxing City from 2019 to 2021 were collected．A generalized additive model was applied to evaluate the effect and laggeel effect of the concentrations of atmospheric particulates for outpatient visits of respiratory disorders after adjusting for secular trend， day-of-the-week effect， holiday effect， and meteorological variables.

Results The daily average concentrations of PM_2.5， PM₁₀， O₃ and NO₂ exceeded the standard， and the proportion of days exceeding the standard was 3.4%， 1.3%， 11.0% and 0.8%， respectively. Every 10 μg·m^-3 increase in PM_2.5 concentration showed the strongest effects on the daily outpatient visits of respiratory disorders， adult and childhood respiratory disorders all on lag07 with ER（95%CI） being 2.29%（1.35%‒3.24%）， 2.31% （1.39%‒3.23%） and 2.65 % （1.36%‒3.96%）， respectively. The maximum ER of outpatient visits for respiratory disorders in children was higher than that in adults. Every 10 μg·m^-3 increase in PM₁₀ concentration showed the strongest effects on the daily outpatient visits of respiratory disorders on lag07， adult respiratory disorders on lag06 and childhood respiratory disorders on lag07 with ER（95%CI） being 1.42% （0.87%‒1.96%）， 1.49%（0.99%‒1.99%） and 1.61% （0.87%‒2.36%）， respectively. The results of double-pollutant model showed that the effect of atmospheric particulate reduced after O₃ was introduced into the model.

Conclusion There are a short-term effect and a laggeel effect of atmospheric particulate on the outpatient visits of respiratory disorders. It is necessary to strengthen the health protection of the respiratory system of the population， especially the children.