Short-term effects of air pollutants and meteorological factors on outpatients with allergic airway disease in Ningbo, China, 2015–2021

Objectives

The allergic airway disease, such as allergic rhinitis, chronic rhinosinusitis, asthma, is a general term of a range of inflammatory disorders affecting the upper and lower airways and lung parenchyma. This study aimed to investigate the short-term effects of air pollutants and meteorological factors on AAD-related daily outpatient visits.

Study design

An ecological study.

Methods

Data on outpatient visits due to AAD (n = 4,554,404) were collected from the platform of the Ningbo Health Information from January 1, 2015 to December 31, 2021. A Quasi-Poisson generalized additive regression model was established to analyze the lag effects of air pollution on daily outpatient visits for AAD. Restricted cubic spline functions were used to explore the potential non-linear relationships between air pollutants and meteorological and daily outpatient visits for AAD.

Results

PM_2.5, PM₁₀, SO₂, NO₂, or CO were associated with daily outpatient visits for AAD, and there was a significant increasing trend in the cumulative lag effects. SO₂ had the largest effect at Lag07, with a 25.3% (95% CI: 21.6%–29.0%) increase in AAD for every 10 μg/m³ increase in exposure concentration. Subgroup analysis showed that the 0–18 years old age group had the strongest effects, especially for AR, and all effects were stronger in the cold season.

Conclusions

Given that patients aged 0–18 are more susceptible to environmental changes, protective measures specifically for children should be taken during dry and cold weather conditions with poor air quality.