Impact of short-term exposure to ambient air pollution on cardiovascular disease outpatient visits: a time-series study in Yichang, China.

Background: Rapid industrialization has exacerbated ambient air pollution in Yichang, China, posing cardiovascular health risks. This study evaluates the short-term impact of ambient air pollutants on cardiovascular disease (CVD) outpatient visits and assesses the effectiveness of environmental policies implemented post-2018.

Methods: We analyzed 510,831 CVD outpatient records alongside daily concentrations of PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃ from five monitoring stations. Generalized additive Poisson regression with distributed lag non-linear models (DLNM) quantified associations between ambient air pollutant exposure (per interquartile range (IQR) increase) and daily visits, adjusting for meteorological factors, time trends, and COVID-19. Effects pre- and post-2018 policy implementation (targeting riverside chemical industry relocation) were compared.

Results: Short-term exposure to NO₂ (lag05, RR = 1.253, 95% CI: 1.192-1.317), SO₂ (lag0, RR = 1.053, 95% CI: 1.011-1.096), and CO (lag01, RR = 1.063, 95% CI: 1.016-1.111) was significantly associated with increased cardiovascular disease outpatient visits. Concentrations of five major ambient air pollutants (excluding O₃) showed significant reductions after 2018 (P < 0.001). The associations of SO₂, CO, and PM₁₀ with CVD visits were attenuated after 2018. NO₂ effects were stronger in colder seasons and remained robust in two-pollutant models. No statistically significant associations were observed for PM₂.₅, PM₁₀, and O₃.

Conclusion: Short-term exposure to NO₂, SO₂, and CO demonstrated statistically significant positive associations with cardiovascular disease outpatient visits. Environmental policies reduced ambient air pollutant levels and attenuated health impacts, supporting continued air quality interventions.