Association between short-term exposure to air pollutants and the number of hospitalizations duo to respiratory system diseases in Miyun District, Beijing, China

Objective To explore the association between short-term exposure to air pollutants and the number of hospitalizations due to respiratory system diseases in Miyun District, Beijing, China.

Methods Data of inpatients from the respiratory ward of Beijing Miyun District Hospital from April 10, 2014 to August 10, 2019, daily air pollutant monitoring data from Beijing Municipal Ecological and Environmental Monitoring Center, and daily meteorological data from China Meteorological Data Service Center were collected. A generalized additive model was performed to evaluate the association of concentrations of fine particulate matter (PM_2.5), particulate matter 10 (PM₁₀), sulfur dioxide(SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and daily maximum 8-h average ozone concentration (O₃-8 h)in air with the number of hospitalizations due to respiratory system diseases, after adjusting for the day-of-the-week effect, holiday effect, temperature, humidity, wind speed, and long-term trend variables of time. The robustness of each pollutant model was evaluated by the two-pollutant model and sensitivity analysis.

Results The number of hospitalizations due to respiratory system diseases increased by 2.29% (95% confidence interval CI: 0.04%-4.60%)for each interquartile range (IQR)increased in the mass concentration of PM₁₀ on lag 7 d and by 5.80% (95% CI: 0.06%-11.86%)for each IQR increased in the mass concentration of O₃-8 h on lag 0 d. Subgroup analysis showed that PM₁₀ (lag 3 d)had a greater association on male (P_interaction=0.047) than female(P_interaction=0.006); CO (lag 3 d)had a greater association on people aged ≥ 80 years than those aged 65-79 years. In the two-pollutant model, the association between O₃-8 h on lag 0 d and the number of hospitalizations due to respiratory system diseases was still statistically significant after adjusting for concentrations of PM_2.5, PM₁₀, NO₂, and CO, suggesting that the positive correlation between exposure to O₃ and the number of hospitalizations due to respiratory system diseases was robust.

Conclusion Short-term exposure to O₃-8 h is associated with an increase in the number of hospitalizations due to respiratory system diseases; the impact of PM₁₀ pollution on the number of hospitalizations due to respiratory system diseases is statistically significant and has a lag effect.