After adjusting for GOLD classes, the smoking status, hypertension, coronary heart disease, PM2.5, and PM10, it was found that patients with AECOPD exposed to higher PM2.5 levels on the day before hospitalization (PM2.5 ≥ 25 mg/L) had 1.19-fold higher odds of having CRP > 10 mg/L when compared to those exposed to PM2.5 < 25 mg/L on the day before hospitalization (95% CI 1.101, 3.315), indicating a significant association of high PM2.5 exposure level with CRP level (p = 0.024). Here, CRP is linked to Hypertension.