Objective The study aimed to quantitatively evaluate the short-term effects of ultrafine particles （UFPs） exposure on the occurrence and mortality of cardio-cerebrovascular diseases.

Methods The number of daily cases of cardio-cerebrovascular events， including stroke and acute myocardial infarction， and mortality of cardio-cerebrovascular diseases， daily concentrations of air pollutants and weather conditions in Minhang， Shanghai from January 1， 2016 to December 31， 2018 were collected. Associations between UFPs and the number of daily cases and deaths were analyzed by the general additive Poisson regression model with the control of meteorological variables， day-of-the-week effects and time trends. Increased percentages of the number of daily cases and deaths and 95%CI were used to indicate the short-term effects of UFPs.

Results During the study period， in the single-pollutant model， an increase of 2022 particles/cm³ showed significant effects with 5.01%（95%CI： 1.22%‒8.94%）and 6.05%（95%CI： 1.53%‒10.80%）increments in the percentages of the number of daily cases and deaths respectively. After adjusting other pollutants in the two-pollutant model， statistically significant associations were also observed.

Conclusion UFPs exposure has acute impacts on the occurrence and mortality of cardio-cerebrovascular diseases.