Reduced incidence of stroke during COVID-19 pandemic was sometimes reported. While decrease in stroke incidence and fear of patients to go to the hospitals were sometimes invoked to explain this decrease, reduction in urban pollution was also hypothesized as a possible cause. We investigated statistically the incidence of ischemic and hemorrhagic stroke, and of transient ischemic attacks, at a large Italian tertiary stroke center during the pandemic. We analyzed statistically the number of transient ischemic attacks (TIA), ischemic strokes (IS) and hemorrhagic strokes (HS) between March 8 and May 2, 2020, the peak of the COVID-19 epidemic in Italy, and compared them with the identical period of 2019. We also analyzed the concentration of small particulate matter (PM10) in 2019 and 2020, to see if it could account for modified incidence of strokes or TIA. We found a large, significant drop in TIA (− 51%) during the pandemic compared to the same period of 2019. By contrast, the number of HS was identical, and IS showed a not significant − 24% decrease. PM10 concentration, already low in 2019, did not further decrease in 2020. Patients kept seeking hospital care when experiencing permanent neurological symptoms (stroke), but they tended not go to the hospital when their symptoms were transient (TIA). The fact that we did not observe a significant decrease in strokes may be explained by the fact that in our city the concentration of small particulate matter did not change compared to 2019.