Short-Term Effect of Inhalable Particulate Matters on Emergency Ambulance Dispatches for Cardiovascular Diseases

Objective To assess the short-term effect of particulate matters with an aerodynamic diameter less than 10 μm (PM₁₀) on emergency ambulance dispatches for cardiovascular diseases (CVDs) and seasonal variations.

Methods The data of daily emergency ambulance dispatches from 2011 to 2014 were collected from Ningbo Emergency Medical Center. A timeseries study using a distributed lag non-linear model was conducted to evaluate the relationship between PM₁₀ and daily emergency ambulance dispatches for CVDs in cold season (from November to April) and warm season (from May to October) after controlling meteorological factors, long-term trend, and day of the week. We also examined the association stratified by sex and age.

Results During the study period, a total of 7 434 cases of CVDs were collected, including 4 123 cases in cold season and 3 311 cases in warm season. In warm season, a 10-μg/m³ increase of PM₁₀ was associated with 2.00% (95%CI: 0.59%-3.42%) increase in emergency ambulance dispatches for CVDs without lag effect identified. No effect was found in full year and cold season. In warm season, the excess risks associated with a 10-μg/m³ increase of PM₁₀ in the males and the≥65 years old age group were 2.41% (95%CI: 0.48%-4.37%) and 1.86% (95%CI: 0.07%-3.69%) respectively. No statistically significant differences were found in the females and those less than 65 years old.

Conclusion These findings suggest that the increase of PM₁₀ are positively associated with the increase of emergency ambulance dispatches for CVDs in warm season; male and the senior may be more sensitive than others.