Relationship between different particle size fractions and all-cause and cause-specific emergency ambulance dispatches

Background Evidence on the relationship between different particle size fractions and emergency ambulance dispatches (EAD) remains limited and sparse. Methods We collected daily data of EAD, ambient air pollution and meteorological data from 2014 to 2018 in Guangzhou, China. We used a generalized additive model with covariate adjustments to estimate the associations between different particle size fractions and EAD related to all-cause, cardiovascular diseases, and respiratory diseases. Several subgroup and sensitivity analyses were also performed. Results Significant associations were observed between PM 2.5 , PM 2.5–10 , PM 10 and EADs. A 10 μg/m 3 increase of PM 2.5, PM 2.5–10 , and PM 10 was associated with an increase of 0.98% (95% CI: 0.67, 1.28%), 2.06% (95% CI: 1.44, 2.68%), and 0.75% (95%CI: 0.53, 0.96%) in all-cause EAD, with an increase of 0.69% (95% CI: 0.00, 1.39%), 2.04% (95% CI: 0.64, 3.45%), and 0.60% (95%CI: 0.11,1.10%) in cardiovascular-related EAD, and an increase of 1.14% (95% CI: 0.25, 2.04%), 2.52% (95% CI: 0.72, 4.35%), and 0.89% (95%CI: 0.25,1.52%) in respiratory-related EAD at lag03, respectively. The results were robust in subgroup and sensitivity analyses. Conclusions This study revealed that PM 2.5 , PM 2.5–10 and PM 10 were significantly related with risks of all-cause and cause-specific EAD. More evidence of high quality may be needed to further support our results in this ecological study.