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.