Carbon Footprinting of North American Emergency Medical Services Systems

Abstract

Objectives. This study was undertaken to characterize the carbon emissions from a broad sample of North American emergency medical services (EMS) agencies, and to begin the process of establishing voluntary EMS-related emission targets. Methods. Fifteen diverse North American EMS systems with more than 550,000 combined annual responses and serving a population of 6.3 million reported their direct and purchased (“Tier 2”) energy consumption for one year. We calculated total carbon dioxide equivalent (CO2e) emissions using Environmental Protection Agency, Energy Information Administration, and locality-specific emission conversion factors. We also calculated per-response and population-based emissions. We report descriptive summary data. Results. Participants included government “third-service” (n == 4), public utility model (n == 1), private contractor (n == 6), and rural rescue squad (n == 4) systems. Call volumes ranged from 800 to 114,280 (median 20,093; interquartile range [[IQR]] 1,100–55,217). Emissions totaled 46,941,690 pounds of CO2e (21,289 metric tons); 75%% of emissions were from diesel or gasoline. For systems providing complete Tier 2 data, median emissions per response were 80.7 (IQR 65.1–106.5) pounds of CO2e and median emissions per service-area resident were 7.8 (IQR 4.7–11.2) pounds of CO2e. Two systems reported aviation fuel consumption for air medical services, with emissions of 2,395 pounds of CO2e per flight, or 0.7 pounds of CO2e per service-area resident. Conclusion. EMS operations produce substantial carbon emissions, primarily from vehicle-related fuel consumption. The 75th percentiles from our data suggest 106.5 pounds of CO2e per unit response and/or 11.2 pounds of CO2e per service-area resident as preliminary maximum emission targets. Air medical services can anticipate higher per-flight but lower population-based emissions.