Toxic air pollution and container port efficiency in the USA

Toxic air pollution has long been ignored in port efficiency analysis, especially for US container ports. This article studied both the traditional efficiency and environmental efficiency of the top 20 container ports in the United States using data envelopment analysis. Our results show that the largest container ports in the United States are the most technical and scale efficient. Economies of scale prevail in US container ports and the optimal operational scales have been reached by the largest ones. Environmental efficiency scores are obtained from an environmental sensitive model, which includes two types of toxic air emissions, SOx and PM2.5. Normalized efficiency scores of the traditional model and the environmental sensitive model are compared with find which ports lie the furthest from average performance in terms of air pollution control. The Ports of Palm Beach, Houston and Jacksonville are found to be the best in environmental performance. Overall on average, the 20 container ports could have saved 106 cranes and 14 852 ft of container berths; reduce 543.24 tons of PM2.5 and 4251.52 tons of SOx; and generate 5.8 million more TEUs in 2005, if they were all producing at the production frontier in that year.