The impact of shipping activities on air quality and residents' health in China's port cities

Abstract

Shipping activities emit pollutants such as NOX, SOX, and PM, which are detrimental to air quality and to the health of local residents. As one of the major shipping nations, China's population and port-related industries concentrate in coastal areas. However, an interesting phenomenon is that the average life expectancy of coastal port cities in China has not significantly decreased in the past few decades, but has instead shown an upward trend, and often higher than that of non-port cities. To explain this, this paper uses panel data from 36 port cities in China from 2001 to 2019. The relationship between shipping activities, air quality, and average life expectancy is investigated through a nonlinear mediation effect model, which is used to study the impact of shipping on health, as well as the mediating role of air quality. Main results underline that except for average turnaround time, other indicators representing shipping intensity are positively correlated with air quality index and average life expectancy, indicating that the economic benefits of ports are closely related to their operational efficiency. Shipping activities have a significant negative impact on the health level of port cities. This impact is influenced by the mediating variable of air quality and has a partial mediating effect. However, the impact of air quality on health presents a complex nonlinear relationship, with an inverted N-shaped curve, and the two inflection points are about 68 and 120 respectively. Our research provides guidance for the sustainable development of port cities, in order to achieve the balance between shipping activities and environment and health.