Observing network effect of shipping emissions from space: A natural experiment in the world’s busiest port

Abstract

Maritime trade and associated emissions are dynamic in nature. Although shipping emissions contribute significantly to air quality and climate change, their trade-governed dynamics remain less explored due to the lack of observational evidence. Here, we use satellite measurements to capture the redistribution of shipping nitrogen oxides (NOx) emissions from Shanghai port, the world’s busiest port, during a natural experiment posted by the localized COVID-19 lockdown in 2022. Viewing the ports as nodes in a network linked by ship journeys, we quantify a lockdown-induced -42% reduction in shipping NOx emissions for Shanghai port. We further identify an emission transfer to its neighboring connected ports, confirmed by comprehensive vessel activity observations. Our study highlights the socioeconomic drivers of shipping emissions, which may add additional layers of complexity to air quality management.

Short-Term Exposure to Fine Particulate Matter and Ozone: Source Impacts and Attributable Mortalities

“…Note that the zeroing-out method quantifies the source sensitivities to air pollutants, which include the interaction of each specific source with all other sources rather than the pure impact from the specific source alone. , CEDS sectors with higher levels of uncertainty include waste burning, residential emissions, and agricultural processes due to the difficulty in accurately tracking energy consumption statistics and uncertainties in the variability in source-specific emission factors. , However, the above sectors play relatively less important roles in our analysis (see Section ). Additionally, due to the use of relative differences in describing sectoral emission impacts, the method is less sensitive to the absolute values of GEOS-Chem simulations, as analyzed in our previous works. , …”

“…Additionally, due to the use of relative differences in describing sectoral emission impacts, the method is less sensitive to the absolute values of GEOS-Chem simulations, as analyzed in our previous works. 53 , 54 …”

“…Additionally, due to the use of relative differences in describing sectoral emission impacts, the method is less sensitive to the absolute values of GEOS-Chem simulations, as analyzed in our previous works. 53 2). Driven by prolonged pollution episodes and high concentrations, both PM 2.5 and O 3 pose significant challenges for health management in South Asia and East Asia, together accounting for 66.0% of global mortalities on average.…”