Impact of shipping emissions regulation on urban aerosol composition changes revealed by receptor and numerical modelling

Abstract

Various shipping emissions controls have recently been implemented at both local and national scales. However, it is difficult to track the effect of these on PM2.5 levels, owing to the non-linear relationship that exists between changes in precursor emissions and PM components. Positive Matrix Factorisation (PMF) identifies that a switch to cleaner fuels since January 2020 results in considerable reductions in shipping-source-related PM2.5, especially sulphate aerosols and metals (V and Ni), not only at a port site but also at an urban background site. CMAQ sensitivity analysis reveals that the reduction of secondary inorganic aerosols (SIA) further extends to inland areas downwind from ports. In addition, mitigation of secondary organic aerosols (SOA) in coastal urban areas can be anticipated either from the results of receptor modelling or from CMAQ simulations. The results in this study show the possibility of obtaining human health benefits in coastal cities through shipping emission controls.

Characteristics of Trace Metal Elements in Ambient Sub-Micron Particulate Matter in a Coastal Megacity of Northern China Influenced by Shipping Emissions from 2018 to 2022

“…Economic development brought about by growing ocean-going trade has negatively impacted urban climate, air quality, and human health [1][2][3][4][5]. SOx, NOx, OC, BC, and heavy metals released from the use of low-grade, high-sulfur fuels by marine vessels pose a serious threat to the atmospheric and marine environments, to the global climate, and to human health [1][2][3].…”

“…Economic development brought about by growing ocean-going trade has negatively impacted urban climate, air quality, and human health [1][2][3][4][5]. SOx, NOx, OC, BC, and heavy metals released from the use of low-grade, high-sulfur fuels by marine vessels pose a serious threat to the atmospheric and marine environments, to the global climate, and to human health [1][2][3]. Particulate emissions from ships affect ocean chemistry and climate change [4], and their metal elements are stored in high concentrations in marine organisms, posing a risk of ingestion by humans and threatening human health [5,6].…”

“…On 1 January 2019, the domestic emission control area (DECA 2.0) expanded upon the DECA 1.0 policy, with the emission control area extending about 12 nautical miles along the entire coastline of the country and ships being required to use 0.5% (m/m) sulfur fuel for navigation and berthing [9,10]. On 1 January 2020, the International Maritime Organization (IMO) issued a regulation that the sulfur content of fuel oil used by ships in the global seas shall not exceed 0.5% m/m in the future (IMO 2020) [2] (Figures S1-S3). At the same time, before the 2022 Beijing Winter Olympics (October 2021-January 2022) (Pre-OWG Beijing 2022), the Ministry of Ecology and Environment implemented a series of policies to adjust the industrial, energy, and transportation structure in Tianjin, Hebei, and surrounding areas.…”