Changes in the SO₂ Level and PM_2.5 Components in Shanghai Driven by Implementing the Ship Emission Control Policy

Area of Science:

• Environmental Science
• Atmospheric Chemistry
• Marine Pollution

Background:

• Air pollution from shipping is a significant environmental concern.
• The implementation of Domestic Emission Control Areas (DECA) aims to mitigate these emissions.
• Understanding the impact of DECA policies on air quality is essential.

Purpose of the Study:

• To evaluate the effectiveness of the DECA policy in Shanghai on ambient SO2 and particle composition.
• To analyze long-term variations in air pollutants before and after DECA implementation.
• To investigate changes in ship fuel oil composition and its relation to ambient particles.

Main Methods:

• Online single particle analysis and SO2 measurements from 2015-2017.
• Analysis of 1094 ship fuel oil samples.
• Comparison of data before and after the DECA policy implementation.

Main Results:

• A significant decrease in SO2 concentrations (27-55%) was observed post-DECA.
• An increase in the proportion of ship-emitted particles, but with lower vanadium content.
• Elemental carbon decreased, while organic carbon components increased due to fuel switching.
• Ship fuel oil analysis confirmed reduced sulfur content, with vanadium still correlated with sulfur in low-sulfur fuels.

Conclusions:

• The DECA policy effectively reduced SO2 emissions from ships in Shanghai.
• While sulfur content decreased, heavy fuel oil remains prevalent in low-sulfur fuels.
• Comprehensive control strategies addressing organic pollutants from ships are necessary to further improve air quality.