Trade-driven relocation of ground-level SO₂ concentrations across Chinese provinces based on satellite observations

The influence of trade on ground-level SO₂ concentrations in China was evaluated based on multiregional input-output (MRIO) analysis, using the ozone monitoring instrument (OMI) SO₂ columns and SO₂ profiles from an atmospheric chemical and transport model, MOZART-4. The provincial sum of ground-level SO₂ concentrations has a good consistency with the provincial SO₂ emissions (R = 0.65, p < 0.01). The provincial SO₂ concentrations presented strong spatial variations, with a range of 5.1-50.6 μg/m³ and an average of 19.7 μg/m³ across China. The international trade increased the SO₂ concentrations in all of the provinces and increased the national population-weighted SO₂ (PWM-SO₂) concentration by 2.9 μg/m³. Interprovincial trade within China decreased the ambient SO₂ concentrations in Beijing, Tianjin, and Chongqing and the provinces in southeast and central China, but increased SO₂ in the remaining provinces of China. In general, interprovincial trade decreased the national PWM-SO₂ concentration by 5.3 μg/m³.