Interprovincial Reliance for Improving Air Quality in China: A Case Study on Black Carbon Aerosol

Black carbon (BC) is of global concern
because of its adverse effects
on climate and human health. It can travel long distances via atmospheric
movement and can be geographically relocated through trade. Here,
we explored the integrated patterns of BC transport within 30 provinces
in China from the perspective of meteorology and interprovincial trade
using the Weather Research and Forecasting with Chemistry (WRF/Chem)
model and multiregional input-output
analysis. In general, cross-border BC transport, which accounts for
more than 30% of the surface concentration, occurs mainly between
neighboring provinces. Specifically, Hebei contributes 1.2 μg·m–3 BC concentration in Tianjin. By contrast, trade typically
drives virtual BC flows from developed provinces to heavily industrial
provinces, with the largest net flow from Beijing to Hebei (4.2 Gg).
Shanghai is most vulnerable to domestic consumption with an average
interprovincial consumption influence efficiency of 1.5 × 10–4 (μg·m–3)/(billion Yuan·yr–1). High efficiencies (∼8 × 10–5 (μg·m–3)/(billion Yuan·yr–1)) are also found from regions including Beijing,
Jiangsu, and Shanghai to regions including Hebei, Shandong, and Henan.
The above source–receptor relationship indicates two control
zones: Huabei and Huadong. Both mitigating end-of-pipe emissions and
rationalizing the demand for pollution-intense products are important
within the two control zones to reduce BC and other pollutants.