Role of export industries on ozone pollution and its precursors in China

Jiamin Ou,Zbigniew Klimont,Zhifu Mi,Heran Zheng,Jing Meng,Cheng Li,Dabo Guan,Zhijiong Huang,Guanglin Jia,Peter K K Louie,Shaohui Zhang,Junyu Zheng,Yuli Shan

doi:10.1038/s41467-020-19035-x

Abstract

This study seeks to estimate how global supply chain relocates emissions of tropospheric ozone precursors and its impacts in shaping ozone formation. Here we show that goods produced in China for foreign markets lead to an increase of domestic non-methane volatile organic compounds (NMVOCs) emissions by 3.5 million tons in 2013; about 13% of the national total or, equivalent to half of emissions from European Union. Production for export increases concentration of NMVOCs (including some carcinogenic species) and peak ozone levels by 20–30% and 6–15% respectively, in the coastal areas. It contributes to an estimated 16,889 (3,839–30,663, 95% CI) premature deaths annually combining the effects of NMVOCs and ozone, but could be reduced by nearly 40% by closing the technology gap between China and EU. Export demand also alters the emission ratios between NMVOCs and nitrogen oxides and hence the ozone chemistry in the east and south coast.

Highlights

This study seeks to estimate how global supply chain relocates emissions of tropospheric ozone precursors and its impacts in shaping ozone formation
O3 in the troposphere is not directly emitted by human activities. It is formed from precursor emissions of non-methane-volatile organic compounds (NMVOCs), nitrogen oxide (NOx), carbon monoxide (CO) and others under photochemical reactions[4]
Though being dwarfed by China’s total emission budget, exportdriven non-methane volatile organic compounds (NMVOCs) emissions (3,794 kt in 2013) were equivalent to half the emissions of the European Union (EU, including EU-27 and UK)[18]. If such emissions were generated by a single country, it would be ranked as the 10th largest NMVOC emitter in the world[19]

Summary

Introduction

This study seeks to estimate how global supply chain relocates emissions of tropospheric ozone precursors and its impacts in shaping ozone formation. Exporting countries might see an increase in the emissions of O3 precursors, but a shift of the O3 formation chemistry due to disproportionate changes of NMVOCs and NOx emissions[4,17]. We utilise China’s 2012 multiregional input–output (MRIO) table, the Global Trade Analysis Database (GTAP) and an air-quality model to estimate the contribution of export demand on O3 precursors and its formation in China.

Results

Conclusion