Ozone Pollution Threatens Food Security in China: New Study Reveals Devastating Impact of COVID-19 Lockdowns

Strategic Insights -

China's rapidly increasing ozone pollution poses a significant threat to food security, with a recent study revealing that rising ozone levels have reduced national-level wheat, rice, and maize yields by 14.51%, 11.10%, and 3.99%, respectively. The study, conducted by researchers from the Chinese Academy of Sciences, analyzed hourly surface ozone data from 2005 to 2020 and found that the accumulated ozone exposure over a threshold of 40 ppb increased by 10% during 2005-2019, but decreased by 5.56% in 2020 due to COVID-19 lockdowns.

Key Takeaways:

  • Ozone pollution has increased by 10% from 2005-2019, with a 5.56% decrease in 2020 due to COVID-19 lockdowns.
  • Rising ozone pollution reduced national-level wheat, rice, and maize yields by 14.51% ± 0.43%, 11.10% ± 0.6%, and 3.99% ± 0.11%, respectively.
  • A Business-As-Usual projection suggested that relative yield loss would potentially reach 8%-18% at the national scale by 2050 if no emission control is implemented.
  • COVID-19 lockdowns in 2020 led to significantly reduced relative yield loss for maize (0.52%) and rice (2.17%), but not for wheat (0.11%), with the largest reduction (1.88%-9.4%) in North China Plain.
  • The study concluded that ozone pollution has significantly affected China's crop yields, production, and economic losses, underscoring the urgent need to curb ozone pollution to safeguard food security.

Statistics:

  • Ozone pollution reduced national-level wheat, rice, and maize yields by 14.51%, 11.10%, and 3.99%, respectively.
  • Accumulated ozone exposure over a threshold of 40 ppb increased by 10% during 2005-2019.
  • Accumulated ozone exposure over a threshold of 40 ppb decreased by 5.56% in 2020 due to COVID-19 lockdowns.
  • Business-As-Usual projection suggested that relative yield loss would potentially reach 8%-18% at the national scale by 2050.
  • COVID-19 lockdowns led to significantly reduced relative yield loss for maize (0.52%) and rice (2.17%) in 2020.

Sources:

  • Ozone pollution induced-yield loss of major staple crops in China and effects from COVID-19. Journal of Environmental Sciences, 2025;157:804-820.
  • Chinese Academy of Sciences. (2025). Ozone pollution induced-yield loss of major staple crops in China and effects from COVID-19. Journal of Environmental Sciences, 157, 804-820.
  • Science Press. (n.d.). Journal of Environmental Sciences. Retrieved from www.journals.elsevier.com/journal-of-environmental-sciences/
  • Wang, S., et al. (2025). Ozone pollution induced-yield loss of major staple crops in China and effects from COVID-19. Journal of Environmental Sciences, 157, 804-820.