A multinational study, led by the UK’s Centre for Ecology & Hydrology, quantifies the negative impact of ozone pollution on crop yields and identifies practical short- and medium-term action that could make crops more resilient.

The research shows that ozone pollution represents a significant challenge to global food production and that taking action to mitigate the effects of ozone pollution on crop yields could contribute to delivering UN Sustainable Development Goal 2, which seeks sustainable solutions to end hunger in all its forms by 2030 and to achieve food security. 

The new paper, Closing the global ozone yield gap: Quantification and co-benefits for multi-stress tolerance, which also involved scientists from the University of Gothenburg, MET Norway and others in the UK, Sweden, Germany, USA, China, Japan and India, is published in the journal Global Change Biology today (August 7, 2018).  

It estimates that ozone pollution reduces the yield of four staple crops by up to 227 million tonnes a year in total across the world, with the average yield loss for these crops being:

  • 12.4% for soybean
    A wheat field
  • 7.1% for wheat
  • 4.4% for rice
  • 6.1% for maize.

The losses are up to 15% in the large wheat-producing areas of India and China. 

While the paper’s authors recommend reducing the polluting gases from vehicles and industry that react to form ozone as the most effective long-term solution, they identify practical, shorter-term actions. These are:

  • Screening of existing crops for their tolerance to ozone
  • Timing of irrigation to avoid periods when there are high ozone levels.

The paper also points to technological innovations that crop breeders and agricultural chemists could take to improve the resilience of crops to ozone pollution, including:

  • Breeding new varieties of crop that cope with ozone better and will have high productivity in an increasingly warmer climate
  • The development of agrochemicals that can protect crops from ozone and other threats such as drought and heat stress but do not have a toxic effect on the environment

Professor Gina Mills, of the Centre for Ecology & Hydrology, lead author of the new paper, says: “What’s new in our study is that we estimate on a global scale how much ozone gets into the plants rather than simply the concentration in the air above them, and compare effects of ozone with effects of other stresses. We found that in some countries where food production is most needed, ozone can be as big a threat to crop yield as drought, heat or nutrient stress, but less of a problem than pests and diseases.”

“It is crucial to increase production to meet the demands of a rapidly growing global population. Therefore, we recommend that, given the negative effects of ozone on staple food crops combined with these other threats, there should be more action to address the yield gap.”

We found that in some countries where food production is most needed, ozone can be as big a threat to crop yield as drought - Professor Gina Mills

Previous research led by the Centre for Ecology & Hydrology found that irrigation can exacerbate the adverse effect of ozone pollution on crops. This is because when the plants have enough water, the stomatal pores on the leaf surface are more likely to be open, but this means that they also absorb ozone.

Therefore, the scientists involved in the research say it is important to have accurate forecasting to predict periods of higher and lower ozone levels so farmers can time irrigation accordingly.

One of the solardomes at Abergwyngregyn where the Centre for Ecology & Hydrology is carrying out crop experiments

As part of its efforts to promote sustainable use of natural resources in Official Development Assistance (ODA) countries, the Centre for Ecology & Hydrology is growing and screening crop plants to determine their sensitivity to ozone, plus carrying out trials with different levels and timing of irrigation.

Using the results from these experiments, which are taking place in solardomes (pictured, right) in North Wales, the scientists will be able to help advise farmers and agronomists across the world on how to reduce the impact of ozone, thus increasing their crop yield.

Contact information

For images, interviews and to arrange a visit to the solardomes, please contact Simon Williams, Media Relations Officer at the Centre for Ecology & Hydrology, UK. Tel. +44 (0) 7920 295384, 01491 69227. Email. simwil@ceh.ac.uk

Lead author

Prof Gina Mills, Centre for Ecology & Hydrology, UK. Email gmi@ceh.ac.uk

Additional information

  • The highest ozone levels are in many of the world’s important crop-growing regions. Production losses due to ozone pollution are believed to be the highest in the large wheat-producing areas of India and China - with more than 15% reduced yield for that crop in parts of the north of the two countries – as well as France and Germany plus the central states of the USA. Modelling in this study suggests that the highest ozone-induced production losses for soybean are in North and South America while for wheat they are in India and China, for rice in parts of India, Bangladesh, China and Indonesia, and for maize in China and the USA.
  • The Centre for Ecology & Hydrology’s experiments on crops in solardomes are part of its SUNRISE project, which seeks to provide scientific evidence and advice to improve livelihoods and wellbeing of people in Official Development Assistance (ODA) countries through reduced environmental risk and improved reliability of the supply of food, water and other natural resources. For more information, see our website

Paper information

Closing the global ozone yield gap: Quantification and cobenefits for multi-stress tolerance. Mills G, Sharps K, Simpson D; Pleijel H, Frei M, Emberson L, Uddling J, Broberg M, Feng Z, Kobayashi K, Agrawal M. Global Change Biology. DOI: https://doi.org/10.1111/gcb.14381
Other reference: Ozone pollution will compromise efforts to increase global wheat production, Mills et al. 2018. Global Change Biology. DOI: https://doi.org/10.1111/gcb.14157


The research was funded by the Natural Environment Research Council (NERC) for CEH’s SUNRISE programme, the Adlerbertska Foundation in Sweden, EMEP (the European Monitoring and Evaluation Programme) and the EU.

Research institution information

Centre for Ecology & Hydrology, UK
The Centre for Ecology & Hydrology (CEH) is the UK's Centre of Excellence for integrated research in the land and freshwater ecosystems and their interaction with the atmosphere. CEH is part of the Natural Environment Research Council (NERC), employs more than 450 people at four major sites in England, Scotland and Wales, hosts more than 150 PhD students and has an overall budget of about £35m. CEH tackles complex environmental challenges to deliver practicable solutions so that future generations can benefit from a rich and healthy environment. http://www.ceh.ac.uk
Follow the latest developments in CEH research via Twitter at @CEHScienceNews

University of Gothenburg, Sweden
The University of Gothenburg, which has 38 000 students and 6000 employees, is environmentally certified and works actively for sustainable development. Strong research and study programmes attract scientists and students from all around the world. https://www.gu.se

Chalmers University of Technology, Sweden
Chalmers conducts research and offers education in technology, science, shipping and architecture. Based in Gothenburg, Chalmers has 10,300 full-time students and 3,100 employees. https://www.chalmers.se

Norwegian Meteorological Institute, Norway
The institute, also known as MET Norway, provides weather forecasts for civilian and military uses, and conducts research in meteorology, oceanography, air pollution and climatology. MET Norway also hosts the Meteorogical Synthesizing Centre West (MSC-W) of EMEP. https://www.met.no/en

Agricultural Research Service, USA
ARS is the principal research agency of the United States Department of Agriculture. Its remit is extending the nation's scientific knowledge and solving agricultural problems. https://www.ars.usda.gov/

University of Bonn, Germany
Founded 200 years ago, the university, which has 38,000 students, is internationally renowned for top-level science and research-oriented study programmes. https://www.uni-bonn.de/

Stockholm Environment Institute at York, UK
SEI is an international non-profit research and policy organization that tackles environment and development challenges, connecting science and decision-making to develop solutions for a sustainable future. Its headquarters are in Sweden but it also operates from six other main locations across the world, including at the University of York where their contribution to this study was conducted. https://www.sei.org/

Chinese Academy of Sciences, China
The academy aims to explore and harness high technology and the natural sciences for the benefit of China and the world. Comprising a comprehensive research and development network, it brings together scientists and engineers from around the world to address both theoretical and applied problems using world-class scientific and management approaches. http://english.cas.cn/

The University of Tokyo, Japan
The university aims to be a world-class platform for research and education, contributing to human knowledge in partnership with other leading global universities. https://www.u-tokyo.ac.jp

Banaras Hindu University, India
This public university is located in Uttar Pradesh. Established in 1916, BHU is one of the largest residential universities in Asia, with more than 30,000 students. A core aim is to help address India’s poverty by focusing on technology and science. www.bhu.ac.in