Ozone Pollution Effects on Agricultural Crop Yields

Tropospheric ozone, a secondary pollutant formed by photochemical reactions of nitrogen oxides and volatile organic compounds, acts as a potent oxidant when absorbed through stomata. Once inside the leaf, ozone generates reactive oxygen species that disrupt photosynthetic machinery, accelerate senescence and impair carbon assimilation. The severity of yield loss varies among crops—soybean and wheat typically exhibit greater sensitivity than maize and rice—depending on genotypic tolerance, local climate and management practices. Globally, ozone-induced yield reductions are estimated in the range of 5–15% for major cereals, amounting to tens of millions of tonnes of lost production each year. These losses translate into significant economic burdens for producers and consumers, undermine food security and pose a barrier to climate-smart agriculture. Research efforts span field-scale exposure experiments, flux-based risk assessments and coupled crop-climate models, all of which converge on the need for integrated strategies. These include breeding or selecting cultivars with improved stomatal regulation and antioxidant capacity, optimising fertilisation and irrigation regimes to mitigate oxidative damage, and implementing air-quality policies targeting precursor emissions. A comprehensive understanding of exposure metrics and critical growth stages is essential to refine impact assessments and guide adaptation measures worldwide.

Research from Nature Portfolio

Recent observational data from Southeast China reveal that rice yields decline nonlinearly with increasing frequency of high-ozone days, particularly during the panicle-formation stage. An additional day above 120 ppb can reduce yield by over 1%, whereas lower thresholds before or after this critical window have negligible effects. These findings emphasise the importance of stage-specific sensitivity and suggest that regional ozone management and cultivar selection timed to reproductive phases could substantially curb losses without extra chemical inputs.

Ozone Pollution Effects on Agricultural Crop Yields publication trend

The graph below shows the total number of articles in ozone pollution effects on agricultural crop yields across all publications each year (not limited to Nature Index journals).

Technical terms

Tropospheric ozone: Ground-level oxidant formed by sunlight-driven reactions of NOₓ and VOCs, harmful to plant tissues.

Stomatal conductance: A measure of gas exchange capacity in leaves that governs ozone uptake and transpiration.

Reactive oxygen species (ROS): Highly reactive molecules generated by ozone within plant cells, causing oxidative damage.

AOT40: Accumulated ozone exposure over a threshold of 40 ppb during daylight hours, used to estimate crop injury risk.

Senescence: Age-related decline in leaf function and chlorophyll content, accelerated by ozone stress.

Yield gap: The difference between attainable and actual crop yield, here specifically due to ozone exposure.

References

1. Assessing the costs of ozone pollution in India for wheat producers, consumers, and government food welfare policies. Proceedings of the National Academy of Sciences of the United States of America (2023).
2. Chronic ozone exposure affects nitrogen remobilization in wheat at key growth stages. The Science of The Total Environment (2023).
3. Closing the global ozone yield gap: Quantification and cobenefits for multistress tolerance. Global Change Biology (2018).
4. Ozone effects on crops and consideration in crop models. European Journal of Agronomy (2018).
5. Stage-specific, Nonlinear Surface Ozone Damage to Rice Production in China. Scientific Reports (2017).