Integrated Assessment of Near-Surface Ozone Impacts on Rice Yield and Sustainable Cropping Strategies in Pearl River Delta (2015–2023)

Near-surface ozone (O3) pollution has emerged as a growing threat to rice production in the Pearl River Delta (PRD), impairing photosynthesis, suppressing crop growth, and reducing yields. This study integrated long-term observational data with spatial crop distribution data and modeling approaches to assess O3-induced impacts on rice yields and associated economic losses across the PRD from 2015 to 2023. The results showed that annual average O3 concentrations during rice-growing periods increased from 41.3 to 66.0 μg/m3, with accumulated AOT40 values reaching 20.1 ppm·h. O3 exposure led to annual average rice yield losses of 10.8% ± 0.8%, including 9.3% for double-early rice and 12.3% for double-late rice. Absolute yield losses totaled approximately 333,000 tons per year, equivalent to the caloric needs of 2.69 million people, with economic losses exceeding CNY 844 million. Vulnerability hotspots were identified in Zhaoqing and Jiangmen, each suffering over 100,000 tons of annual losses. Scenario simulations indicated that a 20% reduction in ambient O3 could recover up to 54,700 tons annually. Future projections under RCP 2.6–8.5 suggested continued yield losses of 14,900 to 23,200 tons per year by 2050. Temporal adjustments to planting calendars may further mitigate these effects. This study highlights the urgent need for integrated mitigation strategies to enhance agricultural resilience in the face of ozone stress in industrialized delta regions.