Tropospheric ozone is a strong oxidant which affects human health, agricultural yields, and ecosystem functioning. Thus, it is very important to understand what factors determine ozone formation in order to control air pollution. It is well known that isoprene participates in ozone formation. In this study, we assess the potential impact of climate change in the Mediterranean region on ozone concentration, through drought-related increase or decrease in isoprene emissions after 1 (short drought scenario—1 year of 35% annual rain restriction) and 3 (long drought scenario—3 repeated years of 35% annual restriction) years of drought stress. Using an original experimental dataset of Downy oak isoprene emissions for several drought conditions and idealized drought scenarios in a modeling framework, we showed that ozone concentrations follow the same pattern than isoprene emissions. The short drought scenario used an isoprene emission factor (which is the standardized emission rate at 30 °C and 1000 μmol m⁻² s⁻¹ of photosynthetically active radiation (PAR)) 83% higher compared with natural drought and, thus, ozone concentrations increased by 5–30 μg m⁻³ (3–17%). The long drought scenario used an isoprene emission factor 26% lower compared with natural drought, and ozone concentrations accordingly decreased by 1–10 μg m⁻³ (0.6–6%). Our results showed that ozone concentration is affected by drought intensity and duration through modification of isoprene emissions indicating that drought stress should be implemented in models (predicting the BVOC emissions).

中文翻译：

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在法国地中海地区，异戊二烯对气候变化条件下臭氧生产的贡献

对流层臭氧是一种强氧化剂，会影响人类健康，农业产量和生态系统功能。因此，了解哪些因素决定臭氧的形成以控制空气污染非常重要。众所周知，异戊二烯参与臭氧的形成。在本研究中，我们通过1（短期干旱情景-一年35％的年度降雨限制的一年）和3（长期干旱）后与干旱相关的异戊二烯排放量的增加或减少，评估了地中海地区气候变化对臭氧浓度的潜在影响。干旱情景-干旱压力连续3年，每年限制35％）。在建模框架中使用针对多种干旱条件和理想干旱情景的Downy橡木异戊二烯排放的原始实验数据集，我们表明，臭氧浓度与异戊二烯排放遵循相同的模式。短期干旱情景使用异戊二烯排放因子（这是30°C和1000μmolm时的标准排放速率与自然干旱相比，光合作用辐射（PAR）的^-2  s ^-1高83％，因此，臭氧浓度增加了5–30μgm ^-3（3–17％）。与自然干旱相比，长期干旱情景使用的异戊二烯排放因子低26％，因此臭氧浓度相应降低了1-10μgm ^-3（0.6-6％）。我们的结果表明，臭氧浓度受异戊二烯排放量变化的干旱强度和持续时间的影响，表明应在模型中进行干旱胁迫（预测BVOC排放量）。