Modeling of the Atmospheric Process of Cyanobacterial Toxins in Algal Aerosol
Modeling of the Atmospheric Process of Cyanobacterial Toxins in Algal Aerosol
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DOI：
10.1021/acsearthspacechem.3c00050
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发表时间：
2023-05
影响因子：
3.4
通讯作者：
Victoria Zorbas;M. Jang;Baharan Emam;Jiwon Choi
中科院分区：
文献类型：
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作者：
Victoria Zorbas;M. Jang;Baharan Emam;Jiwon Choi
利用有害藻类气溶胶反应（HAAR）模型，模拟了臭氧和OH自由基对蓝藻气溶胶中微囊藻毒素-LR（MC-LR）的降解。在室外实验室中观测了蓝藻气溶胶中MC-LR的夜间臭氧分解和白天光氧化过程。HAAR模型模拟了湿度和气溶胶成分对MC-LR衰减的影响。在该模式中，大气氧化剂到藻类气溶胶的气-粒分配的动力学处理使用的吸收和解吸过程。在模型模拟中，以臭氧分解速率常数（3 × 10- 11 cc/molecules/s）估算的MC-LR在66 ppb臭氧下的半衰期为4.6h ± 0.92。根据MC-LR与OH自由基的反应速率常数（6 × 10- 7 cc/molecules/s），在佛罗里达典型的夏季阳光下，白天MC-LR的半衰期估计为6分钟，表明与OH自由基的反应主导白天MC-LR的衰变。在中等的阳光下，典型的风速（9.2公里/小时），分散和HAAR模型预测，25%的气溶胶MC-LR经历的大气过程在0.92公里内从绽放源在佛罗里达最大的湖泊，这表明大气氧化的MC-LR衰变的关键作用。
The degradation of microcystin-LR (MC-LR) in cyanobacterial aerosol with atmospheric oxidants, such as ozone and OH radicals, was predicted by the Harmful Algal Aerosol Reaction (HAAR) model. The ozonolysis of MC-LR in cyanobacterial aerosol at nighttime and its photooxidation during the daytime was observed in an outdoor chamber. The HAAR model simulates the impact of humidity and aerosol compositions on MC-LR decay. In the model, gas-particle partitioning of atmospheric oxidants onto algal aerosol was kinetically treated using the absorption and desorption processes. In the model simulation, the half-life of MC-LR estimated with its ozonolysis rate constant (3 × 10–11cc/molecules/s) is 4.6 h ± 0.92 at 66 ppb ozone. With the reaction rate constant for MC-LR with OH radicals (6 × 10–7cc/molecules/s), the estimated half-life of MC-LR during daytime under Florida’s typical summer sunlight is 6 minutes, suggesting that the reaction with OH radicals dominates daytime MC-LR decay. Under moderate sunlight with a typical wind speed (9.2 km/h), the dispersion and HAAR models predict that 25% of aerosolized MC-LR undergoes the atmospheric process within 0.92 km from a bloom source in Florida’s largest lake, suggesting the critical role of the atmospheric oxidation of MC-LR decay.