Cao Yang, Yue Xu, Liao Hong, Wang Xuemei, Lei Yadong, Zhou Hao
Jiangsu Nanjing Environmental Monitoring Center, Nanjing 210041, China.
Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, School of Environmental Science and Engineering, Nanjing University of Information Science & Technology (NUIST), Nanjing 210044, China.
Sci Total Environ. 2024 Oct 20;948:174821. doi: 10.1016/j.scitotenv.2024.174821. Epub 2024 Jul 16.
China implemented continuous forestation and experienced significant greening tendency in the past several decades. While the ecological project brings benefits to regional carbon assimilation, it also affects surface ozone (O) pollution level through perturbations in biogenic emissions and dry deposition. Here, we use a coupled chemistry-vegetation model to assess the impacts of land use and land cover change (LULCC) on summertime surface O in China during 2000-2019. The LULCC is found to enhance O by 1-2 ppbv in already-polluted areas. In contrast, moderate reductions of -0.4 to -0.8 ppbv are predicted in southern China where the largest forest cover changes locate. Such inconsistency is attributed to the background chemical regimes with positive O changes over VOC-limited regions but negative changes in NO-limited regions. The net contribution of LULCC to O budget in China is 24.17 Kg/s, in which the positive contribution by more isoprene emissions almost triples the negative effects by the increased dry deposition. Although the LULCC-induced O perturbation is much lower than the effects of anthropogenic emissions, forest expansion has exacerbated regional O pollution in North China Plain and is expected to further enhance surface O with continuous forestation in the future.
在过去几十年里，中国持续开展植树造林活动，绿化趋势显著。虽然生态工程给区域碳同化带来了好处，但它也通过生物源排放和干沉降的扰动影响地表臭氧（O）污染水平。在此，我们使用一个耦合化学-植被模型来评估2000-2019年期间土地利用和土地覆盖变化（LULCC）对中国夏季地表O的影响。研究发现，LULCC使已受污染地区的O浓度增加了1-2 ppbv。相比之下，在中国森林覆盖变化最大的南方地区，预计O浓度会适度降低-0.4至-0.8 ppbv。这种不一致归因于背景化学机制，在挥发性有机化合物（VOC）受限区域O浓度呈正变化，而在氮氧化物（NO）受限区域呈负变化。LULCC对中国O收支的净贡献为24.17千克/秒，其中异戊二烯排放增加的积极贡献几乎是干沉降增加的负面影响的三倍。尽管LULCC引起的O扰动远低于人为排放的影响，但森林扩张加剧了华北平原的区域O污染，预计未来随着森林的持续增加，地表O浓度还会进一步升高。
