College of Environment and Climate, Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China.
College of Environment and Climate, Institute for Environmental and Climate Research, Jinan University, Guangzhou 511443, China; Australia-China Centre for Air Quality Science and Management (Guangdong), Guangzhou 511443, China; Guangdong Provincial Observation and Research Station for Atmospheric Environment and Carbon Neutrality in Nanling Forests, China.
Sci Total Environ. 2024 Nov 20;952:175887. doi: 10.1016/j.scitotenv.2024.175887. Epub 2024 Aug 29.
Biogenic volatile organic compounds (BVOCs) significantly impact atmospheric chemistry, with emissions potentially influenced by nitrogen (N) deposition. The response of BVOC emissions to increasing N deposition remains debated. In this study, we examined Eucalyptus urophylla (E. urophylla) using three N treatments: N0, N50, and N100 (0, 50, and 100 kg N hm yr N addition). These treatments were applied to mature E. urophylla trees in a plantation subjected to over 10 years of soil N addition in southern China, a region with severe N deposition. Seventeen BVOCs were measured, with isoprene (36.99 %), α-pinene (38.80 %), and d-limonene (14.27 %) being the predominant compounds under natural conditions. Total BVOC emissions under N50 were nearly double those under N0 and N100, with leaf net CO assimilation identified as the most critical photosynthetic parameter. Isoprene and α-pinene emissions significantly increased under N50 compared to N0, while d-limonene emission decreased under N100. Stronger correlations for individual BVOCs under N50 and N100 compared to N0 might be due to differences in BVOC biosynthetic pathways and storage structures. The localized canopy-scale emission factors (EFs) under N50 were significantly higher than the default values in the Model of Emissions of Gases and Aerosols from Nature (MEGAN), suggesting the model might underestimate BVOC emissions from Eucalyptus in southern China under increased N deposition. Additionally, the secondary pollutant formation potentials of BVOCs were evaluated, identifying isoprene and monoterpenes as primary precursors of ozone and secondary organic aerosols. This study provides insights into the impacts of increased N deposition on BVOC emissions and their contribution to secondary atmospheric pollution. Updating localized BVOC EFs for subtropical tree species in southern China is crucial to reduce uncertainties in BVOC estimations under current and future N deposition scenarios.
生物源挥发性有机化合物 (BVOCs) 对大气化学有重大影响，其排放可能受氮 (N) 沉积的影响。BVOC 排放对增加 N 沉积的响应仍存在争议。在这项研究中，我们使用三种 N 处理（N0、N50 和 N100）对尾叶桉（Eucalyptus urophylla）进行了研究：N0、N50 和 N100（0、50 和 100 kg N hm-2 yr-1 的 N 加量）。这些处理应用于中国南方一个种植园中经过 10 多年土壤 N 加量处理的成熟尾叶桉树上，该地区 N 沉积严重。共测量了 17 种 BVOCs，异戊二烯（36.99%）、α-蒎烯（38.80%）和柠檬烯（14.27%）是自然条件下的主要化合物。N50 下的总 BVOC 排放量几乎是 N0 和 N100 下的两倍，叶片净 CO 同化被确定为最关键的光合作用参数。与 N0 相比，N50 下异戊二烯和α-蒎烯的排放量显著增加，而 N100 下柠檬烯的排放量减少。与 N0 相比，N50 和 N100 下个别 BVOC 的相关性更强，这可能是由于 BVOC 生物合成途径和储存结构的差异所致。N50 下本地化冠层尺度排放因子（EF）明显高于自然排放模型（MEGAN）中的默认值，表明该模型可能低估了中国南方增加 N 沉积下桉树的 BVOC 排放。此外，评估了 BVOCs 的二次污染物形成潜力，确定异戊二烯和单萜为臭氧和二次有机气溶胶的主要前体。本研究提供了对增加的 N 沉积对 BVOC 排放及其对二次大气污染贡献的影响的见解。更新中国南方亚热带树种本地化 BVOC EF 对于减少当前和未来 N 沉积情景下 BVOC 估算的不确定性至关重要。
