College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
Sci Total Environ. 2023 Dec 1;902:165877. doi: 10.1016/j.scitotenv.2023.165877. Epub 2023 Aug 6.
Biogenic volatile organic compounds (BVOCs), which are produced and emitted by plants, have significant chemical reactivity in the atmosphere and impacting climate change. Qinghai Province, a vital component of the plateau, has abundant vegetation resources, primarily grasslands and forests, yet BVOCs emissions and their impact on air quality remain understudied. In this study, the emissions rates and compositions of BVOCs from seven dominant vegetation types in Qinghai Province were sampled and analyzed using a closed-loop stripping dynamic headspace sampling approach combined with GC-MS, and the total emissions of BVOCs in Qinghai province in 2021 were estimated by using G95 model. At the same time, the emission characteristics of various vegetation types were also analyzed. The results showed that the emissions rates and compositions of BVOCs differed significantly among vegetation types, with monoterpenes being the dominant emission composition in coniferous forests, which accounted for >70 % of the total BVOCs emissions, while isoprene being the main composition in alpine meadow, accounting for 84.96 %. The emissions of three typical vegetation types, Picea asperata, alpine meadow and alpine steppe, were monitored daily, revealing significant diurnal and clear unimodal patterns. The study also found that the annual average BVOCs emissions from vegetation sources in Qinghai Province were estimated to be 1550.63 Gg yr, with isoprene contributing the highest proportion of emissions, accounting for 56.94 %. Grassland was the largest BVOCs emission source in Qinghai Province, with an annual average emission of 1438.52 Gg yr. Additionally, BVOCs emissions in Qinghai Province showed strong seasonal and daily variation patterns, with the highest emissions occurring in summer, with the peak in July. These findings provide the characteristics of BVOCs emissions from vegetation sources in the Tibetan Plateau, which will contribute to a better understanding of their impact on atmospheric chemistry and climate change.
生物源挥发性有机化合物（BVOCs）由植物产生和排放，在大气中有显著的化学反应活性，影响气候变化。青海省作为高原的重要组成部分，拥有丰富的植被资源，主要包括草原和森林，但 BVOCs 的排放及其对空气质量的影响仍研究不足。本研究采用闭路式动态顶空采样法结合 GC-MS 对青海省 7 种主要植被类型的 BVOCs 排放速率和组成进行了采样分析，并采用 G95 模型估算了 2021 年青海省 BVOCs 的总排放量。同时，还分析了各种植被类型的排放特征。结果表明，植被类型之间 BVOCs 的排放速率和组成差异显著，针叶林以单萜烯为优势排放成分，占总 BVOCs 排放量的>70%，高山草甸以异戊二烯为主要组成部分，占 84.96%。对三种典型植被类型（青海云杉、高山草甸和高山草原）进行了日排放监测，发现具有明显的日变化和清晰的单峰模式。研究还发现，青海省植被源每年平均 BVOCs 排放量估计为 1550.63 Gg yr，其中异戊二烯的排放量最高，占 56.94%。草原是青海省最大的 BVOCs 排放源，年平均排放量为 1438.52 Gg yr。此外，青海省的 BVOCs 排放量具有很强的季节性和日变化模式，夏季排放量最高，7 月达到峰值。这些发现提供了青藏高原植被源 BVOCs 排放的特征，将有助于更好地了解它们对大气化学和气候变化的影响。
