A Spatial Analysis of Atmospheric Ammonia and Ammonium in the U.K.
A Spatial Analysis of Atmospheric Ammonia and Ammonium in the U.K.
复制标题
英国大气氨和铵的空间分析
作者：
M. Sutton;Y. S. Tang;U. Dragosits;N. Fournier;A. Dore;Ron I. Smith;K. Weston;D. Fowler
随着国际上采取措施减少 SO2 和 NOx 排放，NH3 排放对酸化、氮富营养化和气溶胶形成的影响逐渐受到关注。英国建立了监测网络来测量大气中气态NH3和气溶胶NH4的空间分布和长期趋势。与此同时，还开发了大气化学和传输模型 FRAME，重点关注还原氮 (NHx)。监测数据对于评估模型很重要，而模型对于更详细的空间评估至关重要。全国网络已建立，拥有 80 多个采样点。使用新型低成本 denuder-filterpack 系统对 NH3 和 NH4（最多 50 个站点）进行了测量。此外，改进的 NH3 被动采样方法已应用于探索局部变异性。测量结果证实了 NH3 的高空间变异性（年平均值为 0.06 至 11 mg NH3 m），与其作为地面源排放的主要污染物的性质一致，而 NH4 作为缓慢形成的次级产品，显示出较小的空间变异性（0.14 至 2.4 mg NH4 m）。这些特征在 FRAME 模型中得到再现，该模型提供 5 公里级别的估计。对基础 NH3 排放清单的分析表明，相对于牛的排放量，绵羊的排放量可能被低估，非农业源的排放量可能被高估。模型和测量的结合用于估计不同植被类型的干燥沉降的空间模式。综合方法为评估英国各地 NHx 对国际排放控制的反应提供了基础。
As measures are implemented internationally to reduce SO2 and NOx emissions, attention is falling on the contribution of NH3 emissions to acidification, nitrogen eutrophication, and aerosol formation. In the U.K., a monitoring network has been established to measure the spatial distribution and long-term trends in atmospheric gaseous NH3 and aerosol NH4. At the same time, an atmospheric chemistry and transport model, FRAME, has been developed with a focus on reduced nitrogen (NHx). The monitoring data are important to evaluate the model, while the model is essential for a more detailed spatial assessment. The national network is established with over 80 sampling locations. Measurements of NH3 and NH4 (at up to 50 sites) have been made using a new low-cost denuder-filterpack system. Additionally, improved passive sampling methods for NH3 have been applied to explore local variability. The measurements confirm the high spatial variability of NH3 (annual means 0.06 to 11 mg NH3 m), consistent with its nature as a primary pollutant emitted from ground-level sources, while NH4, being a slowly formed secondary product, shows much less spatial variability (0.14 to 2.4 mg NH4 m). These features are reproduced in the FRAME model, which provides estimates at a 5-km level. Analysis of the underlying NH3 emission inventory shows that sheep emissions may have been underestimated and nonagricultural sources overestimated relative to emissions from cattle. The combination of model and measurements is applied to estimate spatial patterns of dry deposition to different vegetation types. The combined approach provides the basis to assess NHx responses across the U.K. to international emission controls.