Abstract. Atmospheric volatile organic compounds (VOCs) constitute a wide range of species, acting as precursors to ozone and aerosol formation. Atmospheric chemistry and transport models (CTMs) are crucial to understanding the emissions, distribution, and impacts of VOCs. Given the uncertainties in VOC emissions, lack of evaluation studies, and recent changes in emissions, this work adapts the European Monitoring and Evaluation Programme Meteorological Synthesizing Centre – West (EMEP MSC-W) CTM to evaluate emission inventories in Europe. Here we undertake the first intensive model–measurement comparison of VOCs in 2 decades. The modelled surface concentrations are evaluated both spatially and temporally, using measurements from the regular EMEP monitoring network in 2018 and 2019, as well as a 2022 campaign. To achieve this, we utilised the UK National Atmospheric Emissions Inventory to derive explicit emission profiles for individual species and employed a tracer method to produce pure concentrations that are directly comparable to observations. The degree to which the modelled and measured VOCs agree varies depending on the specific species. The model successfully captures the overall spatial and temporal variations of major alkanes (e.g. ethane, n-butane) and unsaturated species (e.g. ethene, benzene) but less so for propane, i-butane, and ethyne. This discrepancy underscores potential issues in the boundary conditions for the latter species and in their primary emissions from, in particular, the solvent and road transport sectors. Specifically, potential missing propane emissions and issues with its boundary conditions are highlighted by large model underestimations and smaller propane-to-ethane ratios compared to the measurement. Meanwhile, both the model and measurements show strong linear correlations among butane isomers and among pentane isomers, indicating common sources for these pairs of isomers. However, modelled ratios of i-butane to n-butane and i-pentane to n-pentane are approximately one-third of the measured ratios, which is largely driven by significant emissions of n-butane and n-pentane from the solvent sector. This suggests issues with the speciation profile of the solvent sector, underrepresented contributions from transport and fuel evaporation sectors in current inventories, or both. Furthermore, the modelled ethene-to-ethyne and benzene-to-ethyne ratios differ significantly from measured ratios. The different model performance strongly points to shortcomings in the spatial and temporal patterns and magnitudes of ethyne emissions, especially during winter. For OVOCs, the modelled and measured concentrations of methanal and methylglyoxal show a good agreement, despite a moderate underestimation by the model in summer. This discrepancy could be attributed to an underestimation of contributions from biogenic sources or possibly a model overestimation of their photolytic loss in summer. However, the insufficiency of suitable measurements limits the evaluation of other OVOCs. Finally, model simulations employing the CAMS inventory show slightly better agreements with measurements than those using the Centre on Emission Inventories and Projections (CEIP) inventory. This enhancement is likely due to the CAMS inventory's detailed segmentation of the road transport sector, including its associated sub-sector-specific emission profiles. Given this improvement, alongside the previously mentioned concerns about the model's biased estimations of various VOC ratios, future efforts should focus on a more detailed breakdown of dominant emission sectors (e.g. solvents) and the refinement of their speciation profiles to improve model accuracy.

中文翻译：

---

在欧洲监测和评估计划地点对模拟与观测的非甲烷挥发性有机化合物进行评估


摘要。大气中的挥发性有机化合物 (VOC) 构成了多种物质，是臭氧和气溶胶形成的前体。大气化学和传输模型 (CTM) 对于了解 VOC 的排放、分布和影响至关重要。鉴于VOC排放的不确定性、评估研究的缺乏以及排放的最新变化，本工作采用欧洲监测和评估计划气象综合中心 - 西部（EMEP MSC-W）CTM来评估欧洲的排放清单。在这里，我们进行了 2 年来首次对 VOC 进行强化模型测量比较。使用 2018 年和 2019 年常规 EMEP 监测网络以及 2022 年活动的测量数据，对建模的表面浓度进行空间和时间评估。为了实现这一目标，我们利用英国国家大气排放清单来得出各个物种的明确排放概况，并采用示踪剂方法来产生可与观测结果直接比较的纯浓度。模拟和测量的 VOC 一致程度因具体物种而异。该模型成功捕获了主要烷烃（例如乙烷、正丁烷）和不饱和物质（例如乙烯、苯）的整体空间和时间变化，但丙烷、异丁烷和乙炔的情况较差。这种差异强调了后一种物种的边界条件及其主要排放（特别是溶剂和道路运输部门）的潜在问题。具体来说，与测量值相比，模型的较大低估和较小的丙烷与乙烷比率凸显了潜在的丙烷排放缺失及其边界条件问题。 同时，模型和测量结果都显示丁烷异构体和戊烷异构体之间具有很强的线性相关性，表明这些异构体对的共同来源。然而，异丁烷与正丁烷和异戊烷与正戊烷的模型比率约为测量比率的三分之一，这主要是由溶剂行业正丁烷和正戊烷的大量排放造成的。这表明溶剂行业的形态特征存在问题，运输和燃料蒸发行业在当前清单中的贡献不足，或两者兼而有之。此外，模拟的乙烯与乙炔和苯与乙炔的比率与测量的比率存在显着差异。不同的模型表现强烈表明了乙炔排放的时空模式和强度的缺陷，特别是在冬季。对于 OVOC，尽管模型在夏季略有低估，但甲醛和甲基乙二醛的建模和测量浓度表现出良好的一致性。这种差异可能是由于低估了生物源的贡献，或者可能是模型高估了夏季的光解损失。然而，适当测量的不足限制了其他 OVOC 的评估。最后，使用 CAMS 清单的模型模拟与使用排放清单和预测中心 (CEIP) 清单的模型模拟相比，与测量结果的一致性稍好一些。这种增强可能是由于 CAMS 清单对道路运输部门的详细细分，包括其相关的子部门特定排放概况。 鉴于这一改进，除了前面提到的对模型对各种 VOC 比率的估计有偏差的担忧之外，未来的工作应集中于对主要排放部门（例如溶剂）进行更详细的细分，并细化其形态分布，以提高模型的准确性。