Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences (CAS), Beijing, 100101, China; University of Chinese Academy of Sciences, Beijing, 100039, China.
Chubu Institute for Advanced Studies, Chubu University, Kasugai, 487-8501, Japan.
Environ Pollut. 2019 Apr;247:216-228. doi: 10.1016/j.envpol.2019.01.028. Epub 2019 Jan 10.
Biomass burning (BB) is one of the largest sources of carbonaceous aerosols with adverse impacts on air quality, visibility, health and climate. BB emits a few specific aromatic acids (p-hydroxybenzoic, vanillic, syringic and dehydroabietic acids) which have been widely used as key indicators for source identification of BB-derived carbonaceous aerosols in various environmental matrices. In addition, measurement of p-hydroxybenzoic and vanillic acids in snow and ice cores have revealed the historical records of the fire emissions. Despite their uniqueness and importance as tracers, our current understanding of analytical methods, concentrations, diagnostic ratios and degradation processes are rather limited and scattered in literature. In this review paper, firstly we have summarized the most established methods and protocols for the measurement of these aromatic acids in aerosols and ice cores. Secondly, we have highlighted the geographical variability in the abundances of these acids, their diagnostic ratios and degradation processes in the environments. The review of the existing data indicates that the concentrations of aromatic acids in aerosols vary greatly with locations worldwide, typically more abundant in urban atmosphere where biomass fuels are commonly used for residential heating and/or cooking purposes. In contrast, their concentrations are lowest in the polar regions which are avoid of localized emissions and largely influenced by long-range transport. The diagnostic ratios among aromatic acids can be used as good indicators for the relative amounts and types of biomass (e.g. hardwood, softwood and herbaceous plants) as well as photochemical oxidation processes. Although studies suggest that the degradation processes of the aromatic acids may be controlled by light, pH and hygroscopicity, a more careful investigation, including closed chamber studies, is highly appreciated.
生物质燃烧（BB）是含碳气溶胶的最大来源之一，对空气质量、能见度、健康和气候都有不利影响。BB 排放出几种特定的芳香酸（对羟基苯甲酸、香草酸、丁香酸和脱氢枞酸），这些酸已被广泛用作各种环境基质中源自 BB 的含碳气溶胶源识别的关键指标。此外，雪和冰芯中对羟基苯甲酸和香草酸的测量揭示了火灾排放的历史记录。尽管它们作为示踪剂具有独特性和重要性，但我们对其分析方法、浓度、诊断比和降解过程的理解相当有限且分散在文献中。在这篇综述论文中，我们首先总结了测量这些芳香酸在气溶胶和冰芯中的最成熟的方法和方案。其次，我们强调了这些酸在环境中的丰度、诊断比和降解过程的地理变异性。对现有数据的综述表明，芳香酸在气溶胶中的浓度在全球范围内差异很大，通常在生物质燃料常用于住宅供暖和/或烹饪的城市大气中更为丰富。相比之下，它们在极地地区的浓度最低，极地地区避免了局部排放，并且主要受到长距离传输的影响。芳香酸之间的诊断比可以作为生物质（如硬木、软木和草本植物）相对数量和类型以及光化学氧化过程的良好指标。尽管研究表明芳香酸的降解过程可能受光、pH 值和吸湿性的控制，但更仔细的研究，包括封闭室研究，非常值得赞赏。
