Dusty cities, smoky skies, and old paint: air quality, climate, health, and cultural impacts of chemistry at atmospheric interfaces

大气颗粒物（PM）影响地球气候，有助于降低空气质量，并为化学反应提供表面；这些反应反过来又会影响污染物气体（例如O3和NO2）的丰度以及与pm相关的物种的命运。在这里，我们提出了四个相关主题的研究，每个主题都探讨了大气界面化学的一个不同方面：1尘埃和非排气PM的光化学：对污染物命运、PM组成和城市空气质量的影响随着车辆排放法规的收紧，非排气源（如道路灰尘、刹车/轮胎磨损）对城市PM负荷的贡献将增加。我们建议研究a)道路粉尘产生的活性氧化剂，以及这种产生对城市污染物命运的影响；b)粉尘催化的有机转化对PM组成和性质的影响；c)道路粉尘/非排气PM化学对城市大气气相组成的影响。2 .北方森林大火对气候、空气质量和健康的影响北方森林大火的频率和强度都在增加。我们建议：a)量化北方野火PM将NO2转化为亚硝酸盐（HONO），这是一种重要的大气氧化剂前体；b)应用尺寸排除色谱法结合UV-Vis检测来研究该PM的吸光特性（即与气候相关）作为燃烧条件的函数；c)评估野火灰烬表面有毒污染物的寿命和命运。在主题1和主题2中，我们使用流管仪器对气体表面相互作用进行量化，从而可以对单个污染物-基质对进行详细研究。然而，这种方法太耗时，不允许对大型PM样本集进行探索性（即非目标）研究。受药物和材料化学方法的药物发现和催化剂筛选的激励，我们建议a)开发和验证一种新的高通量模块化光反应器，用于研究污染物气体- pm相互作用；b)应用该反应器揭示PM组成/性质与反应性之间的预测关系。文物是在类似小气候的环境（如框架和储存箱）中展示和储存的，因此很容易受到外壳材料（如甲醛、乙酸/甲酸）排放的损害。我们建议将主题1-3中开发的策略应用于a)量化与博物馆环境中甲酸取样相关的潜在偏差；B)获得与博物馆储存环境相关的气-面对动力学数据；c)在简单的小气候封闭模型中实现这些数据，这将使我们能够更好地解释/应用在博物馆空气质量运动中获得的污染物测量值。

Atmospheric particulate matter (PM) influences Earth's climate, contributes to air quality reductions, and provides a surface for chemical reactions; these reactions, in turn, can influence the abundance of pollutant gases (e.g. O3 and NO2) and the fate of PM-associated species. Here, we propose research in four linked themes, each of which explores a different aspect of chemistry at atmospheric interfaces: 1-Photochemistry of dust and non--exhaust PM: implications for pollutant fate, PM composition, and urban air quality As vehicle emission regulations tighten, the contribution of non-exhaust sources (e.g. road dust, brake/tire wear) to urban PM loadings will increase. We propose to study a) reactive oxidant production by road dust, and the implications of this production for the fate of urban contaminants; b) the influence of dust--catalyzed organic transformations on PM composition and properties; and c) the impact of road dust/non--exhaust PM chemistry on the gas-phase composition of the urban atmosphere. 2-Climate, air quality, and health impacts of boreal wildfires Boreal wildfires are increasing in both frequency and intensity. We propose to a) quantify the conversion of NO2 to nitrous acid (HONO), an important atmospheric oxidant precursor, by boreal wildfire PM; b) apply size-exclusion chromatography coupled with UV-Vis detection to investigate the light--absorbing (i.e. climate--relevant) properties of this PM as a function of combustion conditions; and c) assess the lifetime and fate of toxic contaminants at the surface of wildfire ash. 3-New high--throughput instrumentation for study of PM-pollutant interactions In Themes 1 and 2, we quantify gas-surface interactions using flow tube instrumentation, which enables the detailed study of individual pollutant-substrate pairs. However, this approach is too time-consuming to permit exploratory (i.e. non-targeted) study of large PM sample sets. Motivated by medicinal and materials chemistry approaches to drug discovery and catalyst screening, we propose to a) develop and validate a new high--throughput modular photoreactor for study of pollutant gas-PM interactions; and b) apply this reactor to uncover predictive relationships between PM composition/properties and reactivity. 4-Exploring air quality challenges in museum environments Cultural heritage objects are displayed and stored in microclimate-like environments (e.g. frames and storage crates) and are thus susceptible to damage by emissions from enclosure materials (e.g. formaldehyde, acetic/formic acid). We propose to apply strategies developed in Themes 1-3 to a) quantify potential biases associated with formic acid sampling in museum environments; b) obtain kinetic data for gas-surface pairs relevant to museum storage environments; and c) implement these data in simple microclimate enclosure models, which will enable us to better interpret/apply pollutant measurements obtained in museum air quality campaigns.