ABSTRACT

Road dust particles play an important role in atmospheric pollution and are associated with adverse human health effects. Traffic emissions are a major source of particles in road dust. However, there has been limited information about the relationship between distance from road and traffic-related elements levels in road dust. We investigated the relationships between proximity to the nearest major roadway and trace element mass fractions in PM₁₀ and PM_2.5 re-suspended from the road surface, based on measurements at three different distance ranges. We found that mass fractions of Ba, Cu, Zr, Zn, Cl, Co, Cr, Ca, Ti in PM₁₀ road dust as well as Zr, Cu, Cl, Zn, Cr, Ti, Mn, Ca, Ni, and Fe in PM_2.5 road dust, significantly decreased with distance from major road. Most of these elements are associated with road traffic emissions, including both tailpipe and non-tailpipe emissions. The decrease rates differed among elements due to differences in local traffic contributions. The decreases for elements which are mainly associated with non-tailpipe traffic emissions (e.g., Ba, Zr) were more dramatic. Our results indicate that traffic emissions, especially non-tailpipe emissions, contribute substantially to road dust, suggesting the need for control strategies for non-tailpipe emissions.

Implications: We investigated the relationships between road proximity with trace element mass fractions in PM10 and PM2.5 re-suspended from the road surface. We observed significant decrease of traffic-related elements in PM10 and PM2.5 road dust with log distance from major road. We also found that the mass fractions for elements, which mainly come from traffic decrease more sharply compared to elements which come from both traffic and other sources. Our results indicate that traffic emissions contribute substantially to road dust, and imply that the distance to major road can be used as a proxy for ambient exposure.

摘要

道路灰尘颗粒在大气污染中起着重要作用，并与对人类健康的不利影响有关。交通排放是道路灰尘中颗粒的主要来源。然而，关于道路距离与道路灰尘中交通相关元素水平之间关系的信息有限。我们基于三个不同距离范围的测量结果，研究了与最近的主要道路的接近度与从路面重新悬浮的PM ₁₀和 PM _{2.5 中}微量元素质量分数之间的关系。我们发现 PM ₁₀道路灰尘中 Ba、Cu、Zr、Zn、Cl、Co、Cr、Ca、Ti 的质量分数以及 Zr、Cu、Cl、Zn、Cr、Ti、Mn、Ca、Ni 和PM _{2.5 中的}铁道路扬尘，随着与主干道距离的增加而显着减少。大多数这些元素都与道路交通排放有关，包括尾气排放和非尾气排放。由于当地交通贡献不同，各要素下降率不同。主要与非尾气排放相关的元素（例如 Ba、Zr）的减少更为显着。我们的研究结果表明，交通排放，尤其是非尾气排放，对道路扬尘的贡献很大，这表明需要对非尾气排放进行控制。

启示：我们研究了道路接近度与从路面重新悬浮的 PM10 和 PM2.5 中微量元素质量分数之间的关系。我们观察到 PM10 和 PM2.5 道路灰尘中与交通相关的元素显着减少，与主要道路的日志距离。我们还发现，与来自交通和其他来源的元素相比，主要来自交通的元素的质量分数下降得更快。我们的结果表明，交通排放对道路扬尘的贡献很大，这意味着到主要道路的距离可以用作环境暴露的替代。