Meta-analysis of polyaromatic hydrocarbons in road dust: An emerging threat in urban environment

Road dust (RD) has emerged as a significant contributor to air pollution in urban areas. It serves as a major reservoir for various contaminants including highly toxic heavy metals and polyaromatic hydrocarbons (PAHs). Therefore, road dust poses threats not only to the environment but also human health, particularly to commuters and residents near roadsides. The abrasion of tyres and the release of carbonaceous materials from vehicle emissions further increases the toxicity of road dust. This study presents a comprehensive review of sources and fate of PAHs in road dust as well as their toxicity in the environment. We have used the Web of Science database from 1989 to 2023. Our study suggests that this research topic has seen a substantial increase in investigations with a rate of ∼40 % since 2008. However, despite an increase in urbanization and industrialization and high toxicity of PAHs in RD, research in developing countries is still limited, primarily due to an inadequate funding and lack of technical advancements. Although atmospheric concentrations of PAHs have declined in developed countries, largely due to the implementation of strict emission standards and air quality regulations, adoption of advanced cleaner fuels and technologies, the demand for transport and energy is more likely to increase in developing countries in the future. Therefore, the study emphasizes the importance of promoting research on RD (size, composition and toxicity) pollution to address and mitigate the impact of PAHs on human health and the environment. Our study highlights that there is a strong need for more research on trade-off between emission and control measures to regulate RD emissions as well as toxic carcinogens including PAHs and heavy metals in urban environment.