Outdoor urban nanomaterials: The emergence of a new, integrated, and critical field of study

Abstract

Engineered nanomaterials (ENMs) are currently widely incorporated in the outdoor urban environmental fabric and numerous new applications and products containing ENMs are expected in the future. As has been shown repeatedly, products containing ENMs have the potential, at some point in their lifetime, to release ENMs into their surrounding environment. However, the expanding body in environmental nanomaterial research has not yet shifted toward ENMs in the context of the complex outdoor urban environment. This is especially surprising because the world's human populations are on a steady march toward more and more urbanization and technological development, accompanied with increased applications for ENMs in the outdoor urban environment. Our objective for this paper is therefore to review, assess, and provide new information in this emerging field. We provide an overview of nanomaterials (NMs, encompassing both ENMs and incidental nanomaterials, INMs) that are likely to be released in the urban environment from outdoor sources by discussing 1) the applications of ENMs that may lead to release of ENMs in urban areas, 2) the recently published data on the release of ENMs from novel nano-enabled applications in the outdoor urban environment, 3) the available literature on the occurrence of INMs in the atmosphere and within/on dust particles, and 4) the potential pathways and fate of NMs in the outdoor urban environment. This review is then followed by three case studies demonstrating the importance of NMs in the outdoor urban environment. The first and second case studies illustrate the occurrence of NMs in urban dust and stormwater ponds, respectively, whereas the third case study discusses the lessons learned from the release of NMs (e.g. Pt, ph and Rh) from automotive vehicle catalytic convertors. This article ends with a discussion of the research priorities needed to advance this emerging field of "outdoor urban nanomaterials" and to assess the potential risks of NMs in the context of urban environments.

Sediment chemistry of urban stormwater ponds and controls on denitrification

“…Instead, we measured a great deal of variation across all of the ponds and found, similar to Baalousha et al. (), that even ponds surrounded by significant buffers of undeveloped land were receiving measurable quantities of urban pollutants via direct deposition.…”

“…of substrates (inorganic N and DOC) nor the concentrations of stressors (metals) were consistently related to surrounding land use across ponds. Instead, we measured a great deal of variation across all of the ponds and found, similar to Baalousha et al (2016), that even ponds surrounded by significant buffers of undeveloped land were receiving measurable quantities of urban pollutants via direct deposition.…”

Natural, incidental, and engineered nanomaterials and their impacts on the Earth system

“…From this, one must tie these insights together to start to gain a more holistic sense of all classes of nanomaterial-Earth system scenarios. For example, accelerating urbanization will affect nanomaterial-mediated processes, with localized consequences to environmental and human health in the built environment (102). Evolution of energy production systems will drive changes in the sources and distribution of nanomaterials, with global-scale consequences.…”

Irrigation Water Quality—A Contemporary Perspective

“…Nanomaterial transformation in fresh water systems is an active field of research [216]. Nanoparticle assessments have concluded that fine particulate matter occurs in a variety of water sources [217][218][219][220][221], so its impact on irrigation water, accumulation in soil, and potential for crop uptake is of paramount significance.…”