E-HKUST601/19
Impact of complex urban built environments on the dynamics of vehicular NO and NO₂ emission dispersion from the tailpipe to the roadside atmosphere

Hong Kong Principal Investigator: Prof Zhi NING (The University of Hong Kong)
European Principal Investigator: Prof Ake SJÖDIN (IVL Swedish Environmental Research Institute)

Air Pollution has adverse effects on public health and environment. The particulate matter and gaseous pollutants are the major components of air pollution. Extensive research followed with stringent regulations haven seen a reduction in the quantity of air pollutants especially the particulate matter. However, the gaseous pollutants concentration, especially NO_x (NO and NO₂), have not shown significant reduction in the past decade. While NO and NO₂ are strongly driven by emissions and atmospheric conversion of emissions from vehicles, the titration of NO with background ozone is also a major contributor given rise to ozone background that has been observed in various urban places, which necessitates the need to understand the dynamics of NO and NO₂ to target control strategies. Hitherto, there was no available research knowledge for enlightening the dynamics of pollution emissions and in identifying the cause for the influence of urban terrain on micro-environmental pollutant concentrations in traffic hotspots of Hong Kong. Hence, this project is aimed at addressing these issues. The project consists of two lines of research. The first will track the real-world NO_x dispersion patterns and their conversion processes from individual vehicle tailpipes to the atmosphere in Hong Kong using on-road sampling methods including portable emissions measurement systems (PEMS), a sensor network cart trailer, and a plume chasing system. The second will include a vertically and horizontally spaced high-density sensor network in roadside for capturing the dispersion and conversion process of vehicle emission from on-road to ambient. Information regarding the meteorological conditions and roadside building characteristics will also be collected to understand their impact on the dynamics of roadside NO_x conditions and conversion processes. The project outcomes will be key to knowledge development in air modelling, control measures and public exposure activities.

E-HKU704/19
Synthesis of High-Performance Nanomaterials: From Safety by Design to Real-World Applications

Hong Kong Principal Investigator: Prof Zheng Xiao GUO (The University of Hong Kong)
European Principal Investigator: Prof Andrew NELSON (University of Leeds)

High-performance nanomaterials hold the key to a sustainable future. Recently, structures in the nano-sized regime are found to be effective catalytic motifs for various energy conversion and storage applications. State-of-the-art nanomaterials are produced via batch methods that generate toxic liquid wastes with unbearable batch-to-batch variations in the size and shape of the as-synthesized nanomaterials, thereby limiting their functional reproducibility and practical applicability. In order to achieve scalable quantities of nanomaterials that are safe to use, new methodologies to synthesize nanomaterials are explored.

Safety by design of nanomaterials (SABYDOMA) is a brand-new concept to address the current challenges in the field of the green synthesis of nanomaterials. SABYDOMA replaces the batch process with a flow system. The as-prepared nanomaterials are subjected to quality control using UV-visible and dynamic light scattering spectroscopic techniques at the point of production. Outliers will be collected and recycled while high-quality nanomaterials will be carried forward for further processing. This flow-through synthesis platform fully integrated with online monitoring modules and automatic decision-making algorithms revamp the way nanomaterials are prepared.

Here, the proposal aims to enhance this paradigm-shifting SABYDOMA concept by equipping the core microfluidic system with three new functionalities. First, first-principle calculations will be tailored for this microfluidic nanomaterial synthesis processes to gain unprecedented understanding over the underlying principles that govern the size and shape selectivity of nanomaterials and unravel unique insights into the structure-toxicity correlation of these nanomaterials that are Safe-by-Design (SbD) nanomaterials. Second, a laser-based strategy will be integrated with the flow system to synthesize nanomaterials on demand in a controllable fashion. Third, an in-situ hybrid bilayer membrane sensor module will be incorporated into the flow platform to enforce the SABYDOMA concept by monitoring the toxicity of as-prepared nanomaterials and their leached compounds in real time.

In addition to developing new preparation methods, designing new online detection schemes, and uncovering key parameters that predict the quality and stability of nanomaterials, the HKU team aims to extend the impact of SbD to real-world situations. Precisely, the functional properties of these SbD nanomaterials such as electrocatalytic activity and photoelectrochemical performance will be explored by further modifications of such nanomaterials in-situ. Learning from our EU counterparts who have set up four case studies with four individual industrial partners, the HKU team also hopes to facilitate knowledge exchange and maximize impact by disseminating key findings in peer-reviewed journals, filing and licensing patents, launching spin-off or start-up companies, and/or initiating industrial collaborations in the Greater Bay Area.