Tse-Lun Chen

This perspective presents a “safety-and-sustainability-by-design” roadmap for 2D materials in air technologies, balancing high-performance applications such as sensing and purification with a deep understanding of life-cycle and toxicological risks.

This chapter investigates the emission sources and characteristics of ultrafine particles (UFPs) in Taiwan’s metropolitan areas, as well as their potential health risks. The research team established mobile air quality monitoring stations in Taipei, New Taipei, and Taichung, employing advanced instruments to collect data on UFP size distribution, chemical composition, and meteorological conditions. The findings show the UFP emissions in urban areas, revealing that traffic is the primary source. Due to complex meteorological conditions and high vehicle density, monitoring airborne UFPs is particularly challenging and necessary in subtropical, traffic-heavy cities like those in Taiwan. Understanding the characteristics of UFPs from various emission sources is essential for formulating effective air pollution control strategies. Additionally, lung-deposited surface area (LDSA) concentrations can be utilized to assess health risks associated with UFPs, contributing to the development of more precise air quality management policies. The research should focus on the chemical composition of various UFP sources for a comprehensive health risk assessment, as well as the development of accurate UFP monitoring and prediction models, potentially using machine learning techniques. Effective traffic management and emission control strategies are necessary to abate UFP emissions and their impact on public health. Overall, this chapter provides critical information on the sources, characteristics, and health risk assessments of UFPs in Taiwan’s metropolitan areas, serving as a reference for formulating air pollution prevention policies and protecting public health.

Resource recovery is crucial for small- and medium-sized enterprises to attain a circular economy. The economic benefits of recovering precious metals from electronic waste, such as waste printed circuit boards (WPCBs), are hindered by secondary pollutant emissions from pretreatment processes. This study aims to recover copper from the WPCB acid leaching process and reduce NOx emissions through the use of a high gravity rotating packed bed (RPB). The results indicate that the copper recovery ratio increases to 99.75% through the displacement reaction between iron powder and copper nitrate. The kinetic analysis of copper dissolution was employed to simulate the NOx emissions during acid leaching, with an R-squared value of 0.872. Three oxidants, including H₂O_2(aq), ClO_2(aq), and O_3(g), with pH adjusted to different NaOH concentrations, were used to remove NOx. The greatest NOx removal rate was achieved using a 0.06 M NaOH solution, with a removal rate of 91.2% for ozone oxidation at a 152-fold gravity level and a gas-to-liquid (G/L) ratio of 0.83. The gas-side mass transfer coefficients (K_Ga) for NOx range from 0.003 to 0.012 1/s and are comparable to previous studies. The results of a life cycle analysis indicate that the NOx removal rate, nitric acid recycling rate, and copper recovery rate are 85%, 80%, and 100%, respectively, reducing the environmental impact on the ecosystem, human health, and resource depletion by 10% compared to a scenario with no NOx removal.