The study of atmospheric ice-nucleating particles via microfluidically generated droplets

Ice-nucleating particles (INPs) play a significant role in the climate and hydrological cycle by triggering ice formation in supercooled clouds, thereby causing precipitation and affecting cloud lifetimes and their radiative properties. However, despite their importance, INP often comprise only 1 in 10³–10⁶ ambient particles, making it difficult to ascertain and predict their type, source, and concentration. The typical techniques for quantifying INP concentrations tend to be highly labour-intensive, suffer from poor time resolution, or are limited in sensitivity to low concentrations. Here, we present the application of microfluidic devices to the study of atmospheric INPs via the simple and rapid production of monodisperse droplets and their subsequent freezing on a cold stage. This device offers the potential for the testing of INP concentrations in aqueous samples with high sensitivity and high counting statistics. Various INPs were tested for validation of the platform, including mineral dust and biological species, with results compared to literature values. We also describe a methodology for sampling atmospheric aerosol in a manner that minimises sampling biases and which is compatible with the microfluidic device. We present results for INP concentrations in air sampled during two field campaigns: (1) from a rural location in the UK and (2) during the UK’s annual Bonfire Night festival. These initial results will provide a route for deployment of the microfluidic platform for the study and quantification of INPs in upcoming field campaigns around the globe, while providing a benchmark for future lab-on-a-chip-based INP studies

Conservation assessment and spatial distribution of endemic orchids in Sabah, Borneo

Orchids are among the most threatened plants due to habitat loss and illegal harvesting for horticultural demands. Sabah is a centre of orchid diversity, with approximately 1300 species of which 250 orchid taxa are endemic to Sabah. In this study, we conducted an IUCN Red List assessment on 136 endemic species and used Maximum Entropy (MaxEnt) to develop species distribution models for 47 species. The species distribution models were developed using presence-only data and six environmental predictors. The accuracy of the models were assessed using the area under the curve (AUC) and models with an AUC of higher than 0.8 stacked together to produce a species richness heatmap. We found that 83% of the researched species were threatened, of which 14 species were assessed to be Critically Endangered, eight species as Endangered and 93 species as Vulnerable. The heatmap shows that all of the species occurred within the Totally Protected Area (TPA) network in western Sabah. The heatmap highlighted the mid-altitude areas adjacent to the Kinabalu and Crocker Range parks and Ulu Sipitang regions as areas with a high species richness that were outside the TPA network. These areas are also important for the conservation of the majority of the species assessed as Critically Endangered and Endangered. Urgent conservation actions are needed to protect these species from extinction. The results from this work will be used as part of an intensive conservation action plan for threatened endemic orchids of Sabah and used to identify important plant areas currently not within the existing TPA networ

Electrostatic particle collection in vacuum; Wettability of Fly Ashes from Four Coal-Fired Power Plants in China; Alternatives for Joining Stainless Steel to Reduce Cr(VI) Emissions and Occupational Exposures; Oxidation and capture of elemental mercury over SiO2–TiO2–V2O5 catalysts in simulated low-rank coal combustion flue gas; Flash infrared radiation disinfection of fibrous filters contaminated with bioaerosols

AIMS: To investigate the effectiveness of infrared (IR) radiation heating in disinfecting air filters loaded with bioaerosols. METHODS AND RESULTS: An irradiation device was constructed considering the unique characteristics of IR and the physical dimensions and radiative properties of air filters. Filters loaded with test bioaerosols were irradiated with the device and flash heated to an ultra-high temperature (UHT). A maximum of 3.77-, 4.38- and 5.32-log inactivation of B. subtilis spores, E. coli, and MS2 virus respectively was achieved within 5 s of irradiation. Inactivation efficiency could be increased by using a higher IR power. Microscopic analysis showed no visible damage from the heat treatment that would affect filtration efficiency. CONCLUSIONS: Because the disinfection was a dry heat process, a temperature greater than 200 degrees C was found necessary to successfully inactivate the test micro- organisms. The results demonstrate that IR is able to quickly disinfect filters given sufficient incident power. Compared to existing filter disinfection technologies, it offers a faster and more effective solution. SIGNIFICANCE AND IMPACT OF THE STUDY: It has been shown that IR heating is a feasible option for filter disinfection; possibly reducing fomite transmission of collected micro-organisms and preventing bioaerosol reaerosolization