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In mid-March 2020, due to the novel coronavirus, my 300-level Environmental Sampling Methods lecture/laboratory course transitioned to distance learning. After this move, the primary focus of the course became the laboratory. To do this, I revised my three remaining laboratory exercises (i.e., water quality, soil quality, environmental microbes) and created two new ones (i.e., toxicology, ultraviolet radiation). For the students to complete the experiments, I shipped low-cost equipment and supplies to them; this shipment included Petri plates and sampling swabs, sterile water, a pH meter and associated calibration powders, a total dissolved solids meter, clay and sand samples, conical tubes, sampling baggies, cyanotype printing paper, and lettuce seeds. I justified this shift toward being primarily laboratory-focused by requiring all the experiments to become inquiry-based, increasing the rigor of the experiments but also keeping the students engaged by allowing them to design their own projects. To keep a sense of community within the class, discussion boards were utilized. To ensure a safe environment at home, each project required preapproval. The discussion below focuses on the details of how the course was modified, how the course was managed, some of the pitfalls I encountered, and how the students exceeded my expectations with the projects they created.

Particulate matter (PM) varies in chemical composition and mass concentration based on location, source, and particle size. This study sought to evaluate the in vitro and in vivo toxicity of coarse (PM10-2.5) and fine (PM25) PM samples collected at 5 diverse sites within California. Coarse and fine PM samples were collected simultaneously at 2 rural and 3 urban sites within California during the summer. A human pulmonary microvascular endothelial cell line (HPMEC-ST1.6R) was exposed to PM suspensions (50 μg/mL) and analyzed for reactive oxygen species (ROS) after 5 hours of treatment. In addition, FVB/N mice were exposed by oropharyngeal aspiration to 50 μg PM, and lavage fluid was collected 24 hrs post-exposure and analyzed for total protein and %PMNs. Correlations between trace metal concentrations, endotoxin, and biological endpoints were calculated, and the effect of particle size range, locale (urban vs. rural), and location was determined. Absolute principal factor analysis was used to identify pollution sources of PM from elemental tracers of those sources. Ambient PM elicited an ROS and pro-inflammatory-related response in the cell and mouse models, respectively. These responses were dependent on particle size, locale, and location. Trace elements associated with soil and traffic markers were most strongly linked to the adverse effects in vitro and in vivo. Particle size, location, source, and composition of PM collected at 5 locations in California affected the ROS response in human pulmonary endothelial cells and the inflammatory response in mice.

Context: There are several ways to assess the noise reducing efficiency of earmuffs, but they usually involve using human participants and/or specialized equipment.Objective: The current study was designed to develop a less labor-intensive, cost-effective, participant-free first-pass method for measuring the efficiency of earmuffs.Methods: We evaluated the noise-cancelling ability of five different types of earmuffs (3M: Optime 98, Optime 105; iDEA USA V201; Tronsmart Encore S6; Bose QuietComfort 35) under laboratory and field conditions. We compared our results to the microphone-in-real-ear (MIRE) method. Lastly, a survey of college-aged students was also conducted to determine which earmuffs were the most comfortable and provided the best fit.Results: Of the five earmuffs studied, the Optime 98 and Bose earmuffs were most effective at reducing noise levels in both the laboratory and field. These earmuffs also received the highest scores for comfort, fit, and perceived ability to reduce noise, with Bose being slightly more preferred than Optime 98. The MIRE method provided the same overall results as the laboratory and field tests.Conclusion: Our method for evaluating the noise-canceling ability of earmuffs could be used to supplement more complicated testing procedures as a first-pass method. [ABSTRACT FROM AUTHOR]