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The lifecycle of black carbon (BC)-containing particles from biomass burns is examined using aircraft and surface observations of the BC mixing state for plume ages from ∼15 min to 10 days. Because BC is nonvolatile and chemically inert, changes in the mixing state of BC-containing particles are driven solely by changes in particle coating, which is mainly secondary organic aerosol (SOA). The coating mass initially increases rapidly (

PurpleAir Sensors (PASs) are low-cost tools to measure fine particulate matter (PM) concentrations and are now widely used, especially in regions with few regulatory monitors. However, the raw PAS data have significant biases, so the sensors must be calibrated to generate accurate data. The U.S. EPA recently developed a national correction equation and have integrated corrected PAS data onto its AirNow website. This integration results in much better spatial coverage for PM2.5 across the U.S. The goal of our study is to evaluate the EPA correction equation for three different types of aerosols: typical urban wintertime aerosol, smoke from biomass burning, and mineral dust. We identified 50 individual pollution events, each having a peak hourly PM2.5 concentration of at least 47 µg m-3 and a minimum of 3 hours over 40 µg m-3 and characterize the primary aerosol type as either typical urban, smoke or dust. For each event, we paired an PAS sampling outside air with a nearby regulatory PM2.5 monitor to evaluate the agreement. All 50 events show statistically significant correlations (R values between 0.71–1.00) between the hourly PAS and regulatory data, but with varying slopes. Using the standard EPA correction for the typical urban and smoke aerosols, we find average slopes of 1.00 and 0.99, respectively. This means that the standard EPA correction is highly effective at generating accurate data for these aerosol types. For heavy smoke events, we find a small change in the slope at very high PM2.5 concentrations (>600 µg m-3), suggesting a ~20 % under-estimate in the corrected PAS data at these extremely high concentrations. For dust events, while the PAS and regulatory data still show significant correlations, the PAS data using the standard correction underestimates the true PM2.5 by a factor of 5–6. We also examined several years of co-located regulatory and PAS data from a site near Owens Lake, CA, which experiences high concentrations of PM2.5 due to both smoke and dust. For this site we find similar results as above; the PAS corrected data are accurate in smoke, but are too low by a factor of 5–6 in dust. Using these data we also find that the ratios of PAS measured PM10 to PM1 mass and 0.3 µm to 5 µm particle counts are significantly different for dust compared to smoke. Given the ability of the PAS data to identify dust aerosols, we propose a modified correction algorithm that significantly improves the PAS data for dust events.

We characterize the aerosol physical and optical properties of 13 transported biomass burning (BB) events. BB events included long-range influence from fires in Alaskan and Siberian Boreal Forests transported to MBO in the free troposphere (FT) over 8–14+ days and regional wildfires in Northern California and Southwestern Oregon transported to MBO in the boundary layer (BL) over 10 h to 3 days. Intensive aerosol optical properties and normalized enhancement ratios for BB events were derived from measured aerosol light scattering coefficients (σscat), aerosol light absorbing coefficients (σabs), fine particulate matter (PM1), and carbon monoxide (CO) measurements made from July to September 2019, with particle size distribution collected from August to September. The observations showed that the Siberian BB events had lower scattering Ångström exponent (SAE), higher mass scattering efficiency (MSE; Δσscat/ΔPM1), and a bimodal aerosol size distribution with a higher geometric mean diameter (Dg). We hypothesize that the larger particles and associated scattering properties were due to the transport of fine dust alongside smoke, in addition to contributions from condensation of secondary aerosol, coagulation of smaller particles, and aqueous phase processing during transport. Alaskan and Siberian Boreal Forest BB plumes were transported long distances in the FT and characterized by lower absorption Ångström exponent (AAE) values indicative of black carbon (BC) dominance in the radiative budget. Significantly elevated AAE values were only observed for BB events with

Wildfires, and the resulting smoke, are an increasing problem in many regions of the world. However, identifying the contribution of smoke to pollutant loadings in urban regions can be challenging at lower concentrations due to the presence of the usual array of anthropogenic pollutants. Here we propose a method using the difference in PM to CO emission ratios between smoke and typical urban pollution. For smoke, emission ratios of PM2.5 to CO are between 200–300 µg m−3 ppb−1, whereas typical urban sources have an emission ratio that is lower by a factor of 4–10. This gives rise to the possibility of using this ratio as an indicator of smoke extent. We use observations a regulatory surface monitoring sites in Sparks, NV, for the period of May–September 2018–2021. During this time, there were many smoke-influenced periods from numerous California wildfires that burned during this period. Using a PM / CO ratio of 30, we can split the data into smoke-influenced and no-smoke periods. We then develop a Monte Carlo simulation, tuned to local conditions, to derive a set of PM2.5 / CO values that can be used to identify smoke influence in urban areas. From the simulation, we find that a smoke enhancement ratio of 140 µg m−3 ppb−1 best fits the observations, which is significantly lower than the ratio observed in fresh smoke plumes. The most likely explanation for this difference is greater loss of PM2.5 during dilution and transport to warmer surface layers. We find that the PM2.5 / CO ratio in urban areas is an excellent indicator of smoke and should prove to be useful to identify biomass burning influence on the policy relevant concentrations of both PM2.5 and O3. Using the results of our Monte Carlo simulation, this ratio can also quantify the influence of smoke on urban PM2.5.

Long et al (2021) conducted a detailed study of possible interferents in measurements of surface O3 by UV spectroscopy, which measures the UV transmission in ambient and O3 scrubbed air. While we appreciate the careful work done in this analysis, there were several omissions and, in one case, the type of scrubber used was mis-identified as manganese dioxide (MnO2), when in fact it was manganese chloride (MnCl2). This misidentification led to the erroneous conclusion that all UV-based O3 instruments employing solid-phase catalytic scrubbers exhibit significant positive artifacts, whereas previous research found this not to be the case when employing MnO2 scrubber types. While the Long study, and our results, confirm the substantial bias in instruments employing an MnCl2 scrubber, a replication of the earlier work with an MnO2 scrubber type and no humidity correction is needed.

The present study was designed to investigate the effects of chronic ingestion of a proprietary beta-alanine supplement on body composition, indices of strength and power performance, and markers of cardiovascular endurance in physically active, college-aged males commissioning within the armed services. Subjects (n = 30) participated in four separate testing sessions, both pre and post assessment consuming either 6.0 g/day beta-alanine or Placebo supplementation for 6 weeks. Parameters evaluated included body fat percentage (BF%), fat free mass (FFM), vertical jump (VJ), 1 repetition maximum back squat (SQ) and bench press (BP), and a repetition maximum bench press (RMBP) at 75% of the attained maximum, maximal oxygen consumption (VO2peak), respiratory exchange ratio (RER), lactate threshold (LT), and peak lactate concentration. For all variables, no significant interactions existed across condition and time (p > .05). In addition, for all variables, no significant differences existed between conditions (p > .05). Beta-alanine did not show any benefit for improving body composition or physical performance parameters in this group of individuals.

The ability to maintain proper body positioning throughout the performance of a push-up is important in order to build strength and to limit the potential for injury. This article describes what to...

The instruction of physical education comes with challenges not typically experienced in a class containing more traditional material e.g., Physics or History. While these academic courses place rigorous demands on the cognitive abilities of students, physical education and lifetime physical activity courses, as taught here at West Point, place a far greater demand on the biomotor capacities and abilities of students. With a flipped classroom, students can be assessed prior to initiating in-class activities to ensure comprehension of cognitive aspects of content. Utilizing a blended environment, or in the case of West Point, the Thayer Method, instructors provide cadets a brief opportunity for questions at the beginning of class prior to assessments [1]. Providing multiple points of review beyond a simple mid- and end-of-year assessment, retention and comprehension of course content will improve relative to a more traditional, lecture-style method [1,2]. The primary intent of this review is to discuss the role of varying pedagogical strategies in the post-secondary physical education setting, specifically as it pertains to a foundations of physical fitness course, at the United States Military Academy, West Point.

Caffeine is one of the most extensively studied and widely used ergogenic aid capable of improving many aspects of sport performance and cognitive abilities [1-12]. Some of the acute effects of caffeine supplementation are increases anaerobic power output and performance, increased muscular strength, endurance, and power, improvements to aerobic endurance, reduced fatigue, decreased RPE and pain, increased voluntary workload, and increased alertness [1-8]. Chronic caffeine consumption has also been shown to have a positive effect on long term memory, locomotor improvements, and overall mood state [9-11]. Some of the positive effects of athletic performance attributed to caffeine ingestion can be explained by its ability to moderate insulin sensitivity, increase plasma free fatty acids (FFAs), and increase plasma epinephrine [12].

Background: Identifying lifestyle factors such as physical activity (PA) patterns and eating behaviors of children may be beneficial in implementing interventions in urban elementary schools. Purpose: To examine PA levels and self-efficacy (SE) in PA and health eating (HE) of third, fourth, and fifth graders in 3 low economic elementary schools in an urban setting. Method: Students (N = 295) were administered SE in PA and HE inventories and given Omron HJ7201TC pedometers. Results: Girls had significantly (P

Objectives: This study investigated the performance enhancing effects of bicarbonate ingestion on soccer specific performance. Design: A randomized and double-blinded study. Methods: Division III collegiate male soccer players (N = 7) participated in the study. Participants ingested either an alkaline treatment (.3 g/kg NaHCO3) or placebo (cornflower) 60 min prior to exercise on two separate testing sessions spaced 7 days apart. Distance to fatigue in the Yo-Yo Intermittent Recovery Test Level 2 was used to assess performance. Capillary blood was sampled pre-ingestion (PE), 60 min post ingestion (PI), exhaustion (EX), following 15 min of recovery (RC) and analyzed for lactate ([La–]) and pH. Results: No significant ( p > .05) differences between conditions existed for performance. A significant ( p .05) existed between time and condition. pH values at PE and PI were significantly greater than EX and RC in both conditions; however, pH was significantly ( p < .05) greater at PI than PE in treatment but not placebo. Conclusion: Bicarbonate ingestion increased extracellular buffering capacity but does not appear to enhance shuttle run performance in Division III soccer players. (Journal of Trainology 2015;4:19-24)

The atmosphere of the Arctic is charged with gaseous and particulate material, mostly of industrial origin during the winter and spring months. Assessing the health and environmental impacts of this phenomenon, known as Arctic Haze, in the U. S. Arctic regions represents the long term goal of this research project. The haze is primarily sulfate, but it also contains industrial signatures of trace heavy metals which have been used to establish source origins. Based on inventories of such tracers, it has been estimated that industrial sources in Eurasia contribute approximately 80 percent of the Arctic Haze, while sources in the northeastern United States make up most of the remaining fraction.