Updates in Air Pollution: Current Research and Future Challenges.

Background: The United Nations has declared that humans have a right to clean air. Despite this, many deaths and disability-adjusted life years are attributed to air pollution exposure each year. We face both challenges to air quality and opportunities to improve, but several areas need to be addressed with urgency. Objective: This paper summarises the recent research presented at the Pacific Basin Consortium for Environment and Health Symposium and focuses on three key areas of air pollution that are important to human health and require more research. Findings and conclusion: Indoor spaces are commonly places of exposure to poor air quality and are difficult to monitor and regulate. Global climate change risks worsening air quality in a bi-directional fashion. The rising use of electric vehicles may offer opportunities to improve air quality, but it also presents new challenges. Government policies and initiatives could lead to improved air and environmental justice. Several populations, such as older people and children, face increased harm from air pollution and should become priority groups for action.

Anthropogenic warming induced intensification of summer monsoon frontal precipitation over East Asia.

Summer monsoon frontal rainfall in East Asia (EA) is crucial for water resources and flood hazards in densely populated areas. Recent studies have documented the increasing intensity of summer frontal rainfall over recent decades. However, the extent of ongoing climate change on the intensification of the EA frontal precipitation system remains uncertain. Using an objective method for detecting frontal systems, we found a 17 ± 3% increase in observed frontal rainfall intensity during 1958 to 2015. Climate model simulations with and without greenhouse gases suggest that anthropogenic warming plays a key role in the intensification of EA summer frontal precipitation by 5.8% from 1991 to 2015. The analysis highlights that enhanced water vapor convergence and reinforced western North Pacific subtropical High collectively increased moisture transport to the region, resulting in intensified EA frontal precipitation. The results lend support to the anthropogenic warming-induced enhancement of the EA frontal precipitation and its persistence in the future.

Intrinsic atmospheric circulation patterns associated with high PM2.5 concentration days in South Korea during the cold season.

Based on observation data and a novel K-mean clustering method, we investigated whether intrinsic atmospheric circulation patterns are related with the occurrence of high particulate matter (PM) concentration days (diameters less than or equal to 2.5 µm (PM2.5)), in Seoul, South Korea, during the cold season (December to March). A simple composite map shows that weak horizontal and vertical ventilation over the Korean Peninsula can cause high PM2.5 concentration (High_PM2.5) days. Also, atmospheric circulations are quite different between one day of High_PM2.5 and periods longer than two days. We also found that two intrinsic atmospheric circulation patterns in Asia, which were obtained by adopting K-mean clustering to the daily 850 hPa geopotential height anomalies for 2005-2020, were associated with High_PM2.5 days. These results indicate that High_PM2.5 days in Seoul, South Korea, occur as a result of intrinsic atmospheric circulation patterns, therefore, they are unavoidable unless the anthropogenic emission sources over the Korean Peninsula, East Asia, or both are reduced. In addition, these two intrinsic atmospheric circulation patterns are more prominent for periods longer than two days while there are no favorable intrinsic atmospheric circulation patterns to induce one day of High_PM2.5, which indicates that a single day of High_PM2.5 tends to occur by a stochastic atmospheric circulation rather than the intrinsic atmospheric circulation patterns.

A novel statistical-dynamical method for a seasonal forecast of particular matter in South Korea.

Societal concerns about air quality in East Asia are still growing despite country-level efforts to reduce air pollution emissions. In coping with this growing concern, the government and the public demand a longer­lead forecast of air quality to ensure sufficient response time until society prepares for countermeasures such as a temporary reduction of specific emission sources. Here we propose a novel method that produces skillful seasonal forecasting of wintertime (December to February) PM10 concentration over South Korea. The method is based on the idea that climate condition and air quality have co-variability in the seasonal time scales and that the state-of-art seasonal prediction model will benefit air quality forecasting. More specifically, a linear regression model is constructed to link observed winter PM10 concentration and climate variables where the predicted climate variables were furnished from NCEP CFSv2 forecast initialized during autumn. In this case, climate variables were selected as predictors of the model because they are not only physically related to air quality but also 'predictable' in CFS hindcast. Through analysis of retrospective forecasts of 20 winters for the period 2001-2020, we found this model shows statistically significant skill for the seasonal forecast of wintertime PM10 concentration.

Response of Indian summer monsoon rainfall to remote carbonaceous aerosols at short time scales: Teleconnections and feedbacks.

The effect of atmospheric aerosols on Indian monsoon is one of the scientifically challenging and societally relevant research issues of the recent decades. Past studies have derived inferences mostly based on local emissions and their impacts thereupon. However, more recent studies have shown that the remote effects driven by aerosols elsewhere could also impact the monsoon system on different time scales. Our study using an atmospheric general circulation model (AGCM) shows that regional carbonaceous aerosol emissions (from North America, Europe and North Africa and Asia) can significantly alter Indian summer monsoon rainfall. It is interesting to note that the effects of remote aerosols are larger and bear a resemblance to each other in comparison to local emissions. Our study reveals that the modulation of large-scale circulation induced by regional warming by carbonaceous aerosols leads to teleconnection patterns around the globe, thereby changing the precipitation depending on the phase of these disturbances. We also find that the effects of remote carbonaceous aerosols are strengthened by modulation/feedback through natural dust aerosols over the Arabian Sea with subsequent increase in rainfall over India. The results signify that the changes in the aerosol emissions in one region could lead to the change in precipitation over other regions through global teleconnection and associated feedbacks induced by regional atmospheric warming and/or cooling.

Statistical Seasonal Forecasting of Winter and Spring PM2.5 Concentrations Over the Korean Peninsula.

Concentrations of fine particulate matter smaller than 2.5 µm in diameter (PM2.5) over the Korean Peninsula experience year-to-year variations due to interannual variation in climate conditions. This study develops a multiple linear regression model based on slowly varying boundary conditions to predict winter and spring PM2.5 concentrations at 1-3-month lead times. Nation-wide observations of Korea, which began in 2015, is extended back to 2005 using the local Seoul government's observations, constructing a long-term dataset covering the 2005-2019 period. Using the forward selection stepwise regression approach, we identify sea surface temperature (SST), soil moisture, and 2-m air temperature as predictors for the model, while rejecting sea ice concentration and snow depth due to weak correlations with seasonal PM2.5 concentrations. For the wintertime (December-January-February, DJF), the model based on SSTs over the equatorial Atlantic and soil moisture over the eastern Europe along with the linear PM2.5 concentration trend generates a 3-month forecasts that shows a 0.69 correlation with observations. For the springtime (March-April-May, MAM), the accuracy of the model using SSTs over North Pacific and 2-m air temperature over East Asia increases to 0.75. Additionally, we find a linear relationship between the seasonal mean PM2.5 concentration and an extreme metric, i.e., seasonal number of high PM2.5 concentration days. Supplementary Information: The online version contains supplementary material available at 10.1007/s13143-022-00275-4.

Sustainable valorization of semiconductor industry tantalum scrap using non-hazardous HF substitute lixiviant.

Global tantalum production from mines averages 1800 tons per year and hardly increases, but demand for tantalum in the electronics industry consistently increasing. Globally, 50% of total tantalum produced is being used for tantalum capacitors manufacturing, almost all demand from various industries is mainly met by primary resources only. Tantalum production and supply predominantly dominated by Congo and Rwanda which accounts for > 50%, add disadvantages for the strategic and economic competitiveness of other nations. To address the monopoly dominated by Congo and Rwanda, and the disparity of tantalum primary reserve, exploitation of secondary resources can alternatively address the drawbacks of primary resource distribution. Currently, hardly < 1% of tantalum getting recycled, and the poor recycling rate of tantalum is mainly contributed by the lack of efficient and sustainable valorization technology for recycling tantalum-bearing scraps like electronic capacitors and semiconductor industry tantalum scrap. In the current investigation, a sustainable tantalum extraction process from scrap dominated by hydrometallurgical route has been developed. Tantalum scrap which is passive to leach for tantalum recovery was calcinated for oxidation of TaN content and followed by tantalum has been leached using a mixture of NaF and HCl, a specially developed novel lixiviant for the purpose as an HF substituent. Calcination process parameter like temperature and time requirement for oxidation was optimized varying one parameter at a time. Then, the efficient leaching condition was optimized for quantitative leaching of tantalum. The process can achieve 99.99% efficient leaching, the process can successfully be applied for feasible industrial-scale tantalum scrap recycling. The HF substituent lixiviant can add advantages to overcome occupational and industrial operation safety challenges associated with HF lixiviant. The reported valorization process can be a sustainable tantalum recycling process that simultaneously can address UNO sustainable development goal, WEEE directive, and UNEP E-Waste Management goal.

Behavioral Economic Assessment of Alcohol and Cigarette Demand in Smokers With Alcohol Use Disorder.

Background and Objectives: Behavioral economic purchase tasks are widely used to assess drug demand in substance use disorder research. Comorbid alcohol use is common among cigarette smokers and associated with greater difficulty in quitting smoking. However, demand for alcohol and cigarettes in this population has not been fully characterized. The present study addressed this gap by examining alcohol and cigarette demand among treatment-seeking smokers with alcohol use disorder (AUD). Methods: Alcohol and cigarette demand was assessed among 99 smokers with AUD. We conducted Principal Component Analysis (PCA) and correlational analyses on the demand indices. Results: Participants showed higher demand for alcohol than for cigarettes, as evidenced lower elasticity (resistance to increasing price) and higher Omax (maximum response output for drug). PCA revealed a two-factor structure (Persistence and Amplitude) for both alcohol and cigarette demand indices. Cigarette-related demand indices were positively correlated with nicotine dependence, but alcohol-related demand indices were not associated with alcohol dependence, suggesting dissociation between alcohol demand and use behaviors. Discussion and Conclusions: Our results suggest that smokers with AUD were more resistant to price elevations in relation to reducing alcohol consumption as compared to cigarette consumption, suggesting preferential demand for alcohol over cigarettes. However, it is unclear how acute substance exposure/withdrawal impacts the demand indices. Scientific Significance: Potentially differential alcohol and cigarette demands among smokers with AUD should be considered in the concurrent treatment of smoking and alcohol.

Effect of Dry-Land Core Training on Physical Fitness and Swimming Performance in Adolescent Elite Swimmers.

BACKGROUND: We aimed to investigate the effect of a 12-week dry-land core training program on physical fitness and swimming performance in elite adolescent swimmers. METHODS: Thirty subjects were selected and assigned to the core training group (CTG, n=15) and the traditional weight training group (WTG, n=15) in Seoul, Korea, between Sep and Dec 2016. The field fitness test was performed to determine the isotonic maximum muscular strength (one repetition maximum of deadlift and cable pulldown), anaerobic power (Wingate test), core stability (sports-specific endurance plank), core muscular power (front abdominal power, side abdominal power), muscular endurance of limbs (push-up, endurance jump), and swim performance improvement (personal record). Differences between groups after the exercise intervention were analyzed using two-way analysis of variance with repeated measures. RESULTS: There were no significant interactions in isotonic maximum strength, anaerobic power (mean power, fatigue index), core muscular power, muscular endurance of limbs (endurance jump), and swim record improvement (P>0.05). The anaerobic peak power (P<0.001), sports-specific endurance plank test (P<0.001), and push-up test (P<0.001) showed significant interaction effects. CONCLUSION: The 12-week dry-land core training program resulted in statistically significant improvements in anaerobic power, core stability, upper extremity muscular endurance, and swimming performance.

The Effects of Initial Rehabilitation Exercise on Range of Motion, Muscular Strength, and Muscle Pain after Surgery for Osteochondritis Dissecans of the Humeral Capitellum in Middle and High School Baseball Players.

BACKGROUND: This study evaluated the effects of a 4-week initial rehabilitation program in middle and high school baseball players who underwent removal of a loose body from osteochondritis dissecans of the capitellum humerus. METHODS: Middle and high school baseball players with osteochondritis dissecans of the capitellum humerus were enrolled in this study. Each had more than 3 yr of experience and had undergone arthroscopic removal of loose bodies from the same expert at Kim's Orthop Special Clinic in Seoul. The initial exercise rehabilitation program was based on a two-stage program. Body composition, range of motion of flexion and extension in the elbow and wrist joints, grip strength, and subjective pain scale were measured before and after rehabilitation. To assess the differences between groups, we used a two-way analysis of variance. RESULTS: The range of motion for flexion and extension of the elbow and wrist joints, grip strength, and score on the visual analog scale each were significantly improved following the 4-week program (P<0.001), had an interactive effect in time × group (P<0.001), and had significance between groups (P<0.05). CONCLUSION: The 4-week initial rehabilitation exercise program might improve the overall range of motion of the elbow joint and has a positive therapeutic effect on grip strength and visual analog scores. However, future well-designed studies with more subjects and multicentric research groups are necessary for verification.

Effects of Cool-Down Exercise and Cold-Water Immersion Therapy on Basic Fitness and Sport-Specific Skills among Korean College Soccer Players.

BACKGROUND: We aimed to examine the effects of cool-down exercise and cold-water immersion therapy on agility, speed, power, balance, and sport-specific skill performance in college soccer players, and to provide baseline data for the development of effective recovery programs. METHODS: In August 2020, 21 male college soccer players in Seoul, Korea, were randomly divided into the following groups: control group (CG, n=7), cool-down exercise group (CDG, n=7), and cool-down exercise plus cold-water immersion group (CDCWG, n=7). Agility, speed, power, balance, and sport-specific skill performance were assessed before and after the intervention. RESULTS: No significant differences in Southeast Missouri (SEMO) Agility Test, 20-m sprint test, vertical jump test, or Y-balance test (right) were observed among the groups; however, there was a significant effect of time (P<0.05) and a significant time × group interaction (P<0.05). Significant effects of time (P<0.001), group (P=0.043), and a time × group interaction (P=0.009) were observed in the Y-balance test (left). There were no between-group differences in the 22-m dribble test, shooting test (left), or shooting test (right); however, there were significant effects of time (P<0.05) and significant time × group interactions (P<0.05). No significant effects of group or time × group interactions were observed for the kicking test (left or right); however, there were significant effects of time (P<0.001). CONCLUSION: Addition of cold-water immersion therapy to a recovery program including cool-down exercise can promote recovery of basic and sport-specific abilities among college soccer players.

Abrupt shift to hotter and drier climate over inner East Asia beyond the tipping point.

Unprecedented heatwave-drought concurrences in the past two decades have been reported over inner East Asia. Tree-ring-based reconstructions of heatwaves and soil moisture for the past 260 years reveal an abrupt shift to hotter and drier climate over this region. Enhanced land-atmosphere coupling, associated with persistent soil moisture deficit, appears to intensify surface warming and anticyclonic circulation anomalies, fueling heatwaves that exacerbate soil drying. Our analysis demonstrates that the magnitude of the warm and dry anomalies compounding in the recent two decades is unprecedented over the quarter of a millennium, and this trend clearly exceeds the natural variability range. The "hockey stick"-like change warns that the warming and drying concurrence is potentially irreversible beyond a tipping point in the East Asian climate system.

Effect of a 12-Week Rehabilitation Exercise Program on Shoulder Proprioception, Instability and Pain in Baseball Players with Shoulder Instability.

BACKGROUND: The shoulder joint has a wide range of motion, but is vulnerable to sport-related injuries. We aimed to evaluate the differences in the proprioception of the shoulder should instability, and shoulder pain in high school baseball players with shoulder instability following a 12-week rehabilitation exercise program. METHODS: We enrolled 13 baseball players with shoulder instability who visited the Orthopedics Department at Konkook University Hospital in Seoul, South Korea and 12 controls without shoulder instability. We examined the dominant shoulder and the non-dominant shoulder for both groups. We restricted participation to individuals who had no other orthomechanical disease in the past six months, except for instability of the shoulder, and no physical limitation to participate in the exercise. We measured the proprioception of the shoulder and shoulder instability, and we also evaluated pain with the Visual Analog Scale before and after the rehabilitation program. To verify the differences between groups, we used a two-way analysis of variance, and a two-way analysis of covariance was used when a significant difference was found at the pretest (baseline between groups). RESULTS: Proprioception was associated with shoulder instability. The Visual Analog Scale rating improved in the dominant shoulder with instability; and a positive change was found in the dominant shoulder without instability after the rehabilitation program (P < 0.05). CONCLUSION: The 12-week rehabilitation exercise program might improve the proprioception and pain of patients with shoulder instability. However, further studies with more participants and a rehabilitation exercise program should be undertaken.

Effects of Scapular Kinetic-Chain Exercise on Muscle Activity in Overhead-Pitching Baseball Players.

BACKGROUND: We aimed to demonstrate the effect of 8 wk of scapular kinetic-chain exercise on muscle activity in collegiate baseball players diagnosed with scapular dyskinesis. METHODS: The subjects were career baseball players with at least a 7-year career assigned into either a SICK (S; scapular malposition, I; inferior border prominence, C; coracoid process pain, K; scapular dyskinesis; n=7) group or a normal group (n=16), respectively. The groups were further divided into SICK-Dominant, SICK-Non-Dominant, Normal-Dominant, and Normal-Non-Dominant to examine the dominant and non-dominant deviation of each group. Twenty-three subjects finally recruited through the Sports Science Institute of Korea National Sport University, Seoul, Korea in Sep 2014. Subjects were only allowed drug treatment for acute injuries during matches or training, and matches, training, and diet were controlled by university dormitory life. RESULTS: There was a significant increase in maximal muscular activation (MA) in elevation motion of Normal-Dominant upper trapezii (UT), mean MA of SICK-Dominant UT, and mean MA of SICK-Dominant lower trapezii (LT) (P<0.05). In depression motion, the mean MAs of SICK-Dominant, Normal-Dominant, and Normal-Non-Dominant UT were significantly increased (P<0.05). The maximal MA of Normal-Dominant LT was significantly increased (P=0.029), and the SICK-Dominant and Normal-Dominant groups showed significantly higher maximal and mean MAs after exercise compared with the Normal-Non-Dominant group (P<0.05). The maximal MA of SICK-Dominant musculi serratus anterior was significantly lower than Normal-Dominant at pre-test (P=0.034), and the mean MA of SICK-Dominant musculi serratus anterior differed from Normal-Dominant and Normal-Non-Dominant (P<0.05) before testing, but only from Normal-Non-Dominant after testing (P=0.031). CONCLUSION: Scapular kinetic-chain exercise improved muscle activation in both overhead-pitching players with scapular dyskinesis and normal players.

A Pilot Study of E-Cigarette Naïve Cigarette Smokers and the Effects on Craving After Acute Exposure to E-Cigarettes in the Laboratory.

BACKGROUND AND OBJECTIVES: Recent surveys confirm continued increases in the use of electronic-cigarettes (e-cigarettes) in adolescents and adults. Users often state that e-cigarettes reduce tobacco craving and withdrawal symptoms in addition to their smoking. Data from laboratory studies and clinical trials have confirmed these statements, though there are inconsistencies in the outcomes. In this pilot study, we set out to evaluate the effects of e-cigarettes, as compared to the participants' own cigarettes, on baseline craving and smoking severity. METHODS: Using a within-subjects, placebo-controlled study design, 15 tobacco-dependent, e-cigarette naïve participants sustained abstinence overnight. They completed distinct phases of this protocol during four separate study sessions. Participants were randomized to an e-cigarette device containing one of three doses of nicotine (0, 18, or 36 mg/ml) or their own cigarette. Each study visit was ~3 hours long and separated by at least 7 days. Visits included assessments of craving and smoking severity. RESULTS: The data showed that after 10 puffs in both the Own cigarette and e-cigarette conditions, breath carbon monoxide levels increased significantly in the former but not the latter. Questionnaire of Smoking Urges and Choices to Smoke scores were not statistically different across groups after two distinct bouts of 10 puffs each. Additionally, E-cigarette Perceptions Questionnaire responses were not significantly different according to dose. CONCLUSION AND SCIENTIFIC SIGNIFICANCE: This experiment provides data demonstrating that e-cigarettes did not reduce craving or smoking severity in e-cigarette naïve users. However, since this was a pilot study, the conclusions that can be drawn are limited. (Am J Addict 2019;28:361-366).

Linking deep convection and phytoplankton blooms in the northern Labrador Sea in a changing climate.

Wintertime convective mixing plays a pivotal role in the sub-polar North Atlantic spring phytoplankton blooms by favoring phytoplankton survival in the competition between light-dependent production and losses due to grazing and gravitational settling. We use satellite and ocean reanalyses to show that the area-averaged maximum winter mixed layer depth is positively correlated with April chlorophyll concentration in the northern Labrador Sea. A simple theoretical framework is developed to understand the relative roles of winter/spring convection and gravitational sedimentation in spring blooms in this region. Combining climate model simulations that project a weakening of wintertime Labrador Sea convection from Arctic sea ice melt with our framework suggests a potentially significant reduction in the initial fall phytoplankton population that survive the winter to seed the region's spring bloom by the end of the 21st century.

Synthesis of submicron silver powder from scrap low-temperature co-fired ceramic an e-waste: Understanding the leaching kinetics and wet chemistry.

The current study focuses on the understanding of leaching kinetics of metal in the LTCC in general and silver leaching in particular along with wet chemical reduction involving silver nanoparticle synthesis. Followed by metal leaching, the silver was selectively precipitated using HCl as AgCl. The precipitated AgCl was dissolved in ammonium hydroxide and reduced to pure silver metal nanopowder (NPs) using hydrazine as a reductant. Polyvinylpyrrolidone (PVP) used as a stabilizer and Polyethylene glycol (PEG) used as reducing reagent as well as stabilizing reagent to control size and shape of the Ag NPs. An in-depth investigation indicated a first-order kinetics model fits well with high accuracy among all possible models. Activation energy required for the first order reaction was 21.242 kJ mol-1 for Silver. PVP and PEG 1% each together provide better size control over silver nanoparticle synthesis using 0.4 M hydrazine as reductant, which provides relatively regular morphology in comparison to their individual application. The investigation revealed that the waste LTCC (an industrial e-waste) can be recycled through the reported process even in industrial scale. The novelty of reported recycling process is simplicity, versatile and eco-efficiency through which waste LTCC recycling can address various issues like; (i) industrial waste disposal (ii) synthesis of silver nanoparticles from waste LTCC (iii) circulate metal economy within a closed loop cycle in the industrial economies where resources are scarce, altogether.

Selective recovery of silver from waste low-temperature co-fired ceramic and valorization through silver nanoparticle synthesis.

Considering the value of silver metal and silver nanoparticles, the waste generated during manufacturing of low temperature co-fired ceramic (LTCC) were recycled through the simple yet cost effective process by chemical-metallurgy. Followed by leaching optimization, silver was selectively recovered through precipitation. The precipitated silver chloride was valorized though silver nanoparticle synthesis by a simple one-pot greener synthesis route. Through leaching-precipitation optimization, quantitative selective recovery of silver chloride was achieved, followed by homogeneous pure silver nanoparticle about 100nm size were synthesized. The reported recycling process is a simple process, versatile, easy to implement, requires minimum facilities and no specialty chemicals, through which semiconductor manufacturing industry can treat the waste generated during manufacturing of LTCC and reutilize the valorized silver nanoparticles in manufacturing in a close loop process. Our reported process can address issues like; (i) waste disposal, as well as value-added silver recovery, (ii) brings back the material to production stream and address the circular economy, and (iii) can be part of lower the futuristic carbon economy and cradle-to-cradle technology management, simultaneously.