Impact of vehicles at the roadside of expressway in urban area: Simultaneous measurement of particle size distribution and positive matrix factorization.

This study conducted real-time monitoring of size-resolved particle concentrations ranging from 9 nm to 10 μm simultaneously at four sites on the park ground and the roof of a five-story apartment buildings in the upwind and downwind areas of the Olympic Expressway next to apartment complex areas of Seoul, Korea. Using a positive matrix factorization model for source apportionment, eight factors were resolved at each monitoring site: four exhaust emissions of vehicles, one non-exhaust emission of vehicle, two regional sources, and one unknown source. After categorizing monitoring data into three cases by wind conditions, impact and contribution of each vehicle-related source on the local road to the roadside pollution was quantified and characterized by subtracting the urban background concentrations.

Increased Trend of Adenovirus Activity After the COVID-19 Pandemic in South Korea: Analysis of National Surveillance Data.

The adenovirus detection rate is <10% throughout the year in South Korea; however, during the summer of 2023, it showed an unusual increase. We analyzed the adenovirus detection rate using data from the Korea Respiratory Integrated Surveillance System before and after coronavirus disease (COVID-19) collected from 2019 to week 36 of 2023. Before the COVID-19 outbreak in 2019, the mean detection rate was 8.

Spatial and PMF analysis of particle size distributions simultaneously measured at four locations at the roadside of highways.

In urban areas, particulate matter emitted from vehicles directly affects the health of citizens near roads. Thus, in this study, particle size distribution was measured by the horizontal and vertical distances along a highway road with heavy traffic to characterize the dispersion phenomena of particulate matter emitted from vehicles. In addition, the contribution of pollution sources was analyzed using a source-receptor model.

Comparison of total PM emissions emitted from electric and internal combustion engine vehicles: An experimental analysis.

Electric vehicles (EVs) are regarded as zero emission vehicles due to the absence of exhaust emissions. However, they still contribute non-exhaust particulate matter (PM) emissions, generated by brake wear, tire wear, road wear, and resuspended road dust. In fact, because EVs are heavier than internal combustion engine vehicles (ICEVs), their non-exhaust emissions are like to be even higher.

Effect of treadwear grade on the generation of tire PM emissions in laboratory and real-world driving conditions.

Tires generally wear out due to the friction between the tire and the road surface. Minimizing tire wear could reduce the non-exhaust particulate matter (PM) emissions from tires. Typically, tire treadwear grade can be used as an indicator of PM emissions from tires.

Chemical Leaching from Tire Wear Particles with Various Treadwear Ratings.

Physical friction between a tire and the road surface generates tire wear particles (TWPs), which are a source of microplastics and particulate matter. This study investigated the trends of chemical leaching from TWPs depending on the treadwear rating of the tire. A road simulator was used to produce TWPs from tires with various treadwear ratings.

Real-time detection of vehicle-originated condensable particulate matter through thermodenuder integrated aerosol measurement method at tailpipes.

Condensable particulate matter (CPM) corresponds to primary particulate matter ≤2.5 μm (PM) obtained through the condensation of gaseous air pollutants caused by temperature drops in the atmosphere. The internal combustion of vehicle engines can produce CPM because of the condensable compounds in the exhaust gas.

SARS-CoV-2 B.1.619 and B.1.620 Lineages, South Korea, 2021.

We report the rapid emergence of severe acute respiratory syndrome coronavirus 2 lineages B.1.619 and B.

Corrigendum to: Genomic epidemiology reveals the reduction of the introduction and spread of SARS-CoV-2 after implementing control strategies in Republic of Korea, 2020.

[This corrects the article DOI: 10.1093/ve/veab077.].

Size-dependent characteristics of diurnal particle concentration variation in an underground subway tunnel.

Understanding characteristics of diurnal particle concentration variation in an underground subway tunnel is important to reduce subway passengers' exposure to high levels of toxic particle pollution. In this study, real-time particle monitoring for eight consecutive days was done at a shelter located in the middle of a one-way underground subway tunnel in Seoul, Republic of Korea, during the summer of 2015. Particle mass concentration was measured using a dust monitor and particle number concentration using an optical particle counter.

Simultaneous determination of 18 psychoactive agents and 6 metabolites in plasma using LC-MS/MS and application to actual plasma samples from conscription candidates.

In Korea, an increasing number of people attempt to evade military conscription by posing as mental health patients. To verify the authenticity of mental illness, there is a need to detect wide range of psychoactive agents in biological specimens of conscription candidates. In this study, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of 18 psychoactive agents and 6 metabolites in human plasma.

Evaluation of the zoonotic potential of multiple subgroups of clade 2.3.4.4 influenza A (H5N8) virus.

Clade 2.3.4.

An LC-MS/MS method for the simultaneous determination of 15 antipsychotics and two metabolites in hair and its application to rat hair.

In recent years, the inappropriate use of antipsychotics by young Korean men has become a social problem. As military service exemptions are given for mental illness, some men pose as mental health patients to avoid military service. In order to verify the authenticity of mental illnesses, we developed simultaneous analytical methods for the detection of 15 antipsychotics and 2 of their metabolites in hair using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis.

Overestimation of on-road air quality surveying data measured with a mobile laboratory caused by exhaust plumes of a vehicle ahead in dense traffic areas.

The unintended influence of exhaust plumes emitted from a vehicle ahead to on-road air quality surveying data measured with a mobile laboratory (ML) at 20-40 km h in dense traffic areas was investigated by experiment and life-sized computational fluidic dynamics (CFD) simulation. The ML equipped with variable sampling inlets of five columns by four rows was used to measure the spatial distribution of CO and NO concentrations when following 5-20 m behind a sport utility vehicle (SUV) as an emitter vehicle equipped with a portable emission monitoring system (PEMS). The PEMS measured exhaust gases at the tailpipe for input data of the CFD simulations.

Generation of Nanoparticles from Friction between Railway Brake Disks and Pads.

In this study, we measured the size distribution of particles ranging in size from 5.6 to 560 nm that were emitted between brake disks and pads under various braking conditions to observe and analyze changes to the resulting particle size distribution over braking time. A peak of 178-275 nm (200 nm peak) was observed in all braking conditions.

Experimental infection of SPF and Korean native chickens with highly pathogenic avian influenza virus (H5N8).

In 2014, an H5N8 outbreak of highly pathogenic avian influenza (HPAI) occurred in South Korea. The H5N8 strain produced mild to moderate clinical signs and mortality rates in commercial chicken farms, especially Korean native chicken farms. To understand the differences between their pathogenicity in SPF chicken and Korean native chicken.

Development of a liquid chromatography-tandem mass spectrometry method for the determination of Grayanotoxins in rat blood and its application to toxicokinetic study.

A sensitive and specific high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed for the determination of Grayanotoxin I (GTX I) and Grayanotoxin III (GTX III) in rat whole blood. Grayanotoxins (GTXs) and clindamycin as internal standard (IS) were extracted from rat blood via solid-phase extraction using PEP solid-phase extraction cartridges. Chromatographic separation of the analytes was achieved on a Kinetex C18 (100 × 2.