Source country-specific burden on health due to high concentrations of PM2.5.

Asian countries face frequent spikes in concentrations of particulate matter smaller than 2.5 µm (PM2.5), which may consist of domestic emissions, transported pollutants from neighboring countries, and secondary aerosol formation (SAF). We aimed to estimate the burden on health in South Korea due to PM2.5 exposure from source countries. We computed the health benefits of meeting air quality guidelines during high pollution periods or spike periods. We used daily mortality counts, PM2.5 concentrations, and primary and secondary contributions to pollutant levels in seven cities and nine provinces in South Korea during 2006-2016. Generalized additive mixed modeling with a Poisson distribution and random effects in 16 regions was used to examine the short-term effects of PM2.5 on mortality. We computed attributable burden due to PM2.5 exposure and the potential benefits of meeting the air quality guidelines set by the World Health Organization (WHO, 25 µg/m3) and the Korea Ministry of Environment (50 and 35 µg/m3 before and after 2015, respectively). A concentration-response curve showed a non-linear relationship between daily mortality counts and PM2.5 levels. The short-term health impacts of PM2.5 were suggested to be 1638 non-accidental deaths in 2016 in South Korea due to daily domestic emissions and pollutants transported from neighboring countries. Of these, 1509, 995, or 238 deaths could have been prevented if the daily mean PM2.5 concentration had been kept below 25, 35, or 50 µg/m3. After accounting for the contribution of SAF to PM2.5, primary sources of PM2.5 resulted in 258-860 and 26-88 deaths due to pollution transported from China and North Korea, respectively, and 162-538 deaths were due to domestic emissions. Meeting the air quality guidelines of the WHO could have prevented most of these deaths.

Elevated fecal calprotectin levels are associated with severity of atopic dermatitis in children.

BACKGROUND: Recent data suggested that imbalance in gut microbiota and gastrointestinal inflammation are associated with the childhood allergic disease. Fecal calprotectin has been used for a non-invasive marker of gut inflammation. OBJECTIVE: The aim of this study was to investigate the relationships between fecal calprotectin level and the clinical severity of atopic dermatitis (AD) in children. METHODS: We enrolled 65 subjects with AD. The concentration of calprotectin was measured in each subject's fecal sample. RESULTS: The geometric mean fecal calprotectin level of the total subjects was 33.1(10.1-108.9) µg/g. Among the 65 subjects, 44(67.7%) showed calprotectin levels lower than 50µg/g(Group 1), and 21(32.3%) were higher than 50µg/g(Group 2). The mean SCORAD index was significantly higher in Group 2 than Group 1(31.0±16.0 vs 22.2±15.3, p=0.046). The geometric mean serum total IgE levels was higher in Group 2 compared to Group 1(361.4[31.6-992.3]IU/mL vs 175.9[44.3-699.2]IU/mL, p=0.040). The mean blood eosinophils were significantly higher in Group 2 than in Group 1(497.7[239.8-1032.8]/µL vs 281.5[121.5-652.0]/µL, p=0.034). The incidence of exposure to environmental tobacco smoke was significantly higher in Group 2 compared to Group 1(76.2% vs 47.7%, p=0.036). Geometric mean fecal calprotectin level in severe AD was significantly higher than that of mild-to-moderate AD(66.7[13.5-330.3]µg/g vs 29.4[10.1-85.6]µg/g, p=0.044). The fecal calprotectin level significantly correlated with the SCORAD index(r=0.303, p=0.014). CONCLUSIONS: Higher fecal calprotectin levels were observed in subjects with severe AD. Elevated fecal calprotectin level as a gastrointestinal inflammatory marker may associate with childhood AD. Measurement of fecal calprotectin might be useful for assessment of severity of childhood AD.

Association of carbon monoxide levels with allergic diseases in children.

BACKGROUND: Air pollution is regarded as a potential reason for the development or aggravation of allergic diseases. OBJECTIVE: To investigate the relationship between exposure to outdoor air pollution during the first year of life and the development of allergic diseases, and to determine the association between outdoor air pollution near the residence and recent symptoms of allergic diseases in children. METHODS: A nationwide cross-sectional survey was conducted in 6- to 7-year-old children. Among them, subjects who had been born (n = 1828) or lived (n = 1894) within 2 km of the nearest air quality monitoring sites were selected. The prevalence of allergic diseases was assessed by using questionnaires. Each subject was examined by pediatricians to determine the presence of eczema. Publicly available data were used regarding the daily ambient concentrations of sulfur dioxide, nitrogen dioxide, ozone, carbon monoxide (CO), and particulate matter. RESULTS: For a 100 ppb increase in the mean daily CO level during the first year of life, the adjusted odds ratio for lifetime allergic rhinitis was 1.10 (95% confidence interval, 1.03-1.19). For a 1 ppm increase in the annual average CO level during the past 12 months, the adjusted odds ratio for the presence of atopic dermatitis on the day of the survey was 8.11 (95% confidence interval, 1.06-62.12). However, the other air pollutants showed no statistical significance. CONCLUSIONS: Higher exposure to CO during infancy increased the risk of development of allergic rhinitis. The risk of current atopic dermatitis symptoms increased in children who were exposed to higher CO levels during the past 12 months.

Developing a Novel Read-Across Concept for Ecotoxicological Risk Assessment of Phosphate Chemicals: A Case Study.

This study introduces a novel concept approach for a read-across assessment, considering species sensitivity differences among phosphate chemicals within structurally similar compound groups. Twenty-five organic chemicals, with a log Kow of 5 or less, were categorized into three functional groups based on acetylcholinesterase (AChE) inhibition as a specific mode of action (MOA). The short-term aquatic toxicity data (LC50) for fish, crustaceans, and insects were collected from the U.S. EPA Ecotoxicology (ECOTOX) Knowledgebase. A geometric mean calculation method was applied for multiple toxic endpoints. Performance metrics for the new read-across concept, including correlation coefficient, bias, precision, and accuracy, were calculated. Overall, a slightly higher overestimation (49.2%) than underestimation (48.4%) in toxicity predictions was observed in two case studies. In Case study I, a strong positive correlation (r = 0.93) between the predicted and known toxicity values of target chemicals was observed, while in Case study II, with limited information on species and their ecotoxicity, showed a moderate correlation (r = 0.75). Overall, the bias and precision for Case study I were 0.32 ± 0.01, while Case study II showed 0.65 ± 0.06; however, the relative bias (%) increased from 37.65% (Case study I) to 91.94% (Case study II). Bland-Altman plots highlight the mean differences of 1.33 (Case study I) and 1.24 (Case study II), respectively. The new read-across concept, focusing on AChE inhibition and structural similarity, demonstrated good reliability, applicability, and accuracy with minimal bias. Future studies are needed to evaluate various types of chemical substances, diverse modes of action, functional groups, toxic endpoints, and test species to ensure overall comprehensiveness and robustness in toxicity predictions.

Performance evaluation of an electrostatic precipitator with a copper plate using an aerosolized SARS-CoV-2 surrogate (bacteriophage phi 6).

The global spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has reminded us of the importance of developing technologies to reduce and control bioaerosols in built environments. For bioaerosol control, the interaction between researchers and biomaterials is essential, and considering the characteristics of target pathogens is strongly required. Herein, we used enveloped viral aerosols, bacteriophage phi 6, for evaluating the performance of an electrostatic precipitator (ESP) with a copper-collecting plate (Cu-plate). In particular, bacteriophage phi 6 is an accessible enveloped virus that can be operated in biosafety level (BSL)-1 as a promising surrogate for SARS-CoV-2 with structural and morphological similarities. ESP with Cu-plate showed >91% of particle removal efficiency for viral aerosols at 77 cm/s of airflow face velocity. Moreover, the Cu-plate presented a potent antiviral performance of 5.4-relative log reduction within <15 min of contact. We believe that the evaluation of ESP performance using an aerosolized enveloped virus and plaque assay is invaluable. Our results provide essential information for the development of bioaerosol control technologies that will lead the post-corona era.

Bronchodilator responses after methacholine and adenosine 5'-monophosphate (AMP) challenges in children with asthma: their relationships with eosinophil markers.

BACKGROUND: Bronchodilator responsiveness (BDR) and eosinophilic inflammation are characteristic features of asthma. Objective. The aim of this study was to compare the relationships of BDR after methacholine challenge or adenosine 5'-monophosphate (AMP) challenge to blood eosinophil markers in children with asthma. METHODS: Methacholine and AMP challenges were performed on 69 children with mild intermittent to moderate persistent asthma. BDR was calculated as the change in forced expiratory volume in 1 second, expressed as percentage change of the value immediately after the each challenge and the value after inhalation of salbutamol. Serum total IgE levels, blood eosinophil counts, and serum eosinophil cationic protein (ECP) levels were determined for each subject. RESULTS: A positive relationship between serum total IgE levels and BDR was found only after the AMP challenge (R(2) = 0.345, p = .001) rather than after the methacholine challenge (R(2) = 0.007, p = .495). Peripheral blood eosinophil counts correlated more significantly with BDR after AMP challenge (R(2) = 0.212, p = .001) than BDR after methacholine challenge (R(2) = 0.002, p = .724). Both BDR after methacholine challenge (R(2) = 0.063, p = .038) and BDR after AMP challenge (R(2) = 0.192, p = .001) were significantly correlated with serum ECP levels. CONCLUSION: BDR after AMP challenge may be more closely related to eosinophilic inflammation, compared with that after methacholine challenge.

Size-fractionated (1-->3)-beta-D-glucan concentrations aerosolized from different moldy building materials.

Release of submicrometer-sized fungal fragments (<1.0 microm) was discovered in earlier studies, which investigated the aerosolization of spores from moldy surfaces. However, the contribution of fungal fragments to total mold exposure is poorly characterized. The purpose of this study was to investigate the size-fractionated concentrations of particulate (1-->3)-beta-D-glucan and numbers of particles aerosolized from the surface of artificially mold-contaminated materials using a novel sampling methodology. Aspergillus versicolor and Stachybotrys chartarum were grown on malt extract agar and building materials (ceiling tiles and gypsum board) for one to six months. Fungal particles released from these materials were collected size-selectively by a newly developed Fragment Sampling System, and (1-->3)-beta-D-glucan in air samples was analyzed by Limulus Amebocyte lysate (LAL) assay. The concentrations of (1-->3)-beta-D-glucan varied from 0.4x10(0) to 9.8x10(2) ng m(-3) in the fragment size and from 1.0x10(1) to 4.7x10(4) ng m(-3) in the spore size range. Numbers of submicrometer-sized particles aerosolized from 6-month old cultures were always significantly higher that those from 1-month old (P<0.001). This can be attributed to increased dryness on the surface of material samples and an increase in fungal biomass over time. The average fragment to spore ratios both in particle numbers and (1-->3)-beta-D-glucan mass were higher for S. chartarum than for A. versicolor. The results indicate that long-term mold damage in buildings may lead to increased contribution of fragments to the total mold exposure. Therefore, the health impact of these particles may be even greater than that of spores, considering the strong association between numbers of fine particles and adverse health effects reported in other studies. Furthermore, the contribution of fragments may vary between species and appears to be higher for S. chartarum than for A. versicolor.

Evaluation of filtration characteristics and microbial recovery rates of commercial filtering facepiece respirators against airborne bacterial particles.

Many brands of filtering facepiece respirators are used against air pollution, including bioaerosols; however, studies have explored exposure to bioaerosols from the inside surfaces of respirators. We evaluated the filtration efficiencies and microbial recovery rates of commercial filtering facepiece respirators against bioaerosols. Eight filtering facepiece respirators and one surgical mask were selected, all with high market shares in the Republic of Korea and certified by national or international standards. The tested filtering facepiece respirators were installed on the head of a mannequin under various airflow velocity and relative humidity (RH) conditions. The filtration efficiency against Staphylococcus epidermidis and Escherichia coli bioaerosols, the pressure drop of the filter, and the relative recovery rates for the bacteria were evaluated. The filtration efficiency of each filtering facepiece respirator ranged from 82% to 99%, depending on the filtration grade. The pressure drop was significantly affected by variations in the surrounding RH. The mean relative recovery rates of all filtering facepiece respirators were 14 ±â€¯4.8% and 9 ±â€¯4.7% for S. epidermidis and E. coli, respectively. These results indicate that airborne microorganisms can survive and accumulate on the surfaces of filtering facepiece respirators, which may lead to harmful health outcomes. Our findings will be useful as background information for the development of commercial filtering facepiece respirators while considering their biological properties and reliable guidance to users.

Aerosolization of particulate (1-->3)-beta-D-glucan from moldy materials.

Mold-damaged building materials may contain biologically active agents, such as (1-->3)-beta-D-glucan, allergens, and mycotoxins, which have been associated with adverse health effects. The release of these components from contaminated surfaces into the air is not well understood. The purpose of this study was to characterize the release of particulate (1-->3)-beta-D-glucan from the surface of artificially mold-contaminated materials. Aspergillus versicolor and Stachybotrys chartarum were grown on malt extract agar (MEA), white ceiling tiles, and a wall-papered gypsum board for 1 and 6 months. The (1-->3)-beta-D-glucan on the surfaces of moldy materials and in air samples collected from these materials was analyzed by the Limulus amebocyte lysate assay. The aerosolization ratio was defined as the amount of (1-->3)-beta-D-glucan in the air divided by the amount on the surface. The results showed that the aerosolization of particulate (1-->3)-beta-D-glucan was influenced mainly by the type of material and the fungal species. For A. versicolor, the aerosolization ratios of particulate (1-->3)-beta-D-glucan released from the three types of material were not significantly different. However, the ratios for S. chartarum released from ceiling tiles and gypsum board were significantly higher than the ratios for this organism released from MEA (P < 0.001) and were comparable to those for A. versicolor. These findings indicate that the use of MEA in aerosolization experiments is likely to underestimate the release of S. chartarum particles from building materials. These results provide important background information for design of future laboratory or animal experiments, as well as for interpretation of field measurement data.

Fungal Fragments in Moldy Houses: A Field Study in Homes in New Orleans and Southern Ohio.

Smaller-sized fungal fragments (<1 µm) may contribute to mold-related health effects. Previous laboratory-based studies have shown that the number concentration of fungal fragments can be up to 500 times higher than that of fungal spores, but this has not yet been confirmed in a field study due to lack of suitable methodology. We have recently developed a field-compatible method for the sampling and analysis of airborne fungal fragments. The new methodology was utilized for characterizing fungal fragment exposures in mold-contaminated homes selected in New Orleans, Louisiana and Southern Ohio. Airborne fungal particles were separated into three distinct size fractions: (i) >2.25 µm (spores); (ii) 1.05-2.25 µm (mixture); and (iii) < 1.0 µm (submicrometer-sized fragments). Samples were collected in five homes in summer and winter and analyzed for (1→3)-ß-D-glucan. The total (1→3)-ß-D-glucan varied from 0.2 to 16.0 ng m(-3). The ratio of (1→3)-ß-D-glucan mass in fragment size fraction to that in spore size fraction (F/S) varied from 0.011 to 2.163. The mass ratio was higher in winter (average = 1.017) than in summer (0.227) coinciding with a lower relative humidity in the winter. Assuming a mass-based F/S-ratio=1 and the spore size = 3 µm, the corresponding number-based F/S-ratio (fragment number/spore number) would be 10(3) and 10(6), for the fragment sizes of 0.3 and 0.03 µm, respectively. These results indicate that the actual (field) contribution of fungal fragments to the overall exposure may be very high, even much greater than that estimated in our earlier laboratory-based studies.

Are children with asthma in South Korea also associated with vitamin D deficiency?

Recently, epidemiologic studies have shown that the lack of serum vitamin D levels may be associated with high asthma prevalence, but its effect is still controversial, depending on season, area, and food consumption. We aimed to examine the association of serum vitamin D levels with the prevalence of pediatric asthma in Korea. A total of 80 children (50 asthmatic children and 30 healthy controls) aged 6-14 years were participated in this study. Serum vitamin D levels were measured and compared between the two groups. Moreover, the relationship of serum vitamin D levels with results of pulmonary function test and environmental factors (lifestyle habits and residential factors) collected by a questionnaire survey were examined in asthmatic patients. Serum vitamin D levels in asthmatic children (16.63±4.20 ng/mL) were significantly lower than that in healthy controls (24.24±6.76 ng/mL) (p<0.05). Also, we found that the prevalence of asthma increase to 0.79-fold (odds ratio, 0.79; 95% confidence interval, 0.71 to 0.88; p<0.001) as serum vitamin D level is 1 ng/mL decreases. The increased time spent in outdoor could affect the increases of serum vitamin D levels significantly. However, no associations of serum vitamin D with pulmonary function and residential environmental factors (i.e., housing type, living floor, and indoor activity time) were observed. Our findings suggest that serum vitamin D levels were also associated with pediatric asthma in Korea. Moreover, management of serum vitamin D level in asthmatic children would be a promising approach for preventing exaggeration of their severity.

Clinical and immunological effects of a forest trip in children with asthma and atopic dermatitis.

Asthma and atopic dermatitis are common allergic diseases, and their prevalence has increased in urban children. Recently, it is becoming understood that forest environment has favorable health effects in patients with chronic diseases. To investigate favorable clinical and immunologic effects of forest, we examined changes in clinical symptoms, indirect airway inflammatory marker, and serum chemokines before and after a short-term forest trip. The forest trips were performed with 21 children with asthma and 27 children with atopic dermatitis. All participating children were living in air polluted urban inner-city. We measured spirometry and fractional exhaled nitric oxide (FeNO) in children with asthma and measured scoring atopic dermatitis (SCORAD) index and Thymus and Activation-Regulated Chemokine (TARC)/CCL17 and Macrophage-Derived Chemokine (MDC)/CCL22 levels in children with atopic dermatitis before and after the forest trip. Indoor air pollutants such as indoor mold, particulate matter 10 (PM10) and total volatile organic compounds (TVOCs) of each child's home and the accommodations within forest were measured. A significant increase in forced vital capacity (FVC) and a significant decrease in FeNO were observed after the forest trip in children with asthma. SCORAD indices and MDC/CCL22 levels were significantly decreased after the forest trip in children with atopic dermatitis. Airborne mold and PM10 levels in indoor were significantly lower in the forest accommodations than those of children's homes; however, TVOC levels were not different between the two measured sites. Short-term exposure to forest environment may have clinical and immunological effects in children with allergic diseases who were living in the urban community.

Predictive value of C-reactive protein in response to macrolides in children with macrolide-resistant Mycoplasma pneumoniae pneumonia.

PURPOSE: The prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) has increased worldwide. The aim of this study was to estimate the proportion of MRMP in a tertiary hospital in Korea, and to find potential laboratory markers that could be used to predict the efficacy of macrolides in children with MRMP pneumonia. METHODS: A total of 95 patients with M. pneumoniae pneumonia were enrolled in this study. Detection of MRMP was based on the results of specific point mutations in domain V of the 23S rRNA gene. The medical records of these patients were reviewed retrospectively and the clinical course and laboratory data were compared. RESULTS: The proportion of patients with MRMP was 51.6% and all MRMP isolates had the A2063G point mutation. The MRMP group had longer hospital stay and febrile period after initiation of macrolides. The levels of serum C-reactive protein (CRP) and interleukin-18 in nasopharyngeal aspirate were significantly higher in patients who did not respond to macrolide treatment. CRP was the only significant factor in predicting the efficacy of macrolides in patients with MRMP pneumonia. The area under the curve for CRP was 0.69 in receiver operating characteristic curve analysis, indicating reasonable discriminative power, and the optimal cutoff value was 40.7 mg/L. CONCLUSION: The proportion of patients with MRMP was high, suggesting that the prevalence of MRMP is rising rapidly in Korea. Serum CRP could be a useful marker for predicting the efficacy of macrolides and helping clinicians make better clinical decisions in children with MRMP pneumonia.

Relationships between exhaled nitric oxide and atopy profiles in children with asthma.

PURPOSE: We examined whether fractional exhaled nitric oxide (FeNO) levels are associated with atopy profiles in terms of mono-sensitization and poly-sensitization in asthmatic children. METHODS: A total of 119 children underwent an assessment that included FeNO measurements, spirometry, methacholine challenge, and measurement of blood eosinophil count, serum total IgE, and serum eosinophil cationic protein (ECP). We also examined sensitization to five classes of aeroallergens (house dust mites, animal danders, pollens, molds, and cockroach) using skin prick testing. The children were divided into three groups according to their sensitization profiles to these aeroallergens (non-sensitized, mono-sensitized, and poly-sensitized). RESULTS: The geometric means (range of 1 SD) of FeNO were significantly different between the three groups (non-sensitized, 18.6 ppb [10.0-34.7 ppb]; mono-sensitized, 28.8 ppb [16.6-50.1 ppb]; and poly-sensitized, 44.7 ppb [24.5-81.3 ppb], P=0.001). FeNO levels were correlated with serum total IgE concentrations, peripheral blood eosinophilia, and serum ECP levels to different degrees. CONCLUSIONS: FeNO levels vary according to the profile of atopy, as determined by positive skin prick test results to various classes of aeroallergens. FeNO is also moderately correlated with serum total IgE, blood eosinophilia, and serum ECP. These results suggest that poly-sensitized asthmatic children may have the highest risk of airway inflammation.