The perception of air pollution and its health risk: a scoping review of measures and methods.

BACKGROUND: Although there is increasing awareness of the health risks of air pollution as a global issue, few studies have focused on the methods for assessing individuals' perceptions of these risks. This scoping review aimed to identify previous research evaluating individuals' perceptions of air pollution and its health effects, and to explore the measurement of perceptions, as a key resource for health behaviour. METHODS: The review followed the methodological framework proposed by Arksey and O'Malley. PubMed and Web of Science were searched. After initial and full-text screening, we further selected studies with standardised scales that had previously been tested for reliability and validity in assessing awareness and perceptions. RESULTS: After full-text screening, 95 studies were identified. 'Perception/awareness of air quality' was often measured, as well as 'Perception of health risk.' Only nine studies (9.5%) used validated scaled questionnaires. There was considerable variation in the scales used to measure the multiple dimensions of risk perception for air pollution. CONCLUSION: Few studies used structured scales to quantify individuals' perceptions, limiting comparisons among studies. Standardised methods for measuring health risk perception are needed.

Main findings: Among 95 studies assessing health risk perception of air pollution, only nine studies used standardised scales.Added knowledge: There was considerable variation in the scales measuring the multiple dimensions of risk perception for air pollution, which makes comparison among the studies difficult.Global health impact for policy and action: This review highlights the need for the development of globally standardised scale to measure the health risk perception of air pollution.

Anaerobic gram-negative rod bacteremia as a marker of gastrointestinal cancer in Japanese patients: a single-center retrospective study.

BACKGROUND: Gram-negative rod (GNR) bacteremia has been suggested as a clinical marker of occult cancer; however, no studies are available in this regard in the Japanese population. Here, we investigated the risk factors for gastrointestinal cancer with GNR bacteremia. METHODS: Patients with GNR bacteremia admitted to St. Luke's International Hospital between January 2011 and July 2021 were included. The clinical data of patients with and without cancer, 1 year before and after GNR bacteremia diagnosis, were compared. Univariate analysis was performed using χ2 and Fisher's exact tests for categorical variables and the Mann-Whitney U test for continuous variables, while multivariable analysis was performed using logistic regression analysis, and a P of <0.05 was considered statistically significant. RESULTS: Of 2,296 GNR bacteremia-positive patients, 96 were associated with gastrointestinal cancer, and univariate analysis showed significant differences between the gastrointestinal cancer and comparison groups in terms of mean body mass index (BMI; 20.5 vs. 21.8 kg/m2), Enterobacterales detection (64.6% vs. 81.3%), and anaerobic GNR detection (24.0% vs. 8.5%). Thirty-five (36%) and 61 (64%) patients had upper and lower gastrointestinal cancer, respectively. There were 23 patients with anaerobic GNR bacteremia related to 24 strains (upper and lower gastrointestinal cancer, 5 and 18 cases, respectively). Multivariate analysis identified anaerobic GNR [odds ratio, 3.440; 95% confidence interval (CI): 2.085-5.675, P<0.001] as a significant risk factor for cancer. CONCLUSIONS: Anaerobic GNR in blood cultures may be a risk factor for gastrointestinal cancer. Therefore, it is necessary consider cancer workup, such as endoscopy, for patients with anaerobic GNR bacteremia.

Early childhood neurodevelopmental milestones in children with allergic diseases: the Japan Environment and Children's Study (JECS).

This study investigated the potential link between early childhood allergic diseases and neurodevelopmental milestone attainment during the first 3 years of life. Utilizing data from a large-scale prospective birth cohort study in Japan, encompassing 87,986 children, we examined physician-diagnosed and caregiver-reported allergic conditions, including atopic dermatitis (AD), asthma, and food allergy (FA). Neurodevelopmental milestones were assessed using the Ages and Stages Questionnaires at 1, 1.5, 2, 2.5, and 3 years of age. Stabilized inverse probability-weighted generalized estimating equation models were employed to estimate odds ratios (ORs). Our analysis revealed no significant association of AD and asthma with delay in communication, gross motor, fine motor, problem-solving, and personal-social skills during the initial 3 years of life. However, children with FA showed an increased likelihood of experiencing gross motor delay compared with that shown by those without FA (weighted adjusted OR: 1.14). Despite this, no significant association of FA with other developmental domains was observed. Early childhood allergies may not influence neurodevelopmental delays. However, there is a potential association between FA and delays, specifically in gross motor skills, that warrants routine developmental monitoring and additional investigations.

Comparison of the inward leakage rate between N95 filtering facepiece respirators and modified surgical masks during the COVID-19 pandemic.

BACKGROUND: Owing to shortage of surgical and N95 filtering facepiece respirators (FFRs) during the COVID-2019 pandemic, various masks were developed to prevent infection. This study aimed to examine the inward leakage rate (ILR) of sealed face masks and modified surgical masks using a quantitative fit test and compared it with the ILR of unmodified N95 FFRs. METHODS: We conducted paired comparisons of ILRs of bent nose-fit wire masks, double masks, and N95 FFRs from October to December 2021. To measure the protective effectiveness of masks, participants wore masks, and the number of particles outside and inside the mask were measured. The ILR was based on the percentage of particles entering the mask using a fit tester. RESULTS: We enrolled 54 participants (20 men and 34 women) in this study. The median ILR for surgical masks without and with a W-shaped bend in the nose-fit wire were 96.44% and 50.82%, respectively. The nose-fit wire adjustment reduced the ILR of surgical masks by a mean of 28.57%, which was significantly lower than the ILR without adjustment (P < 0.001). For double masks, with surgical or polyurethane masks on top of the W-shaped mask, the ILR did not differ significantly from that of N95. Although the filtration performance of double surgical masks matched that of N95 masks, their ILR was notably higher, indicating that double masks do not provide equivalent protection. CONCLUSIONS: Wearing N95 masks alone is effective in many cases. However, surgical mask modifications do not guarantee consistent effectiveness. Properly selected, sealed masks with a good fit overcome leakage, emphasizing their crucial role. Without evidence, mask-wearing may lead to unexpected infections. Education based on quantitative data is crucial for preventing adverse outcomes.

Surveillance and risk assessment of health screening for vaccine-preventable diseases among international students in Japan: A cross-sectional study in 2020.

We conducted a cross-sectional study using a structured questionnaire in three major Japanese cities from August 03 to 24, 2020 to clarify the current situation of health checkups, including vaccine-preventable diseases (VPDs), among international students at Japanese universities (JUs) and Japanese language schools (JLSs). The total response rate was 36%: 69 JUs (31%) and 137 JLSs (39%). Over 90% of these institutions conducted chest X-ray screening for tuberculosis among their students, whereas only 24.6% of JUs and 15.3% of JLSs performed general blood tests for health screening. Only 14.5% and 2.2% of the JUs and JLSs, respectively, required the submission of vaccination or antibody certificates for admission. The difficulties in requesting vaccination certificates from international students are due to poor legal requirements and concerns about rising costs for schools. From 2017 to 2019, 183 international students, principally from East Asia and Southeast Asia, were infected with VPDs, particularly tuberculosis (99 cases) and varicella (71 cases). Whereas the majority of Japanese educational institutions screen international students for tuberculosis (TB) at admission, only a few institutions request proof of antibody testing relating to other VPDs or of vaccination. These findings will help formulate guidelines for checkups related to vaccination for international students required to protect the educational institutions in Japan from the spread of VPDs. In addition, providing multifaceted social support, including financial compensation for institutions and enhanced international students' health issues, would be helpful.

Predicting bacteremia caused by Streptococcus anginosus group: A new scoring method.

BACKGROUND: Viridans group streptococci (VGS) are the most common causative organisms of infective endocarditis. Among VGS, the Streptococcus anginosus group (SAG) is often associated with abscess formation, and delayed diagnosis leads to increased morbidity and mortality. This study aims to examine the factors associated with SAG bacteremia and develop a predictive scoring method. METHODS: This single-center retrospective case-control study of patients with VGS bacteremia compared the background and clinical characteristics between the SAG and non-SAG groups. The univariate analysis used the χ2 test and t-test. The multivariate analysis was conducted using logistic regression. RESULTS: Out of 161 patients, 95 had SAG and 66 had non-SAG bacteremia. Age >63 years: 2 points (odds ratio [OR] = 3.52, 95% confidence interval [CI]: 1.64-7.54); solid tumor: 2 points (OR = 4.44, 95% CI: 1.42-6.77); C-reactive protein >7.61 mg/dL: 3 points (OR = 5.40, 95% CI: 2.49-11.72), and white blood cell count >8550/µL: 2 points (OR = 2.76, 95% CI: 1.29-2.91) were found to be independently associated with SAG bacteremia. After totaling the above variables and adding 1 point for diabetes mellitus, the area under the receiver operating curve was 0.81 (95% CI: 0.74-0.88). The sensitivity and specificity were 51% and 88%, respectively, at a cut-off of 6 points. CONCLUSIONS: In patients with VGS bacteremia, a score of 6 points or higher using this method predicts SAG with high specificity.

Antidepressant-like effect of male mating behavior through oxytocin-induced CREB signaling.

Male sexual activity reduces the level of depression through oxytocin (OT) release within the brain. In this study, we showed that male mating behavior reduces depression-like behavior through OT-induced cAMP response element binding protein (CREB) signaling in the hippocampus. Moreover, we showed that mating behavior in wild-type (WT) male mice increased CREB phosphorylation in hippocampus, whereas that OT receptor knockout (OTR KO) male mice had no effect on CREB phosphorylation. CREB phosphorylation in hippocampus was also increased after OT induction in hippocampal slices prepared from WT mice. In addition, male mating behavior induced the expression of brain-derived neurotrophic factor (BDNF), which was not observed in OTR KO mice. Antidepressant-like effect of mating behavior had no effect in OTR KO mice. These findings suggest that male sexual activity has antidepressant effects through OT-induced CREB signaling in the hippocampus.

Simulation of the transition metal-based cumulative oxidative potential in East Asia and its emission sources in Japan.

The aerosol oxidative potential (OP) is considered to better represent the acute health hazards of aerosols than the mass concentration of fine particulate matter (PM2.5). The proposed major contributors to OP are water soluble transition metals and organic compounds, but the relative magnitudes of these compounds to the total OP are not yet fully understood. In this study, as the first step toward the numerical prediction of OP, the cumulative OP (OPtm*) based on the top five key transition metals, namely, Cu, Mn, Fe, V, and Ni, was defined. The solubilities of metals were assumed constant over time and space based on measurements. Then, the feasibility of its prediction was verified by comparing OPtm* values based on simulated metals to that based on observed metals in East Asia. PM2.5 typically consists of primary and secondary species, while OPtm* only represents primary species. This disparity caused differences in the domestic contributions of PM2.5 and OPtm*, especially in large cities in western Japan. The annual mean domestic contributions of PM2.5 were 40%, while those of OPtm* ranged from 50 to 55%. Sector contributions to the OPtm* emissions in Japan were also assessed. The main important sectors were the road brake and iron-steel industry sectors, followed by power plants, road exhaust, and railways.

Progress toward HIV elimination goals: trends in and projections of annual HIV testing and condom use in Africa.

OBJECTIVES: To estimate trends in and projections of annual HIV testing and condom use at last higher-risk sex and to calculate the probability of reaching key United Nations Programme on AIDS (UNAIDS)'s target. DESIGN: We included 114 nationally-representative datasets in 38 African countries from Demographic and Health Surveys and Multiple Indicator Cluster Surveys with 1 456 224 sexually active adults age 15-49 from 2003 to 2018. METHODS: We applied Bayesian mixed effect models to estimate the coverage of annual HIV testing and condom use at last higher-risk sex for every country and year to 2030 and the probability of reaching UNAIDS testing and condom use targets of 95% coverage by 2030. RESULTS: Seven countries saw downward trends in annual HIV testing and four saw decreases in condom use at higher-risk sex, whereas most countries have upward trends in both indicators. The highest coverage of testing in 2030 is predicted in Swaziland with 92.6% (95% credible interval: 74.5-98.1%), Uganda with 90.5% (72.2-97.2%), and Lesotho with 90.5% (69.4%-97.6%). Meanwhile, Swaziland, Lesotho, and Namibia will have the highest proportion of condom use in 2030 at 85.0% (57.8-96.1%), 75.6% (42.3-93.6%), and 75.5% (42.4-93.2%). The probabilities of reaching targets were very low for both HIV testing (0-28.5%) and condom use (0-12.1%). CONCLUSIONS: We observed limited progress on annual HIV testing and condom use at last higher-risk sex in Africa and little prospect of reaching global targets for HIV/AIDS elimination. Although some funding agencies are considering withdrawal from supporting Africa, more attention to funding and expanding testing and treatment is needed in this region.

Plasma Oxytocin Concentrations During and After Gestation in Japanese Pregnant Women Affected by Anxiety Disorder and Endometriosis.

BACKGROUND: Oxytocin has a key role in mother-infant bonding, maternal care, social interaction, and stress-related psychiatric disorders. However, the factors determining oxytocin concentrations during and after pregnancy such as medical history related to nursing or parental behavior are unknown. To elucidate these, we analyzed the relationships between oxytocin concentrations during and after pregnancy, and medical history assessed in the Japan Environment and Children's Study (JECS). METHODS: We then selected the pregnant women with a medical history of anxiety disorder and endometriosis as cases and pregnant women without medical history as controls adjusting the cohort for age and parity for a nested case-control study, after which 162 women remained for analysis. We evaluated 162 pregnant women from JECS using answers provided in a questionnaire and by measuring plasma oxytocin concentration by ELISA during the first (T1) and second (T2) trimesters of pregnancy, and after childbirth (T3). RESULTS: Oxytocin concentration increased in a time dependent manner, consistent with previous reports. There were weak negative correlations between oxytocin concentration at T1 and the mother's age and height, but no correlation with other factors. The mean oxytocin concentrations of pregnant women with a history of an anxiety disorder (n = 7) and endometriosis (n = 13) were significantly lower than those of pregnant women with no such history at T2 and T3. CONCLUSION: These results suggest that oxytocin concentrations during and after pregnancy were affected by a past history of anxiety disorder and endometriosis. This is the first study of the relationship between oxytocin concentration and endometriosis. To elucidate the molecular mechanisms, further study is needed.

Modeling Transition Metals in East Asia and Japan and Its Emission Sources.

Emission inventories of anthropogenic transition metals, which contribute to aerosol oxidative potential (OP), in Asia (Δx = 0.25°, monthly, 2000-2008) and Japan (Δx = 2 km, hourly, mainly 2012) were developed, based on bottom-up inventories of particulate matters and metal profiles in a speciation database for particulate matters. The new inventories are named Transition Metal Inventory (TMI)-Asia v1.0 and TMI-Japan v1.0, respectively. It includes 10 transition metals in PM2.5 and PM10, which contributed to OP based on reagent experiments, namely, Cu, Mn, Co, V, Ni, Pb, Fe, Zn, Cd, and Cr. The contributions of sectors in the transition metals emission in Japan were also investigated. Road brakes and iron-steel industry are primary sources, followed by other metal industry, navigation, incineration, power plants, and railway. In order to validate the emission inventory, eight elements such as Cu, Mn, V, Ni, Pb, Fe, Zn, and Cr in anthropogenic dust and those in mineral dust were simulated over East Asia and Japan with Δx = 30 km and Δx = 5 km domains, respectively, and compared against the nation-wide seasonal observations of PM2.5 elements in Japan and the long-term continuous observations of total suspended particles (TSPs) at Yonago, Japan in 2013. Most of the simulated elements generally agreed with the observations, while Cu and Pb were significantly overestimated. This is the first comprehensive study on the development and evaluation of emission inventory of OP active elements, but further improvement is needed.

The impact of exposure to desert dust on infants' symptoms and countermeasures to reduce the effects.

BACKGROUND: The association between particulate matter (PM), including desert dust, and allergic symptoms has not been well studied. We examined whether PM exacerbated nose/eye/respiratory symptoms in infants, with a focus on the desert dust element, and assessed possible countermeasures. METHODS: We conducted a panel study of 1492 infants from October 2014 to July 2016 in 3 regions in Japan as an adjunct study of the Japan Environment and Children's Study. Infants' daily symptom scores and behaviors were acquired by web-based questionnaires sent to mothers, who answered within a day using mobile phones. Odds ratios (OR) for symptom development per increased fine PM or desert dust exposure were estimated. Regular use of medications and behaviors on the day of exposure were investigated as possible effect modifiers. RESULTS: Infants developed nose/eye/respiratory symptoms significantly more often in accordance with fine particulate levels (adjusted OR per 10 µg/m3 increase: 1.04, 95% confidence interval [CI]: 1.01-1.07). A model including both fine particulates and desert dust showed reduced OR for fine particulates and robust OR for desert dust (adjusted OR per 0.1/km increase: 1.16, 95% CI: 1.09-1.23). An increased OR was observed both in infants who had previously wheezed and in those who had never wheezed. Receiving information on the particulate forecast, reducing time outdoors, closing windows, and regular use of leukotriene receptor antagonists were significant effect modifiers. CONCLUSIONS: Transborder desert dust arrival increased the risk of nose/eye/respiratory symptoms development in infants. Regular use of leukotriene receptor antagonists and other countermeasures reduced the risk.

Association between vitamin D deficiency and allergic symptom in pregnant women.

BACKGROUND: Vitamin D has been reported to affect both innate, and acquired immunity with immune cells such as dendritic cells having the vitamin D receptors. The co-occurrence of the high prevalence of allergic diseases and vitamin D deficiency globally documented in recent decades, has prompted a hypothesis on whether there is a reasonable association between them. OBJECTIVE: To investigate the association between serum vitamin D deficiency and allergic symptoms. METHODS: Historical cohort. On a cohort study for the association between desert dust exposure and allergic symptoms in 3,327 pregnant women during spring and fall in 2011-2013 in Japan conducted as an adjunct study to the Japan Environment and Children's Study, we promptly acquired subjects' daily allergic symptom scores by sending a web-based questionnaire to each participant on some days. Of the 29,434 answers provided by 3,327 participating pregnant women, we extracted 13,356 answers from 1,475 pregnant women that were answered within a 3-month period after blood samplings. And we measured 25(OH)D levels on those samples to investigate the association between their vitamin D deficiency (serum 25(OH)D < 20ng/mL) and the occurrence of any allergic symptom (allergic symptom score> 0) within 3 months. RESULTS: Serum 25(OH)D was less than 20ng/mL in 1,233 of 1,745 samples (70.7%). The adjusted odds ratio (aOR) for occurrence of any allergic symptom in deficient cases compared with non-deficient cases was 1.33 (95% CI: 1.07-1.64, p = 0.01). Further, vitamin D deficiency significantly enhanced the risk increase at desert dust events and at pollen exposure (p-values for interaction <0.1). CONCLUSION: We confirmed the association between serum vitamin D deficiency and allergic symptoms in Japanese pregnant women.

High frequency of vitamin D deficiency in current pregnant Japanese women associated with UV avoidance and hypo-vitamin D diet.

BACKGROUND: As a consequence of indoor occupations and reduced exposure to sunlight, concerns have been raised that vitamin D deficiency is widespread in developed countries. Vitamin D is known to be associated with increased risks of morbidity and mortality in various diseases. OBJECTIVE: To investigate the serum vitamin D status and its relation with life-style factors in pregnant Japanese women. METHODS: Among a cohort for 3,327 pregnant women who participated in an the adjunct study of the Japan Environment and Children's Study during 2011-2013, in which data were obtained on various life-style factors, including both dietary intake of vitamin D and frequency of UV exposure, this study consisted of 1,592 pregnant women, from whom 2,030 serum samples were drawn in Jan, Apr, Jul, and Oct, and the association between serum 25(OH)D level and life-style factors were analyzed using linear mixed models. RESULTS: Serum 25(OH)D levels were less than 20ng/mL in 1,486 of 2,030 samples (73.2%). There was an obvious seasonal change, with serum 25(OH)D levels of less than 20 ng/mL in 89.8% and 47.8% of samples in spring (April) and autumn (October), respectively. Both the frequency spent under sunlight and dietary intake of vitamin D were significantly associated with serum 25(OH)D level. An increase in sunlight exposure of more than 15 min for 1 to 2 days per week in non-winter, or dietary intake of 2 µg/day of vitamin D resulted in an elevation of 1 ng/mL in serum 25(OH)D levels. CONCLUSION: These findings indicate that vitamin D deficiency is very severe in Japanese pregnant women, especially those rarely exposed to sunlight. The benefits of UV rays should also be informed of when its risk is alerted, and clinicians should propose the adequate UV exposure level.

Associations Between Metal Levels in Whole Blood and IgE Concentrations in Pregnant Women Based on Data From the Japan Environment and Children's Study.

BACKGROUND: Metal exposures could possibly affect allergic responses in pregnant women, although no studies have yet shown a clear relationship between the two, and such exposures might also affect the development of allergic diseases in children. METHODS: We investigated the relationship between metal concentrations in whole blood and immunoglobulin E (IgE; total and specific) in 14,408 pregnant women who participated in the Japan Environment and Children's Study. The subjects submitted self-administered questionnaires, and blood samples were collected from them twice, specifically, during the first trimester and again during the second/third trimester. Concentrations of the metals Cd, Pb, Hg, Se, and Mn, as well as serum total and allergen-specific IgEs for egg white, house dust-mites (HDM), Japanese cedar pollen (JCP), animal dander, and moth, were measured. Allergen-specific IgE(s) were divided based on concentrations <0.35 or ≥0.35 UA/mL, and the metal levels were divided into quartiles. RESULTS: Multivariable logistic regression analysis showed that there was a significant negative correlation between HDM- and animal dander-specific IgEs and Hg and Mn concentrations. Conversely, there was a significant positive relationship between JCP-specific IgE and Hg and Se concentrations. CONCLUSIONS: Metal exposures may be related to both increases and decreases in allergen-specific IgEs in pregnant women.

Erratum for Yokoyama et al., "Skipping Breakfast and Risk of Mortality from Cancer, Circulatory Diseases and All Causes: Findings from the Japan Collaborative Cohort Study".

[This corrects the article on p. 55 in vol. 59, PMID: 27046951.].

Prediction of health effects of cross-border atmospheric pollutants using an aerosol forecast model.

Health effects of cross-border air pollutants and Asian dust are of significant concern in Japan. Currently, models predicting the arrival of aerosols have not investigated the association between arrival predictions and health effects. We investigated the association between subjective health symptoms and unreleased aerosol data from the Model of Aerosol Species in the Global Atmosphere (MASINGAR) acquired from the Japan Meteorological Agency, with the objective of ascertaining if these data could be applied to predicting health effects. Subjective symptom scores were collected via self-administered questionnaires and, along with modeled surface aerosol concentration data, were used to conduct a risk evaluation using generalized estimating equations between October and November 2011. Altogether, 29 individuals provided 1670 responses. Spearman's correlation coefficients were determined for the relationship between the proportion of the participants reporting the maximum score of two or more for each symptom and the surface concentrations for each considered aerosol species calculated using MASINGAR; the coefficients showed significant intermediate correlations between surface sulfate aerosol concentration and respiratory, throat, and fever symptoms (R = 0.557, 0.454, and 0.470, respectively; p < 0.01). In the general estimation equation (logit link) analyses, a significant linear association of surface sulfate aerosol concentration, with an endpoint determined by reported respiratory symptom scores of two or more, was observed (P trend = 0.001, odds ratio [OR] of the highest quartile [Q4] vs. the lowest [Q1] = 5.31, 95% CI = 2.18 to 12.96), with adjustment for potential confounding. The surface sulfate aerosol concentration was also associated with throat and fever symptoms. In conclusion, our findings suggest that modeled data are potentially useful for predicting health risks of cross-border aerosol arrivals.

Variations in the structure of airborne bacterial communities in Tsogt-Ovoo of Gobi desert area during dust events.

Asian dust events transport the airborne bacteria in Chinese desert regions as well as mineral particles and influence downwind area varying biological ecosystems and climate changes. However, the airborne bacterial dynamics were rarely investigated in the Gobi desert area, where dust events are highly frequent. In this study, air samplings were sequentially performed at a 2-m high above the ground at the sampling site located in desert area (Tsogt-Ovoo of Gobi desert; Mongolia 44.2304°N, 105.1700°E). During the dust event days, the bacterial cells and mineral particles increased to more than tenfold of concentrations. MiSeq sequencing targeting 16S ribosomal DNA revealed that the airborne bacteria in desert area mainly belonged to the classes Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Bacilli, Alpha-proteobacteria, Beta-proteobacteria, and Gamma-proteobacteria. The bacterial community structures were different between dust events and non-dust events. The air samples collected at the dust events indicated high abundance rates of Alpha-proteobacteria, which were reported to dominate on the leaf surfaces of plants or in the saline lake environments. After the dust events, the members of Firmicutes (Bacilli) and Bacteroidetes, which are known to form endospore and attach with coarse particles, respectively, increased their relative abundances in the air samples. Presumably, the bacterial compositions and diversities in atmosphere significantly vary during dust events, which carry some particles from grassland (phyllo-sphere), dry lake, and sand surfaces, as well as some bacterial populations such as Firmicutes and Bacteroidetes maintain in the atmosphere for longer time.

Health Impact Assessment of Asian Dust/Cross-border Air Pollutant and Necessary Preventive Measure.

The health effects of Asian dust (mineral dust) originating from dry lands such as the Gobi Desert and Taklamakan Desert have recently been a concern. In addition to Asian dust, transboundary airborne microparticles that reach Japan include various types of aerosol, such as artificial air pollutants and smoke from combustion. They originate from densely populated areas and are transported along the same route as Asian dust. We analyzed environmental factors and subjective symptoms involving the respiratory organ, nose, eyes, and skin using a conventional equation for estimation, and found that symptoms with a significant risk of worsening varied according to the type of pollutants reaching Japan. We also analyzed the synergistic effects of Asian dust and pollens on nasal symptoms using a two-pollutant model. The odds ratio for symptoms at the time of arrival of a high concentration of Asian dust was 1.37 (95% confidence interval: 1.19-1.58), but the odds ratio adjusted for pollens was 1.18 (95% confidence interval: 1.04-1.34). Although the influence on nasal symptoms overlapped somewhat between Asian dust and pollens, that of Asian dust remained significant. Regarding preventive measures against symptoms, we examined the rate of particle leakage into masks. We found that it is important to wear a mask that fits an individual's facial features and has no gap between the face and the mask. In addition, we report our attempt to construct models for predicting aerosol arrival and forecasting health to establish preventive measures against aerosols.