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Background Our hypothesis was that exposure to fine particulate matter (PM2.5) is related to abnormal cord insertion, which is categorized as a form of placental implantation abnormality. We investigated the association between exposure to total PM2.5 and its chemical components over the first trimester and abnormal cord insertion, which contributes to the occurrence of adverse birth outcomes. Methods From the Japan Perinatal Registry Network database, we used data on 83 708 women who delivered singleton births at 39 cooperating hospitals in 23 Tokyo wards (2013–2015). We collected PM2.5 on a filter and measured daily concentrations of carbon and ion components. Then, we calculated the average concentrations over the first trimester (0–13 weeks of gestation) for each woman. A multilevel logistic-regression model with the hospital as a random effect was used to estimate the odds ratios (ORs) of abnormal cord insertion. Results Among the 83 708 women (mean age at delivery = 33.7 years), the frequency of abnormal cord insertion was 4.5%, the median concentration [interquartile range (IQR)] of total PM2.5 was 16.1 (3.61) μg/m3 and the OR per IQR for total PM2.5 was 1.14 (95% confidence interval = 1.06–1.23). In the total PM2.5-adjusted models, total carbon, organic carbon, nitrate, ammonium and chloride were positively associated with abnormal insertion. Organic carbon was consistently, and nitrate tended to be, associated with specific types of abnormal insertion (marginal or velamentous cord insertion). Conclusions Exposure to total PM2.5 and some of its components over the first trimester increased the likelihood of abnormal cord insertion.

HO 2 uptake kinetics onto ambient aerosols play pivotal roles in tropospheric chemistry but are not fully understood. Field measurements of aerosol chemical and physical properties should be linked to molecular-level kinetics; however, given that the HO 2 reactivity of ambient aerosols is low, traditional analytical techniques are unable to achieve this goal. We developed an online approach to precisely investigate the lower-limit values of (i) the HO 2 reactivities of ambient gases and aerosols and (ii) HO 2 uptake coefficients onto ambient aerosols ( γ ) during the 2019 Air QUAlity Study (AQUAS) in Yokohama, Japan. We identified the effects of individual chemical components of ambient aerosols on γ . The results were verified in laboratory studies on individual chemical components: transition metals play a key role in HO 2 uptake processes, and chemical components indirectly influence such processes (i.e., by altering aerosol surface properties or providing active sites), with smaller particles tending to yield higher γ values than larger particles owing to the limitation of gas-phase diffusion being smaller with micrometer particles and the distribution of depleting species such as transition metal ions being mostly distributed in accumulation mode of aerosol. The modeling of γ utilized transition metal chemistry derived by previous studies, further confirming our conclusion. However, owing to the high NO concentrations in Yokohama, peroxy radical loss onto submicron aerosols has a negligible impact on O 3 production rate and sensitivity regime.

PMData were obtained from the Japan Perinatal Registry Network database, which includes all live births and stillbirths after 22 weeks of gestation at 39 cooperating hospitals in 23 Tokyo wards (2013-2015). At one fixed monitoring site, we performed daily filter sampling of fine particles and measured daily concentrations of carbon and ion components. The average concentrations of total PMAmong 82,773 women (mean age at delivery = 33.7 years) who delivered singleton births, 3,953 (4.8%) had GDM. In the multiexposure period model, an association between total PMThis is the first evidence that exposure to total PM

Background Maternal exposure to fine particulate matter (PM2.5) was associated with pregnancy complications. However, we still lack comprehensive evidence regarding which specific chemical components of PM2.5 are more harmful for maternal and foetal health. Objective We focused on exposure over the first trimester (0–13 weeks of gestation), which includes the early placentation period, and investigated whether PM2.5 and its components were associated with placenta-mediated pregnancy complications (combined outcome of small for gestational age, preeclampsia, placental abruption, and stillbirth). Methods From 2013 to 2015, we obtained information, from the Japan Perinatal Registry Network database, on 83,454 women who delivered singleton infants within 23 Tokyo wards (≈627 km2). Using daily filter sampling of PM2.5 at one monitoring location, we analysed carbon and ion components, and assigned the first trimester average of the respective pollutant concentrations to each woman. Results The ORs of placenta-mediated pregnancy complications were 1.14 (95% CI = 1.08–1.22) per 0.51 μg/m3 (interquartile range) increase of organic carbon and 1.11 (1.03–1.18) per 0.06 μg/m3 increase of sodium. Organic carbon was also associated with four individual complications. There was no association between ozone and outcome. Significance There were specific components of PM2.5 that have adverse effects on maternal and foetal health.

Ozone (O3)-induced health effects vary in terms of severity, from deterioration of lung function and hospitalization to death. Several studies have reported a linear increase in health risks after O3 exposure. However, current evidence suggests a non-linear U- and J-shaped concentration-response (C-R) function. The potential increasing risks with decreasing O3 concentrations may seem counterintuitive from the traditional standpoint that decreasing exposure should lead to decreasing health risks. Tus, the question of whether the increasing risks with decreasing concentrations are truly O3-induced or might be from other C-R mechanisms. If these potential risks were not accounted for, this may have contributed to the risks observed at the low ozone concentration range. In this study, we examined the short-term effects of photochemical oxidant (Ox, parts per billiion) on outpatient cardiorespiratory visits in 21 Japanese cities after adjusting for other air pollutant-specific C-R functions. Daily cardiorespiratory visits from January 1, 2014 to December 31, 2016 were obtained from the Japanese Medical Data Center Co. Ltd. Similar period of meteorological and air pollution variables were obtained from relevant data sources. We utilized a time-stratified case crossover design coupled with the generalized additive mixed model (TSCC-GAMM) to estimate the association between Ox and cardiorespiratory outpatient visits, after adjusting for several covariates. A total of 2,588,930 visits were recorded across the study period, with a mean of 111.87 and a standard deviation of 138.75. The results revealed that crude Ox-cardiorespiratory visits exhibited a U-shaped pattern. However, adjustment of the oxides of nitrogen, particularly nitrogen monoxide (NO), attenuated the lower risk curve and subsequently altered the shape of the C-R function, with a substantial reduction observed during winter. NO- and nitrogen dioxide (NO2)-adjusted Ox-cardiorespiratory associations increased nearly linearly, without an apparent threshold. Current evidence suggests the importance of adjusting the oxides of nitrogen in estimating the Ox C-R risk functions.

Objective We investigated which trimester of exposure to PM2.5 and its components was associated with birth and placental weight, and the fetoplacental weight ratio. Methods The study included 63,990 women who delivered singleton term births within 23 Tokyo wards between 2013 and 2015. Each day, we collected fine particles on a filter, and analyzed their chemical constituents, including carbons and ions. Trimester-specific exposure to each pollutant was estimated based on the average daily concentrations. Results Over the third trimester, sulfate exposure tended to be inversely associated with birth weight, and decreased placental weight (difference for highest vs lowest quintile groups = -6.7 g, 95% confidence interval = -12.5 to -0.9). For fetoplacental weight ratio, there was no relationship. Conclusions Sulfate exposure over the third trimester may reduce birth weight, particularly placental weight.

Transboundary air pollution (TAP) and local air pollution (LAP) influence the air quality of urban areas. Fukuoka, located on the west side of Japan and affected by TAP from the Asian continent, is a unique example for understanding the contribution of LAP and TAP. Gaseous species and particulate matter (PM) were measured for approximately three weeks in Fukuoka in the winter of 2018. We classified two distinctive periods, LAP and TAP, based on wind speed. The classification was supported by variations in the concentration of gaseous species and by backward trajectories. Most air pollutants, including NOx and PM, were high in the LAP period and low in the TAP period. However, ozone was the exception. Therefore, our findings suggest that reducing local emissions is necessary. Ozone was higher in the TAP period, and the variation in ozone concentration was relatively small, indicating that ozone was produced outside of the city and transported to Fukuoka. Thus, air pollutants must also be reduced at a regional scale, including in China.

Fine particulate matter (PM2.5) in the atmosphere is of high priority for air quality management efforts to address adverse health effects in human. We believe that emission control policies, which are traditionally guided by source contributions to PM mass, should also consider source contributions to PM health effects or toxicity. In this study, we estimated source contributions to the toxic potentials of organic aerosols (OA) as measured by a series of chemical and in-vitro biological assays and chemical mass balance model. We selected secondary organic aerosols (SOA), vehicles, biomass open burning, and cooking as possible important OA sources. Fine particulate matter samples from these sources and parallel atmospheric samples from diverse locations and seasons in East Asia were collected for the study. The source and atmospheric samples were analyzed for chemical compositions and toxic potentials, i.e. oxidative potential, inflammatory potential, aryl hydrocarbon receptor (AhR) agonist activity, and DNA-damage, were measured. The toxic potentials per organic carbon (OC) differed greatly among source and ambient particulate samples. The source contributions to oxidative and inflammatory potentials were dominated by naphthalene-derived SOA (NapSOA), followed by open burning and vehicle exhaust. The AhR activity was dominated by open burning, followed by vehicle exhaust and NapSOA. The DNA damage was dominated by vehicle exhaust, followed by open burning. Cooking and biogenic SOA had smaller contributions to all the toxic potentials. Regarding atmospheric OA, urban and roadside samples showed stronger toxic potentials per OC. The toxic potentials of remote samples in summer were consistently very weak, suggesting that atmospheric aging over a long time decreased the toxicity. The toxic potentials of the samples from the forest and the experimentally generated biogenic SOA were low, suggesting that toxicity of biogenic primary and secondary particles is relatively low.

Daily PM2.5 (particulate matter with aerodynamic diameter &le, 2.5 &mu, m) samples were simultaneously collected at two background sites (Wajima Air Monitoring Station (WAMS) and Fukue-Jima Atmosphere and Aerosol Monitoring Station (FAMS)) in Japan in the East Asian winter and summer monsoon periods of 2017 and 2019, to compare the characteristics of air pollutants among different regions and to determine the possible variation during the long-range transport process. Polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and water-soluble inorganic ions (WSIIs) were analyzed. Despite the PM2.5 concentrations at FAMS (8.90 &ndash, 78.5 &micro, g/m3) being higher than those at WAMS (2.33 &ndash, 21.2 &micro, g/m3) in the winter monsoon period, the average concentrations of &sum, PAHs, &sum, NPAHs, and &sum, WSIIs were similar between the two sites. Diagnostic ratios indicated PAHs mainly originated from traffic emissions and mostly aged, whereas NPAHs were mostly secondarily formed during long-range transport. WSIIs at WAMS were mainly formed via the combustion process and secondary reactions, whereas those at FAMS mainly originated from sea salt and dust. Backward trajectories revealed the air masses could not only come from Asian continental coastal regions but also distant landlocked areas in the winter monsoon period, whereas most came from the ocean in the summer monsoon period. These findings can provide basic data for the establishment of prediction models of transboundary air pollutants in East Asia.

New particle formation (NPF) in the East Asian region is strongly influenced by photochemical processes during the long-range transport of air pollutants. Our previous measurements (Seto et al., 2013; Chandra et al., 2016) relating to the incomplete and weak NPF (onset diameter > 10 nm) on Fukue Island in Japan (downstream from the Asian continent) suggested nucleation in the upstream region. The vertical structure of atmospheric nanoparticle concentrations (particle size > 6 nm and altitude 35,000 particles cm–3) than in our previous measurements (from 2012 to 2016, ~20,000 particles cm–3) with a particle size as small as 5 nm, affected by the long-range transport of air pollutants under a high-pressure system, was detected. A sudden increase in particle number and SO2 concentrations with weak NPF caused by a change in the air mass origin (Event II: < 10,000 particles cm–3) as well as no NPF with aged sulfate particles during conditions with low particle number and SO2 concentrations (< 0.15 ppb) (Event III: < 2,000 particles cm–3) were also observed.

Total OH reactivity, which gives the instantaneous loss rate of OH radicals due to reactive species, is an invaluable technique to understand regional air quality, as it gives the overall reactivity of the air mass, the fraction of each trace species reactive to OH, the fraction of missing sinks, O3 formation potential, etc. Total OH reactivity measurement was conducted in a small suburban forest located ∼30 km from Tokyo during the air quality study at field museum TAMA (AQUAS-TAMA) campaign in early autumn 2012 and summer 2013. The average measured OH reactivities during that autumn and summer were 7.4 s−1 and 11.4 s−1, respectively. In summer, isoprene was the major contributor, accounting for 28.2% of the OH reactivity, as a result of enhanced light-dependent biogenic emission, whereas NO2 was major contributor in autumn, accounting for 19.6%, due to the diminished contribution from isoprene as a result of lower solar strength. Higher missing OH reactivity 34% was determined in summer, and linear regression analysis showed that oxygenated VOCs could be the potential candidates for missing OH reactivity. Lower missing OH reactivity 25% was determined in autumn and it was significantly reduced (11%) if the interference of peroxy radicals to the measured OH reactivity were considered.

Field measurements performed in the Keihin coastal industrial area during summer 2019 were used to characterize the air quality and ozone production potential. The total hydroxyl radical (OH) reactivity was found to be moderate, peaking with a 2-h average of 29.0 s−1, corresponding to an OH lifetime of ∼34 ms. The average hourly total OH reactivity was 11.4 ± 5.2 s−1 (average ± standard deviation), and the measured OH sinks (from over 90 trace species) accounted for 92.3% of the total OH reactivity. Compared with a previous series of campaigns in urban/suburban Japan, this field work investigated an area often overlooked for atmospheric observations and found the smallest missing OH reactivity (on average, 0.88 s−1). The near-zero missing OH reactivity indicated that photochemical procedures were less important to the Yokohama air quality study (AQUAS–Yokohama) than the ubiquitous substantial secondary products in other areas. This study also demonstrated that oceanic air masses may quickly flush coastal industrial areas and that a limited activity of photochemistry due to elevated NOx effectively terminates OH radical recycling. A comparison with other campaigns in Japan exhibited a positive correlation with oxidants (ozone and formaldehyde), indicating secondary products have a critical role in explaining missing OH reactivity. The ozone production potential was corresponding to a volatile organic compound (VOC)-limited regime, while the missing OH reactivity led to an ∼8% increase in ozone formation. Finally, a positive correlation was found between the ozone production rate and the reactivity ratio between VOCs and NOx, in both the current study and various other field campaigns in urban areas.

Emissions of polluted air in East Asia have gradually decreased over the last decade. Those air pollutants have been transported over long distances and influenced new particle formation (NPF) in the downstream region. We obtained 5-year data of the mobility size distribution and SO2 and particulate (PM2.5) emissions on Fukue Island (32.75°N, 128.68°E), Japan. Frequent NPF events in the 2013 campaign were observed around 60% under the transboundary transport of polluted air by northwesterly wind. In contrast to the data obtained in the last 2-year campaign (2016–2017), these NPF events (

The lung deposited surface area (LDSA) measured by diffusion charging (DC) method has been recently receiving increased attention as it is believed to accurately represent the surface reactivity of the particles, including ultrafine particles. To characterize regional and seasonal behaviors of the LDSA in the atmosphere and the factors controlling them, we measured the LDSA concentrations, using the DC method, and other physicochemical properties at three sites in Japan, including urban and rural areas. Comparisons among the three sites in the same season showed the highest LDSA concentration at the urban site Fukuoka, due to high concentrations and low particle sizes. In addition, this urban site frequently recorded high LDSA concentrations with high specific LDSAs, which represents the high contribution of ultrafine particles to the LDSA concentration. This is because the site was dominated by ultrafine black carbon particles emitted from surrounding cities, along with low contribution of long-range transported particles from the continent. In contrast, the dominance of these transported particles, which is typically observed at the three sites during this season, caused the specific LDSA to fall within a low and narrow range. However, even at rural areas, the active formation of organic particles in the summer caused high specific LDSAs, although their concentrations were low. Thus, the particles in urban areas, where ultrafine particles are probably emitted with high concentration from surrounding cities, have the potential to cause a greater adverse effect on human health even for the identical LDSA concentration. In addition, our observations showed that the LDSA of atmospheric aerosol particles measured by the DC method can be roughly represented by the theoretical LDSA of particles assuming spherical shape. Our characterizations using the specific LDSAs provide useful information for applying the LDSAs as the toxicity indicator of atmospheric aerosol particles, including ultrafine particles.

To determine the effects of long-range transport of aerosols from an upwind area in East Asia to a downwind area in Japan, we chemically analyzed aerosols collected simultaneously on Tuoji Island (Shandong Province, China), Fukue Island (Nagasaki Prefecture, Japan), and Cape Hedo (Okinawa Prefecture, Japan). We focused on changes in the metallic composition of PM2.5 aerosols during long-range transport. The average mass concentrations of PM2.5 at the three sites decreased in the order Tuoji Island > Fukue Island ≈ Cape Hedo (48.3 ± 4.5, 13.9 ± 1.5, and 13.2 ± 0.9 μg/m3, respectively). The fraction of coarse particles in total suspended particles estimated by (1–PM2.5/TSP) was highest on Cape Hedo, indicating that the contribution of sea salts was increased by long-range transport of the aerosols over the ocean. Enrichment factor analysis revealed that at all three sites, Al, K, Ca, Mn, Fe, Co, Sr, and Ba originated from soil; whereas Cr, Ni, Cu, Zn, As, Mo, Ag, Cd, Sn, Sb, Tl, and P appeared to be of anthropogenic origin. Na was the most abundant element on Cape Hedo, indicating the addition of sea salts during aerosol transport. The V concentration was highest at Fukue Island, which was ascribed to V emission from ships. Sixty-one percent of the V on Fukue Island and 62% of the V on Cape Hedo were determined to have originated from ships, implicating of data obtained on dates during which backward trajectory analysis indicated that the same air mass passed over Tuoji Island, Fukue Island, and Cape Hedo in that order.

Ground-based measurements of black carbon (BC) were performed near an industrial source region in the early summer of 2014 and at a remote island in Japan in the spring of 2015. Here, we report the temporal variations in the transport, size distributions, and mixing states of the BC-containing particles. These particles were characterized using a continuous soot monitoring system, a single particle soot photometer, and an aerosol chemical speciation monitor. The effects of aging on the growth of BC-containing particles were examined by comparing the ground-based observations between the near-source and remote island sites. Secondary formation of sulfate and organic aerosols strongly affected the increases in BC coating (i.e., enhancement of cloud condensation nuclei activity) with air mass aging from the source to the outflow regions. The effects of wet removal on BC microphysics were elucidated by classifying the continental outflow air masses depending on the enhancement ratios of BC to CO (ΔBC ∕ ΔCO), which were used as an indicator of the transport efficiency of BC. It was found that ΔBC ∕ ΔCO ratios were controlled mainly by the wet removal during transport in the planetary boundary layer (PBL) on the timescale of 1–2 days. The meteorological conditions and backward trajectory analyses suggested that air masses strongly affected by wet removal originated mainly from a region in southern China (20–35° N) in the spring of 2015. Removal of large and thickly coated BC-containing particles was detected in the air masses that were substantially affected by the wet removal in the PBL, as predicted by Köhler theory. The size and water solubility of BC-containing particles in the PBL can be altered by the wet removal as well as the condensation of non-BC materials.

A rapid decrease in PM2.5 concentrations in China has been observed in response to the enactment of strong emission control policies. From 2012 to 2017, total emissions of SO2 and NOx from China decreased by approximately 63% and 24%, respectively. Simultaneously, decreases in the PM2.5 concentration in Japan have been observed since 2014, and the proportion of stations that satisfy the PM2.5 environmental standard (daily, 35 µg/m3; annual average, 15 µg/m3) increased from 37.8% in fiscal year (FY) 2014 (April 2014 to March 2015) to 89.9% in FY 2017. However, the quantitative relationship between the PM2.5 improvement in China and the PM2.5 concentration in downwind regions is not well understood. Here, we (1) quantitatively evaluate the impacts of Chinese environmental improvements on downwind areas using source/receptor analysis with a chemical transport model, and (2) show that these rapid emissions reductions improved PM2.5 concentrations both in China and its downwind regions, but the difference between SO2 and NOx reduction rates led to greater production of nitrates (e.g., NH4NO3) due to a chemical imbalance in the ammonia–nitric acid–sulfuric acid–water system. Observations from a clean remote island in western Japan and numerical modeling confirmed this paradigm shift.

Numerous epidemiological studies have demonstrated that short-term exposure to ambient PM

Background The selection of drugs as third-line therapy for patients with Kawasaki disease (KD) who are resistant to second-line therapy remains controversial. Methods We reviewed the medical records of 354 patients (216 males/137 females) with KD who were treated in our department from July 2003 to January 2016. The age range was 1 month to 10 years, and the median age was 2 years and 1 month. A combination of 2 g/kg intravenous immunoglobulin (IVIG) plus 30 mg/kg of aspirin was used as first-line therapy. Patients who were refractory to the first-line therapy were administered 2 mg/kg of prednisolone (PSL) in combination with IVIG. Five patients who were refractory to the second-line therapy were treated with cyclosporine A (CsA) combined with PSL as the thirdline therapy. Results All five patients immediately responded to the third-line therapy. One of the five patients showed a transient dilatation of the coronary artery that regressed to its normal size by the 60th day of illness. Conclusions We suggest that the combination of CsA and steroids might be a promising therapeutic strategy for refractory KD.

The change in the ozone production rate on reducing its precursors, namely, ozone production sensitivity, is important information for developing a strategy to reduce ozone. We expanded a conventional sensitivity analysis theory by including peroxy radical loss by uptake onto particle surfaces in the aim of examining their potential impact. We also propose a new concept of absolute sensitivity that enables us to evaluate the quantitative effectiveness of precursor reduction toward mitigating ozone production over a given period and area. This study applies the theory to observations in Tsukuba, a city in Japan. The relative sensitivity analysis shows that ozone production was more sensitive to volatile organic compounds (VOCs) in the morning and evening, and it became more sensitive to NOx in the afternoon. NO depletion was a main trigger in this sensitivity regime transition. The absolute sensitivity analysis indicates that the VOC-sensitive period in the morning determines the total ozone production sensitivity in a day. While particles did not have significant impact on regime classification in Tsukuba, they have a potential to decrease the mitigating effect of VOC reduction on ozone production and to moderate the enhancement effect of NOx reduction depending upon uptake coefficients. A further study will benefit from a combination with an observation-constrained box model simulation or chemical transport modeling system, which may provide sensitivity analysis over a large spatial and temporal range.

Due to economic growth in China, emissions of gaseous components from factories and automobiles have been increasing, which has resulted in severe air pollution. During the winter and spring seasons, Japan, which is on the leeward side of the Asian continent, is on the receiving end of this increasingly problematic transboundary air pollution. In this study, the mass concentration and chemical components of the particulate PM2.5 were continuously observed using an automatic analyzer at Kumamoto on the west coast of Japan from October 2014 to March 2015. A greater number of high PM2.5 days were observed in winter than in autumn. This seasonal change in concentrations was believed to be due to transboundary air pollution traveling from the Asian continent due to seasonal monsoons. The analysis of the chemical composition of PM2.5 supported this idea. The factors leading to high PM2.5 concentrations were investigated and categorized into transboundary air pollution, local air pollution, and volcanic activity based on the analysis of sulfate (SO42–) and sulfur dioxide (SO2) concentrations and model simulations. The average concentration of chemical components showed that local air pollution also influenced air quality in Kumamoto .

Field observations to investigate the correlation between New Particle Formation (NPF) and the long-range transport of air pollutants in the East Asia region were carried out on a rural Island of Japan in the East-China Sea (Fukue Island, 32.8°N, 128.7°E) over three periods (February 23 to March 7, 2013; November 7 to 20, 2013; and November 2 to 24, 2014). Frequent NPF events were identified (16 events in 50 days), typically in association with sudden increases in particle number concentrations and the successive growth of particles to mobility diameters of several tens of nanometers. The NPF events were classified into two types (A and B) according to the initially detected particle sizes (onset diameters). Type-A consisted of strong NPF events with onset diameters as small as 5 nm. Type-B consisted of NPF events whose onset (

Fine particulate matter (PM2.5) is composed of a variety of chemical components, and the dependency of the health effects of total PM2.5 on specific components is still under discussion. We hypothesised that specific PM2.5 components are responsible for the health effects, and investigated the association between PM2.5 components and mortality in 23 Tokyo wards. We obtained mortality data from the Ministry of Health, Labour and Welfare for the period from April 2013 to March 2017. At a monitoring site within the study area, we collected daily samples of PM2.5 on a filter, and determined the daily mean concentrations of total carbon (organic carbon and elemental carbon) and ions such as nitrate and sulphate. A case-crossover design was employed, and a conditional logistic regression model was used to estimate the strength of the association. Over the study period, we identified 280,460 total non-accidental deaths, and the average daily mean concentration of total PM2.5 was 16.0 (standard deviation = 8.9) μg/m3. We observed a positive association of total PM2.5 with total, cardiovascular, and respiratory mortality. After adjustment for total PM2.5 and its components associated with mortality in the single-component models, the percentage increase per interquartile range (2.3 μg/m3) increase in the average total carbon concentration of the case- and previous-day was 2.1% (95% confidence interval = 1.0 to 3.1%) for total mortality. Carbon elements were associated with respiratory but not cardiovascular mortality. Our results suggest that specific components of PM2.5 account for its adverse health effects.

Several studies have noted that the existence of comorbidities lead to an increase in the risk of premature mortality and morbidity. Most of the studies examining the effects of air pollution on comorbidity visits were from Northern American countries, with scarce literature from Asia. This study contributes to existing, yet limited understanding of air pollution-comorbidity by examining the effects of daily air pollutants on outpatient single morbidity and comorbid cardiorespiratory visits in Japan. A total of 1,452,505 outpatient cardiorespiratory visits were recorded among the 21 Japanese cities from 2013 to 2016. Daily outpatient cardiorespiratory visit data were obtained from a health insurance claims database managed by the Japan Medical Data Center Co., Ltd. (JMDC). A time-stratified case crossover analysis coupled with Generalized Additive Mixed Model was used to analyze the association of daily air pollutants (particulate matter 2.5 μm or less in diameter, ozone and nitrogen dioxide) on daily single (respiratory and cardiovascular) and comorbidity health outcomes. We further examined single and cumulative effects for 0–3 and 0–14 lag periods. Ozone, NO2, and PM2.5 were positively associated with cardiorespiratory visits in either shorter or longer lags, with more apparent comorbidity associations with NO2 exposure. A 10-unit increase in NO2, after adjusting for ozone, was associated with a 2.24% (95% CI: 1.34–3.15) and 6.49% (95% CI: 5.00–8.01) increase in comorbidity visit at Lag 0 (of Lag 0–3) and cumulative lag 0–3, respectively. Our results contribute to existing evidence suggesting that short-term and extended exposure to air pollution elicit health risks on cardiovascular, respiratory and comorbid clinic visits. Exposure to NO2, in particular, was associated with increase in the risk of single and comorbidity cardiorespiratory visits. Results can be potentially utilized for both individual health (e.g. risk population health management) and health facility management (e.g. health visit influx determination).

Numerous epidemiological studies have demonstrated that short-term exposure to ambient PM2.5 increases mortality and morbidity. Investigating the association using hourly ambient PM2.5 exposure may provide important insights, as current evidence is limited mostly to daily lag term. This study aimed to investigate the hourly association between ambient PM2.5 concentrations and all-cause emergency ambulance dispatches (EAD) in 11 cities in Japan. We used a time-stratified case-crossover design and examined the hourly lags of ambient PM2.5 up to 24 h (unconditional distributed lags and moving average lags) using a conditional Poisson regression model. A significant increase in all-cause EAD was observed at lag 0 h [relative risk (RR): 1.0037 (95% CI: 1.0000, 1.0074)] and all moving average lags. The highest RR was observed within the first 6 h (at lag 0–5 h) [RR: 1.0091 (95% CI: 1.0068, 1.0114)], with a slight ascending pattern. This was followed by a descending pattern at lags 0–11, 0–17, and 0–23 h, but significant positive RR was observed even at lag 0–23 h, when the lowest RR was observed [RR: 1.0072 (95% CI: 1.0044, 1.0100)]. Though similar pattern was observed among the elderly, a different pattern was observed among the children (gradually ascending pattern). We conclude that all-cause EAD could be triggered by ambient PM2.5 exposure with very short lags.

Background: From around 2012, the use of automated equipment for fine particulate matter (PM2.5) measurement with equivalence to a reference method has become popular nationwide in Japan. This enabled us to perform a national health effect assessment employing PM2.5 concentrations based on the standardized measurement method. We evaluated the association between non-accidental mortality and short-term exposure to PM2.5 and coarse particulate matter (PM), with the latter estimated as the difference between suspended particulate matter and PM2.5, for the fiscal years 2012–2014. Methods: This was a time-stratified case-crossover study in 100 highly-populated Japanese cities. Mortality data was obtained from the Ministry of Health, Labour and Welfare. City-specific estimates of PM-mortality association were calculated by applying a conditional logistic regression analysis, and combined with a random-effects meta-analysis. Results: The respective averages of daily mean concentration were 14.6 µg/m3 for PM2.5 and 6.4 µg/m3 for coarse PM. A 10 µg/m3 increase in PM2.5 concentrations for the average of the day of death and the previous day was associated with an increase of 1.3% (95% confidence interval (CI), 0.9–1.6%) in total non-accidental mortality. For cause-specific mortality, PM2.5 was positively associated with cardiovascular and respiratory mortality. After adjustment for PM2.5, we observed a 1.4% (95% CI, 0.2–2.6%) increase in total mortality with a 10 µg/m3 increase in coarse PM. Conclusion: The study revealed that short-term exposure to PM2.5 had adverse effects on total non-accidental, cardiovascular, and respiratory mortality in Japan. Coarse PM exposure also increased the risk of total mortality.

Nasogastric tube feeding is a common method of parenteral nutrition. We observed ulcers on the epiglottis caused by a nasogastric tube in three adults with severe motor and intellectual disabilities (SMID) during examination with a laryngeal fiberscope while swallowing. These ulcers were healed by changing the method of inserting the nasogastric tube. The patients were three men aged 25, 39, and 55 years. The muscle tone of the whole body was increased in all of the patients. Two patients had severe scoliosis, and the other patient had lordosis in the thoracic vertebrae and had received laryngo-tracheal diversion. All of the patients received intermittent or continuous respiratory care. The pharynx of the patients with severe scoliosis became thinner and the feeding tubes ran obliquely. The feeding tube in the patient who received laryngo-tracheal diversion entered the cut and closed trachea through the glottis. Ulcers were observed on the laryngeal side of the epiglottis in all of the patients. The ulcers were healed by preventing feeding tubes from running obliquely or by using the naso-gastric tube made of different materials in the patients with severe scoliosis. In the patient who received laryngo-tracheal diversion, we succeeded in avoiding the glottis by keeping his face forward while inserting the feeding tube. Then feeding tubes were changed with guidewires, and the ulcers were healed. When using nasogastric tube feeding for persons with SMID with a large increase in muscle tone and/or with severe scoliosis, adopting a method of inserting feeding tubes that avoids damaging the epiglottis with a laryngeal fiberscope is required.

Aerosol chemical species were measured using an Aerodyne quadrupole aerosol mass spectrometer (Q-AMS) in spring 2010, in Fukuoka. The main species were sulfate and organics. Organic data were analyzed using the Positive Matrix Factorization (PMF) method. Two distinct periods (Period 1 and 2) were selected. Period 1 (from March 19 at 19:50 to March 20 at 10:00) was influenced by trans-boundary air pollution. Low-volatile, oxygenated organic aerosols (LV-OOA) were dominant and the hydrocarbon-like organic aerosols (HOA) fraction was as low as 15%. About one-fourth (26%) of the observation period in Fukuoka was influenced by trans-boundary air pollution. In Period 2 (from March 22 at 00:00 to March 22 at 23:50), both local emissions and trans-boundary air pollutants influenced Fukuoka air quality. The HOA fraction was relatively high, although the LV-OOA fraction was about one-third of OA. The trans-boundary air pollution was analyzed using the oxidation state of organic aerosols (OA), obtained by the PMF method.

Poor air quality is globally the largest environmental health risk. Epidemiological studies have uncovered clear relationships of gaseous pollutants and particulate matter (PM) with adverse health outcomes, including mortality by cardiovascular and respiratory diseases. Studies of health impacts by aerosols are highly multidisciplinary with a broad range of scales in space and time. We assess recent advances and future challenges regarding aerosol effects on health from molecular to global scales through epidemiological studies, field measurements, health-related properties of PM, and multiphase interactions of oxidants and PM upon respiratory deposition. Global modeling combined with epidemiological exposure-response functions indicates that ambient air pollution causes more than four million premature deaths per year. Epidemiological studies usually refer to PM mass concentrations, but some health effects may relate to specific constituents such as bioaerosols, polycyclic aromatic compounds, and transition metals. Various analytical techniques and cellular and molecular assays are applied to assess the redox activity of PM and the formation of reactive oxygen species. Multiphase chemical interactions of lung antioxidants with atmospheric pollutants are crucial to the mechanistic and molecular understanding of oxidative stress upon respiratory deposition. The role of distinct PM components in health impacts and mortality needs to be clarified by integrated research on various spatiotemporal scales for better evaluation and mitigation of aerosol effects on public health in the Anthropocene.

Observation of the ambient aerosol surface area concentrations is important to understand the aerosol toxicity because an increased surface area may be able to act as an enhanced reaction interface for certain reactions between aerosol particles and biological cells, as well as an extended surface for adsorbing and carrying co-pollutants that are originally in gas phase. In this study, the concentration of aerosol surface area was measured from April 2015 to March 2016 in Fukuoka, Japan. We investigated the monthly and diurnal variations in the correlations between the aerosol surface area and black carbon (BC) and sulfate concentrations. Throughout the year, aerosol surface area concentration was strongly correlated with the concentrations of BC, which has a relatively large surface area since BC particles are usually submicron agglomerates consisting of much smaller (tens of nanometers) sized primary soot particles. The slopes of the regression between the aerosol surface area and BC concentrations was highest in August and September 2015. We presented evidence that this was caused by an increase in the proportion of airmasses that originated on the main islands of Japan. This may enhance the introduction of the BC to Fukuoka from the main islands of Japan which we hypothesize to be relatively fresh or “uncoated”, thereby maintaining its larger surface area.

There is a discrepancy in the reported incidence of childhood immune thrombocytopenic purpura (ITP) between Europe (2.9-5.3 per 100 000 persons) and Japan (1.91). Ise district is a suitable area in which to conduct epidemiological study because there is little fluctuation in the sociodemographic factors. We performed a retrospective population-based study to clarify the incidence of primary childhood ITP. We calculated person-years for children aged