Asian Dust Events Research Articles

Association Between Asian Dust Exposure and Pneumonia Hospitalization in Western Japan: A Case-Crossover Study.

Epidemiological studies have reported that Asian dust (AD), a type of desert dust, has harmful effects on human health. This study aimed to examine the association between AD exposure and hospitalization due to pneumonia. Data on patients in Western Japan admitted for pneumonia were included from a real-world database derived from electronic medical records. We used the meteorological observatory data of the most populous city in each prefecture, in which AD event was defined as a loss of visibility from a distance ≤10 km. A case-crossover design and conditional logistic regression model were used. Overall, 12 938 patients were included, and AD exposure events were observed for 557 days. Exposure to an AD event five days prior to hospitalization was significantly associated with hospitalization for pneumonia after adjusting for weather variables (odds ratio = 1.17). These findings suggest that AD exposure is associated with an increased rate of admission for pneumonia in Western Japan.

Characteristic Variation of Particulate Matter-Bound Polycyclic Aromatic Hydrocarbons (PAHs) during Asian Dust Events, Based on Observations at a Japanese Background Site, Wajima, from 2010 to 2021

Asian dust (AD) events and total suspended particles (TSPs) were observed at the Kanazawa University Wajima Air Monitoring Station (KUWAMS), a Japanese background site, during the East Asian winter monsoon periods (from November to May of the following year) from 2010 to 2021. Nine kinds of polycyclic aromatic hydrocarbons (PAHs) were determined in each TSP sample. In this study, a total of 54 AD events were observed. According to the different pathways of long-range transportation, AD events were divided into AD-high events (transported at higher altitudes, approximately 4000 m) and AD-low events (transported at lower altitudes, approximately 2500 m). The TSP concentrations increased sharply in the AD events and were higher in the AD-high events (39.8 ± 19.5 μg/m3) than in the AD-low events (23.5 ± 10.5 μg/m3). AD did not have a significant effect on the ΣPAHs characteristic variation, as ΣPAHs (ΣPAHs = fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene, and indeno [1,2,3-cd]pyrene) concentrations in non-AD periods, AD-high events, and AD-low events were 543 ± 374, 404 ± 221, and 436 ± 265 pg/m3, respectively. The PAH compositions were also consistent. As a result, the TSP concentration was affected by the input air mass transported at higher altitudes from the desert region while the PAH concentration was impacted by the air mass at lower altitudes, which carried the PAHs emitted from fossil fuels and biomass combustion in northeastern China. Moreover, the health risks of PAHs were calculated with the inhalation lifetime cancer risk, which ranged from 10−6 to 10−5 ng/m3, indicating a potential carcinogenic risk at the KUWAMS during the East Asian winter monsoon periods.

Sources of aeolian magnetite at a remote site in Japan: Dominantly Asian desert dust or anthropogenic emissions?

Asian dust (AD) profoundly impacts human health and the environment, and the soluble Fe in AD is essential for nutrient supply to the ocean and atmospheric chemistry. To accurately assess the impacts of AD, it must be separated from other natural and anthropogenic sources in the total aerosol loading. In this study, coarse aerosol samples (Dp > 2.5 μm) collected in Noto, a remote coastal area in Japan, were analyzed through an environmental magnetic analysis. A comparison of the metal content and Pb isotopic ratios revealed that the magnetization of aerosols, which reflects magnetite content, highly correlated with AD inflow. That is, aerosol magnetite is preferentially concentrated in atmospheric particles during AD events; therefore, AD-affected samples can easily be identified and distinguished from those primarily affected by transboundary air pollution by using magnetic measurements. Based on the magnetization intensity of an AD reference material (CJ-2), the AD loading for ambient samples was estimated to be 5.2–32 μg/m3, similar to that calculated based on the Al mass concentration. Moreover, magnetism is strongly linked with Fe solubility in the ambient samples. This is notable because such information has been obtained previously only through labor-intensive chemical speciation involving sequential extraction. Therefore, magnetism can be used as a new measure of both AD loading and Fe solubility via non-destructive measurements.

Measurement report: Stoichiometry of dissolved iron and aluminum as an indicator of the factors controlling the fractional solubility of aerosol iron – results of the annual observations of size-fractionated aerosol particles in Japan

Abstract. The atmospheric deposition of iron (Fe) promotes primary production in the surface ocean, which results in the enhanced uptake of carbon dioxide into surface seawater. Given that microorganisms in seawater utilize dissolved Fe (d-Fe) as a nutrient, the bioavailability of Fe in aerosol particles depends on its solubility. However, the factors controlling fractional Fe solubility (Fesol %) in aerosol particles have not been fully understood. This study performed annual observations of the total and dissolved metal concentrations in size-fractionated (seven fractions) aerosol particles at Higashi-Hiroshima, Japan. The feasibility of the molar concentration ratio of d-Fe relative to dissolved Al ([d-Fe] / [d-Al]) as an indicator of sources of d-Fe in aerosol particles was investigated because this ratio is likely dependent on the emission sources of Fe (e.g., mineral dust, fly ash, and anthropogenic Fe oxides) and their dissolution processes (proton- and ligand-promoted dissolutions). Approximately 70 % of the total Fe in total suspended particulates (TSPs) was present in coarse aerosol particles, whereas about 70 % of d-Fe in TSPs was mainly found in fine aerosol particles. The average Fesol % in fine aerosol particles (11.4 ± 7.0 %) was higher than that of coarse aerosol particles (2.19 ± 2.27 %). In addition, the average ratio of [d-Fe] / [d-Al] in coarse aerosol particles (0.408 ± 0.168) was lower than that in fine aerosol particles (1.15 ± 0.80). The range of [d-Fe] / [d-Al] ratios in the coarse aerosol particles (0.121–0.927) was similar to that obtained by proton-promoted dissolution of mineral dust (0.1–1.0), which indicates that the d-Fe in coarse aerosol particles was derived from mineral dust. The [d-Fe] / [d-Al] ratios of fine aerosol particles ranged from 0.386 to 4.67, and [d-Fe] / [d-Al] ratios greater than 1.50 cannot be explained by proton- and ligand-promoted dissolutions (1.00 < [d-Fe] / [d-Al] < 1.50). The [d-Fe] / [d-Al] ratio correlated with the enrichment factor of Fe in fine aerosol particles (r: 0.505), which indicates that anthropogenic Fe with a high [d-Fe] / [d-Al] ratio was the source of d-Fe in fine aerosol particles. The high [d-Fe] / [d-Al] ratio was attributed to anthropogenic Fe oxides emitted from high-temperature combustions. Finally, the fraction of anthropogenic Fe oxides to d-Fe in TSPs was calculated based on the [d-Fe] / [d-Al] ratio of aerosols and their emission source samples. As a result, the fraction of anthropogenic Fe oxides to d-Fe in TSPs varied from 1.48 % to 80.7 %. A high fraction was observed in summer when air masses originated from industrial regions in Japan. By contrast, approximately 10 % of d-Fe in the TSPs collected in spring and during Asian dust events was derived from anthropogenic Fe oxides when air masses were frequently transported from East Asia to the Pacific Ocean. Thus, mineral dust was the dominant source of d-Fe in Asian outflow to the Pacific Ocean.

Adverse impacts of Asian dust events on human health and the environment—A probabilistic risk assessment study on particulate matter-bound metals and bacteria in Seoul, South Korea

This study aimed to assess the impact of Asian dust (AD) on the human health and the environment. Particulate matter (PM) and PM-bound trace elements and bacteria were examined to determine the chemical and biological hazards associated with AD days and compared with non-AD days in Seoul. On AD days, the mean PM10 concentration was ∼3.5 times higher than that on non-AD days. Elements generated from the Earth's crust (Al, Fe, and Ca) and anthropogenic sources (Pb, Ni, and Cd) were identified as major contributors to coarse and fine particles, respectively. During AD days, the study area was recognized as “severe” for pollution index and pollution load index levels, and “moderately to heavily polluted” for geoaccumulation index levels. The potential cancer risk (CR) and non-CR were estimated for the dust generated during AD events. On AD days, total CR levels were significant (in 1.08 × 10−5–2.22 × 10−5), which were associated with PM-bound As, Cd, and Ni. In addition, inhalation CR was found to be similar to the incremental lifetime CR levels estimated using the human respiratory tract mass deposition model. In a short exposure duration (14 days), high PM and bacterial mass deposition, significant non-CR levels, and a high presence of potential respiratory infection-causing pathogens (Rothia mucilaginosa) were observed during AD days. Significant non-CR levels were observed for bacterial exposure, despite insignificant levels of PM10-bound elements. Therefore, the substantial ecological risk, CR, and non-CR levels for inhalation exposure to PM-bound bacteria, and the presence of potential respiratory pathogens, indicate that AD events pose a significant risk to both human lung health and the environment. This study provides the first comprehensive examination of significant non-CR levels for bacteria and carcinogenicity of PM-bound metals during AD events.

Modeling a severe wintertime Asian dust event observed in the East Asia region: Sensitivity of the WRF-Chem dust emission schemes

This study investigates the capability of the Weather Research and Forecasting-Chemistry (WRF-Chem) model in modeling a severe wintertime Asian dust event, which originated from the East Asia dust source region during 20–22 February 2015. The WRF-Chem simulations were conducted changing with the five embedded dust emission schemes of the UC01, UC04, UC11, GO01, and GA19 schemes. The model reasonably simulated meteorological fields, capturing the characteristic meteorological features over the dust source regions during the severe wintertime Asian dust event. A good meteorological comparison led to the reasonable simulation of the occurrence and transport of the Asian dust plumes, comparing well with the surface dust occurrence reports and the satellite-detected dust signals of aerosol optical depth (AOD) and extinction coefficient. However, considerable (approximately fivefold) differences existed in the dust emission amounts simulated by the different dust emission schemes. From the model-measurement comparison of surface PM10 concentration, it was found that the UC01 and UC04 schemes could simulate the severe wintertime Asian dust plumes in the dust source regions, capturing the dust occurrence timing and the concentration level reasonably. However, the performance of the schemes significantly depended on near-surface wind speed and soil moisture amount. On the contrary, the UC11, GO01, and GA19 schemes failed to simulate the dust plumes, revealing intrinsic limitations for severe wintertime dust plume simulation. Furthermore, this study suggests the realistic representation of the Asian dust source region and the inclusion of frozen soil parameterization in the WRF-Chem model to predict severe wintertime Asian dust events realistically.

Field test of an enhanced LIPS to direct‐monitor the elemental composition of particulate matters in polluted air

AbstractLaser‐induced plasma spectroscopy (LIPS, also LIBS) is a promising technique for the challenging issues associated with the real time and in‐situ monitoring of the elements in aerosol particulate matter. A prototype of Aero‐LIPS had been set up with the techniques of aerosol beam focusing, enhanced plasma emission collector, and conditional data filter to demonstrate the potential application of air pollution composition monitoring. It can identify more than 40 elements from aerosols and continuously monitor 20 elements with a time interval of 10 min. In the field test of an Asian dust event, the major elements, such as Ca, Mg, Al, Si, Cl, P, and S, were real‐time monitored, which weighted 77.9% part of the particulate matter. The evolutions of temporal elemental concentrations went well along with the particle matter concentration. In the test, several persistent lines of U and Th have been identified from dusted air, although their concentrations range in the level of nano‐grams per cubic meter. Further work is ongoing to directly determine the detection limit of U and Th to confirm the potential application for nuclear emission safeguard.

Environmental impacts of three Asian dust events in the northern China and the northwestern Pacific in spring 2021

In March 2021, China experienced three dust events (Dust-1, 2, 3), especially the first of which was reported as the strongest one in recent ten years. Their environmental impacts have received great attention, demanding comprehensive study to assess such impacts quantitatively. Multiple advanced measurement methods, including satellite, ground-based lidar, online aerosol speciation instrument, and biogeochemical Argo float, were applied to examine and compare the transport paths, optical and chemical properties, and impacts of these three dust events on urban air quality and marine ecosystem. The results showed that Dust-1 exhibited the largest impacts on urban area, increasing PM10 concentration in Beijing, Shuozhou, and Shijiazhuang up to 7525, 3819, and 2992 μg m−3, respectively. However, due to fast movement of the Mongolian low-pressure cyclone, the duration of northwest wind over the land was quite short (e.g., only 10 h in Beijing), which prevented the transport of dust plume to the northwestern Pacific, resulting in limited impact on the ocean. Dust-2 and Dust-3, though weaker in intensity, were transported directly to the sea, and led to a substantial increase in chlorophyll-a concentration (up to near 3 times) in the northwestern Pacific, comparing to climatological value. This indicates that the impacts of dust events on ocean was not necessarily and positively correlated to their impacts on land. Based on the analyses of land-ocean-space integrated observational data and synoptic systems, this study examined how marine ecosystem responded to three significant Asian dust events in spring 2021 and quantitatively assessed the overall impacts of mega dust storms both on land and ocean, which could also provide an interdisciplinary research methodology for future research on strong aerosol emission events such as wildfire and volcanic eruption.

Detection of East Asian Dust Events from Himawari-8/AHI Thermal Infrared Observations Based on Feedforward Neural Network and Robust Principal Component Analysis'

Detection of East Asian Dust Events from Himawari-8/AHI Thermal Infrared Observations Based on Feedforward Neural Network and Robust Principal Component Analysis'

Long-range transport of airborne bacteria over East Asia: Asian dust events carry potentially nontuberculous Mycobacterium populations.

The nontuberculous mycobacterial pulmonary disease (NTM-PD) caused by Mycobacterium species has increased in prevalence all over the world. The distributions of NTM-PD are possibly determined by the westerly wind traveling at high altitudes over East Asia. However, the long-range transport of Mycobacterium species has not been demonstrated by analyzing the bacterial communities in aerosols such as desert mineral particles and anthropogenic pollutants transported by the westerly wind. Here, airborne bacterial compositions were investigated including Mycobacterium species in high-elevation aerosols, which were captured in the snow cover at 2,450m altitude on Mt. Tateyama. This was further compared to the ground-level or high-altitude aerosols collected at six sampling sites distributed from Asian-dust source region (Tsogt-Ovoo) to downwind areas in East Asia (Asian continental cities; Erenhot, Beijing, Yongin, Japanese cities; Yonago, Suzu, Noto Peninsula). The cell concentrations and taxonomic diversities of airborne bacteria decreased from the Asian continent to the Japan area. Terrestrial bacterial populations belonging to Firmicutes and Actinobacteria showed higher relative abundance at high-elevation and Japanese cities. Additionally, Mycobacterium species captured in the snow cover on Mt. Tateyama increased in relative abundance in correspondence to the increase of black carbon concentrations. The relative abundance of Mycobacterium sequences was higher in the aerosol samples of Asian continental cities and Japanese cities than in the desert area. Presumably, anthropogenic pollution over East Asia carries potential Mycobacterium species, which induce NTM-PD, thereby impacting upon the public health.

Prediction of health effects of Asian dust in Japan

BACKGROUND AND AIM The 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 data acquired from the Japan Meteorological Agency's (JMA's) Model of Aerosol Species in the Global Atmosphere (MASINGAR) aerosol model with the objective of ascertaining if the data could be applied for predicting health effects. METHODS Subjective symptom scores were collected using self-administered questionnaires and used with the JMA model’s surface concentration data to conduct a risk evaluation using a multiple linear mixed model, from 2013 to 2015. Altogether, 160 individuals provided 16226 responses. Data regarding climate (temperature, humidity, and atmospheric pressure) and environmental factors (NO2, SO2, and Ox) were used as covariates. We calculated the association between the surface dust concentration and symptoms. RESULTS A strong association was also observed for nasal and cough symptoms (P for trend < 0.001). The differences in scores of nasal symptoms (sneezing and runny) of the highest quartile [Q4] vs. the lowest [Q1] were 0.039 (95% confidence interval (CI): 0.02–0.01, p < 0.05) and 0.046 (95% CI: 0.002–0.02, p < 0.05), respectively. The differences in scores of cough symptoms were 0.036 (95% confidence interval (CI): 0.002–0.01, p < 0.05). CONCLUSIONS This study suggests that predictive models for pollutants’ arrival can be used to capability to foresee and possibly prevent the health impact of long-range transport of air pollutants, recommending the potential role of aerosol forecast models in health care. MASINGAR is the Global Spectral Model (GSM), this has the potential that can contribute to health predictions all over the world. KEYWORDS Asian dust, Health forecast, Allergic symptoms, Air pollution

Chemical Characteristics of Water-Soluble Inorganic Ions in Different Types of Asian Dust in Wajima, a Background Site in Japan

Two Asian dust (AD) events were observed in March 2021 (AD1: 16 March 2021 00:00 UTC~17 March 2021 12:00 UTC and AD2: 28 March 2021 00:00 UTC~31 March 2021 12:00 UTC). To determine the chemical characteristics of water-soluble inorganic ions (WSIIs) in different types of Asian dust, the total suspended particulates (TSP) were collected at Kanazawa University Wajima Air Monitoring Station (KUWAMS), a background site in Japan from 27 February to 4 March, 2021. Based on the lidar observations and the backwards trajectory analysis results, AD events were divided into two types: ADN (aerosols were mainly mineral dust) and ADP (aerosols were mixtures of spherical particles). During ADs, the concentrations of the TSP and WSII increased, with the highest TSP concentration in ADN (38.6 μg/m3) and the highest WSII concentration in ADP (5.82 μg/m3). The increase in (cations)/(anions) during AD indicates that the input of AD aerosol buffered the aerosol acidity. Additionally, a significant increase in Cl depletion, along with ADN events, was found (Cl depletion = 73.8%). To comprehensively analyse the different types of ADs on WSIIs, we refer to the previous data from 2010 to 2015 at KUWAMS. As a result, the increased Cl depletion was caused by the heterogeneous reaction of HNO3 with sea salt when the air mass passed over the Japanese Sea. Additionally, the chemical form of SO42− was highly dependent on the source and pathway, while SO42− mainly came from natural soil dust in ADN and from anthropogenic emissions in ADP. The enhancement of secondary NO3− was observed in AD via the heterogeneous hydrolysis of N2O5.

Aerosol Mineralogical Study Using Laboratory and IASI Measurements: Application to East Asian Deserts

East Asia is the second-largest mineral dust source in the world, after the Sahara. When dispersed in the atmosphere, mineral dust can alter the Earth’s radiation budget by changing the atmosphere’s absorption and scattering properties. Therefore, the mineralogical composition of dust is key to understanding the impact of mineral dust on the atmosphere. This paper presents new information on mineralogical dust during East Asian dust events that were obtained from laboratory dust measurements combined with satellite remote sensing dust detections from the Infrared Atmospheric Sounding Interferometer (IASI). However, the mineral dust in this region is lifted above the continent in the lower troposphere, posing constraints due to the large variability in the Land Surface Emissivity (LSE). First, a new methodology was developed to correct the LSE from a mean monthly emissivity dataset. The results show an adjustment in the IASI spectra by acquiring aerosol information. Then, the experimental extinction coefficients of pure minerals were linearly combined to reproduce a Gobi dust spectrum, which allowed for the determination of the mineralogical mass weights. In addition, from the IASI radiances, a spectral dust optical thickness was calculated, displaying features identical to the optical thickness of the Gobi dust measured in the laboratory. The linear combination of pure minerals spectra was also applied to the IASI optical thickness, providing mineralogical mass weights. Finally, the method was applied after LSE optimization, and mineralogical evolution maps were obtained for two dust events in two different seasons and years, May 2017 and March 2021. The mean dust weights originating from the Gobi Desert, Taklamakan Desert, and Horqin Sandy Land are close to the mass weights in the literature. In addition, the spatial variability was linked to possible dust sources, and it was examined with a backward trajectory model. Moreover, a comparison between two IASI instruments on METOP-A and -B proved the method’s applicability to different METOP platforms. Due to all of the above, the applied method is a powerful tool for exploiting dust mineralogy and dust sources using both laboratory optical properties and IASI detections.

Characteristics of Meteorological Parameters and Ionic Components in PM<sub>2.5</sub> during Asian Dust Events on November 28 and 30, 2018 at Busan

Characteristics of Meteorological Parameters and Ionic Components in PM<sub>2.5</sub> during Asian Dust Events on November 28 and 30, 2018 at Busan

Mega Asian dust event over China on 27–31 March 2021 observed with space-borne instruments and ground-based polarization lidar

Under the background of global climate change, the frequency of extreme weather events is ever-increasing. Climatic anomaly in dust source areas and intensive Mongolian cyclones jointly cause the reoccurrence of super dust storms in spring 2021. A mega dust storm broke out in southeast Mongolia on 27 March and significantly impacted air quality in China until 31 March. However, neither intensity nor affected areas are well depicted by the forecasting model. Here we report the horizontal distribution, transport path, dissipation, and influence on surface air quality of this event with the combination of space-borne and ground-based observations. Prudent analysis indicates a longer duration (5 days) and farther-south affected areas (25°N) than the previous report. Dust plumes were first transported to North and Northeast China, the Bohai Sea, and the Yellow Sea (28 March), and then respectively moved eastward to Korea-Japan regions and southward over mainland China (29 March), with PM10 values > 500 μg m−3 in 64 cities. Dust aerosols over the Yellow Sea retraced to the coastal areas of East China on 29 March, resulting in severe degradation of air quality over mainland China (25–40°N and 105–120°E) during 29–31 March. On 31 March, dust particles in this region were gradually removed, attributed to the wet removal and the enhanced south branch of westerlies. In central China, ground-based polarization lidar observed dust ∼26 h earlier (1600 LT, 27 March) than surface PM10 measurements. The dust plume showed a triple-layer vertical structure. The bottom layer mixed with local anthropogenic aerosols, concentrating most dust particles (>100 μg m−3); the upper two were composed of pure dust particles with lower mass concentration (<50 μg m−3). This study reveals the capacity of comprehensive observations with multiple approaches from both space and ground in real-time monitoring of mega dust storms and validating the sand storm forecasting.

Different Transport Behaviors between Asian Dust and Polycyclic Aromatic Hydrocarbons in Urban Areas: Monitoring in Fukuoka and Kanazawa, Japan

To clarify different effects of Asian dust (AD), long-range transported from Asian continent, on total suspended particles (TSP) and polycyclic aromatic hydrocarbons (PAHs) in Japan, TSP were simultaneously collected during AD periods (from 1 March to 31 May 2020 and 2021) in Fukuoka and Kanazawa. During AD days, decided by Light Detection and Ranging and Japan Meteorological Agency, TSP concentrations increased significantly (p &lt; 0.001) at two sampling sites. PAH concentrations increased in Kanazawa (p &lt; 0.001) but not in Fukuoka on AD days. Correlation coefficients (r) between daily TSP and total PAHs concentrations were weak in Kanazawa: 0.521 (non-AD) and 0.526 (AD) (p &lt; 0.01), and in Fukuoka: 0.321 (non-AD) and 0.059 (AD). However, correlation between seasonal (average monthly) TSP and total PAH concentrations were stronger: 0.680 (Kanazawa) and 0.751 (Fukuoka). The reasons might be that seasonal variations of TSP and total PAHs in two cities depend equally on planetary scale westerly, while daily TSP and total PAHs variations in each city varied by different transportation distances from AD and PAHs sources in the Asian continent to Japan. Different local sources and meteorological conditions were considered. These results are important for elucidating the causes of chronic and acute respiratory diseases.

Development and evolution of an anomalous Asian dust event across Europe in March 2020

Abstract. This paper concerns an in-depth analysis of an exceptional incursion of mineral dust over southern Europe in late March 2020 (27–30 March 2020). This event was associated with an anomalous circulation pattern leading to several days of PM10 (particulate matter with an aerodynamic diameter less than 10 µm) exceedances in connection with a dust source located in central Asia; this is a rare source of dust for Europe, which is more frequently affected by dust outbreaks from the Sahara Desert. The synoptic meteorological configuration was analyzed in detail, and the aerosol evolution during the transit of the dust plume over northern Italy was assessed at high time resolution by means of optical particle counting at three stations, namely Bologna, Trieste, and Mt. Cimone, allowing for the revelation of the transport timing among the three locations. Back-trajectory analyses supported by Copernicus Atmosphere Monitoring Service (CAMS) maps allowed for the location of the mineral dust source area in the Aralkum region. Therefore, the event was analyzed by observing the particle number size distribution with the support of chemical composition analysis. It is shown that the PM10 exceedance recorded is associated with a large fraction of coarse particles, which is in agreement with mineral dust properties. Both the in situ number size distribution and the vertical distribution of the dust plume were cross-checked using lidar ceilometer and aerosol optical depth (AOD) data from two nearby stations and showed that the dust plume (in contrast to those originating from the Sahara Desert) traveled close to the ground (up to a height of about 2 km). The limited mixing layer height caused by high concentrations of absorbing and scattering aerosols caused the mixing of mineral dust with other locally produced ambient aerosols, thereby potentially increasing its morbidity effects.

Long-Range Transport of Airborne Bacteria by Westerly Winds: Asian Dust Events Carry Potential Mycobacterium Populations Causing Nontuberculous Mycobacterial Pulmonary Disease

Long-Range Transport of Airborne Bacteria by Westerly Winds: Asian Dust Events Carry Potential Mycobacterium Populations Causing Nontuberculous Mycobacterial Pulmonary Disease

Bacterial Characteristics of Dust Particle Saltation in Gobi Dust Sites, Mongolia

The Gobi Desert is a major source of Asian dust events, and the resulting health hazards have increased significantly in recent years. We reported that a variety of live bacteria were distributed in the Gobi Desert in relation to land use. Bacterial distribution was confirmed in the environment and on the land used by animals; however, bacterial saltation due to dust events has not been investigated in detail. In this study, to understand the distribution of surface bacteria in the atmosphere by dust saltation, live bacteria in four dust-generating areas in the Gobi area were monitored using an artificial dust generating device. The live bacteria were detected by experimental saltation at a wind speed of 6.5–8 m/s in all areas. A certain number of live bacteria are constantly saltated by dust events, and these bacteria depend on land use. Moreover, the bacterial saltation strain depended on land use and diversity, indicating that live bacteria are lifted into the environment by dust events. These findings indicate that dust events saltate environmental bacteria on the ground, suggest the risk of animal-derived bacterial saltation affected by land use, and present cross-border public health challenges to be considered in the future.

Description of Dust Emission Parameterization in CAS‐ESM2 and Its Simulation of Global Dust Cycle and East Asian Dust Events

AbstractThe dust emission parameterization in the Chinese Academy of Sciences Earth System Model version 2 (CAS‐ESM2) is described with emphasis on the implementation process and simulations of global dust cycle and East Asia dust event statistics. The parameterization is based on the scheme of Shao (2004; http://doi.org/10.1029/2003JD004372) which considers two major dust emission mechanisms, namely, saltation bombardment and aggregation disintegration. Shao (2004; http://doi.org/10.1029/2003JD004372) scheme was well tested against field observations and has been widely used in regional dust modeling. Here this scheme is implemented into a global climate model for the first time and thus provides an independent solution for simulating global dust emissions. With this scheme, CAS‐ESM2 reasonably simulates the main dust emission regions in the Earth and reproduces the observations of dust deposition flux and surface dust concentrations at most stations. Compared to the synoptic records of dust events, the model also captures the general patterns and seasonal variations of dust activities in East Asia. However, the model underestimates the frequency of strong dust events (instantaneous surface dust concentrations &gt;1,000 μg m−3) due to the weaker surface winds simulated by the model. The model tends to simulate much weaker and longer‐lasting dust events in Eastern Sources (35–49°N, 94–126.5°E) of northern China, suggesting the weaker and slower‐moving synoptic weather systems associated with dust events in the model. Overall CAS‐ESM2 performs well in simulating the key aspects of global dust distribution and East Asian dust events, yet some biases remain to be improved.