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The COVID-19 pandemic is reshaping the global trade and supply chains, and some developed countries may consider relocating strategic manufacturing operations out of China, providing new opportunities for some South and Southeast Asian countries. Since the shift of manufacturing is accompanied by redistribution of emission sources of air pollutants, the impacts on environment and human health of the countries directly involved and their neighbors, should be considered. We used the Community Earth System Model, the Integrated Exposure-Response (IER) model and Willingness To Pay (WTP) method, to simulate fine particulate matter (PM2.5) and the socio-economic responses to shifting manufacturing from China to Indonesia or India. Our results show that significant effects on PM2.5 related mortality and economic cost for these deaths were seen in many East, Southeast and South Asian countries, particularly those immediately downwind of these three countries. Transferring all of export-related manufacturing to Indonesia resulted in significant mortality decreases in China and South Korea by around 78k (5 per 100k) and 1k (2 per 100k) respectively, while Indonesia’s mortality significantly increased (73.7k; 29 per 100k), as well as India, Pakistan and Nepal. When manufacturing was transferred to India, mortality rates in East Asia show similar responses to the Indonesian scenario, while mortalities in India increased dramatically by 87.9k (6 per 100k), and mortalities in many neighbors of India also severely increased. Shifting manufacturing to India in our simulations led to more Asian countries showing significant changes in PM2.5 related deaths and economic costs than an equivalent shift to Indonesia. This is because of the maritime Indonesian setting as well as patterns of surface winds. Nevertheless, the economic costs for these deaths were much smaller than national GDP changes in China (0.9% of GDP vs. 18.3% of GDP), India (2.7% of GDP vs. 84.3% of GDP) or Indonesia (9.4% of GDP vs. 337% of GDP) due to shifting all of export-related production lines from China to India or Indonesia. Perhaps the most concerning aspect of this study is the damage to “innocent” victims of any manufacturing shifts in third countries that do not see any domestic economic gains. Morally, part of the benefits of economic activity should be used to compensate the neighboring communities where mortality increases occur.

The diversification or decoupling of production chains from China to alternative Asian countries such as India or Indonesia would impact the spatial distribution of anthropogenic emissions, with corresponding economic impacts due to mortality associated with particulate matter exposure. We evaluated these changes using the Community Earth System Model, the Integrated Exposure-Response (IER) model and Willingness To Pay (WTP) method. Significant effects on PM2.5 related mortality and economic cost for these deaths were seen in many East, Southeast and South Asian countries, particularly those immediately downwind of these three countries. Transferring all of export-related manufacturing to Indonesia resulted in significant mortality decreases in China and South Korea by 78k (5 per 100k) and 1k (2 per 100k) respectively, while Indonesia’s mortality significantly increased (73.7k; 29 per 100k), as well as India, Pakistan and Nepal. When production was transferred to India, mortality rates in East Asia show similar changes to the Indonesian scenario, while mortalities in India increased dramatically (87.9k; 6 per 100k), and mortalities in many neighbors of India were also severely increased. Nevertheless, the economic costs for these deaths were much smaller than national GDP changes in China (0.9% of GDP vs. 18.3% of GDP), India (2.7% of GDP vs. 84.3% of GDP) or Indonesia (9.4% of GDP vs. 337% of GDP) due to shifting all of export-related production lines from China to India or Indonesia. Morally, part of the benefits of economic activity should be used to compensate the neighboring communities where mortality increases occur.

Historical snow cover over the Northern Hemisphere was examined in the satellite-based NOAA-CDR data for the period of 1970–2019. Observed annual snow cover fraction (SNF) has reduced over most areas by up to 2%/decade, while annual snow cover area (SCA) has reduced by 2 × 105 km2/decade. However, SCA in the October–December season has increased by about 5 × 105 km2/decade. CMIP5 and CMIP6 historical experiments were validated against the NOAA-CDR data. Snow cover was generally well simulated in both CMIPs, with CMIP6 models performing better. The biases in SCA reduction were larger and smaller during summer and winter, respectively. The observed increase of October–November–December SCA in the 2000s was not reproduced. Climate projections of future snow cover were evaluated in CMIP6. SNF is projected to decrease in the next 80 years, under all four scenarios evaluated (SSP126, SSP245, SSP370 and SSP585). The higher the greenhouse emissions in the shared socio-economic pathways, the faster the reduction. Under the SSP585 scenario, the rate of SCA reduction is projected to exceed −1.2 × 106 km2/decade. By 2081–2100, annual (January–March) SCA is projected to decrease by more than 30% (20%). Under the SSP126 scenario, annual (January–March) SCA is projected to only reduce by about 10% (5%) relative 1995–2014 values. The reduction of Greenhouse gas emissions is critical to controlling the loss of snow cover; future snow cover only stabilizes under the SSP126 scenario, but continue to decrease under the other three scenarios.

Biomass burning in the Maritime Continent frequently results in region-wide haze pollution, causing concerns for aviation and maritime navigation. Indonesian peat smoke is high in sulfates and water soluble organic carbon, and we show that in Singapore, particle hygroscopic growth results in a strongly non-linear relationship between visibility and aerosol concentration under humid conditions. Thus, even for a tropical coastal city, the consideration of ambient relative humidity is desirable when forecasting for visibility deterioration caused by haze aerosols.

We have carried out a comprehensive analysis of six air pollutants (particles with an aerodynamic diameter less than 2.5 μm (PM2.5) and less than 10 μm (PM10), carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3)) in western China, including the spatiotemporal characteristics of air pollutants, their relationship with meteorological factors and emission sources, and the efficiency of emission control strategies for the region. Based hourly observations at 23 sites in western China from June 2016 to May 2017, concentrations of most pollutants were higher outside the Tibetan Plateau, lowest in summer and highest in winter, the exception being O3. This was partially because meteorological conditions in winter were found to the most unfavorable to pollutant dispersion and dilution than other seasons. Pollutant concentrations at most sites were correlated with the residential emissions which were higher in winter, but anti-correlated with the industrial emissions which were lower during the winter holiday period. The Weather Research and Forecasting with Chemistry (WRF-Chem) simulations of four pollution control strategies indicated that reduction of residential emissions is crucial to alleviate PM2.5, PM10, and CO pollution in western China, although reduction of industrial and transport emissions can reduce SO2 and NO2, respectively. Since PM2.5 and PM10 were also found to be the species most and next frequently responsible for extremely serious pollution in western China, respectively, we recommend pollution control regulations that target residential emissions.

Erbium-doped magnesium zinc oxides were prepared through spray pyrolysis deposition at 450 &deg, C with an aqueous solution containing magnesium nitrate, zinc acetate, erbium acetate, and indium nitrate precursors. Diodes with different erbium-doped magnesium zinc oxide thicknesses were fabricated. The effect of erbium-doped magnesium zinc oxide was investigated. The crystalline structure and surface morphology were analyzed using X-ray diffraction and scanning electron microscopy. The films exhibited a zinc oxide structure, with (002), (101), and (102) planes and tiny rods in a mixed hexagonal flakes surface morphology. With the photoluminescence analyses, defect states were identified. The diodes were fabricated via a metallization process in which the top contact was Au and the bottom contact was In. The current&ndash, voltage characteristics of these diodes were characterized. The structure resistance increased with the increase in erbium-doped magnesium zinc oxide thickness. With a reverse bias in excess of 8 V, the light spectrum, with two distinct green light emissions at wavelengths of 532 nm and 553 nm, was observed. The light intensity that resulted when using a different operation current of the diodes was investigated. The diode with an erbium-doped magnesium zinc oxide thickness of 230 nm shows high light intensity with an operational current of 80 mA. The emission spectrum with different injection currents for the diodes was characterized and the mechanism is discussed.

A shipborne micro-pulse lidar (Sigma Space Mini-MPL) was used to measure aerosol extinction coefficient over the northern region of the South China Sea from 9 August to 7 September 2016, the first time a mini-MPL was used for aerosol observation over the cruise region. The goal of the experiment was to investigate if the compact and affordable mini-MPL was usable for aerosol observation over this region. The measurements were used to calculate vertical profiles of volume extinction coefficient, depolarization ratio, and atmospheric boundary layer height. Aerosol optical depth (AOD) was lower over the southwest side of the cruise region, compared to the northeast side. Most attenuation occurred below 3.5 km, and maximum extinction values over coastal areas were generally about double of values offshore. The extinction coefficients at 532 nm (aerosol and molecular combined) over coastal and offshore areas were on average 0.04 km-1 and 0.02 km-1, respectively. Maximum values reached 0.2 km−1 and 0.14 km−1, respectively. Vertical profiles and back-trajectory calculations indicated vertical and horizontal layering of aerosols from different terrestrial sources. The mean volume depolarization ratio of the aerosols along the cruise was 0.04. The mean atmospheric boundary layer height along the cruise was 653 m, with a diurnal cycle reaching its mean maximum of 1041 m at 12:00 local time, and its mean minimum of 450 m at 20:00 local time. Unfortunately, only 11% of the measurements were usable. This was due to ship instability in rough cruise conditions, lack of stabilization rig, water condensation attached to the eye lens, and high humidity attenuating the echo signal. We recommend against the use of the mini-MPL in this cruise region unless substantial improvements are made to the default setup, e.g., instrument stabilization, instrument protection cover, and more theoretical work taking into account atmospheric gas scattering or absorption.

© 2019 Elsevier B.V. To alleviate air pollution in western China, experiencing rapid economic growth following national western development strategies, an accurate and compressive assessment of PM2.5 sources is critical. Here, we firstly investigated the spatiotemporal variation in PM2.5 and analyzed its association with weather conditions and emission changes. Then, WRF-Chem simulations were conducted for an entire year to obtain various emission sectors' contributions to the PM2.5 mass by a hybrid method, which considers both the proportions of various components as well as each sector contributing to these components. The results showed that residential emissions had the largest contribution to PM2.5 because of its dominating contribution for primary components of PM2.5 (BC and POA), which can explain >70% of PM2.5. Seasonally, the residential contributions to PM2.5 were higher in the non-monsoon period than in the monsoon period because of the higher contribution ratios to primary components. Regionally, as an essential source of the gaseous precursors, the industrial and transportation sectors were the second-largest contributors to PM2.5 in the highly populated urban (HP) and remote background (RM) regions, respectively. Further assessment of emission reduction measures indicated that eliminating 50% of residential emissions induced a 29.4% and 33.1% decrease in the annual PM2.5 mass of the HP and RM regions, respectively, with higher decrease proportions in non-monsoon. By comparison, eliminating 50% of industrial emissions caused a significantly lower decrease in PM2.5 for both HP (10%) and RM (4.6%). Eliminating 50% of transportation emissions led to PM2.5 concentrations to decline by 9.3% in RM, which was greater than the 4.6% reduction caused by eliminating 50% of industrial emissions. Therefore, in addition to focusing on the residential sector, especially in non-monsoon in western China, the transportation sector should be a focus to alleviate PM2.5 pollution on the Tibetan Plateau. The outcome of this study provides valuable information for policy-makers to make strategies to mitigate air pollution in western China.

This paper presents a study of haze in Singapore caused by biomass burning in Southeast Asia over the six year period from 2010 to 2015, using the Lagrangian dispersion model, NAME. The major contributing source regions are shown to be Riau, Peninsular Malaysia, South Sumatra, and Central and West Kalimantan. However, we see differences in haze concentrations and variation in the relative contributions from the various source regions between monitoring stations across Singapore, as well as on an inter-annual timescale. These results challenge the current popular assumption that haze in Singapore is dominated by emissions/burning from only Indonesia. It is shown that Peninsular Malaysia is a large source for the Maritime Continent off-season biomass burning impact on Singapore. As should be expected, the relatively stronger southeast monsoonal winds that coincide with increased biomass burning activities in the Maritime Continent create the main haze season from August to October (ASO), which brings particulate matter from several and varying source regions to Singapore. In contrast, atypical haze episodes in Singapore are characterised by atypical weather conditions, ideal for biomass burning, and emissions dominated by a single source region (for each event). The two most recent atypical haze events in mid 2013 and early 2014 have different source regions, whereas a different set of five regions dominate as major contributing source regions for most of the recent ASO haze seasons. Haze in Singapore varies across year, season, and location it is influenced by local and regional weather, climate, and regional burning. The study shows that even across small scales, such as in Singapore, variation in local meteorology can impact concentrations of particulate matter significantly, and emphasises the importance of the scale of modelling both spatially and temporally.

Previous studies on the response of the South Asian summer monsoon to the direct radiative forcing caused by anthropogenic absorbing aerosols have emphasized the role of premonsoonal aerosol forcing. This study examines the roles of aerosol forcing in both pre- and postonset periods using the Community Earth System Model, version 1.0.4, with the Community Atmosphere Model, version 4. Simulations were perturbed by model-derived radiative forcing applied (i) only during the premonsoonal period (May–June), (ii) only during the monsoonal period (July–August), and (iii) throughout both periods. Soil water storage is found to retain the effects of premonsoonal forcing into succeeding months, resulting in monsoonal central India drying. Monsoonal forcing is found to dry all of India through local responses. Large-scale responses, such as the meridional rotation of monsoon jet during June and its weakening during July–August, are significant only when aerosol forcing is present throughout both premonsoonal and monsoonal periods. Monsoon responses to premonsoonal forcing by the model-derived “realistic” distribution versus a uniform wide-area distribution were compared. Both simulations exhibit central India drying in June. June precipitation over northwestern India (increase) and southwestern India (decrease) is significantly changed under realistic but not under wide-area forcing. Finally, the same aerosol forcing is found to dry or moisten the July–August period following the warm or cool phase of the simulations’ ENSO-like internal variability. The selection of years used for analysis may affect the precipitation response obtained, but the overall effect seems to be an increase in rainfall variance over northwest and southwest India.

Despite the knowledge that the potential temperature of an air parcel has a dependence on its water vapour content, potential temperature is often still calculated as if the parcel were dry, assuming that this moisture dependence is negligible. We show that such a dry potential temperature approximation is not suitable for tropical regions. Moisture gradient terms are seen in the isentropic primitive equations when Exner and Montgomery functions are generalised with moist specific heat capacities, forming a contribution to the horizontal momentum tendency comparable to that by the Montgomery function. This reflects how local horizontal gradients in potential temperature created by inhomogeneous water vapour distribution are relatively significant compared to gradients created by inhomogeneous temperature, in a large-scale background of weak horizontal temperature gradient. In such an environment, water plays an active role in tropical atmospheric dynamics without the uptake or release of latent heat during phase changes. Hence, we suggest that the tropical troposphere is a place where the atmosphere can behave dynamically as a binary-component fluid at local and regional scales.

The zinc oxides (ZnO) films with different bismuth (Bi) doping were prepared by spray pyrolysis deposition at 450°C with aqueous solution contained zinc acetate and bismuth nitrate precursors. Under ultra-violate light illumination, the photodegradation of methyl orange for these ZnO films were studied. In the singly doped ZnO, the 5% Bi doped ZnO shows the relatively high photocatalytic activity. The reaction rate was achieved and possible reason was discussed. It is found that the raction rate can be enhanced by increasing the surface doping. The absorption coefficient was investigated and possible reason was discussed.

The direct radiative effect of absorbing aerosols consists of absorption-induced atmospheric heating together with scattering- and absorption-induced surface cooling. It is thus important to understand whether some of the reported climate impacts of anthropogenic absorbing aerosols are mainly due to the coexistence of these two opposite effects and to what extent the nonlinearity raised from such coexistence would become a critical factor. To answer these questions specifically regarding the South Asia summer monsoon with focus on aerosol-induced changes in monsoon onset, a set of century-long simulations using the Community Earth System Model, version 1.0.3 (CESM 1.0.3), of NCAR with fully coupled atmosphere and ocean components was conducted. Prescribed direct heating to the atmosphere and cooling to the surface were applied in the simulations over the Indian subcontinent, either alone or combined, during the aerosol-laden months of May and June. Over many places in the Indian subcontinent, the nonlinear effect dominates in the changes of subcloud layer moist static energy, precipitation, and monsoon onset. The surface cooling effect of aerosols appears to shift anomalous precipitative cooling away from the aerosol-forcing region and hence turn the negative feedback to aerosol-induced atmospheric heating into a positive feedback on the monsoon circulation through latent heat release over the Himalayan foothills. Moisture processes form the critical chain mediating local aerosol direct effects and onset changes in the monsoon system. NRF (Natl Research Foundation, S’pore) ASTAR (Agency for Sci., Tech. and Research, S’pore) Published version

Boron doping on the structural, optical and electrical properties in BZO films fabricated by spray pyrolysis were investigated. The carrier concentration of ∼1019cm−3 and optical transmittance about 90% in the infrared region was achieved.

Thin films of Cuprous Oxide (Cu 2 O) with different deposition temperatures have been deposited on glass substrates by spray pyrolysis. The films were investigated in terms of morphological surface, structural and electrical properties exhibited p-type conduction.

The device — Au/Ni/CIS/TCO device grown on ITO glass or FTO glass. As ITO glass be the substrates, the fill factor is better than the device deposited on FTO glass. This result showed that the FTO glass better than ITO glass.

Boron-doped zinc oxide (BZO) thin films have been fabricated by spray pyrolysis on a glass substrate. The morphology and electrical properties of the thin films were investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were performed. It was found that [B]/[Zn] ratio altered both the microstructure and concentration of the BZO thin films. The film grain size was reduced by increasing the [B]/[Zn] ratio. The highest Hall mobility was 3.65 cm2 V-1 s-1 for the undoped ZnO thin film, and the highest carrier concentration of 1.0×1019 cm-3 was achieved for the as-deposited BZO thin film with [B]/[Zn] = 1.5 at. %. Conductivity was determined at different measurement temperatures and shallow donors provided the dominate conduction mechanism for the as-deposited BZO thin films. After 600 °C annealing, shallow level reduction and donors with a high activation energy of 129±6 meV in the BZO thin films were characterized, and the shallow donors that dominate the carrier concentration for the as-deposited spray-pyrolized BZO thin film were eliminated.