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PM2.5 pollution exposure is the leading cause of disease burden globally, especially in low- and middle-income countries, including Vietnam. Therefore, economic damage in this context must be quantified. Long An province in the Southern Key Economic (SKE) region was selected as a research area. This study aimed to evaluate PM2.5-related human health effects causing early deaths attributable to respiratory, cardiovascular, and circulatory diseases in all ages and genders. Health end-points and health impact estimation, economic loss model, groups of PM2.5 concentration data, data of exposed population, data of baseline premature mortality rate, and data of health impact functions were used. Hourly PM2.5 concentration data sets were generated specifically using the coupled Weather Research and Forecasting Model (WRF)/Community Multiscale Air Quality Modelling System (CMAQ) models. Daily PM2.5 pollution levels considered mainly in the dry season (from January to April 2018) resulted in 12.9 (95% CI - 0.6; 18.7) all-cause premature deaths per 100,000 population, of which 7.8 (95% CI 1.1; 7.1), 1.5 (95% CI - 0.2; 3.1), and 3.6 (95% CI - 1.5; 8.5) were due to respiratory diseases (RDs; 60.54%), cardiovascular diseases (CVDs; 11.81%), and circulatory system diseases (CSDs; 27.65%) per 100,000 population, respectively. The total economic losses due to acute PM2.5 exposure-related premature mortality cases reached 62.0 (95% CI - 2.7; 89.6) billion VND, equivalent to 8.3 (95% CI - 0.4; 12.0) million USD. The study outcomes contributed remarkably to the generation and development of data sources for effectively managing ambient air quality in Long An.

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The Lower Mekong Delta region (LMD) accounts for 90% of Vietnam's rice exports; however, the air quality in the LMD is remarkably reduced by ground-level ozone (O3) pollution. This study aimed to quantify the relative yield and economic value losses in rice-growing crop seasons affected by ground-level O3 concentrations across the LMD. The results of this study can serve as a basis for extensive assessments for the following years and support environmental managers to propose control measures of O3 precursor emissions (NOx and VOCs) from man-made sectors, as well as build protective solutions for rice farming in LMD. Two ground-level O3 exposure metrics of M7 and AOT40 reflecting ground-level O3 pollution impacts, combined with the model of exposure-relative yield relationship (or surface O3-crop models), were used to assess losses of crop production (CPL) and economic cost losses (ECL) caused by rice crop yield reductions. For the M7 metric of ground-level O3 exposure, the average value was 14.746 ppbV, with levels ranging from 13.959 ppbV to 15.502 ppbV, and the affected area was spread across 1309.39 thousand hectares. The AOT40 exposure metric reached an average value of 11.490 ppbV, with a range of 0.000-31.665 ppbV. The highest exposure level was 17.503-31.653 ppbV, covering an area of 747.01 thousand hectares. The total CPL of the three rice crops over the LMD was 9593.52 tonnes (accounting for 0.039% of the total value of rice production in the region), with a total corresponding EPL of 62.405 billion VND (equivalent to 2761.01 thousand USD). The results are considered a baseline study to serve as a basis for extensive assessments for the following years and support for the environmental managers to propose control measures of O3 precursor emissions (NOx and VOCs) from man-made sectors as well as build protective solutions in rice farming in LMD shortly.

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Ho Chi Minh City (HCMC) is changing and expanding quickly, leading to environmental consequences that seriously threaten human health. PM2.5 pollution is one of the main causes of premature death. In this context, studies have evaluated strategies to control and reduce air pollution; such pollution-control measures need to be economically justified. The objective of this study was to assess the socio-economic damage caused by exposure to the current pollution scenario, taking 2019 as the base year. A methodology for calculating and evaluating the economic and environmental benefits of air pollution reduction was implemented. This study aimed to simultaneously evaluate the impacts of both short-term (acute) and long-term (chronic) PM2.5 pollution exposure on human health, providing a comprehensive overview of economic losses attributable to such pollution. Spatial partitioning (inner-city and suburban) on health risks of PM2.5 and detailed construction of health impact maps by age group and sex on a spatial resolution grid (3.0 km × 3.0 km) was performed. The calculation results show that the economic loss from premature deaths due to short-term exposure (approximately 38.86 trillion VND) is higher than that from long-term exposure (approximately 14.89 trillion VND). As the government of HCMC has been developing control and mitigation solutions for the Air Quality Action Plan towards short- and medium-term goals in 2030, focusing mainly on PM2.5, the results of this study will help policymakers develop a roadmap to reduce the impact of PM2.5 during 2025-2030.

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PM2.5 exposure data are important for air quality management. Optimal planning and determination of locations where PM2.5 is continuously monitored are important for urban areas in Ho Chi Minh City (HCMC), a megacity with specific environmental problems. Objectives of the study to propose an automatic monitoring system network (AMSN) to measure outdoor PM2.5 concentrations in HCMC using low-cost sensors. Data related to the current monitoring network, population, population density, threshold reference standards set by the National Ambient Air Quality Standard (NAAQS) and the World Health Organisation (WHO), and inventory emissions from various sources, both anthropogenic and biogenic, were obtained. Coupled WRF/CMAQ models were used to simulate PM2.5 concentrations in HCMC. The simulation results were extracted from the grid cells, from which the values of points exceeding the set thresholds were determined. The population coefficient was calculated to determine the corresponding total score (TS). Optimisation of the monitoring locations was statistically performed using Student's t-test to select the official locations for the monitoring network. TS values ranged from 0.0031 to 3215.9. The TSmin value was reached in the Can Gio district and the TSmax value was reached in SG1. Based on the t-test results, 26 initial locations were proposed for a preliminary configuration, from which 10 optimal monitoring sites were selected to develop the AMSN of outdoor PM2.5 concentration measurements in HCMC towards 2025.

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The Mekong Delta region (MDR), also known as Vietnam's rice bowl, produced a bountiful harvest of about 23.8 million tons in 2020, accounting for 55.7% of the country's total production, providing food security for 20% of the world population. With the rapid pace of industrialisation and urbanisation, the concentration of ozone in the lower atmosphere has risen to a level that reduces crop yields, especially rice, and is therefore the subject of research. This study aims to simulate the spatiotemporal distribution of ground-level ozone in the area and evaluate the impact of precursor emissions and meteorological factors on the spatiotemporal distributions of ozone concentrations. The study area was divided into seven zones, including six agro-ecological zones (AEZs) and one low-mountainous area, mainly to clarify the role of emissions in each AEZ. The simulation results showed that ground-level O3 in the MDR ranged from 40.39 to 52.13 µg/m3. In six agro-ecological zones, the average annual ground-level O3 concentration was relatively high and was the highest in zone 6 (CPZ) and zone 3 (LXZ) with values of 96.18 µg/m3 (exceeding 1.60 times the WHO Guidelines 2021) and 94.86 µg/m3 (exceeding 1.58 times the WHO Guidelines 2021), respectively. In each zone, the annual average O3 concentration tended to gradually increase from the inner delta to coastal areas. Two types of precursors, NOx and NMVOCs, are the main contributors to O3 pollution, with the largest contribution coming from zone 1 (FAZ) with 91.5 thousand tons of NOx/year and 455.2 thousand tons of NMVOCs/year. Among the meteorological factors considered, temperature (T), relative humidity (RH), and surface pressure (P) were the three main factors that contributed to the increase in ground-level ozone. The spatio-temporal distribution of ground-level O3 in the MDR was influenced by emission precursors from different zones as well as meteorological factors. The present results can help policy-makers formulate plans for agro-industrial development in the entire region.

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Vietnam has been one of the nations strongly affected by climate change; hence, finding and promoting solutions in order to adapt and proactively respond to climate change have played an extremely significant role. A strategy of developing a low-carbon economy with eco-friendly production and consumption models, limiting the use of fossil fuels, and rising clean as well as renewable energy have been built with the aim to reduce total greenhouse gas (GHG) emissions by roughly 8% by the year 2030 compared to the business-as-usual (BAU) scenario under the Paris Agreement 2015, in particular, focusing on producing a plan to drop considerably methane (CH4) emission and recover energy from landfill sites as the waste sector has been the third-highest GHG contributor in Vietnam. This study concentrates on forecasting and evaluating CH4, CO, H2S, and CH3SH emissions for a case study in the Mekong Delta region of Vietnam: in specific, two dumping sites of Thanh Hoa and Kien Tuong according to four different scenarios so that the landfill gas (LFG) emissions are controlled under the local authority orientation of installing a gas collection system and treating captured gases by an LFG flaring approach from 2021 to 2030. Quantification of the generated LFG is carried out using a mathematical modeling method having validation with field measured data, which is a WebGIS software named EnLandFill with integrated mathematical models, environmental information, and databases allowing analysis of the main influence of two L0 and k factors on LFG emission levels. On the one hand, based on the development planning of Long An province from 2021 to 2030, the municipal solid waste (MSW) volume is estimated at around 3.5 million tonnes and the potential waste generation index is predicted between 0.7 and 1.2 kg person-1 day-1. A large amount of CH4 emissions are considered to be a remarkable contributor to GHG emissions. It can be seen that there are about 32.1-253.6 million m3 CH4 (or equivalent to 512-589 thousand tCO2-eq) and 1.0-5.1 million m3 CH4 (or equivalent to 16-81 thousand tCO2-eq) created at Thanh Hoa and Kien Tuong dumping sites, respectively, under the established scenarios in the 2021-2030 period. On the other hand, the proposal of scenario 4 is found to be the optimal solution for GHG emission control and decline from this study area in the next years. Furthermore, the obtained study outcomes are considered as a basis for planning and managing the issues of MSW in Long An province until 2050 towards a circular economy.

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Vietnam has a great demand for stone exploitation for the development of the country's infrastructure, reaching 181 million m3 in 2020. Mining activities are always accompanied by environmental pollution, negatively affecting public health. To accurately assess the level of pollution, as well as quantify the effect of air pollution on human health, a number of structures, methods, and models provide tools to assess the benefits of this control for public health and related economic values. However, there has been no research in Vietnam applied specifically to this type of stone exploitation. This study offers a model to evaluate the economic damage caused by dust exposure from activities related to quarrying, overcoming the lack of continuous monitoring data. The area selected for research is Binh Duong province, in the Ho Chi Minh megapolis, Vietnam, which has two construction quarries, Thuong Tan and Tan My, with a current annual production of approximately 4-5 million m3. The calculation results show that the damage to human health is estimated at approximately 9,643 billion dong a year, equivalent to 15.03 million USD. In addition, if the standard criteria are tightened, damage will continue to increase. This study also analyses some of the difficulties and limitations in the modelling process.

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Methane is considered to be one of the main causes of global warming. Quantifying methane emissions from landfills is the subject of many studies, especially emphasizing the role of two parameters: methane generation potential capacity (L0), methane generation rate (k). In this study, we propose a system of integrated environmental information and mathematical model named EnLandFill (ENvironmental information - model integrated system for air emission and dispersion estimation from LandFill) that allows calculation L0 from database and experimentally to determine optimal k. To perform experimental calculations, meteorological data were extracted from the WRF model and verified with real measurements. The novelty of this study lies in the inferred database system, the math model bank, especially the dispersion model, taking note account the complex topography, meteorological factors that change by the hour. EnLandFill was applied to Phuoc Hiep Landfill (PHLF) in Ho Chi Minh City as a case study, the results have identified the amount of methane released that is equal to 44,094,697.88 m3/year in 2019, but EnLandFill is designed to be general, applicable to other landfill entities.