Benzene, toluene, ethylbenzene, and xylenes (BTEX) are carcinogenic pollutants. However, the average concentration in 1 h of some pollutants belonging to BTEX, such as benzene, in Ho Chi Minh City (HCMC) is higher than the national standard QCVN 06:2009/BTNMT by about ten times. This research is the first to calculate the emission of BTEX for developing countries on a city scale. This paper developed a method to calculate cold emission factors based on hot emission factors for BTEX. Five spreadsheets developed and calculated these cold emission factors for five vehicle categories. A comprehensive emission inventory (EI) for BTEX was conducted in HCMC to determine the cause of BTEX pollution. An innovative methodology with bottom-up and top-down combination was applied to conduct BTEX EI, in which the EMISENS model was utilized to generate the EI for road traffic sources, and the emission factors method was utilized for other emission sources. Among emission reasons, motorcycles contribute the highest to HCMC air pollution, responsible for 93%, 90%, 98.9%, and 91.5% of benzene, toluene, ethylbenzene, and xylene, respectively. Cars contributed 5%, 6%, 0.8%, and 6.5% of benzene, toluene, ethylbenzene, and xylene, respectively. For LDVs, the emission from benzene, toluene, ethylbenzene, and xylene accounted for 1%, 2%, 0.2%, and 1.9%. The major reasons for point sources were metal production, which had 1%, 2%, and 0.1% for benzene, toluene, ethylbenzene, and xylenes emissions. The area source had a minority emission of total BTEX in Ho Chi Minh City. Our findings can be used to invest in the most significant sources to reduce BTEX in HCMC. Our approach can be applied in similar urban areas in BTEX EI. This research also developed nine measures to reduce BTEX in HCMC for human health protection.

This study assesses air quality and health impact in Hanoi, Vietnam, using the Community Multiscale Air Quality (CMAQ) model and health impact assessment to evaluate the effectiveness of traffic emission reduction strategies under two scenarios. An updated emission inventory was used as the input data for the CMAQ model. The Weather Research and Forecasting (WRF-CMAQ) model (version 5.4), incorporating the CB6 chemical mechanism, was applied alongside a calibrated meteorological model to simulate pollutant dispersion. The model achieved strong performance in PM_2.5 simulation, with a correlation coefficient (R) of 0.78, an index of agreement (IOA) of −0.5, a Normalized Mean Bias (NMB) of 7.11%, and a normalized mean error (NME) of 28.51%. Seasonal analysis revealed higher concentrations of CO, NO₂, O₃, and SO₂ in January compared to July, driven by traffic and industrial emissions. Improved air quality in July was attributed to favorable meteorological conditions, such as increased rainfall and clean airflows from the sea. Spatial distribution highlighted elevated pollutant levels in urban areas, while PM_2.5 was significantly influenced by long-range transport and atmospheric processes. However, fine dust concentrations remained high in suburban areas, driven by secondary emissions and nearby industrial zones. An emission reduction scenario based on the Hanoi city policy decree focusing on traffic sources demonstrated its potential to reduce NO₂, SO₂, and PM_2.5 concentrations, though the impacts varied across time and space. Health impact due to population exposure to PM_2.5 shows that the densely populated suburbs surrounding the urban core have the largest impact in terms of mortality and cardiovascular diseases hospitalization. As PM_2.5 has the largest impact on these two health endpoints, only PM_2.5 impact assessment is performed. Health impact due to air pollution is higher in January (dry season) with estimated 625 deaths and 124 cardiovascular diseases (cvd) hospitalization as compared with estimated 94 deaths and 18 cvd hospitalization in July (wet season). One of the research questions posed by the city authority is whether converting diesel buses to electric buses can yield environmental and health benefits. Our work shows that the scenario based on Hanoi city decree of replacing 50% of fossil fuel combustion buses with electric buses by 2035 does not yield perceptible change in mortality health effect. This is due to emission from buses being small as compared to those from the whole transport sector and other sectors. This study emphasizes the need for integrated, targeted emission control strategies to address spatial and temporal variability in pollution. The findings offer valuable insights for policymakers to develop effective measures in urban planning for improving air quality and protecting the health of people in Hanoi.

Ho Chi Minh City (HCMC) is the largest city in Vietnam, with the highest economic growth rate and the most populous density in the country. By the year 2019, HCMC currently has 8.99 million people with 24 districts. Ho Chi Minh city has robust industrial and service development; therefore, HCMC focuses on developing large-scale livestock facilities with a large number of pigs and limiting small livestock facilities. According to statistic data, HCMC has a total of 290.152 pigs in 2018. These livestock facilities are mainly built in Cu Chi, Hoc Mon, Binh Chanh, Can Gio, and Nha Be districts. These livestock facilities in HCMC have inefficient waste treatment systems located interleaved with residential areas. So that, environmental issues are also a big challenge for the city's government because of the great influence of odor on the surrounding environment causing by the wind direction. The main purposes of this study are (i) calculation of odor emissions from livestock facilities, (ii) simulation of the odor from livestock facilities , and (iii) development of the safe distance of odor for livestock facilities in HCMC. The study results show that, the concertrations from livestock facilitties with capacity from from 50 to 200 pigs and 200 to 500 pigs are lower than QCVN 06:2009/BTNMT. The minimum distance for the livestock facility with capacity from over 500 to 1,000 pigs and over 1,000 pigs to the residential area are 230m and 650m, respectively. The procedure for calculating the odor isolation distance developing in this study could apply for other livestock facilities in other provinces, cities.

This study investigates the potential for a localised Emission Control Area (ECA) in the Ho Chi Minh City seaport, Vietnam, using the FVM-TAPOM model to simulate air pollution from shipping activities, including SO2, PM10, PM2.5, and NO2. The simulation used 2022 emission inventory data for shipping activities and accounted for meteorological conditions, revealing that the Cat Lai port area has the highest pollution concentration. Three ECA options were evaluated based on their cost implications and potential impact on port competitiveness, using a cost-benefit analysis. Option No. 1, encompassing the upstream of the Binh Khanh intersection is viable and selected for its balance of emission reduction and economic feasibility. PostECA implementation simulations demonstrated significant reductions in SO2 and NO2 concentrations in the Cat Lai port area. Maximum 1-hour average concentrations of SO2 and NO2 are expected to decrease from 360 µg/m3 to 260 µg/m3 and from 120 µg/m3 to 64 µg/m3 in the dry season, and from 340 µg/m3 to 320 µg/m3 and from 115 µg/m3 to 80 µg/m3 in the rainy season, respectively. The study concludes that while the selected ECA effectively reduces pollution to meet air quality standards, the forecast shows that by 2030, air pollution is expected to decrease by 171% for NO2, 70% for SO2, 39% for PM10, and 37% for PM2.5 compared to current levels.