Characteristics of ammonia gas and fine particulate ammonium from two distinct urban areas: Osaka, Japan, and Ho Chi Minh City, Vietnam

2017 ◽  
Vol 24 (9) ◽  
pp. 8147-8163 ◽  
Author(s):  
Duong Huu Huy ◽  
Le Tu Thanh ◽  
To Thi Hien ◽  
Kazushi Noro ◽  
Norimichi Takenaka
2021 ◽  
Vol 13 (21) ◽  
pp. 12175
Author(s):  
Le-Minh Ngo ◽  
Hai-Binh Nguyen ◽  
Thi-Phuong Uyen Nguyen ◽  
Thi-Minh Dieu Nguyen

As with many metropolitan areas, social housing (SH) provision, which can improve living standards and social welfare, is crucial for urban socio-economic development strategies in Ho Chi Minh City (HCMC). However, there have been issues relating to promoting social housing in the Vietnamese context resulting from the property market and the design. The former is a failure to attract investors. The latter relates to lacking housing models for the mid- and low-income communities. Currently, many low-income families who have low access to the general job market in HCMC have to make a living by running their own business at home. This situation leads to low-income housing establishments in some residential areas. Thus, the planning approach in social housing needs to solve both the demand for low-cost housing and promoting self-employed activities. In this paper, mixed methods, including observation, questionnaires, interviews, data aggregation, and comparison, were conducted with supporting legal conditions and corresponding operating conditions to propose appropriate designs for the SH for self-employed people in HCMC. First, observing and analyzing urban spaces helped identify the unused urban areas that solve the investment issue. Then, after studying the development of social housing in different contexts via the questionnaire and in-depth interviews, self-employed households’ basic information and their business needs in using SH spaces were identified in some districts. Then, based on the legal framework and practical projects, optimal space designs were formed.


2018 ◽  
Vol 35 (2) ◽  
pp. 58-84 ◽  
Author(s):  
Yana Jin ◽  
Shiqiu Zhang

Fine particulate pollution (PM2.5) is a leading mortality risk factor in the People's Republic of China (PRC) and many Asian countries. Current studies of PM2.5 mortality have been conducted at the national and provincial levels, or at the grid-based micro level, and report only the exposure index or attributable premature deaths. Little is known about the welfare implications of PM2.5 mortality for urban areas. In this study, we estimate the total cost of PM2.5 mortality, the benefit of its reduction achieved through meeting various air quality targets, and the benefit of mortality reduction achieved through a uniform 10 micrograms per cubic meter decrease in PM2.5 concentration in the urban areas of 300 major cities in the PRC. Significant heterogeneity exists in welfare indicators across rich versus poor and clean versus dirty cities. The results indicate that cities in the PRC should accelerate the fine particulate pollution control process and implement more stringent air quality targets to achieve much greater mortality reduction benefits.


Author(s):  
Nguyen Minh Ha ◽  
Vo Phuoc Tai ◽  
Nguyen Quang Thai

During the last 20 years, Vietnam has had a prompt economic development, the people have the trend for emigrating from the rural to urban areas, industrial zones and the trading-service centre where it is essential for labor needs to serve for the industrial and service development in order to look for the better jobs. The wave of emigrants have not only contributed to an increase in population in Ho Chi Minh City (HCMC) and other urban centers in Vietnam but also augmented pressure in the infrastructure system and the issues of social life. With the method of Exploratory Factor Analysis (EFA), this research had indicated the main factors impacting on making a decision for migration to the Ho Chi Minh City, by the collected data directly from 277 surveyed forms of immigrants to HCMC. There are 6 decisive factors including: (1) HCMC‟s politics and policies; (2) the family situation and the embroilment of the friends and fellow-countrymen; (3) better quality needs of life and individual aspirations; (4) the job opportunities and occupational development conditions; (5) the job demands with stable incomes; and (6) the marriage and living with relatives.


Atmosphere ◽  
2017 ◽  
Vol 8 (12) ◽  
pp. 62 ◽  
Author(s):  
Xinlei Ge ◽  
Yanan He ◽  
Yele Sun ◽  
Jianzhong Xu ◽  
Junfeng Wang ◽  
...  

2012 ◽  
Vol 12 (14) ◽  
pp. 6335-6355 ◽  
Author(s):  
U. Im ◽  
M. Kanakidou

Abstract. Megacities are large urban agglomerations with intensive anthropogenic emissions that have significant impacts on local and regional air quality. In the present mesoscale modeling study, the impacts of anthropogenic emissions from the Greater Istanbul Area (GIA) and the Greater Athens Area (GAA) on the air quality in GIA, GAA and the entire East Mediterranean are quantified for typical wintertime (December 2008) and summertime (July 2008) conditions. They are compared to those of the regional anthropogenic and biogenic emissions that are also calculated. Finally, the efficiency of potential country-based emissions mitigation in improving air quality is investigated. The results show that relative contributions from both cities to surface ozone (O3) and aerosol levels in the cities' extended areas are generally higher in winter than in summer. Anthropogenic emissions from GIA depress surface O3 in the GIA by ~ 60% in winter and ~ 20% in summer while those from GAA reduce the surface O3 in the GAA by 30% in winter and by 8% in summer. GIA and GAA anthropogenic emissions contribute to the fine particulate matter (PM2.5) levels inside the cities themselves by up to 75% in winter and by 50% (GIA) and ~ 40% (GAA), in summer. GIA anthropogenic emissions have larger impacts on the domain-mean surface O3 (up to 1%) and PM2.5 (4%) levels compared to GAA anthropogenic emissions (<1% for O3 and ≤2% for PM2.5) in both seasons. Impacts of regional anthropogenic emissions on the domain-mean surface pollutant levels (up to 17% for summertime O3 and 52% for wintertime fine particulate matter, PM2.5) are much higher than those from Istanbul and Athens together (~ 1% for O3 and ~ 6% for PM2.5, respectively). Regional biogenic emissions are found to limit the production of secondary inorganic aerosol species in summer up to 13% (non-sea-salt sulfate (nss-SO42−) in rural Athens) due to their impact on oxidant levels while they have negligible impact in winter. Finally, the responses to country-based anthropogenic emission mitigation scenarios inside the studied region show increases in O3 mixing ratios in the urban areas of GIA and GAA, higher in winter (~ 13% for GIA and 2% for GAA) than in summer (~ 7% for GIA and <1% for GAA). On the opposite PM2.5 concentrations decrease by up to 30% in GIA and by 20% in GAA with the highest improvements computed for winter. The emission reduction strategy also leads to domain-wide decreases in most primary pollutants like carbon monoxide (CO) or nitrogen oxides (NOx) for both seasons. The results show the importance of long range transport of pollutants for the air quality in the East Mediterranean. Thus, improvements of air quality in the East Mediterranean require coordinated efforts inside the region and beyond.


1995 ◽  
Vol 27 (5) ◽  
pp. 793-808 ◽  
Author(s):  
D Forbes

Since the mid-1970s, Vietnam experienced a period of transition to socialism, before bringing in economic reforms which led to the gradual dismantling of the subsidised system of planning and the opening up of the country to the global capitalist economy. Economic reform and renovation has important implications for the urban areas of Vietnam. The emergence of markets and the abandonment of many restrictions on travel resulted in a freeing up of the urbanisation process during the 1980s and early 1990s. These processes are considered, and the implications for Vietnam's largest urban area, Ho Chi Minh City, are examined. The likely impact of Vietnam's long-term socioeconomic strategy on the urban network in the remainder of the decade is considered.


Author(s):  
Zhanyong Wang ◽  
Hong-Di He ◽  
Feng Lu ◽  
Qing-Chang Lu ◽  
Zhong-Ren Peng

Air quality time series near road intersections consist of complex linear and nonlinear patterns and are difficult to forecast. The backpropagation neural network (BPNN) has been applied for air quality forecasting in urban areas, but it has limited accuracy because of the inability to predict extreme events. This study proposed a novel hybrid model called GAWNN that combines a genetic algorithm and a wavelet neural network to improve forecast accuracy. The proposed model was examined through predicting the carbon monoxide (CO) and fine particulate matter (PM2.5) concentrations near a road intersection. Before the predictions, principal component analysis was adopted to generate principal components as input variables to reduce data complexity and collinearity. Then the GAWNN model and the BPNN model were implemented. The comparative results indicated that GAWNN provided more reliable and accurate predictions of CO and PM2.5 concentrations. The results also showed that GAWNN performed better than BPNN did in the capability of forecasting extreme concentrations. Furthermore, the spatial transferability of the GAWNN model was reasonably good despite a degenerated performance caused by the unavoidable difference between the training and test sites. These findings demonstrate the potential of the application of the proposed model to forecast the fine-scale trend of air pollution in the vicinity of a road intersection.


Sign in / Sign up

Export Citation Format

Share Document