Influence of Urban-Growth Pattern on Air Quality in China: A Study of 338 Cities

Air pollution in China is a serious problem and an inevitable threat to human health. This study evaluated the relationship between air quality and urban growth pattern in China by conducting empirical research involving 338 prefecture-level and above cities. Spatial regression techniques considering spatial autocorrelation were applied to correct the calculation bias. To obtain local and accurate results, a conception of eight economic zones was adopted to delineate cities into different groups and to estimate regression separately. An additional six urban form and socioeconomic indicators served as controlling variables. Significant and positive relationships between the aggregated urban growth pattern index and air pollution were observed in Northeast China, northern coastal China, and Northwest China, indicating that a high degree of urban aggregation is associated with poor air quality. However, a negative parameter was obtained in southern coastal China, showing an opposite association on urban aggregation and air quality. Nonsignificant connections among the other four zones were found. The findings also highlighted that land use mix, population density, and city size exerted varied and significant influence on air quality across eight economic zones. Overall, this study indicated that understanding the quantitative relationships between urban forms and air quality can provide policymakers with alternative ways to improve air quality in rapidly developing China.

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Quantifying Air Pollutant Variations during COVID-19 Lockdown in a Capital City in Northwest China

Atmosphere ◽

10.3390/atmos12060788 ◽

2021 ◽

Vol 12 (6) ◽

pp. 788

Author(s):

Rong Feng ◽

Hongmei Xu ◽

Zexuan Wang ◽

Yunxuan Gu ◽

Zhe Liu ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Rural Areas ◽

Vehicle Emissions ◽

Motor Vehicle ◽

Northwest China ◽

Air Pollutant ◽

Capital City ◽

Air Pollution Control ◽

Motor Vehicle Emissions

In the context of the outbreak of coronavirus disease 2019 (COVID-19), strict lockdown policies were implemented to control nonessential human activities in Xi’an, northwest China, which greatly limited the spread of the pandemic and affected air quality. Compared with pre-lockdown, the air quality index and concentrations of PM2.5, PM10, SO2, and CO during the lockdown reduced, but the reductions were not very significant. NO2 levels exhibited the largest decrease (52%) during lockdown, owing to the remarkable decreased motor vehicle emissions. The highest K+ and lowest Ca2+ concentrations in PM2.5 samples could be attributed to the increase in household biomass fuel consumption in suburbs and rural areas around Xi’an and the decrease in human physical activities in Xi’an (e.g., human travel, vehicle emissions, construction activities), respectively, during the lockdown period. Secondary chemical reactions in the atmosphere increased in the lockdown period, as evidenced by the increased O3 level (increased by 160%) and OC/EC ratios in PM2.5 (increased by 26%), compared with pre-lockdown levels. The results, based on a natural experiment in this study, can be used as a reference for studying the formation and source of air pollution in Xi’an and provide evidence for establishing future long-term air pollution control policies.

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The Relationship between Land Cover and Sociodemographic Factors

Urban Science ◽

10.3390/urbansci4040068 ◽

2020 ◽

Vol 4 (4) ◽

pp. 68

Author(s):

Daniel L. Mendoza

Keyword(s):

Air Pollution ◽

Air Quality ◽

Urban Form ◽

Capita Income ◽

Sociodemographic Factors ◽

Tree Cover ◽

Quality Data ◽

Minority Populations ◽

Per Capita Income ◽

Per Capita

Multiple social and environmental justice concerns are linked to the urban form such as the distribution of socioeconomic class populations, healthcare spending, air pollution exposure, and human mobility. Because of this, the implications of the relationships between built urban form, sociodemographic factors, and air quality warrant analysis at a high spatial resolution. This study used 1m resolved LiDAR data to characterize land use in Salt Lake County, Utah, and associate it with sociodemographic and air quality data at the census block group and zip code levels. We found that increasing tree cover was associated with higher per capita income and lower minority populations while increasing built cover was linked to lower per capita income and higher minority populations. Air quality showed less strong correlations, however, decreased non-irrigated cover, increased built cover, and higher amounts of households living under poverty were related to higher long-term PM2.5 exposure. Due to regional air pollution concerns, several policy efforts have been undertaken to improve air quality and reduce negative health outcomes in Utah which are being informed by regulatory and research-grade air quality sensors.

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The relationship between urban form and air pollution depends on seasonality and city size

Environmental Science and Pollution Research ◽

10.1007/s11356-018-1743-6 ◽

2018 ◽

Vol 25 (16) ◽

pp. 15554-15567 ◽

Cited By ~ 25

Author(s):

Yupeng Liu ◽

Jianguo Wu ◽

Deyong Yu ◽

Qun Ma

Keyword(s):

Air Pollution ◽

Urban Form ◽

City Size ◽

The Relationship

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Air pollution and emigration behaviors – evidence of Hanoi

10.31219/osf.io/tcwb6 ◽

2022 ◽

Author(s):

Nguyen Quang-Loc ◽

Ananya Singh ◽

Saanvi Jain ◽

Khangai Shirchin

Keyword(s):

Air Pollution ◽

Air Quality ◽

Bayesian Analysis ◽

Urban Growth ◽

Developing Economies ◽

Psychological Process ◽

The People ◽

Economic Forces ◽

The Government ◽

Collaborative Activities

Expeditious increase in population and industrialization has led to alarming rates of air pollution in all countries. However, developing economies have had to face a more adverse and severe impact. This had led to many changes in the day to day living of citizens. In this paper we have focused on the psychological process and predictors of migration intention of the people living in Hanoi, Vietnam. Two stratified random datasets of 475 people were used, and Bayesian analysis was performed on this dataset. We found out that the intent to move was negatively associated to the individual’s satisfaction with air quality. We also found that people who have family members that have fallen victim to a disease caused by air pollution are more likely to migrate. This paper discusses an important topic: immigration of the younger demographic, i.e. the Hanoi workforce, which may cause restrictions and hurdles in the city's urbanisation and development. The findings suggest that, if measures against air pollution are not taken, economic forces may be disrupted, posing a threat to urban growth. As a result, collaborative activities and steps need to be taken by the government to curb this unfortunate consequence.

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Spatiotemporal Variations in Particulate Matter and Air Quality over China: National, Regional and Urban Scales

Atmosphere ◽

10.3390/atmos12010043 ◽

2020 ◽

Vol 12 (1) ◽

pp. 43

Author(s):

Hao Luo ◽

Yong Han ◽

Xinghong Cheng ◽

Chunsong Lu ◽

Yonghua Wu

Keyword(s):

Air Pollution ◽

Particulate Matter ◽

Air Quality ◽

Wind Speed ◽

Wind Direction ◽

Industrial Development ◽

Northwest China ◽

Temporal And Spatial Distribution ◽

Ambient Exposure ◽

Pm2.5 Concentration

Ambient exposure to particulate matter (PM) air pollution is known to have an adverse effect on public health worldwide. Rapid increase rates of economic and urbanization, industrial development, and environmental change in China have exacerbated the occurrence of air pollution. This study examines the temporal and spatial distribution of PM on national, regional and local scales in China during 2014–2016. The relationships between the PM2.5 concentration rising rate (PMRR) and meteorological parameters (wind speed and wind direction) are discussed. The dataset of Air Quality Index (AQI), PM10 (PM diameter < 10 μm ) and PM2.5 (PM diameter < 2.5 μm) were collected in 169, 369, and 367 cities in 2014, 2015, and 2016 over China, respectively. The results show that the air quality has been generally improved on the national scale, but deteriorated locally in areas such as the Feiwei Plain. The northwest China (NW) and Beijing-Tianjin-Hebei (BTH) regions are the worst areas of PM pollution, which are mainly manifested by the excessive PM10 caused by blowing dust in spring in NW and the intensive emissions of PM2.5 in winter in BTH. With the classified seven geographic regions, we demonstrate the significant spatial difference and seasonal variation of PM concentration and PM2.5/PM10 ratio, which indicate different emission sources. Furthermore, the dynamic analysis of the PM2.5 pollution process in 11 large urban cities shows dramatic effects of wind speed and wind direction on the PM2.5 loadings.

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Spatial Analysis of Exposure to Traffic-Related Air Pollution in Mexico: Implications for Urban Planning to Improve Public Health

Applied Spatial Analysis and Policy ◽

10.1007/s12061-021-09415-1 ◽

2021 ◽

Author(s):

Ruben Garnica-Monroy ◽

Veronica Garibay-Bravo ◽

Alonso Gonzalez-Gonzalez ◽

Hilda Martínez Salgado ◽

Malinalli Hernández-Reyes

Keyword(s):

Air Pollution ◽

Air Quality ◽

Urban Form ◽

Urban Areas ◽

Heavy Traffic ◽

Similar Proportion ◽

Population Exposure ◽

Health Authorities ◽

Increased Risk ◽

Hospital Patients

AbstractIn cities, traffic is one of the major determinants for air quality. Studies have shown that proximity to roadways with heavy traffic has been linked with increased incidence and prevalence of a range of health effects such as adverse birth outcomes, dementia, asthma, and increased risk of bronchitis, wheezing, deficits in lung function growth and airway inflammation, especially among children. In Mexico, 103 urban areas have air quality monitoring, whilst more than 2,000 cities lack any information and only 29 have monitoring systems that are robust enough to estimate exposure. This poses serious limitations for environmental and health authorities when aiming at assessing current exposure levels to Traffic-Related Air Pollution (TRAP) with the purpose of designing and implementing policies to reduce the impacts of poor air quality in the population. This study proposes an approach to estimate the population potentially exposed to TRAP using Space Syntax’s accessibility index as the urban form variable. We selected the ten most accessible roads of the five Mexican cities to estimate the proportion of vulnerable population (residents, employees, schoolchildren, hospital patients) with the highest potential exposure to TRAP at a distance of 500 m. Our findings show a similar proportion of the population continually exposed to TRAP due to the proximity to roads with heavy traffic than studies using more complex models. Finally, this study presents alternatives to reduce current population exposure to traffic emissions in Mexican cities.

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Urban and air pollution: a multi-city study of long-term effects of urban landscape patterns on air quality trends

Scientific Reports ◽

10.1038/s41598-020-74524-9 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Lu Liang ◽

Peng Gong

Keyword(s):

Air Pollution ◽

Air Quality ◽

Urban Form ◽

Urban Landscape ◽

Fine Particulate Matter ◽

Development Stage ◽

Landscape Patterns ◽

Long Term Effects ◽

Development Levels

Abstract Most air pollution research has focused on assessing the urban landscape effects of pollutants in megacities, little is known about their associations in small- to mid-sized cities. Considering that the biggest urban growth is projected to occur in these smaller-scale cities, this empirical study identifies the key urban form determinants of decadal-long fine particulate matter (PM2.5) trends in all 626 Chinese cities at the county level and above. As the first study of its kind, this study comprehensively examines the urban form effects on air quality in cities of different population sizes, at different development levels, and in different spatial-autocorrelation positions. Results demonstrate that the urban form evolution has long-term effects on PM2.5 level, but the dominant factors shift over the urbanization stages: area metrics play a role in PM2.5 trends of small-sized cities at the early urban development stage, whereas aggregation metrics determine such trends mostly in mid-sized cities. For large cities exhibiting a higher degree of urbanization, the spatial connectedness of urban patches is positively associated with long-term PM2.5 level increases. We suggest that, depending on the city’s developmental stage, different aspects of the urban form should be emphasized to achieve long-term clean air goals.

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Is Compact Urban Form Good for Air Quality? A Case Study from China Based on Hourly Smartphone Data

Land ◽

10.3390/land10050504 ◽

2021 ◽

Vol 10 (5) ◽

pp. 504

Author(s):

Man Yuan ◽

Mingrui Yan ◽

Zhuoran Shan

Keyword(s):

Air Pollution ◽

Air Quality ◽

Urban Form ◽

Urban Areas ◽

Census Data ◽

Population Distribution ◽

Pearson Correlation ◽

Air Pollutant ◽

Compact Development ◽

Pollution Exposure

In previous studies, planners have debated extensively whether compact development can improve air quality in urban areas. Most of them estimated pollution exposure with stationary census data that linked exposures solely to residential locations, therefore overlooking residents’ space–time inhalation of air pollutants. In this study, we conducted an air pollution exposure assessment by scrutinizing one-hour resolution population distribution maps derived from hourly smartphone data and air pollutant concentrations derived from inverse distance weighted interpolation. We selected Wuhan as the study area and used Pearson correlation analysis to explore the effect of compactness on population-weighted concentrations. The results showed that even if a compact urban form helps to reduce pollution concentrations by decreasing vehicle traveling miles and tailpipe emissions, higher levels of building density and floor area ratios may increase population-weighted exposure. With regard to downtown areas with high population density, compact development may locate more people in areas with excessive air pollution. In all, reducing density in urban public centers and developing a polycentric urban structure may aid in the improvement of air quality in cities with compact urban forms.

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