Determining broad scale associations between air pollutants and urban forestry: A novel multifaceted methodological approach

Role of residential greenspace in the trajectory of major neurological disorders: A longitudinal study in UK Biobank

BACKGROUND

Stroke and dementia are major neurological disorders that contribute significantly to disease burden and are interlinked in terms of risk. Nevertheless, there is currently no study investigating the influence of residential greenspace on the trajectory of these neurological disorders.

METHODS

This longitudinal study utilized data from the UK Biobank. Exposure to residential greenspace was measured by the percentage of total greenspace coverage within a 300-meter buffer zone surrounding the participants' residences. A multistate model was employed to illustrate the trajectory of major neurological disorders, and a piecewise Cox regression model was applied to explore the impact of residential greenspace on different time courses of disease transitions.

RESULTS

With 422,649 participants and a median follow-up period of 12.5 years, 8568 (2.0 %), 5648 (1.3 %), and 621 (0.1 %) individuals developed incident stroke, dementia, and comorbidity of both conditions, respectively. An increase in residential greenspace by one interquartile range was associated with reduced risks of transitions from baseline to stroke, dementia, and death, as well as from stroke to comorbidity. The corresponding hazard ratios (HRs) were 0.967 (95 % CI: 0.936, 0.998), 0.928 (0.892, 0.965), 0.925 (0.907, 0.942), and 0.799 (0.685, 0.933), respectively. Furthermore, the protective effect of residential greenspace on the transition from stroke or dementia to comorbidity was particularly pronounced within the first year and over 5 years after stroke and during the 2 to 3 years after dementia onset, with HRs of 0.692 (0.509, 0.941), 0.705 (0.542, 0.918), and 0.567 (0.339, 0.949), respectively.

CONCLUSION

This study observed a protective role of residential greenspace in the trajectory of major neurological disorders and contributed to identifying critical progression windows. These findings underscore the significance of environment-health interactions in the prevention of neurological disorders.

Exploring the effect of ecological land structure on PM2.5: A panel data study based on 277 prefecture-level cities in China

In the context of serious urban air pollution and limited land resources, it is important to understand the environmental value of ecological land. Previous studies focused mostly on the effectiveness of a particular type of green space or the total amount of ecological land on PM_2.5 and have rarely analyzed the association between ecological land structure and PM_2.5 systematically and quantitatively. Therefore, we took 277 cities in China as an example, comprehensively compared the results of different models, and selected a spatial Durbin model using time-fixed effects to dissect the degree of influence of ecological land and different land types within it on PM_2.5. The urban ecological land use structure was closely related to PM_2.5, and the higher the proportion of ecological land use was, the lower the PM_2.5. The degree and direction of influence of different types of land functions within ecological land on PM_2.5 differed, with forests, shrubs, and grasslands causing a weakening impact on PM_2.5, while wetlands and waters did not have a weakening role. The degree of reduction of PM_2.5 by a single type of ecological land was significantly smaller than that by a composite type of ecological land. Green space should be comprehensively considered, designed and adjusted in urban planning to continuously optimize the ecological spatial structure, increase landscape diversity and maximize ecological benefits. The findings of this study help with exploring the effects of land use structure under the goal-oriented control of air pollution and provide theoretical reference and decision-making support for formulating precise air pollution control policies and optimizing the spatial development of national land.

Phytoremediation as a potential technique for vehicle hazardous pollutants around highways

With the synchronous development of highway construction and the urban economy, automobiles have entered thousands of households as essential means of transportation. This paper reviews the latest research progress in using phytoremediation technology to remediate the environmental pollution caused by automobile exhaust in recent years, including the prospects for stereoscopic forestry. Currently, most automobiles on the global market are internal combustion vehicles using fossil energy sources as the primary fuel, such as gasoline, diesel, and liquid or compressed natural gas. The composition of vehicle exhaust is relatively complex. When it enters the atmosphere, it is prone to a series of chemical reactions to generate various secondary pollutants, which are very harmful to human beings, plants, animals, and the eco-environment. Despite improving the automobile fuel quality and installing exhaust gas purification devices, helping to reduce air pollution, the treatment costs of these approaches are expensive and cannot achieve zero emissions of automobile exhaust pollutants. The purification of vehicle exhaust by plants is a crucial way to remediate the environmental pollution caused by automobile exhaust and improve the environment along the highway by utilizing the ecosystem's self-regulating ability. Therefore, it has become a global trend to use phytoremediation technology to restore the automobile exhaust pollution. Now, there is no scientific report or systematic review about how plants absorb vehicle pollutants. The screening and configuration of suitable plant species is the most crucial aspect of successful phytoremediation. The mechanisms of plant adsorption, metabolism, and detoxification are reviewed in this paper to address the problem of automobile exhaust pollution.

Assessment of particulate matter inhalation during the trip process with the considerations of exercise load

A Particulate Matter (PM) inhalation model considering exercise load is established to evaluate the impact of PM on residents' travel health. The study chooses PM detectors to collect PM concentrations at the various transportation space, including walking, bicycle, bus, taxi, and subway. A multiple linear regression model revised by road greening is utilized to study the influence factors that have a potential impact on the PM concentration. The air inhalation model with the consideration of exercise load can be acquired by connecting the heart rate (HR) and individual characteristics. The PM_2.5 and PM₁₀ inhalation for a complete trip of traveler can be estimated using the proposed model based on air inhalation per time unit, travel time, and PM concentration. The analysis results using the experimental data in Xi'an indicate that PM concentrations in taxi carriage, bus carriage, and subway carriage are significantly different from those obtained from environmental monitoring stations. However, the difference is not significant in the locations of sidewalk, non-motorized lane, taxi station, bus station, subway concourse, and subway platform. PM concentration and humidity in background environment have a positive influence on the increase of PM concentration in transportation environment, while temperature and wind speed are negative. The mean values of air inhalation per time unit for male and female using each mode are in the range of 9.6-26.8 L/min and 9.8-27.8 L/min, respectively. Exposure time in non-motorized transportation has a large effect on PM inhalation of travelers, walking connections and waiting in motorized transportation are the main contributing states to PM inhalation of travelers. The results of the study can be used to predict travelers' PM inhalation in completed trips, and provide recommendations for travelers to choose a healthier mode.

Associations of residential green space with incident type 2 diabetes and the role of air pollution: A prospective analysis in UK Biobank

BACKGROUND

Green space is a newly modifiable environmental factor which would bring health benefits, and identifying potential pathways is important to better promote public health. Nowadays, limited evidence is available on residential green space and risk of incident type 2 diabetes (T2D). To evaluate the longitudinal association between residential green space and incident T2D, and further illustrate the role of air pollution, we conducted a prospective analysis in UK Biobank.

METHODS

Incident cases of T2D were ascertained through medical linkage of hospital admissions. Residential green space indicated by percentage of green space at 300 m buffer was estimated using land use data. Annual average air pollution was modelled using Land Use Regression model. Cox proportional hazard regression models were used to determine the association between the exposure and incident T2D. Effect modification of air pollution was assessed using log-likelihood tests. Casual mediation analysis including interaction of green space and air pollution was used to quantity pure natural indirect effect of air pollution.

RESULTS

Of 379,238 participants at baseline, 15564 incident T2D cases were identified with 12.4 years of follow-up. In main models, individuals who exposed to residential green space at 300 m buffer in high level (≥75 %) had 14.4 % (95 % CI: 8.0 %, 20.3 %) lower risk of incident T2D compared with those in low level (<25 %). This association was modified by NO₂, with green space indicating higher protective effect in low NO₂ level (P_interaction = 0.098). PM_2.5 had a high mediation effect of 37.0 % in the association.

CONCLUSION

Elevated residential green space level was associated with lower risk of incident T2D, and air pollution played an important role in this association. These findings would contribute to policy making and healthy city construction to take air pollution into consideration while planning green space, which would maximize public health benefits.

Quantitative analysis of lake-cooling effect in Hefei City, China, based on multispectral remote sensing and its response to urban expansion

Urban expansion has intensified the heat-island effect, and the negative impact on the natural environment has gradually become considerable. However, urban lakes can significantly alleviate the heat-island effect caused by urbanization. Based on four-phase multispectral remote-sensing images during 2005-2020, 17 lakes in the main and surrounding urban areas of Hefei, China, were selected as the objects of our research. Each lake's cooling intensity and distance were calculated; cooling-efficiency data for different lakes were compared and analyzed considering lake areas and regional differences. The following conclusions were drawn: (1) The mean temperature of the lake had a strong positive correlation with the cooling-intensity efficiency and the cooling-distance efficiency, and it was the leading influencing factor of the cooling-intensity efficiency and the cooling-distance efficiency. The mean explanation degree was as high as 63.33% and 51.70%, respectively. (2) The lake area and the distance from the lake to the city center had a negative correlation with the cooling-intensity efficiency and cooling-distance efficiency and were the secondary factors that affect the cooling-intensity efficiency and cooling-distance efficiency. (3) The lakes around the urban area were far away from the main urban area where the heat-island effect was most concentrated, the ability of absorbing the high surface temperature caused by the heat-island effect was limited, and the cooling-intensity efficiency and cooling-distance efficiency were reduced by ~ 6.6 °C/km² and ~ 607.47 m/km², respectively, compared with the lakes in the main urban area. (4) With urban expansion and the intensified urban heat-island effect, the cooling-intensity efficiency of lakes in the main urban area gradually increased, whereas the cooling-distance efficiency of lakes decreased.

Three-Dimensional Landscape Pattern Characteristics of Land Function Zones and Their Influence on PM2.5 Based on LUR Model in the Central Urban Area of Nanchang City, China

China's rapid urbanization and industrialization process has triggered serious air pollution. As a main air pollutant, PM_2.5 is affected not only by meteorological conditions, but also by land use in urban area. The impacts of urban landscape on PM_2.5 become more complicated from a three-dimensional (3D) and land function zone point of view. Taking the urban area of Nanchang city, China, as a case and, on the basis of the identification of urban land function zones, this study firstly constructed a three-dimensional landscape index system to express the characteristics of 3D landscape pattern. Then, the land-use regression (LUR) model was applied to simulate PM_2.5 distribution with high precision, and a geographically weighted regression model was established. The results are as follows: (1) the constructed 3D landscape indices could reflect the 3D characteristics of urban landscape, and the overall 3D landscape indices of different urban land function zones were significantly different; (2) the effects of 3D landscape spatial pattern on PM_2.5 varied significantly with land function zone type; (3) the effects of 3D characteristics of landscapes on PM_2.5 in different land function zones are expressed in different ways and exhibit a significant spatial heterogeneity. This study provides a new idea for reducing air pollution by optimizing the urban landscape pattern.

Green space exposure during pregnancy and umbilical cord blood levels of liver enzymes

Evidence has suggested better pregnancy outcomes due to exposure to greenspace; however, the studies on such an association with the level of liver enzymes in the cord blood are still nonexistent. Hence, this study investigated the relationship between exposure to greenspace during the entire pregnancy and gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) levels in cord blood samples. We selected 150 pregnant women from our pregnancy cohort in Sabzevar, Iran (2018). Greenspace exposure was characterized based on (i) residential distance to green space, (ii) time spent in public/private green spaces, (iii) residential surrounding greenspace, (iv) visual access to greenspace, and (v) number of indoor natural pot plants at home. We developed linear regression models to investigate the adjusted associations of greenspace exposure with enzyme levels. Each one interquartile range (IQR) increase in the residential surrounding greenspace (100 m buffer) was related to a reduction of -12.58 (U/L) (95% CI -22.86, -2.29), -3.35 (U/L) (95% CI -5.50, -1.20), and -0.57 (U/L) (95% CI -1.12, -0.02) in the levels of GGT, AST, and ALT, respectively. Moreover, a similar association was observed for the time the participants spent in green spaces. A decrease in the residential distance to large green spaces was related with lower cord blood levels of AST, ALT, and GGT. Having a window with greenspace view at home was significantly related to lower AST level. The results for the indoor plant pots were not conclusive. Our findings suggested an inverse relationship between greenspace exposure during pregnancy and cord blood levels of liver enzymes. Further studies in other settings and populations are needed to confirm our findings.

Evaluating and comparing the green wall retrofit suitability across major Australian cities

Urban densification continues to present a unique set of economic and environmental challenges. A growing shortage of green space and infrastructure is intrinsically linked with urban growth and development. With this comes the loss of ecosystem services such as urban heat island effects, reduction of air quality and biodiversity loss. Vertical greenery systems (VGS) offer an adaptive solution to space-constrained areas that are characteristic of dense urban areas, and can potentially improve the sustainability of cities. However, in order to promote VGS uptake, methods are required to enable systematic appraisal of whether existing walls can be retrofitted with VGS. Further, feasibility studies that quantify the potential for retrofit suitability of VGS across entire urban areas are lacking. This study established an evaluation tool for green wall constructability in urban areas and validated the assessment tool by determining the quantity of walls in five major Australian cities that could potentially have VGS incorporated into the existing infrastructure. Each wall was analysed using an exclusionary set of criteria that evaluated and ranked a wall based on its suitability to VGS implementation. Sydney and Brisbane recorded the greatest proportional length of walls suitable for VGS, with 33.74% and 34.12% respectively. Conversely, Perth's urban centre was the least feasible site in which to incorporate VGS, with over 97% of surveyed walls excluded, mainly due to the prevalence of <1 m high fence lines and glazed shopfronts. This study aimed to evaluate feasibility assessments of green wall retrofitability in highly urbanised areas with the intention of creating an analytical method that is accessible to all. This method, coupled with the promising number of feasible walls found in this study, emphasises the need for more government policy and incentives encouraging green wall uptake and could play a pivotal role in the expansion of green infrastructure and urban forestry.

Indoor-outdoor relationships of airborne nanoparticles, BC and VOCs at rural and urban preschools

Health risks caused by exposure to black carbon (BC) and nanoparticles (NP) are well studied, although no standard currently exists for them worldwide. Exposure to children may lead to serious health effects due to their increased vulnerability and longer time spend inside the classrooms, making it important to assess the factors that affect air quality in preschools. Thus, this work aims to evaluate indoor-outdoor (I/O) relationships of NPs in the 10-420 nm range, BC and volatile organic compounds (VOCs) at rural and urban preschools (aged 3-5 years) between May 2016 and July 2017. Factorial analysis was applied to identify the possible emission sources. Prior communalities were estimated by the squared multiple correlations with all other variables. We used the varimax rotation method and the criterion for factor selection was the number of eigenvalues greater than one. Results indicate that BC and NP were 4- and 3.2-times higher in urban outdoor caused by traffic emissions, respectively. Highest concentrations occurred during rush hours and during the pickup time of children. In urban school, BC was directly related to accumulation mode (N_49-205), while in the rural area, BC was related to local traffic and particles from pulp industries in the regional background. Nucleation mode (N_11-36) was related to traffic emissions in urban school, while in the rural school was related with secondary formation of particles. Mean I/O ratios of BC and NP in the urban (0.54; 0.51) and rural (0.71; 0.91) schools, respectively, suggested that their higher concentrations occurred in outdoors. VOCs were higher indoor in urban (I/O = 1.97) and rural (I/O = 2.22) sites, indicating these pollutants are generated inside, regardless of urban or rural sites. These findings suggest the necessity of improving ventilation and commuting styles to lower the exposure of children to air pollutants in and around school environments.

Effect of Urban Greening on Incremental PM2.5 Concentration During Peak Hours

In China, severe haze is a major public health concern affecting residents' health and well-being. This study used hourly air quality monitoring data from 285 cities in China to analyze the effect of green coverage (GC) and other economic variables on the incremental PM_2.5 concentration (ΔPM_2.5) during peak hours. To detect possible non-linear and interaction effect between predictive variables, a kernel-based regularized least squares (KRLS) model was used for empirical analysis. The results show that there was considerable heterogeneity between cities regarding marginal effect of GC on ΔPM_2.5, which could potentially be explained by different seasons, latitude, urban maintenance expenditure (UE), real GDP per capita (PG), and population density (PD). Also described in this study, in cities with high UE, the growth of GC, PG, and PD always remain a positive impact on mitigation of haze pollution. This shows that government expenditure on urban maintenance can reduce or mitigate the environmental pollution from economic development. In addition, the influence of other urban elements on air quality had also been analyzed so that different combinations of mitigation policies are proposed for different regions in this study to meet the mitigation targets.

Role of Vegetation as a Mitigating Factor in the Urban Context

It is known that the urban environment amplifies the effects of climate change, sometimes with disastrous consequences that put people at risk. These aspects can be affected by urban vegetation and planting design but, while there are thousands of papers related to the effects of climate change, a relatively limited number of them are directly aimed at investigating the role of vegetation as a mitigating factor in the urban context. This paper focuses on reviewing the research on the role of urban vegetation in alleviating the adverse conditions of the urban environment in order to provide some practical guidelines to be applied by city planners. Through an analysis of the documents found in Scopus, Web of Science, and Google Scholar using urban vegetation and climate change-related keywords we selected five major issues related to the urban environment: (1) particulate matter, (2) gaseous pollution, (3) noise pollution, (4) water runoff, (5) urban heat island effect. The analysis of existing knowledge reported here indicates that the roles of urban vegetation on the adverse effect of climate change could not be simply deemed positive or negative, because the role of urban green is also strongly linked to the structure, composition, and distribution of vegetation, as well as to the criteria used for management. Therefore, it could help to better understand the roles of urban green as a complex system and provide the foundation for future studies.

Maternal exposure to ambient particulate matter and green spaces and fetal renal function

Exposure to air pollution has been associated with different harmful effects and exposure to greenspace has been related to improved human health. However, the available evidence on the impact of these exposures on renal function is still scarce. The aim of this study was to determine the relationship between exposure to ambient levels of PM₁, PM_2.5, PM₁₀ and indicators of exposure to traffic as well as greenspace during pregnancy and fetal renal function based on the umbilical cord blood. This study was based on 150 pregnant women residing in Sabzevar, Iran (2018). Multiple linear regression models were developed to estimate the association of glomerular filtration rate (GFR), creatinine (Cr) and blood urea nitrogen (BUN) with exposure to air pollution, traffic, and greenspace (one at a time) controlled for relevant covariates. There was an inverse significant association between exposure to PM₁, PM_2.5, PM₁₀ and total street length in a 100 m buffer around the home and eGFR. Increase in distance to major road and residential surrounding greenness (100 m buffer) was associated with increase in eGFR. We observed a significant direct association between exposure to PMs as well as street length in 100 m buffer and serum level of Cr. There was also an inverse association between distance to major road and NDVI in 100 m buffer and Cr. The associations for blood urea nitrogen (BUN) were not statistically significant. Our results suggest that exposure to air pollution during pregnancy could have negative impact and exposure to greenspace could have positive impact on renal function of fetal.

Urban Vegetation in Air Quality Management: A Review and Policy Framework

Recent episodes of high air pollution concentration levels in many Polish cities indicate the urgent need for policy change and for the integration of various aspects of urban development into a common platform for local air quality management. In this article, the focus was placed on the prospects of improving urban air quality through proper design and protection of vegetation systems within local spatial planning strategies. Recent studies regarding the mitigation of air pollution by urban greenery due to deposition and aerodynamic effects were reviewed, with special attention given to the design guidelines resulting from these studies and their applicability in the process of urban planning. The conclusions drawn from the review were used to conduct three case studies: in Gdańsk, Warsaw, and Poznań, Poland. The existing local urban planning regulations for the management of urban greenery were critically evaluated in relation to the findings of the review. The results indicate that the current knowledge regarding the improvement of urban air quality by vegetation is not applied in the process of urban planning to a sufficient degree. Some recommendations for alternative provisions were discussed.