Estimating economic and environmental benefits of urban trees in desert regions

Transforming urban air quality: Green infrastructure strategies for the urban centers of Ethiopia

Urban green infrastructure (GI) plays a crucial role in improving air quality by removing pollutants and reducing emissions from structures. However, in Ethiopia, inadequate GI planning, largely due to limited awareness among planners and policymakers, can undermine the benefits of GI and worsen urban air quality issues. In this study, we demonstrate how the GI strategy approach can enhance air quality and assess the negative impacts of biogenic volatile organic compounds (BVOCs) emitted by certain tree species in Ethiopia, using Hawassa as a case study. We utilized a customized i-Tree Eco model to estimate annual pollutant removal and BVOC emissions and applied the Kriging method in ArcGIS to map their spatial distribution. In Hawassa, GI systems removed 274.2 t of pollutants annually, valued at $1.79 million, with SO2 being the most and CO the least removed pollutants. Air pollution removal was highest during the dry season (37.4%) compared to the long (29.7%) and short rainy seasons (32.9%). Conversely, trees emitted 35.78 t of BVOCs annually, with monoterpene and isoprene being nearly equal contributors. Eucalyptus genus, Casuarina equisetifolia, and Schinus molle species were the top BVOC emitters despite their low population percentages in the study area. While GI types such as urban parks and institutional compounds are effective at pollutant removal, they also exhibit higher BVOC emissions. Our findings highlight the need for optimized species selection, improved GI planning, and enhanced policy support to maximize GI effectiveness, providing valuable insights for planners and policymakers in integrating GI into urban spatial planning.

Variation in Leaf Functional Traits of Populus laurifolia Ldb and Ulmus pumila L. Across Five Contrasting Urban Sites in Ulaanbaatar, Mongolia

Amid urbanization, studying leaf functional traits of woody plants in urban environments is essential for understanding how urban green spaces function and how they can be effectively managed sustainably. In this study, we investigated the effects of different growing conditions on the morpho-physiological traits of Populus laurifolia and Ulmus pumila across five contrasting urban sites. The leaf area (LA), leaf length (LL), leaf width (LW), leaf biomass (LB), specific leaf area (SLA), leaf chlorophyll concentration, chlorophyll fluorescence parameters, leaf water potential at predawn (Ψpd) and midday (Ψmd), leaf performance index (PIabs), and phenotypic plasticity index (PPI) were compared across five contrasting urban sites. The soil chemical and physical properties were also compared between sites. There were significant differences in soil physicochemical characteristics between sites. We found significant effects of site on most of the morpho-physiological traits measured, except for Ψmd. The leaf chlorophyll concentration of P. laurifolia and U. pumila varied significantly between sites. The Ψpd was significantly different between years and sites. In U. pumila, the mean PPI for morphological traits (0.20) was lower than that for physiological traits (0.21). In conclusion, we revealed significant variations in the morpho-physiological traits of P. laurifolia and U. pumila across the five urban sites. Hence, long-term, large-scale studies are recommended to examine how diverse species respond to different urban growing conditions and to include other ecologically important plant traits for a better understanding of urban trees in a changing environment.

Air pollution burden of disease over highly populated states in the Middle East

Background

Recent epidemiological research has proven that air pollution triggers the risk of morbidity and mortality due to respiratory and cardiovascular-related diseases. More specifically, fine particulate matter with a diameter of <2.5 μm (PM2.5) can penetrate deeply into the lung and bloodstream, causing critical adverse effects on human health.

Objective

It is found that there is inadequate published research related to the health impact of ambient air pollution in the Middle East region. Some states are well studied, while others are not. This work aims to evaluate the health impact of long-term exposure to PM2.5 in the nine most populated countries in the Middle East region, with a total population of about 363 million (in 2012).

Methods

In this study, the human health impacts in terms of total mortality and the estimated attributable proportion (AP) due to long-term exposure to ambient PM2.5 were estimated using the World Health Organization method and software (AirQ+).

Results

In 2012, the annual median PM2.5 concentrations ranged from 34 μg/m3 in Turkey and Syria to 108 μg/m3 in Saudi Arabia. The total estimated mortalities in the nine most populated countries in the Middle East due to long-term exposure to fine particulate matter was about 152,925 (half of which were residents in Egypt). Moreover, the relative risk (RR) was the highest for Saudi Arabia at 1.8031 and the lowest for Turkey and Syria at a value of 1.1553. The highest AP (central value) was 44.5% in Saudi Arabia, while the lowest was 13.4% in Turkey and Syria.

Conclusions

The results indicate a significant impact of air pollution due to long-term exposure to fine particles resulting in early mortality. This urges the collaboration between the governments and different sectors to adopt stringent regulations to control the anthropogenic sources related to traffic and industrial emissions in the Middle East in order to reduce the health burden of air pollution.

The role of China's terrestrial carbon sequestration 2010-2060 in offsetting energy-related CO2 emissions

Energy consumption dominates annual CO2 emissions in China. It is essential to significantly reduce CO2 emissions from energy consumption to reach national carbon neutrality by 2060, while the role of terrestrial carbon sequestration in offsetting energy-related CO2 emissions cannot be underestimated. Natural climate solutions (NCS), including improvements in terrestrial carbon sequestration, represent readily deployable options to offset anthropogenic greenhouse gas emissions. However, the extent to which China's terrestrial carbon sequestration in the future, especially when target-oriented managements (TOMs) are implemented, can help to mitigate energy-related CO2 emissions is far from certain. By synthesizing available findings and using several parameter-sparse empirical models that have been calibrated and/or fitted against contemporary measurements, we assessed China's terrestrial carbon sequestration over 2010-2060 and its contribution to offsetting national energy-related CO2 emissions. We show that terrestrial C sequestration in China will increase from 0.375 ± 0.056 (mean ± standard deviation) Pg C yr-1 in the 2010s to 0.458 ± 0.100 Pg C yr-1 under RCP2.6 and 0.493 ± 0.108 Pg C yr-1 under the RCP4.5 scenario in the 2050s, when TOMs are implemented. The majority of carbon sequestration comes from forest, accounting for 67.8-71.4% of the total amount. China's terrestrial ecosystems can offset 12.2-15.0% and 13.4-17.8% of energy-related peak CO2 emissions in 2030 and 2060, respectively. The implementation of TOMs contributes 11.9% of the overall terrestrial carbon sequestration in the 2020s and 23.7% in the 2050s. The most likely strategy to maximize future NCS effectiveness is a full implementation of all applicable cost-effective NCS pathways in China. Our findings highlight the role of terrestrial carbon sequestration in offsetting energy-related CO2 emissions and put forward future needs in the context of carbon neutrality.

Urban Gardens’ Potential to Improve Stormwater Management: A Comparative Analysis among Urban Soils in Sorocaba, São Paulo, Brazil

Permeable surfaces are increasingly rare in urban centers, but they have the utmost importance for stormwater infiltration. In this context, green spaces are key to reducing problems caused by runoff. This work aimed to evaluate the physical characteristics of the soil used for agroecological gardening, in comparison with parks, wasteland, and riparian forest in Sorocaba, São Paulo, Brazil. During the one-year data collection, urban gardens were superior to other areas in hydraulic conductivity (35.8 mm h−1), humidity (25.8%), and soil penetration resistance (1.21 MPa). On the other hand, the riparian forest showed signs of soil degradation, with low water infiltration rates (121.9 mm h−1) and humidity (14.4%). These findings highlight the importance of better soil management solutions to avoid compaction, such as the protection and conservation of riparian forests. Furthermore, the encouragement of urban gardens and parks with multiple uses can be an option for the enhancement of stormwater management in cities, since this practice has the potential to improve the physical characteristics of urban soils and provide several ecosystem services.

Usage of urban green space and related feelings of deprivation during the COVID-19 lockdown: Lessons learned from an Italian case study

This study investigated perceptions and behavioral patterns related to urban green space (UGS) in Italian cities, during the period of national lockdown imposed due to the outbreak of SARS-CoV-2 in the spring of 2020. A survey was used to examine the responses of population groups in different municipal areas, comparing those in government-defined "red zones", mostly in the northern regions of the country, with "non-red zones" in the rest of the country, where the rate of infection was much lower. A total of 2100 respondents participated in the survey. The majority of respondents declared themselves to be habitual users of UGS, especially of parks or green areas outside the town - mainly visiting for relaxation and physical exercise, but also for observing nature. In the northern regions people more commonly reported the adoption of sustainable practices, in terms of the utilization of tools for "green mobility". During the lockdown, habits changed significantly: only one third of respondents reported visiting UGS, with frequent visits made mainly for the purpose of walking the dog. Other motivations included the need for relaxing, mostly in the red zones, and for physical exercise in non-red zones. The reduction in travel to urban parks was accompanied by increased visitation of gardens and other green spaces in close proximity, as social distancing and other regulations imposed restrictions on movement. In all regions, respondents who could not physically access UGS expressed a feeling of deprivation which was exacerbated by living in towns located in red zones, being a usual visitor of UGS and having no green view from the window. The extent to which these visitors missed UGS depended on the frequency of visitation before the pandemic and the UGS distance, as well as the type of previous activity. In fact, those activities that were most common before the pandemic were missed the most, reinforcing the importance of green areas for social gathering, sports, and observing nature - but simply "spending time outdoors" was also mentioned, even by those who visited UGS during the lockdown, as the time outdoors was not enough or not fully enjoyed. The feeling of missing UGS was only partially alleviated by the green view from the window - only a more open view to a natural landscape or adaptation to a view with little greenery reduced such feeling.