Improve Air Quality Research Articles

Impact of improved air quality during complete and partial lockdowns on surface energetics and atmospheric boundary layer.

Impact of improved air quality during complete and partial lockdowns on surface energetics and atmospheric boundary layer.

Urban form regulation for synergetic PM2.5 and O3 control: A multi-indicator constrained DNN simulation.

Urban form regulation for synergetic PM2.5 and O3 control: A multi-indicator constrained DNN simulation.

Transboundary emission contribution to PM2.5 concentrations in Indian cities

Abstract Targeting urban air quality improvements in India, the National Clean Air Program (NCAP) was launched in 2018 to reduce PM2.5 concentrations by 20-30% in 122 initial cities over a 5-year period. However, considering the regional nature of air pollution nationwide and the significant emission load from rural areas, a potentially large fraction of urban PM2.5 might originate from emissions outside of a city’s boundary, i.e., transboundary emissions. Here, we couple top-down (STILT-PM2.5) and bottom-up (WRF-Chem) modeling approaches with a new, nationwide, monthly-resolved, and fine-scale (5km x 5km) anthropogenic emission inventory to assess the impact of transboundary emissions to urban PM2.5 concentrations across 143 cities (122 NCAP and 67 Million Plus (MP, cities with population > 1 million) among which 46 cities are also NCAP cities). We find that, on average, ~85% (STILT-PM2.5: 82% [95% CI: 80-85%; IQR: 77-94%] & WRF-Chem: 89% [95% CI: 87-91%; IQR: 88-96%)) of urban PM2.5 across the 143 cities originates from transboundary emissions, with domestic biomass burning (32%), energy generation (16%), and industry (15%) being the leading average emission sources to the transboundary contribution. In addition, 107 of the 122 NCAP cities from both modeling approaches have annual transboundary PM2.5 contributions exceeding 80%, indicating that an entire mitigation of within-boundary emissions alone in these cities will not achieve the most conservative targets outlined as part of NCAP. Our findings underscore the need for multi-scale, regional action planning and implementation to achieve PM2.5-air quality targets throughout India.

Use of graphene nanocomposites for air disinfection in dental clinics: A game-changer in infection control.

This manuscript features the promising findings of a study conducted by Ju et al, who used graphene nanocomposites for air disinfection in dental clinics. Their study demonstrated that, compared with conventional filters, graphene nanocomposites substantially improved air quality and reduced microbial contamination. This manuscript highlights the innovative application of graphene materials, emphasizing their potential to enhance dental clinic environments by minimizing secondary pollution. On the basis of the unique antimicrobial properties of graphene and the original study's rigorous methodology, we recommend using graphene nanocomposites in clinical settings to control airborne infections.

Evaluation of the Monetary Value of Air Pollutants’ Reduction by Forests in South Korea

The economic value of forests as public goods is often underestimated. This study evaluates the public benefit of air quality improvement by forests in South Korea from 2014 to 2020. The monetary value of air quality improvement, particularly in five air pollutants (i.e., SO2, NO2, PM10, PM2.5, and O3), has gradually increased from KRW 6.0767 trillion in 2014 to KRW 6.5511 trillion in 2017. However, the value decreased from KRW 5.8712 trillion in 2018 to KRW 5.2597 trillion in 2020, possibly due to a decrease of forest area and air pollutant concentrations. In 2020, following the COVID-19 pandemic, the concentrations of air pollutants decreased remarkably from the previous year. For a more objective assessment, it is necessary to examine the total area of green space, including green facilities and urban forests, which are not included in the national data used in the study. Furthermore, key assessment items such as the percentage of vegetation cover, deposition rate, and pollutant removal costs should be modified and adapted to domestic conditions. To this end, monitoring data on the air quality impacts of forests should be utilized in order to facilitate the study of the air quality improvement function of forests at different temporal and spatial scales.

Causal analysis of PM2.5 propagation characteristics during the winters of 2015 to 2023 in Hubei Province, China

To discuss the causes and characteristics of occasional severe winter pollution in Wuhan, Hubei Province, China amidst the continuous improvement of the atmospheric environment, this research utilizes air quality monitoring data from various cities in Hubei Province during the winters of 2015–2023, analyzing changes in air quality in Hubei Province using PM2.5 concentration values as an indicator. We employ the Convergent Cross Mapping (CCM) method, using Wuhan and other cities in Hubei Province as examples, to reveal the causal impact of other cities within Hubei Province on winter PM2.5 pollution in Wuhan from a causality perspective. The results indicate an improvement in air quality during the winters of 2015–2023 in Hubei Province. The PM2.5 concentration in Wuhan during winter is influenced by four other cities within Hubei Province, indicating a clear causal relationship between the PM2.5 concentrations in these two regions. The Convergent Cross Mapping (CCM) method accurately identifies both the strength and direction of the causal relationship between two variables, providing invaluable guidance for subsequent research in atmospheric environmental governance.

Incorporating Cooking Emissions To Better Simulate the Impact of Zero-Emission Vehicle Adoption on Ozone Pollution in Los Angeles.

Despite decades of emission control measures aimed at improving air quality, Los Angeles (LA) continues to experience severe ozone pollution during the summertime. We incorporate cooking volatile organic compound (VOC) emissions in a chemical transport model and evaluate it against observations in order to improve the model representation of the present-day ozone chemical regime in LA. Using this updated model, we investigate the impact of adopting zero-emission vehicles (ZEVs) on ozone pollution with increased confidence. We show that mitigating on-road gasoline emissions through ZEV adoption would benefit both air quality and climate by substantially reducing anthropogenic nitrogen oxides (NOx) and carbon dioxide (CO2) emissions in LA by 28 and 41% during the summertime, respectively. This would result in a moderate reduction of O3 pollution, decreasing the average number of population-weighted O3 exceedance days in August from 9 to 6 days, and would shift the majority of LA, except for the coastline, into a NOx-limited regime. Our results also show that adopting ZEVs for on-road diesel and off-road vehicles would further reduce the number of O3 exceedance days in August to an average of 1 day.

Assessing the Impact of Climatic Factors and Air Pollutants on Cardiovascular Mortality in the Eastern Mediterranean Using Machine Learning Models

Cardiovascular diseases are the most common cause of death worldwide, with atmospheric pollution, and primarily particulate matter, standing out as the most hazardous environmental factor. To explore the exposure–response curves, traditional epidemiological studies rely on generalised additive or linear models and numerous works have demonstrated the relative risk and the attributable fraction of mortality/morbidity associated with exposure to increased levels of particulate matter. An alternative, probably more effective, procedure to address the above issue is using machine learning models, which are flexible and often outperform traditional methods due to their ability to handle both structured and unstructured data, as well as having the capacity to capture non-linear, complex associations and interactions between multiple variables. This study uses five advanced machine learning techniques to examine the contribution of several climatic factors and air pollutants to cardiovascular mortality in the Eastern Mediterranean region, focusing on Thessaloniki, Greece, and Limassol, Cyprus, covering the periods 1999–2016 and 2005–2019, respectively. Our findings highlight that temperature fluctuations and major air pollutants significantly affect cardiovascular mortality and confirm the higher health impact of temperature and finer particles. The lag analysis performed suggests a delayed effect of temperature and air pollution, showing a temporal delay in health effects following exposure to air pollution and climatic fluctuations, while the seasonal analysis suggests that environmental factors may explain greater variability in cardiovascular mortality during the warm season. Overall, it was concluded that both air quality improvements and adaptive measures to temperature extremes are critical for mitigating cardiovascular risks in the Eastern Mediterranean.

Exploring the socioeconomic and environmental impacts of carbon capture technologies in Bangladesh for sustainable green environments

PurposeThis study aims to comprehensively examine the environmental, health, economic and social benefits of carbon capture technologies (CCTs) in Bangladesh, thereby contributing to sustainable green environments.Design/methodology/approachThis study adopts a unique approach to quantitative surveys and primary data analysis. It actively involves diverse stakeholders in data collection, including policymakers, industry professionals and the public, ensuring a comprehensive understanding of the subject matter.FindingsImplementing CCTs in Bangladesh brings about a host of benefits. It not only leads to a significant reduction in CO2 (carbon dioxide) emissions, thereby improving air quality and public health but also it stimulates public awareness and education, bolstering support for CCTs. The economic benefits are diverse, encompassing job creation and industry expansion, painting a promising picture for Bangladesh’s future. In essence, CCTs can enhance Bangladesh’s social well-being and quality of life, presenting a viable roadmap for sustainable, long-term development.Research limitations/implicationsWhile this study provides significant insights into the impact of CCTs on people’s lives in Bangladesh, it is essential to recognize its limitations. However, this ongoing study is crucial in advancing sustainable technologies, underscoring the necessity for continual research and enhancement to ensure a sustainable future.Originality/valueThis study stands out for its comprehensive examination of the social effects of CCTs in a developing country. Integrating diverse data types and methods provides unique insights to policymakers, business leaders and academics. These insights empower decision-makers to advocate for green technologies and sustainable development in similar contexts, fostering informed decision-making and strategic planning.

Urban Greenspace, Climate Adaptation and Health Co-Benefits: Municipal Policy and Practice in London

Climate change poses a significant threat to human health and wellbeing, yet its health impacts can be mitigated through effective local action. Green spaces offer numerous climate benefits to cities, including improving air quality, water management and providing local cooling effects, with subsequent health benefits. Despite such benefits, the current municipal policy and practice faces challenges in aligning climate, health and greenspace interventions on the ground. This paper looks at the municipal evidence base in London. Employing a policy-engaged approach, it draws on semi-structured interviews and focus group discussions with London boroughs to unpack what greenspace indicators are measured and why; what feeds into municipal evaluation frameworks; and how greenspace, climate adaptation and health are integrated across London’s municipalities. The findings reveal limited and fragmented approaches to measuring the multiple benefits of greenspace interventions, with weak links to climate and health outcomes, and little policy alignment at the municipal level. This has broader implications for data-driven governance models pursued by cities worldwide and for integrating greenspace–climate–health policy and practice within the spatial and political context of cities. The paper concludes by summarising research findings, presenting policy recommendations and highlighting areas of future research.

Virtual Power Plants: Bridging Utility and Customer Gaps to Facilitate Clean Energy Transitions

Abstract The U.S. electric grid has been challenged by extreme weather, load growth, peak demand increase, and intermittency of renewable energy resources as it continues its transition and modernization. As historic efforts such as peaker power plants reveal significant limitations in addressing the challenges, virtual power plants (VPPs) have emerged as a cost-effective alternative. VPPs are aggregations of distributed energy resources that can provide grid services like traditional power plants. This article revisits VPP analyses and finds that VPPs could 1) enhance grid reliability by managing peak demand; 2) facilitate decarbonization by promoting renewable energy resources or address integration challenges; 3) generate financial benefits for utilities and ratepayers; and 4) yield societal benefits by improving air quality and environmental inequity. This study surveys VPPs in the U.S. in terms of program design, customer segments, types of distributed energy resources, capacity, enrollment, compensation, and performance when resources are called for dispatch. Also, we test the responsiveness of a VPP in California that discharged its batteries into the grid during historic heat waves in 2022, demonstrating energy savings, emissions reductions, and financial savings for both the utility company and ratepayers. New business models may be required to take advantage of triple win situations for utilities and ratepayers.

Providing Solutions to Decarbonize Energy-Intensive Industries for a Sustainable Future in Egypt by 2050

Around 75% of worldwide greenhouse gas (GHG) emissions are generated by the combustion of fossil fuels (FFs) for energy production. Tackling climate change requires a global shift away from FF reliance and the decarbonization of energy systems. The energy, manufacturing, and construction sectors contribute a significant portion of Egypt’s total GHG emissions, largely due to the reliance on fossil fuels in energy-intensive industries (EIIs). Decarbonizing these sectors is essential to achieve Egypt’s sustainable development goals, improve air quality, and create a resilient, low-carbon economy. This paper examines practical, scalable solutions to decarbonize energy-intensive industries in Egypt, focusing on implementing renewable energy sources (RESs), enhancing energy efficiency, and integrating new technologies such as carbon capture, utilization, and storage (CCUS) and green hydrogen (GH). We also explore the policy incentives and economic drivers that can facilitate these changes, as the government aims to achieve net-zero GHG emissions for a sustainable transition by 2050.

How Risk Perception of Air Pollution Influences Consumers’ Pro-Environmental Behaviors: An Empirical Study Based on the Extended Theory of Planned Behavior

Air pollution is a critical global issue affecting sustainable development, and effectively addressing air pollution requires consumers to improve air quality through daily pro-environmental behaviors. This study aims to explore the influence mechanisms of multidimensional risk perception variables on consumers’ pro-environmental behaviors. It introduces risk effect, risk controllability, risk trust, and risk acceptability and incorporates multidimensional risk perception variables into the theory of planned behavior (TPB) model. The results of the structural equation model indicate that risk effect, risk trust, and risk acceptability of air pollution significantly influence pro-environmental behaviors through behavioral intentions. Moreover, the risk effect, risk trust, and risk acceptability of air pollution significantly influence consumers’ pro-environmental behaviors through the chain-mediating effect of attitudes and behavioral intentions. The risk controllability does not affect consumers’ behavioral intentions or pro-environmental behaviors. Through the integration of multidimensional risk perception and the validation of the behavioral intention–behavior gap, this study provides new perspectives for research related to consumer pro-environmental behavior. It also provides references for the government to communicate with consumers about risks, solve air pollution problems, and achieve sustainable development.

The Impact of Meteorological Factors and Canopy Structure on PM2.5 Dynamics Under Different Urban Functional Zones in a Subtropical City

PM2.5 pollution has intensified with rapid urbanization and industrialization, raising concerns about its health and environmental impacts. Both meteorological factors and urban forests play crucial roles in influencing PM2.5 concentrations. However, limited attention has been given to the direct impact of canopy structure on PM2.5 levels at a larger scale. This study analyzes the temporal variation of PM2.5, including seasonal and diurnal patterns, across different functional zones (park, traffic, and residential zones) in a subtropical region. It also investigates the seasonal responses of PM2.5 to meteorological factors (temperature, humidity, and precipitation) and canopy structure characteristics, including canopy diameter (CD), canopy thickness (CT), canopy area (CA), canopy volume (CV), canopy height ratio (CH), leaf area index (LAI), and tree canopy cover (CO). The results show that among different functional zones, PM2.5 concentrations were the highest in park zones, followed by traffic zones. Seasonal variations in PM2.5 concentrations were the highest in winter (84.00 ± 45.97 μg/m3), with greater fluctuations, and the lowest in summer (36.85 ± 17.63 μg/m3 µg/m3), with smaller fluctuations. Diurnal variation followed an “N”-shaped curve in spring, summer, and autumn, while a “W”-shaped curve was observed in winter. Correlation analysis indicated significant negative correlations between PM2.5 and humidity, temperature, and rainfall, while CD, CA, and CV showed positive correlations with PM2.5. Notably, PM2.5 exhibited greater sensitivity to changes in canopy structure in winter, followed by autumn. Despite these findings, the influence of canopy structure on PM2.5 concentrations was considerably smaller compared to meteorological factors. In particular, every 1 m2 increase in canopy area could raise PM2.5 levels by 0.864 μg/m3, whereas an average increase of 1 mm in rainfall could raise PM2.5 by 13.665 μg/m3. These findings provide valuable guidance for implementing protective measures, improving air quality, optimizing urban greening strategies, and enhancing public health outcomes.

Assessing Biogas from Wastewater Treatment Plants for Sustainable Transportation Fuel: A Detailed Analysis of Energy Potential and Emission Reductions

This study assesses the potential for biogas production from wastewater treatment plants (WWTPs) in Adana, Türkiye, and evaluates the feasibility of transitioning a fleet of 83 municipal buses (ranging from 15 to 24 years old) to operate exclusively on biogas generated from these WWTPs. Biogas production data from three distinct WWTPs in Adana were analyzed, revealing a total annual biogas production of 5,394,346 Nm3. Replacing the diesel fleet with biogas-powered buses was found to yield a significant reduction in environmental impacts. CO2 emissions were reduced by 84%, particulate matter emissions decreased by 84.4%, and nitrogen oxides (NOX) dropped by 80%. These findings highlight the substantial potential of wastewater-derived biogas as a renewable energy source in public transportation, not only reducing reliance on non-renewable fuels but also contributing to improved air quality and energy efficiency. Transitioning to biogas-powered buses presents a promising model for sustainable public transportation, with broader implications for reducing the environmental footprint of urban transit systems.

Natural experiments in urban air quality: lessons from car-free days and COVID-19 lockdowns in Kigali, Rwanda

ABSTRACT A lack of long-term air quality monitoring data in African countries such as Rwanda poses a significant challenge as urbanization leads to declining air quality. This study uses four years of data on particulate matter air pollution (PM2.5) to understand the current drivers of air pollution, the success of current interventions and the potential for further actions. PM2.5 data were collected using low-cost and reference monitors in two sites in Kigali. Results show that PM2.5 levels in Kigali exceeded the recommended WHO air quality guidelines. Using the COVID-19 lockdown as a natural experiment, we find that reduced travel activity of over 80% led to PM2.5 levels declining by 33%, suggesting that transport may account for a smaller share of particulate emissions than is assumed in government literature. We also find that a program to encourage non-motorized transport in Kigali called ‘Car-Free Days’ reduced by PM2.5 15% when it was held between 2017 and 2020. This reduction is expected to have resulted in more than 200 disability-adjusted life years saved in Kigali annually, about 150 hospital visits, and 600 lost working days being avoided. We conclude by reflecting on the policies for improving air quality in Kigali City.

A Study on the Influence of an Outdoor Built Environment on the Activity Behavior of the Elderly in Small Cities in Cold Regions—A Case Study of Bei’an City

Under the dual constraints of limited resources and cold climate, the built environment of small cities in cold areas has a particularly prominent impact on the outdoor activities of the elderly and the need for aging optimization. Based on a questionnaire survey and field measurement data, combined with multiple linear regression, Spearman correlation analysis, and difference analysis, this paper systematically discusses the effects of different built environment characteristics on outdoor activity behaviors (frequency, intensity, and stay time) of the elderly in Bei’an City, Heilongjiang Province, China. The difference in environmental satisfaction of the elderly with different genders, ages, and education levels was analyzed. The results show that green coverage, air quality, leisure facilities, and barrier-free facilities are the core environmental factors that significantly improve the activity behavior of the elderly. In contrast, noise level, road damage, and inadequate facility maintenance significantly inhibit the activity willingness of the elderly. It was found that older adults are more dependent on barrier-free facilities and site safety, while younger people pay more attention to sports facilities and social space. Older women pay more attention to environmental details and cultural elements, while men tend to evaluate environmental functionality and so on. Further analysis shows that green environments and leisure facilities in cold climates provide visual beauty and play an important role in improving air quality and enhancing mental health. These elements are particularly critical in winter activities for older people, demonstrating the potential of the built environment to promote health and social participation. Starting from the unique background of small cities in cold regions, this study verified the applicability of the WHO age-friendly city framework in small cities in cold climates through empirical data, and revealed the necessity of climate-adaptive design (such as winter anti-slip facilities and cold-resistant greening) to improve the activity behavior of the elderly, providing a regional supplement to the existing theories.

Solvothermal Synthesis of Unsupported NiMo Catalyst with High Activity in Hydrodesulfurization of 4,6-Dimethyldibenzothiophene

Environmental legislation has focused its attention on improving air quality. In this context, the presence of sulfur compounds in fuels, such as diesel and gasoline, is undesirable. When sulfur is combusted, compounds are emitted as SOx (SO2 and SO3) into the atmosphere, causing acid rain and respiratory diseases. For this reason, environmental norms have been established to reduce the sulfur content of fuels. Sulfur (mainly as alkylbenzothiophenes, dibenzothiophenes and alkyldibenzothiophenes) is removed in refineries through a process called hydrodesulfurization (HDS). HDS is performed at an industrial level with the use of NiMo, CoMo or NiW catalysts supported on alumina. Unsupported MoS2 (bulk) catalysts have recently attracted attention due to their high activity and selectivity in HDS. In this study, bulk NiMo catalyst precursors were synthesized using solvothermal methods with varying pH and solvothermal synthesis time. The precursors and catalysts were characterized using scanning electron microscopy with energy dispersive X-ray spectroscopy (EDS) microanalysis, X-ray diffraction (XRD), textural properties using liquid nitrogen physisorption at 77 K, Raman spectroscopy and high-resolution transmission electron microscopy (HTREM). The results indicate that the morphology of the NiMoO4 precursors synthesized in an ethanol/water mixture varies, forming “grains,” “flakes” or “rods,” depending on the dwell time and synthesis conditions. The catalytic activity results show that the bulk NiMo catalyst synthesized at 2 h presented higher selectivity and catalytic activity in the HDS of 4,6-DMDBT when compared to a supported reference catalyst (NiMo/γ-Al2O3).

Cooler streets for a cycleable city: assessing policy alignment

Cooler streets for a cycleable city: assessing policy alignment

Harnessing Street Canyons for Comprehensive Nature-Based Solutions

Transport areas in urban environments typically cover 10–20% of a city’s area. Due to their hierarchical structure and network layout, they present a unique opportunity to integrate Nature-based Solutions (NbSs) within cities strategically. In Poland, however, the current use of NbSs in streetscapes tends to be sporadic, localized, and often resulting from grassroots initiatives. This study aimed to assess how much the provision of ecosystem services (ESs) in cities depends on and can be enhanced by NbSs. To explore this, simulations were conducted using six NbSs scenarios, selected based on an analysis of solutions specifically designed for streets and their characteristics. This research focused on a densely built and populated district of Warsaw. The findings revealed that applying NbSs can significantly reduce stormwater runoff, increase carbon sequestration, and improve air quality. The level of ES provision depends on the solutions used, with the introduction of woody vegetation, particularly tall shrubs and trees, proving most effective. The results show that the scenario-based approach allows for flexible streetscape design, enabling the application of individually selected NbSs. Moreover, the approach helps to select optimal elements that enhance the provision of ES crucial to adapting cities to climate change.