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This review article delves into the multifaceted relationship between climate change, air quality, and respiratory health, placing a special focus on the process of particle deposition in the lungs. We discuss the capability of climate change to intensify air pollution and alter particulate matter physicochemical properties such as size, dispersion, and chemical composition. These alterations play a significant role in influencing the deposition of particles in the lungs, leading to consequential respiratory health effects. The review paper provides a broad exploration of climate change's direct and indirect role in modifying particulate air pollution features and its interaction with other air pollutants, which may change the ability of particle deposition in the lungs. In conclusion, climate change may play an important role in regulating particle deposition in the lungs by changing physicochemistry of particulate air pollution, therefore, increasing the risk of respiratory disease development. Climate change influences particle deposition in the lungs by modifying the physicochemical properties of particulate air pollution, thereby escalating the risk of respiratory disease development. It is crucial for healthcare providers to educate patients about the relationship between climate change and respiratory health. People with conditions such as asthma, COPD, and allergies must understand how changes in weather, air pollution, and allergens can exacerbate their symptoms. Instruction on understanding air quality indices and pollen predictions, along with recommendations on adapting everyday activities and medication regimens in response, is essential. [ABSTRACT FROM AUTHOR]

Maritime shipping is considered a major air pollutant that directly affects global warming and climate change. This study aims to design an emission control route (ECR) that can contribute to long-term initiatives along with emission prevention policies. Applying a scenario analysis, this paper has analyzed the impact of ECR implementation on air quality in the shipping route between Korea and Japan. In this study, the ECR is defined as eco-friendly shipping routes that recommend maintaining a specific level of speed while sailing. Based on the navigation trajectories of 55 O/Ds, which were extracted by the automatic identification system (AIS) data of 135 container ships for each port call during one year, the ECR domains were designated. To analyze the introduction impacts, this study employed a scenario analysis based on the current Vessel Speed Reduction Program (VSRP) recommendation of 12 knots or less. The results demonstrated that the introduction of ECR in the liner services between Korea and Japan would increase the average travel time by 10.47–16.98%. However, according to the results of the scenario analysis, the introduction of the ECR can reduce emissions by 25.65% to 39.73%. By suggesting the initial concept of ECR and analyzing the emission reduction effects of its implementation, this study provides useful insights for a balance between economic and environmental performance. [ABSTRACT FROM AUTHOR]

Asia is one of the continents that is the most affected by the impacts of climate change. Asian countries need to take climate actions and mitigate emissions from the urban passenger transport sector. Despite some progress in improving urban mobility in Asian cities, greenhouse gas emissions from the transport sector continue to rise. Policy makers who are responsible for managing mobilities must play a major role in decarbonizing the transport sector. In this context, this paper reviews the efforts of selected Asian countries and cities towards reducing greenhouse gas emissions from the urban transport sector. It will analyze their pledges in the Nationally Determined Contributions submitted to the United Nations Framework Convention on Climate Change and will review their relevant transport sector strategies, policies, and practices. It will also look at trends in transport sector emissions and air pollution in different cities, including the short-term impacts of COVID-19. Lastly, it reviews governance issues and the roles that institutions should play to implement polices to decarbonize transport. Based on this analysis, this paper offers policy suggestions to accelerate actions, enhance cross-sectoral coordination, and move towards carbon neutrality in the transport sector in Asia. [ABSTRACT FROM AUTHOR]

This paper presents an overall performance assessment of hybrid-electric medium-range transport aircraft, with the aim to evaluate the potential of such a propulsion technology towards the reduction in the environmental impact of aviation transport, in terms of both local air quality degradation in airport areas and climate change. The proposed approach presents distinct analyses of the environmental impact of transport aircraft, distinguishing climate-changing effects from local pollution effects so that the integration of hybrid-electric propulsion is carried out to face the two issues specifically. The proposed analysis, although of conceptual nature, presents a clear scenario in which, given the technological limitations of batteries, the use of hybrid-electric propulsion on medium-haul aircraft can only be useful to reduce local pollution. In contrast, other solutions are needed to mitigate the climate-changing impact. [ABSTRACT FROM AUTHOR]

In recent years, our world has experienced significant disruptions due to the COVID-19 pandemic, and Russia's 2022 invasion of Ukraine, impacting human activities and the global environment. This paper explored air quality changes in Ukraine due to COVID-19, and Russia's invasion of Ukraine using on-demand with a what-you-see-is-what-you-get approach. During the COVID-19 pandemic, strict quarantine policies in Ukraine led to a 2% reduction in tropospheric NO2 concentration before the lockdown and 4% during the lockdown period. Cities like Kyiv, Donetsk, and Dnipro exhibited reductions of 5%, 11%, and 16%, respectively. Total SO2 column concentration decreased by 6% before the lockdown and 2.5% during the lockdown period, except in high population density areas. Kyiv showed the highest reduction of 17% in SO2 concentration, while Donetsk and Dnipro exhibited an 11% reduction. However, during the Russian invasion, there was a significant increase in tropospheric NO2 concentration in heavily destroyed Kharkiv while most eastern regions experienced a reduction. The total SO2 column was 48% higher before the war but reduced throughout the country after the war, except for in Kyiv and a few central regions. These findings can contribute to analyzing air pollution and building digital twin simulations for future reconstruction scenarios. [ABSTRACT FROM AUTHOR]

Air pollution is a growing concern in India, and its adverse health effects are well documented. Climate change is likely to exacerbate this problem by altering weather patterns and increasing the frequency and severity of extreme events. This paper examines the potential impact of climate change on ambient air pollution in India and its implications for policy design. Our analysis reveals that pollution in India is highly sensitive to variation in weather, particularly in the densely populated Indus-Gangetic Plain. Using our estimated relationship between weather and pollution, we predict that changing weather patterns will increase average PM2.5 concentrations by 3.1 µg/m3, leading to a loss of 364 million years of life expectancy. To address this challenge, we propose an emissions fee calibrated to be highest in regions most vulnerable to persistently high levels of pollution and most sensitive to future deterioration in air quality due to climate change. [ABSTRACT FROM AUTHOR]

Vertical greening systems (VGS) are promising green infrastructure (GI) techniques for addressing urban resilience issues, like mitigating high temperatures and air pollution. This research aims to develop a conceptual framework to help designers better understand the VGS' effects on buildings and urban areas, focusing on thermal performance and air quality improvement in hot, humid climates. The framework consists of three steps: (1) Identifying climate problems that hinder the improvement of built environment resilience in hot climates; (2) Selecting VGS as a type of GI that can enhance urban resilience; (3) Identifying the common key factors that impact both thermal performance and air quality while developing VGS at the urban and building scales. The results show that the framework can be customized to suit hot climate conditions. However, when applying VGS in built environment with specified climate conditions, the construction of VGS, greenery coverage ratio, plant species, facade orientation, and VGS formation have the most significant influences on their environmental performance. Additionally, the air gap between VGS and the facade has optimal performance in hot, humid climates. The paper concludes with some recommendations for future research and practice on VGSs in hot and humid climates. [ABSTRACT FROM AUTHOR]

Air pollution is considered one of the greatest environmental threats to human health in our era. This study aimed to evaluate the linkages between related research and studies on air quality management and the global sustainable development goals (SDGs) and to investigate strengths, weaknesses, opportunities, and threats (SWOT) of air quality management strategies in Thailand. By employing the Scale Assessment Method, the results found that SDGs related to human well-being, cities, and climate change were associated with several studies with medium to high level of agreement and evidence. In accordance with SDG 3, many scholars have been performed to investigate the relationship between both long-term and short-term exposure of air pollution and human health. In SDG 11, many cities are increasing concerned about air pollution, especially the annual mean of particulate matter in cities. Regarding SDG 13, although there is no specific headline goal on air pollution and climate change, there are some research papers available on the development of combined climate change and air quality database in Thailand. In terms of SWOT analysis, availability of research database on multi-pollutant models and research prioritization on air pollution topics were identified as key strengths. Lack of integration of air pollution and cross-cutting issues were defined as major weakness. Impacts of COVID-19 on the research direction and budget allocation were categorized as threats in driving air quality management and research development. Multi-dimensional and inter-sectoral actions for driving air pollution-related SDGs in Thailand should be more strengthened. [ABSTRACT FROM AUTHOR]

Climate change has, and will continue to have, a disproportionate impact on communities of color. Already, it is clear that systemic racism has led to increased temperatures in predominantly Black neighborhoods as compared to white neighborhoods in the same cities. A legacy of discriminatory housing policies in California is correlated with worse air quality and health disparities, both of which could be further exacerbated as temperatures rise. As cities and states begin developing climate change adaptation plans, it is imperative that they develop equity-based solutions that take into account how discriminatory practices are leading to disproportionate climate impacts. If such impacts are not accounted for, they will be exacerbated in the future. This paper analyzes equity-based climate adaptation strategies for heat, which is already the deadliest weather-related disaster in the U.S., and how they could be applied to Los Angeles. [ABSTRACT FROM AUTHOR]

Asia is one of the continents that is the most affected by the impacts of climate change. Asian countries need to take climate actions and mitigate emissions from the urban passenger transport sector. Despite some progress in improving urban mobility in Asian cities, greenhouse gas emissions from the transport sector continue to rise. Policy makers who are responsible for managing mobilities must play a major role in decarbonizing the transport sector. In this context, this paper reviews the efforts of selected Asian countries and cities towards reducing greenhouse gas emissions from the urban transport sector. It will analyze their pledges in the Nationally Determined Contributions submitted to the United Nations Framework Convention on Climate Change and will review their relevant transport sector strategies, policies, and practices. It will also look at trends in transport sector emissions and air pollution in different cities, including the short-term impacts of COVID-19. Lastly, it reviews governance issues and the roles that institutions should play to implement polices to decarbonize transport. Based on this analysis, this paper offers policy suggestions to accelerate actions, enhance cross-sectoral coordination, and move towards carbon neutrality in the transport sector in Asia.

Wildfires emit atmospheric aerosols, affecting climate and air quality. Siberia is a known source region of wildfires. However, comprehensive knowledge regarding the impact associated with particulate matter pollution due to Siberian wildfires on climate and air quality and their effects on mortality and the economy under present and near‐future warmer atmospheric conditions remains poor. Thus, we performed model sensitivity experiments (atmospheric model and coupled atmosphere‐ocean model settings) simulating the effects of changing Siberian wildfire emissions under the present and near‐future climate conditions, using the Model for Interdisciplinary Research on Climate version 5 (MIROC5). Increased Siberian wildfire smoke likely caused a cooling effect in broad areas of the Northern Hemisphere and worsened the air quality near the source and in the downwind region (i.e., East Asia). The more Siberian wildfires occur, the more air pollution is present in those regions, which likely increases mortality and welfare losses there. However, the total impact of changing temperature on the gross domestic product under present and near‐future climate conditions is ambiguous. Our comprehensive results on the air quality changes due to Siberian wildfires under present and near‐future climate conditions suggest that increased efforts to limit the aerosol impact of Siberian wildfires are crucial to prevent possible excess mortality and economic losses. Plain Language Summary: Comprehensive knowledge of worsening air quality due to increased Siberian wildfires and its impact on climate and economy is needed to assess the impact of such fires both near their source and in the surrounding regions. Therefore, we performed global climate model simulations and analyzed the changing atmospheric aerosol emissions, including a precursor gas, from Siberian wildfires under the present and near‐future climate conditions using the Japanese global climate model called MIROC5. The increased aerosol emissions from Siberian wildfires generated a cooling effect in broad areas of the Northern Hemisphere and worsened the air quality near the source and in the downwind areas of East Asia. The effects we observed are associated with excess mortality and economic welfare losses. Future studies are needed to fully understand and prevent those negative impacts. Key Points: Comprehensive impacts of increasing Siberian wildfires on air quality, climate, and economy were estimated using the MIROC5 climate modelWe observed a cooling effect broadly across the Northern Hemisphere and worsened air quality near wildfire source and downwind regionsThe effects are closely related to lowering achievement rates of PM2.5 environmental standards, excess mortality, and economic losses [ABSTRACT FROM AUTHOR]

Unhealthy air quality conditions can strongly affect long-term human health and wellbeing, yet many air quality data products focus on near real-time alerts or short-term forecasts. Understanding the full state of air quality also requires examining the longer term frequency and intensity of poor air quality at ground level, and how it might change over time. We present a new modeling framework to compute climate-adjusted estimates of air quality hazards for the contiguous United States (CONUS) at 10 km horizontal resolution. The framework blends results from statistical, machine-learning, and climate- chemistry models -- including a bias-adjusted version of the EPA Community Multiscale Air Quality Model (CMAQ) time series as described in (Wilson et al., 2022) -- for ground-level ozone, anthropogenic fine particulate matter (PM2.5), and wildfire smoke PM2.5 into consistent estimates of days exceeding the "unhealthy for sensitive groups" (orange colored) classification on the EPA Air Quality Index for 2023 and 2053. We find that joint PM2.5 and ozone orange+ days range from 1 day to 41 days across CONUS, with a median value of 2 days, across all years. Considering all properties across CONUS, we find that 63.5% percent are exposed to at least one orange or greater day in 2023, growing to 72.1% in 2053. For a 7-day threshold, 3.8% and 5.7% of properties are exposed in 2023 and 2053, respectively. Our results also support the identification of which parts of the country are most likely to be impacted by additional climate-related air quality risks. With growing evidence that even low levels of air pollution are harmful, these results are an important step forward in empowering individuals to understand their air quality risks both now and into the future. [ABSTRACT FROM AUTHOR]

This document is an editorial published in the journal Frontiers in Environmental Science. It discusses the crucial issues of air quality, atmospheric environment, and climate change in low- and middle-income countries. The editorial highlights the complex relationship between air quality and climate change, emphasizing the need to reduce emissions for both improving air quality and mitigating the impact of climate change. It also mentions the severe air pollution problems faced by many developing countries in South Asia and Southeast Asia, particularly with regard to particulate matter (PM2.5) exceeding the World Health Organization's guidelines. The editorial introduces a research topic on air quality, atmospheric environment, and climate change in low- to upper-middle-income countries, and briefly summarizes the findings and highlights of seven articles published in this topic. These articles cover various aspects such as air quality modeling, bioaerosols, remote sensing, and the impact of land use and climate factors on air pollution. The editorial concludes by suggesting the importance of understanding air pollution in the face of changing climatic conditions and land use patterns for effective planning and management strategies. It also highlights the positive impact of electronic government on air quality and recommends prioritizing e-government policies for air quality improvement. [Extracted from the article]

The article deals with the research of the influence of plants on the potential energy savings in the field of ventilation of intelligent buildings. It is known that selected plants can effectively reduce the concentration of carbon dioxide even in the indoor environment of buildings in poor lighting conditions. The paper presents a theoretical simulation method that shows the potential of selected plants to reduce the concentration of carbon dioxide in the indoor environment and thus reduce the requirement for the amount of supplied air in intelligent buildings which are air-conditioned based on the current and required concentration of carbon dioxide. The results of the research are very influential; in terms of overall percentage savings, plants have the most significant effect in buildings with lower indoor air quality (IDA4+), while they have a less significant effect in areas with high air quality according to carbon dioxide concentration (IDA2, IDA3). Research with the help of computer simulation shows that the implementation of 1 m2 of living green plants, depending on the quality class of the IDA indoor environment, can bring savings on the amount of supplied air in the range of 0.058 % to 1.997 % for a typical office for 4 people. [ABSTRACT FROM AUTHOR]

apidly changing wildfire regimes across the Western United States have driven more frequent and severe wildfires, resulting in wide-ranging societal threats from wildfires and wildfire-generated smoke. However, common measures of fire severity focus on what is burned, disregarding the societal impacts of smoke generated from each fire. We combine satellite-derived fire scars, air parcel trajectories from individual fires, and predicted smoke PM2.5 to link source fires to resulting smoke PM2.5 and health impacts experienced by populations in the contiguous United States from April 2006 to 2020. We quantify fire-specific accumulated smoke exposure based on the cumulative population exposed to smoke PM2.5 over the duration of a fire and estimate excess asthma-related emergency department (ED) visits as a result of this exposure. We find that excess asthma visits attributable to each fire are only moderately correlated with common measures of wildfire severity, including burned area, structures destroyed, and suppression cost. Additionally, while recent California fires contributed nearly half of the country’s smoke-related excess asthma ED visits during our study period, the most severe individual fire was the 2007 Bugaboo fire in the Southeast. We estimate that a majority of smoke PM2.5 comes from sources outside the local jurisdictions where the smoke is experienced, with 87% coming from fires in other counties and 60% from fires in other states. Our approach could enable broad-scale assessment of whether specific fire characteristics affect smoke toxicity or impact, inform cost-effectiveness assessments for allocation of suppression resources, and help clarify the growing transboundary nature of local air quality. [ABSTRACT FROM AUTHOR]

Elevated tropospheric ozone concentrations driven by anthropogenic precursor emissions are an environmental hazard scientifically similar to the depletion of the stratospheric ozone layer and global climate change; however, the tropospheric ozone issue lacks the generally accepted, international assessment efforts that have greatly informed our understanding of the other two. Here, we briefly review those successful science-into-policy approaches and outline the elements required to conduct a similar process for tropospheric ozone. Particular emphasis is placed on the need to establish a conceptual model to fully understand the underpinning science, useful policy metrics, and motivating international policy forums for regulating anthropogenic ozone production over the hemispheric and global scales, thereby expanding beyond the traditional regional, air basin approach that has dominated air quality regulatory philosophy to date. [ABSTRACT FROM AUTHOR]

In recent years, to improve air quality, significant efforts have been made to reduce regional aerosols including China, Europe and North America, which have potential impacts on climate. In this study, fast and slow climate responses in China to changes in domestic and foreign anthropogenic emissions of aerosols and precursors from 2013 to 2019 are investigated using the Community Earth System Model version 1 (CESM1). Aerosol emissions changes, especially reductions in China, North America and Europe, during 2013–2019 resulted in surface air temperature increases across the Northern Hemisphere. Global aerosol changes induce a regional warming of 0.2 °C in China, equally contributed by domestic and foreign emissions changes. China's domestic emission reductions lead to a regional average temperature rise of 0.1°C, primarily driven by rapid atmospheric adjustments over eastern China. Foreign aerosol changes, particularly reductions in North America and Europe, also contributed to a 0.1°C warming in China through slow oceanic processes. This warming in China induced by foreign aerosol changes is due to a teleconnection between the aerosol-induced anomalous regional warming in Eastern U.S.-North Atlantic Ocean-Europe and the downstream East Asian climate through anomalous wave trains propagation. The comparable influence of domestic and foreign aerosol changes on climate in China underscores the importance of international collaboration in climate mitigation endeavors. [ABSTRACT FROM AUTHOR]

Several countries are currently evaluating the potential health impacts of climate change (CC), particularly in relation to the complex connections between CC-induced weather fluctuations. China, heavily affected by CC, provides clear evidence of its effects. Previous research in animal sciences indicates that factors like temperature, humidity, precipitation, and wind speed can affect animal epidemics. In China, a major global hub for animal husbandry, these factors pose significant challenges, warranting further investigation into their quantitative relationship with disease outbreaks. This study investigates the influence of these climatic conditions on epizootic diseases in China. In the current study, using data from 278 village-level surveys and daily meteorological data spanning 2012 to 2018, we used a fixed-effect model for analysis. The findings reveal that increasing temperatures and wind speeds exacerbate disease development, while the precipitation anomaly index negatively impacts animal epidemics, with humidity showing minimal influence. Addressing CC's potential impact on animal disease, governments, organizations, and farmers need to pay more attention to the impacts of climate change on animal diseases and work together to better cope with the impacts through policies, measures, and research. [ABSTRACT FROM AUTHOR]

The evolution towards Smart Cities is the process that many urban centers are following in their quest for efficiency, resource optimization and sustainable growth. This step forward in the continuous improvement of cities is closely linked to the quality of life they want to offer their citizens. One of the key issues that can have the greatest impact on the quality of life of all city dwellers is the quality of the air they breathe, which can lead to illnesses caused by pollutants in the air. The application of new technologies, such as the Internet of Things, Big Data and Artificial Intelligence, makes it possible to obtain increasingly abundant and accurate data on what is happening in cities, providing more information to take informed action based on scientific data. This article studies the evolution of pollutants in the main cities of Castilla y León, using Generative Additive Models (GAM), which have proven to be the most efficient for making predictions with detailed historical data and which have very strong seasonalities. The results of this study conclude that during the COVID-19 pandemic containment period, there was an overall reduction in the concentration of pollutants. [ABSTRACT FROM AUTHOR]

Elevated surface concentrations of ozone and fine particulate matter (PM2.5) can lead to poor air quality and detrimental impacts on human health. These pollutants are also termed Near‐Term Climate Forcers (NTCFs) as they can also influence the Earth's radiative balance on timescales shorter than long‐lived greenhouse gases. Here we use the Earth system model, UKESM1, to simulate the change in surface ozone and PM2.5 concentrations from different NTCF mitigation scenarios, conducted as part of the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP). These are then combined with relative risk estimates and projected changes in population demographics, to estimate the mortality burden attributable to long‐term exposure to ambient air pollution. Scenarios that involve the strong mitigation of air pollutant emissions yield large future benefits to human health (25%), particularly across Asia for black carbon (7%), when compared to the future reference pathway. However, if anthropogenic emissions follow the reference pathway, then impacts to human health worsen over South Asia in the short term (11%) and across Africa (20%) in the longer term. Future climate change impacts on air pollutants can offset some of the health benefits achieved by emission mitigation measures over Europe for PM2.5 and East Asia for ozone. In addition, differences in the future chemical environment over regions are important considerations for mitigation measures to achieve the largest benefit to human health. Future policy measures to mitigate climate warming need to also consider the impact on air quality and human health across different regions to achieve the maximum co‐benefits. Plain Language Summary: Ground level ozone (O3) and fine particulate matter (PM2.5) are two major air pollutants that are associated with adverse effects to human health. In addition, changes in their atmospheric concentrations can also influence the rate of climate change on a timeframe shorter than that for long‐lived greenhouse gases. In this study we use a global Earth system model to simulate the change in concentrations of surface O3 and PM2.5 across numerous future mitigation scenarios, which are then used to quantify the impact on the air pollution health burden. A large reduction in the air pollutant health burden of the population, particularly across Asia, is calculated in scenarios that have large reductions in air pollutant sources. However, impacts on health can increase across large parts of Africa in a scenario where emissions of air pollutants are not reduced. Future climate warming increases the exposure to air pollutants across regions such as Europe and East Asia, with a detrimental impact on human health. Measures to limit future climate warming and improve regional air pollutant health burdens are interconnected and important to consider together when designing future policies. Key Points: Strong mitigation of aerosols and ozone precursors leads to large future benefits to the air pollution health burden, particularly over AsiaFuture climate change can offset the health benefits of a reduced air pollution health burden from emissions mitigation over Europe and East AsiaIt is important to consider future chemical environments when designing measures to maximize benefits to climate, air quality, and health [ABSTRACT FROM AUTHOR]

Changes in anthropogenic aerosol emissions have strongly contributed to global and regional trends in temperature, precipitation, and other climate characteristics and have been one of the dominant drivers of decadal trends in Asian and African precipitation. These and other influences on regional climate from changes in aerosol emissions are expected to continue and potentially strengthen in the coming decades. However, a combination of large uncertainties in emission pathways, radiative forcing, and the dynamical response to forcing makes anthropogenic aerosol a key factor in the spread of near-term climate projections, particularly on regional scales, and therefore an important one to constrain. For example, in terms of future emission pathways, the uncertainty in future global aerosol and precursor gas emissions by 2050 is as large as the total increase in emissions since 1850. In terms of aerosol effective radiative forcing, which remains the largest source of uncertainty in future climate change projections, CMIP6 models span a factor of 5, from - 0.3 to - 1.5 W m -2. Both of these sources of uncertainty are exacerbated on regional scales. The Regional Aerosol Model Intercomparison Project (RAMIP) will deliver experiments designed to quantify the role of regional aerosol emissions changes in near-term projections. This is unlike any prior MIP, where the focus has been on changes in global emissions and/or very idealised aerosol experiments. Perturbing regional emissions makes RAMIP novel from a scientific standpoint and links the intended analyses more directly to mitigation and adaptation policy issues. From a science perspective, there is limited information on how realistic regional aerosol emissions impact local as well as remote climate conditions. Here, RAMIP will enable an evaluation of the full range of potential influences of realistic and regionally varied aerosol emission changes on near-future climate. From the policy perspective, RAMIP addresses the burning question of how local and remote decisions affecting emissions of aerosols influence climate change in any given region. Here, RAMIP will provide the information needed to make direct links between regional climate policies and regional climate change. RAMIP experiments are designed to explore sensitivities to aerosol type and location and provide improved constraints on uncertainties driven by aerosol radiative forcing and the dynamical response to aerosol changes. The core experiments will assess the effects of differences in future global and regional (Africa and the Middle East, East Asia, North America and Europe, and South Asia) aerosol emission trajectories through 2051, while optional experiments will test the nonlinear effects of varying emission locations and aerosol types along this future trajectory. All experiments are based on the shared socioeconomic pathways and are intended to be performed with 6th Climate Model Intercomparison Project (CMIP6) generation models, initialised from the CMIP6 historical experiments, to facilitate comparisons with existing projections. Requested outputs will enable the analysis of the role of aerosol in near-future changes in, for example, temperature and precipitation means and extremes, storms, and air quality. [ABSTRACT FROM AUTHOR]

South Korea is a signatory of the Paris Agreement and has announced its aim to achieve carbon neutrality by 2050. However, South Korea's current policy trajectory is not compatible with maintaining a global temperature rise below 2 °C. Climate change has not been a dominant electoral issue in South Korea, with national concerns being prioritized. A Paris-Agreement-compatible development pathway could synergistically improve ambient air quality in South Korea. This research examines the gains of a climate action pathway that would achieve 2050 carbon neutrality, compared to a business-as-usual (BAU) pathway, in South Korea. The work aims to add further evidence to the potential national gains from strong climate action across all sectors in South Korea. The paper argues that by focusing on and estimating national gains, the momentum for enhanced climate policy action can be intensified by framing robust climate action as an opportunity rather than a cost. Through a climate action pathway, South Korea could avoid 835 years of life lost (YLL) in 2030, 2237 YLL in 2040 and 3389 YLL in 2050. Through this pathway, South Korea could also cumulatively abate 5539 million tons of CO2 equivalent (MtCO2e) in greenhouse gas emissions over the 2022–2050 period. [ABSTRACT FROM AUTHOR]

Wildfires are a serious problem that affects wildlife all over the world which is human beings together with nature, both play a fundamental role in the cause of wildfires. Wildfires may start quite inconspicuously, but can rapidly accelerate to become fierce and uncontrollable, at which point they also pose serious health problems to humankind. To clarify this problem descriptive method was applied which described the basic issue and explained all outcomes accurately and clearly. So, the review illustrates that from an anthropological perspective, greater numbers of people are now living closer to forests (and rural areas in general), which although seemingly satisfactory and beneficial to them, has also led to an increase in the destruction of forests, due to intentionally, and unintentionally generated fires. In addition to the human impact, climate change and other natural phenomena are also destroying the forests. This review indicates the connection between wildfires and climate change, it also studies the effects of wildfires on health and air quality, in addition, the paper highlights the particularly challenging situation in India, which, due to its substantial share of global forestland, is proportionately more impacted by these fires. Besides, the review mentioned the analytical method to predict fire propagation.

Extreme weather events are happening more frequently as a result of global climate change. Dust storms broke out in the spring of 2017 in China and drastically impacted the local air quality. In this study, a variety of data, including aerosol vertical profiles, surface particle concentration, meteorological parameters, and MODIS–derived aerosol optical depth, as well as backward trajectory analysis, were employed to analyze two dust events from April to May in Beijing. The dust plumes were mainly concentrated below 0.8 km, with peak PM10 values of 1000 μg·m−3 and 300 μg·m−3 in the two cases. The aerosols showed different vertical distribution characteristics. The pure dust in case 1 from 4 to 5 May 2017 had a longer duration (2 days) and presented a larger aerosol extinction coefficient (2.27 km−1 at 355 nm and 1.25 km−1 at 532 nm) than that of the mixed dust in case 2 on 17 April 2017 (2.01 km−1 at 355 nm and 1.33 km−1 at 532 nm). The particle depolarization ratio (PDR) remained constant (0.24 ± 0.03 in case 1) from the surface to 0.8 km in height. In contrast, the PDR profile in the mixed dust (case 2) layer was split into two regions—large values exceeding 0.15 above 0.6 km and small values of 0.11 ± 0.03 below 0.6 km. The influence of meteorological information on aerosol distribution was also investigated, and wind was predominant through the observing period. The pure dust in case 1 was mainly from Mongolia, with strong northwest winds, while the near-surface mixed pollution was caused by the combination of long-transported sand and local emission. Furthermore, lidar-derived profiles of dust mass concentrations in the two cases were presented. This study reveals the vertical characteristics of dust aerosols in the production and dissipation of localized dust events and confirms the efficacy of thorough observations with multiple approaches from the ground to space to monitor dust events in real time. [ABSTRACT FROM AUTHOR]

The western United States has experienced severe drought in recent decades, and climate models project increased drought risk in the future. This increased drying could have important implications for the region’s interconnected, hydropower-dependent electricity systems. Using power-plant level generation and emissions data from 2001 to 2021, we quantify the impacts of drought on the operation of fossil fuel plants and the associated impacts on greenhouse gas (GHG) emissions, air quality, and human health. We find that under extreme drought, electricity generation from individual fossil fuel plants can increase up to 65% relative to average conditions, mainly due to the need to substitute for reduced hydropower. Over 54% of this drought-induced generation is transboundary, with drought in one electricity region leading to net imports of electricity and thus increased pollutant emissions from power plants in other regions. These drought-induced emission increases have detectable impacts on local air quality, as measured by proximate pollution monitors. We estimate that the monetized costs of excess mortality and GHG emissions from drought-induced fossil generation are 1.2 to 2.5x the reported direct economic costs from lost hydro production and increased demand. Combining climate model estimates of future drying with stylized energy- transition scenarios suggests that these drought-induced impacts are likely to remain large even under aggressive renewables expansion, suggesting that more ambitious and targeted measures are needed to mitigate the emissions and health burden from the electricity sector during drought. [ABSTRACT FROM AUTHOR]

Climatic condition is triggering human health emergencies and earth's surface changes. Anthropogenic activities, such as built-up expansion, transportation development, industrial works, and some extreme phases, are the main reason for climate change and global warming. Air pollutants are increased gradually due to anthropogenic activities and triggering the earth's health. Nitrogen Dioxide (NO2), Carbon Monoxide (CO), and Aerosol Optical Depth (AOD) are truthfully important for air quality measurement because those air pollutants are more harmful to the environment and human's health. Earth observational Sentinel-5P is applied for monitoring the air pollutant and chemical conditions in the atmosphere from 2018 to 2021. The cloud computing-based Google Earth Engine (GEE) platform is applied for monitoring those air pollutants and chemical components in the atmosphere. The NO2 variation indicates high during the time because of the anthropogenic activities. Carbon Monoxide (CO) is also located high between two 1-month different maps. The 2020 and 2021 results indicate AQI change is high where 2018 and 2019 indicates low AQI throughout the year. The Kolkata have seven AQI monitoring station where high nitrogen dioxide recorded 102 (2018), 48 (2019), 26 (2020) and 98 (2021), where Delhi AQI stations recorded 99 (2018), 49 (2019), 37 (2020), and 107 (2021). Delhi, Kolkata, Mumbai, Pune, and Chennai recorded huge fluctuations of air pollutants during the study periods, where ~ 50–60% NO2 was recorded as high in the recent time. The AOD was noticed high in Uttar Pradesh in 2020. These results indicate that air pollutant investigation is much necessary for future planning and management otherwise; our planet earth is mostly affected by the anthropogenic and climatic conditions where maybe life does not exist. [ABSTRACT FROM AUTHOR]

Climate change has become one of the leading problems around the world. The transport sector is one of the major contributors to climate change. At the same time, climate change is also affecting transportation facilities and travel behaviour. This study proposed a bibliometric approach to explore the structure evolution development trends of this knowledge domain with a broader search scope and more objective results compared with a manual review. A total of 4073 peer-reviewed articles were collected from the WoS core collection database to conduct scientometric analysis. The collaboration analysis shows that the US, China, and European countries dominate this field, and international organisations' and government agencies' reports on climate change form the basis of this research field. A total of 14 co-citation clusters were identified, and the research on climate change and transportation primarily focused on the topics of policy options, travel behaviour, the COVID-19 lockdown, environmental cost, and air quality. Keyword co-occurrence evolution analysis was also conducted to track the latest research trends. Based on the results, we propose trends in four areas for future research. This study provides a holistic knowledge map for climate change and transportation research's past, present, and future. [ABSTRACT FROM AUTHOR]

This work presents new climate and emissions scenarios to investigate changes on future meteorology and air quality in the U.S. Here, we employ a dynamically downscaled Weather Research and Forecasting model coupled with chemistry (WRF/Chem) simulations that use two Intergovernmental Panel on Climate Change scenarios (i.e., A1B and B2) integrated with explicitly projected emissions from a novel Technology Driver Model (TDM). The projected 2046–2055 emissions show widespread reductions in most gas and aerosol species under both TDM/A1B and TDM/B2 scenarios over the U.S. The WRF/Chem simulations show that under the combined effects of the TDM/A1B climate and emission changes, the maximum daily average 8-h ozone (MDA8 h O3) increases by ~3 ppb across the U.S. mainly due to widespread increases in near-surface temperature and background methane concentrations, with some contributions from localized TDM emission changes near urban centers. For the TDM/B2 climate and emission changes, however, the MDA8 h O3 is widely decreased, except near urban centers where the relative TDM emission changes and O3 formation regimes leads to increased O3. The number of O3 exceedance days (i.e., MDA8 h O3 > 70 ppb) for the entire domain is significantly reduced by a grid cell maximum of up to 43 days (domain average ~0.5 days) and 62 days (domain average ~2 days) for the TDM/A1B and TDM/B2 scenarios, respectively, while in the western U.S., larger O3 increases lead to increases in nonattainment areas, especially for the TDM/A1B scenario. The combined effects of climate and emissions (for both A1B and B2 scenarios) will lead to widespread decreases in the daily 24-h average (DA24 h) PM2.5 concentrations, especially in the eastern U.S. (max decrease up to 93 µg m−3). The PM2.5 changes are dominated by decreases in anthropogenic emissions for both the TDM/A1B and TDM/B2 scenarios, with secondary effects on decreasing PM2.5 from climate change. The number of PM2.5 exceedance days (i.e., DA24 h PM2.5 > 35 µg m−3) is significantly reduced over the eastern U.S. under both TDM/A1B and B2 scenarios, which suggests that both climate and emission changes may synergistically lead to decreases in PM2.5 nonattainment areas in the future. [ABSTRACT FROM AUTHOR]

The improvement of the urban microclimate in the densely-built central areas of Mediterranean cities should be a key objective of integrated urban and transport planning and design in accordance with the UN Sustainable Development Goals on energy, sustainable cities, and climate action. The urban climate of cities in warm regions, already burdened by the urban heat island effect, is expected to worsen further due to the global climate crisis. This study investigates the performance of common environmental street design strategies on microclimate, thermal comfort, and air quality under extreme heat conditions in the Mediterranean city of Thessaloniki, Greece. A typology of streets was selected using criteria such as road functional classification and orientation, land uses, building height/street width ratio, the sky view factor, and the continuity/discontinuity of buildings. A conservative scenario (use of cool/photocatalytic and porous materials for sidewalks, lighter pavements, additional tree planting, installations of green roofs) and a radical scenario (pedestrianization and total traffic prohibition) of environmental design interventions were simulated using the ENVI-met 5.1 software. The research findings demonstrated that the car-free interventions combined with the use of environmentally friendly materials in the public realm could significantly reduce the heat island effect and mitigate gaseous pollutants. The perceived air temperature (Physiological Equivalent Temperature—PET index) can decrease by up to 15 °C in well-shaded locations and near building corners, while nitrogen oxides can be reduced by up to 87% when considering a more radical pedestrianization scenario. The standardization of environmental interventions following a typology of urban streets could support planners and decision-makers in detecting the appropriate solutions for improving the urban microclimate. [ABSTRACT FROM AUTHOR]

Quantification and control of NOx and CO2 emissions are essential across the world to limit adverse climate change and improve air quality. We present a new top-down method, an improved superposition column model to estimate day-to-day NOx and CO2 emissions from the large city of Wuhan, China, located in a polluted background. The latest released version 2.3.1 TROPOMI (TROPOspheric Monitoring Instrument) NO2 columns and version 10r of the Orbiting Carbon Observatory-2 (OCO-2)-observed CO2 mixing ratio are employed. We quantified daily NOx and CO2 emissions from Wuhan between September 2019 and October 2020 with an uncertainty of 31 % and 43 %, compared to 39 % and 49 % with the earlier v1.3 TROPOMI data, respectively. Our estimated NOx and CO2 emissions are verified against bottom-up inventories with minor deviations (<3 % for the 2019 mean, ranging from -20 % to 48 % on a daily basis). Based on the estimated CO2 emissions, we also predicted daily CO2 column mixing ratio enhancements, which match well with OCO-2 observations (<5 % bias, within ±0.3 ppm). We capture the day-to-day variation of NOx and CO2 emissions from Wuhan in 2019–2020, which does not reveal a substantial "weekend reduction" but does show a clear "holiday reduction" in the NOx and CO2 emissions. Our method also quantifies the abrupt decrease and slow NOx and CO2 emissions rebound due to the Wuhan lockdown in early 2020. This work demonstrates the improved superposition model to be a promising new tool for the quantification of city NOx and CO2 emissions, allowing policymakers to gain real-time information on spatial–temporal emission patterns and the effectiveness of carbon and nitrogen regulation in urban environments. [ABSTRACT FROM AUTHOR]

The goal of this study is to analyze how levels of air pollution changed between countries with their restriction policy of lockdown to cope with the COVID-19 pandemic. The study design compares average changes of CO, NO2, SO2, O3, PM2.5 and PM10 concentrations based on measurements at ground level in January, February, and March for the years 2019, 2020, 2021, and 2022 (during the COVID-19 pandemic crisis) to average values of a 2015–2018 baseline period (ex-ante COVID-19 pandemic) between 300 cities in 19 countries of five geoeconomic regions. Results reveal that the maximum reduction in air pollutant concentrations is given by: CO (−4367.5%) in France, NO2 (−150.5%) in China and Australia, SO2 (−154.1%) in Israel, O3 (−94.1%) in China, PM2.5 (−41.4%) in Germany, and PM10 (−157.4%) in Turkey. Findings show that the effects of restriction policies for COVID-19 pandemic on air quality vary significantly between countries, depending on the different geographical, economic, industrial and social characteristics of the countries. These results clarify the critical relationship between control measures for pandemic crises and levels of air pollution in countries that can support best practices of environmental policy for pathways of sustainable development. [ABSTRACT FROM AUTHOR]

Forests are complex ecosystems comprising various trophic levels responsible for carrying out various biogeochemical processes and providing ecosystem services. However, forests in Asia are doubly challenged by climate change and air pollution. The rapidly changing air quality, with increasing concentration of greenhouse gases (GHGs), trace gases, volatile organic compounds (VOCs), and ozone (O3) also causes global warming leading to climate change, thus jointly creating a challenging condition for the forest ecosystem. The impact on forest ecosystems of the two anthropogenic stressors, viz., climate change and air pollution, requires global attention. These two stressors have been widely studied separately but their combined impact on the forest ecosystem has not been studied extensively, particularly in the Asian region. In this review article, we attempt to explore the importance of interlinking air pollution and climate change impact on Asian forests, by studying the decline of different forest types as a background and markers of forest ecosystem degradation. Our main aim is to understand and summarise the past and ongoing research in this area and to facilitate researchers and policymakers to upgrade their research, policies, and management strategies in the area of integration of air pollution and climate change impact on forest ecosystems in the Asian region. [ABSTRACT FROM AUTHOR]

In 2019, South Korea's Framework Act on The Management of Disasters and Safety was revised to include respirable particulate matter as a social disaster. Urban air pollution, especially particulate matter pollution, has been a serious threat to socioeconomic development and public health. In order to address this problem, strong climate crisis response strategies and policies to improve urban air quality are necessary. Therefore, it is of great importance to assess the frequency of urban air pollution occurrence and its influencing factors. The objective of this study is to develop consistent methodologies for the construction of an index system and for assessing the influencing factors of urban particulate matter pollution based on population, social welfare, land use, environmental, transportation, and economic governance considerations. We applied the local indicators of spatial association and geographical detector methods, and 35 influencing factors were selected to assess their influence on urban air pollution occurrence in 229 cities and counties in South Korea. The results indicated the spatial pattern of the particulate matter concentration in these locations showed strong spatial correlation, and it was confirmed that there was a difference in distribution according to the season. As a result of the analysis of influencing factors, it was found that environment and land use characteristics were the main influencing factors for PM10 and PM2.5. The explanatory power between the two influencing factors of particulate matter was greater than that of a single influencing factor. In addition, most influencing factors resulted in both positive and negative effects on urban fine particulate matter pollution. The interaction relationship of all factors showed a strong action effect in the case of both PM10 and PM2.5, so it was confirmed that all influencing factors were interdependent. In particular, the findings proved that combining the two factors would have a more pronounced effect on particulate matter than when they were independent. We confirmed the significant results for the factors affecting particulate matter. This study offers suggestions on reducing urban air pollution occurrence that can be used to provide a basis and reference for the government to form policies on urban air pollution control in cities and counties. [ABSTRACT FROM AUTHOR]

Poor air quality remains the largest environmental health risk in Europe, despite the EU policy efforts. Especially in cities, the synergistic interactions between the urban heat island and urban pollution result in premature mortality, associated with cardiovascular and respiratory diseases. Mediterranean urban areas are particularly susceptible under the consideration that the intensity, frequency, and duration of heat waves will increase due to climate change. The LIFE SIRIUS project designates that air quality management needs to go beyond traditional approaches in order to consider synergistic effects. This paper assesses the impact of temperature on daily mortality from 2004 to 2019 in the Republic of Cyprus with the use of a Generalized Additive Model (GAM). The association between mean daily temperature and mortality is nonlinear, implying that a prompt rise in deaths occurs when temperatures are high, while for colder temperatures, the effect is delayed. We report an inverted J-shaped relationship between mean temperature and mortality, with the most prominent effects on human health documented at low temperatures. The population under study appears to be acclimatized to local conditions, as mortality increases after 10 days of exposure to the environmental risk. The results of this study will assist in the definition of city-specific thresholds above which health warnings for the protection of the local population will be issued, in the framework of LIFE SIRIUS.

Using 30 years of satellite observations, two sand and dust storms (SDS) source locations (hotspots) were detected on the southern side of the Mesopotamian Flood Plain. Around 40 million people in the region are affected by the two hotspots, including populations in Iraq, Iran, Kuwait, Saudi Arabia, Qatar, Bahrain, and Emirates. Both hotspots encompass roughly 8212 km2 and contribute 11% to 85% in 2005 and 2021, respectively, of the total SDS in the region. Dust physical (particle surface area and size percentages) and chemical (mineralogy, major and trace elements, and radionuclides) properties show close similarities between source and downwind samples during SDS originated solely from the two hotspots. Deposited dust size particles show a finning trend towards the north in the Middle East compared to the south. A comprehensive assessment of the chemical and physical properties of soil and dust samples was conducted as an essential step in developing and implementing a mitigation plan in order to establish a success story in reducing SDS, improving air quality, and benefiting the gulf countries and neighboring regions. [ABSTRACT FROM AUTHOR]

The daily variation of ground‐level ozone (O3), a harmful pollutant, is positively correlated with air temperature (T) in many midlatitude land regions in the summer. The observed temporal regression slope between O3 and T (dO3/dT) is referred to as the "ozone‐climate change penalty" and has been proposed as a way to predict the impact of future climate warming on O3 from observations. Here, we use two chemical transport models to show that the spatial variation of dO3/dT is primarily determined by simultaneous meridional advection of O3 and T. Furthermore, the sign and magnitude of dO3/dT can be approximated by their climatological meridional gradient ratio (O3 gradient divided by T gradient). Consideration of expected changes in the meridional gradients of T and O3 due to climate change indicates that dO3/dT will likely change. Caution is needed when using the observed climate penalty to predict O3 changes. Plain Language Summary: At Earth's surface, ozone is a harmful pollutant. In the summer, we observe higher ozone concentrations on hotter days over land in the midlatitudes. This leads researchers to expect higher ozone concentrations as a result of global warming, based on chemistry that associates higher ozone concentrations with higher temperatures. Here, we show that the relationship between ozone and temperature is largely controlled by the north‐south movement of air which simultaneously transports ozone and heat. Therefore, the background spatial distributions of ozone and temperature determine how ozone and temperature covary. The ozone‐temperature relationship in the future may look different from today, because global warming is not spatially uniform. We advise caution in using observed ozone‐temperature relationship to estimate future ozone changes. Key Points: Transport by meridional advection of O3 and T explains the spatial variation in the daily O3‐T relationshipDaily regression slope dO3/dT can be approximated by the ratio of O3 and T mean meridional gradients when temperature gradients are strongGradient ratio suggests dO3/dT will change with warming, making it questionable to use observed dO3/dT in O3 projections [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has emphasized the need for infection risk analysis and assessment of ventilation systems in indoor environments based on air quality criteria. In this context, simulations and direct measurements of CO2 concentrations as a proxy for exhaled air can help to shed light on potential aerosol pathways. While the former typically lack accurate boundary conditions as well as spatially and temporally resolved validation data, currently existing measurement systems often probe rooms in non-ideal, single locations. Addressing both of these issues, a large and flexible wireless array of 50 embedded sensor units is presented that provides indoor climate metrics with configurable spatial and temporal resolutions at a sensor response time of 20 s. Augmented by an anchorless self-localization capability, three-dimensional air quality maps are reconstructed up to a mean 3D Euclidean error of 0.21 m. Driven by resolution, ease of use, and fault tolerance requirements, the system has proven itself in day-to-day use at ETH Zurich, where topologically differing auditoria (at-grade, sloped) were investigated under real occupancy conditions. The corresponding results indicate significant spatial and temporal variations in the indoor climate rendering large sensor arrays essential for accurate room assessments. Even in well-ventilated auditoria, cleanout time constants exceeded 30 min. [ABSTRACT FROM AUTHOR]

Featured Application: Key conclusions and recommendations are proposed to enlighten decision makers in view of the next regulations on vehicle emissions in Europe and worldwide through the synergistic contexts of air quality and climate change. Airborne particulate matter (PM) is a pollutant of concern not only because of its adverse effects on human health but also on visibility and the radiative budget of the atmosphere. PM can be considered as a sum of solid/liquid species covering a wide range of particle sizes with diverse chemical composition. Organic aerosols may be emitted (primary organic aerosols, POA), or formed in the atmosphere following reaction of volatile organic compounds (secondary organic aerosols, SOA), but some of these compounds may partition between the gas and aerosol phases depending upon ambient conditions. This review focuses on carbonaceous PM and gaseous precursors emitted by road traffic, including ultrafine particles (UFP) and polycyclic aromatic hydrocarbons (PAHs) that are clearly linked to the evolution and formation of carbonaceous species. Clearly, the solid fraction of PM has been reduced during the last two decades, with the implementation of after-treatment systems abating approximately 99% of primary solid particle mass concentrations. However, the role of brown carbon and its radiative effect on climate and the generation of ultrafine particles by nucleation of organic vapour during the dilution of the exhaust remain unclear phenomena and will need further investigation. The increasing role of gasoline vehicles on carbonaceous particle emissions and formation is also highlighted, particularly through the chemical and thermodynamic evolution of organic gases and their propensity to produce particles. The remaining carbon-containing particles from brakes, tyres and road wear will still be a problem even in a future of full electrification of the vehicle fleet. Some key conclusions and recommendations are also proposed to support the decision makers in view of the next regulations on vehicle emissions worldwide. [ABSTRACT FROM AUTHOR]

Dust storms are meteorological hazards associated with several adverse health impacts including eye irritations, respiratory and cardiovascular disorders, and vehicular road accidents due to poor visibility. This study investigated relations between admissions from a large, public hospital that serves people living in Northern Cape and Free State provinces, South Africa during 2011 to 2017, and meteorological variables (temperature and air quality) during two dust storms, one in October 2014 (spring) and the second in January 2016 (summer), identified from the media as no repository of such events exists for South Africa. Distributed nonlinear lag analysis and wavelet transform analysis were applied to explore the relationships between hospital admissions for respiratory and cardiovascular diseases, eye irritation, and motor vehicle accidents; maximum temperature, and two air quality 'proxy measures,' aerosol optical depth and Ångström exponent, were used as ground-based air quality data were unavailable. Eye irritation was the most common dust-related hospital admission after both dust storm events. No statistically significant changes in admissions of interest occurred at the time of the two dust storm events, using either of the statistical methods. Several lessons were learnt. For this type of study, ground-based air quality and local wind data are required; alternative statistical methods of analysis should be considered; and a central dust storm repository would help analyze more than two events. Future studies in South Africa are needed to develop a baseline for comparison of future dust storm events and their impacts on human health. [ABSTRACT FROM AUTHOR]

The COVID-19 global pandemic and associated government lockdowns dramatically altered human activity, providing a window into how changes in individual behavior, enacted en masse, impact atmospheric composition. The resulting reductions in anthropogenic activity represent an unprecedented event that yields a glimpse into a future where emissions to the atmosphere are reduced. Furthermore, the abrupt reduction in emissions during the lockdown periods led to clearly observable changes in atmospheric composition, which provide direct insight into feedbacks between the Earth system and human activity. While air pollutants and greenhouse gases share many common anthropogenic sources, there is a sharp difference in the response of their atmospheric concentrations to COVID-19 emissions changes, due in large part to their different lifetimes. Here, we discuss several key takeaways from modeling and observational studies. First, despite dramatic declines in mobility and associated vehicular emissions, the atmospheric growth rates of greenhouse gases were not slowed, in part due to decreased ocean uptake of CO2 and a likely increase in CH4 lifetime from reduced NOx emissions. Second, the response of O3 to decreased NOx emissions showed significant spatial and temporal variability, due to differing chemical regimes around the world. Finally, the overall response of atmospheric composition to emissions changes is heavily modulated by factors including carbon-cycle feedbacks to CH4 and CO2, background pollutant levels, the timing and location of emissions changes, and climate feedbacks on air quality, such as wildfires and the ozone climate penalty. [ABSTRACT FROM AUTHOR]

The widely used Moderate Resolution Imaging Spectroradiometer (MODIS) Dark‐Target (DT) aerosol product fails to accurately retrieve Aerosol Optical Depth (AOD) over shallow and turbid Coastal Waters (CWs). To fill in gaps, and to improve land to ocean AOD continuity, we developed a coastal water retrieval algorithm at a spatial resolution of 1 km (CW‐1km). CW‐1km relies on observed top‐of‐atmosphere reflectance at 2.1 μm (ρ2.1), both to derive AOD and to perform a spatial variation test that enhances the existing DT masks for clouds and land. We show that the CW‐1km improves spatial continuity of AOD between land, coast, and open ocean, while also increasing AOD product availability by 47.0%. Comparing with 15 years of marine aerosol network measurements, CW‐1km AODs are validated to have a normalized mean bias of 1.0%, which is much smaller than 17.6% for the original DT product. Plain Language Summary: The Moderate Resolution Imaging Spectroradiometer (MODIS)‐retrieved Aerosol Optical Depth (AOD) products have been widely used by the research community to study aerosol impacts on air quality, weather, and climate changes. However, AOD products are often missing or highly biased over Coastal Waters (CWs), due to CW being turbid, shallow, and mixed with the land. Here, we have created a new algorithm (CW‐1km) that retrieves AOD with a spatial resolution of 1 km. This new CW algorithm greatly improves spatial coverage and provides a smooth AOD transition from land to coastal to open waters and does not shown the spatial gaps and erroneous values as found in the MODIS AOD products over CW. The improvement in both accuracy and retrieval coverage can further enhance air quality and climate studies in coastal regions, which is also where over 60% of global human population reside. Our CW algorithm can be ported to existing and future satellite sensors to improve the retrieval of aerosol distribution over coastal and estuarine water areas. Key Points: The Coastal Water (CW) algorithm for Moderate Resolution Imaging Spectroradiometer Aerosol Optical Depth (AOD) retrieval at 1 km over shallow and turbid CW is developedThe 2.1‐μm Top‐of‐Atmosphere reflectance spatial variation test improves the land mask near coastline and cloud mask over turbid CWCW‐1km AOD agrees with in situ measurements, increases availability, and removes the artifacts of AOD from land to open ocean [ABSTRACT FROM AUTHOR]

South Korea is a signatory of the Paris Agreement and has announced its aim to achieve carbon neutrality by 2050. However, South Korea’s current policy trajectory is not compatible with maintaining a global temperature rise below 2 °C. Climate change has not been a dominant electoral issue in South Korea, with national concerns being prioritized. A Paris-Agreement-compatible development pathway could synergistically improve ambient air quality in South Korea. This research examines the gains of a climate action pathway that would achieve 2050 carbon neutrality, compared to a business-as-usual (BAU) pathway, in South Korea. The work aims to add further evidence to the potential national gains from strong climate action across all sectors in South Korea. The paper argues that by focusing on and estimating national gains, the momentum for enhanced climate policy action can be intensified by framing robust climate action as an opportunity rather than a cost. Through a climate action pathway, South Korea could avoid 835 years of life lost (YLL) in 2030, 2237 YLL in 2040 and 3389 YLL in 2050. Through this pathway, South Korea could also cumulatively abate 5539 million tons of CO2 equivalent (MtCO2e) in greenhouse gas emissions over the 2022–2050 period.

Climate is an essential component in the sustainability of tourism cities. Coastal tourism cities face unprecedented challenges under a changing climate. The complexity of the tourism–climate interface predicates the need for tools that can assess the weather and climate accurately. Tourism climate indices have been widely developed to evaluate the temporal and spatial distribution of climate resources, but these indices are not entirely applicable to coastal cities facing air pollution. This study developed a Coastal Tourism Climate Index (CTCI) to assess the tourism climate suitability of Chinese coastal cities. The CTCI was developed to include five variables: thermal comfort, sunshine, precipitation, wind, and air quality. This index was applied and verified in the case of nine coastal tourism cities in China compared to the Holiday Climate Index (HCI: Beach). According to the results, the CTCI is more suitable for coastal tourism climate assessment in China. Finally, corresponding countermeasures are put forward for the balanced and sustainable development of Chinese coastal tourism cities. This study takes the lead in applying big data to the development and validation of tourism climate indices. These findings provide novel insights for the tourism climate assessment of coastal destinations facing air pollution. [ABSTRACT FROM AUTHOR]