Explore the vast range of titles available.

Air pollution is a serious challenge in South Korea and worldwide, and negatively impacts human health and mortality rates. To assess air quality and the spatiotemporal characteristics of atmospheric particulate matter (PM), PM concentrations were compared with meteorological conditions and the concentrations of other airborne pollutants over South Korea from 2015 to 2020, using different linear and non-linear models such as linear regression, generalized additive, and multivariable linear regression models. The results showed that meteorological conditions played a significant role in the formation, transportation, and deposition of air pollutants. PM2.5 levels peaked in January, while PM10 levels peaked in April. Both were at their lowest levels in July. Further, PM2.5 was the highest during winter, followed by spring, autumn, and summer, whereas PM10 was the highest in spring followed by winter, autumn, and summer. PM concentrations were negatively correlated with temperature, relative humidity, and precipitation. Wind speed had an inverse relationship with air quality; zonal and vertical wind components were positively and negatively correlated with PM, respectively. Furthermore, CO, black carbon, SO2, and SO4 had a positive relationship with PM. The impact of transboundary air pollution on PM concentration in South Korea was also elucidated using air mass trajectories.

The River Chief System (RCS) in China plays a crucial role in addressing transboundary water pollution (TWP), which is vital for achieving the Sustainable Development Goal of \"clean water.\" This study examines the static and dynamic effects of the RCS on TWP using a difference-in-difference-in-differences (DDD) model and manually collected RCS data from 104 counties between 2007 and 2020. The results show that the RCS significantly reduces chemical oxygen demand (COD) by 15.9% and ammonia nitrogen (NH 3 -N) by 22.9% in border counties, though it has no notable impact on dissolved oxygen (DO). Additionally, RCS intensity contributes to a 13.8% reduction in COD. However, no sustained dynamic effects are observed for COD or NH 3 -N reduction over time. Several robustness checks confirm the validity of these findings. Heterogeneity analysis indicates that the RCS’s impact is more pronounced in counties with higher economic development, upstream locations, lower initial pollution levels, and younger local government leaders. This study not only provides critical insights for water resource management in China but also offers international relevance for addressing TWP governance challenges in transboundary water bodies.

Despite a downward trend in pollutant levels because of a series of emission control policies, the Pearl River Delta (PRD) region continues to suffer from a high number of fine particulate matter (PM2.5) events and the resultant public health impacts. To effectively control PM2.5 in the region, a comprehensive understanding of source contribution and PM2.5 responses to various emission species is critical. We applied the Community Multiscale Air Quality Modeling System together with the high-order decoupled direct method, to simulate air quality and PM2.5 sensitivity and examined PM2.5 responses to emission species in the PRD region in the four seasons of 2010. We employed a concentration-response function to quantify the resultant number of premature mortalities attributable to outdoor PM2.5. We estimated that local and transboundary air pollution (TAP) contributed 27% and 73%, respectively, of the region's PM2.5. In absolute terms, the largest impacts from local and TAP occurred in winter. With respect to relative contributions among the different sources, regional TAP (between cities in the region) (R-TAP) and local contributions had the largest effect in summer, whereas superregional TAP (from outside of the region) contributed the most in fall and winter. Outdoor PM2.5 pollution caused 20 160 (95% confidence interval: 5100-39 310) premature mortalities every year in the PRD region. Averaging among cities, 50%, 20%, and 30% of these deaths were attributable to S-TAP, R-TAP, and local contributions, respectively. Precursor gas emissions (i.e. NH3, volatile organic compounds, SO2, and NOx) affect PM2.5 level in a nonlinear manner; thus, individual pollutant control strategies are less effective for improving PM2.5 pollution than an integrated strategy. On the basis of our findings, we recommend that controls for multiple emission species should be implemented to control PM2.5 pollution in the region.

South Asia’s worsening air pollution crisis represents one of the most urgent public health and environmental challenges of the 21st century. Nearly two billion people—over one-quarter of the global population—reside in this region, where air quality levels routinely exceed World Health Organization (WHO) guidelines by factors of 10 to 15. This has translated into an unprecedented health burden, with approximately two million premature deaths annually, widespread chronic respiratory and cardiovascular disease, and rising economic losses. According to recent World Bank estimates, welfare losses amount to over 5% of regional GDP, a figure far exceeding the projected costs of coordinated mitigation. Despite this, South Asia continues to lack a binding regional framework capable of addressing its shared airshed. Existing cooperative efforts—such as the Malé Declaration on Control and Prevention of Air Pollution (1998)—have provided a useful platform for dialog and pilot monitoring, but they remain voluntary, under-resourced, and insufficient to manage the transboundary nature of the crisis. National-level programs, including India’s National Clean Air Programme (NCAP), Bangladesh’s National Air Quality Management Plan (NAQMP), and Nepal’s National Air Quality Management Action Plan (AQMAP), demonstrate domestic commitment but are constrained by fragmentation, limited financing, and lack of regional integration. This gap represents the central knowledge and governance challenge that prompted the present commentary. To address it, we propose a dual-track architecture designed to institutionalize binding regional cooperation. Track A would establish a United Nations-anchored South Asian Transboundary Air Pollution Protocol, under the auspices of the United Nations Environment Programme, the World Health Organization (WHO), and the United Nations Economic and Social Commission for Asia and the Pacific (UNESCAP). This protocol would codify legally enforceable emission standards, compliance committees, financial mechanisms, and harmonized monitoring. Track B would establish a South Asian Association for Regional Cooperation (SAARC) Prime Ministers’ Council on Air Quality (SPMCAQ) to provide political leadership, align domestic implementation, and authorize rapid responses to cross-border haze events. Lessons from the Indian Ocean Experiment, the ASEAN Agreement on Transboundary Haze Pollution, and Europe’s Convention on Long-Range Transboundary Air Pollution demonstrate that legally binding agreements combined with high-level political ownership can achieve durable reductions in pollution despite geopolitical tensions. By situating South Asia within these global precedents, the proposed framework provides a pragmatic, enforceable, and politically resilient pathway to protect health, reduce economic losses, and deliver cleaner air for nearly one-quarter of humanity.

We estimate the degree and scope of PM2.5-induced negative price shock in Korea’s local housing markets, taking a two-stage hedonic approach. For the analysis, Korea’s local PM2.5 levels are treated as endogenous and are instrumented with regional air pollutants from China. We find that a unit µg/m3 PM2.5 level increase in a Korean city is associated with a 3.7% decline in local residential property value. Long-range transboundary pollution has significant effects on Korea’s local PM2.5 levels with an elasticity of 0.05. These results enrich the sparse hedonic literature on local air-quality valuation in connection to long-range transboundary pollution in East Asia. The advanced methodological features presented in our two-staged identification strategy with a novel instrument is another contribution of this paper.

Climate policies targeting CO2 emissions from fossil fuels can simultaneously reduce emissions of air pollutants and their precursors, thus mitigating air pollution and associated health impacts. Previous work has examined co-benefits of climate policy from reducing PM2.5 in rapidly-developing countries such as China, but have not examined co-benefits from ozone and its transboundary impact for both PM2.5 and ozone. Here, we compare the air quality and health co-benefits of China's climate policy on both PM2.5 and ozone in China to their co-benefits in three downwind and populous countries (South Korea, Japan and the United States) using a coupled modeling framework. In a policy scenario consistent with China's pledge to peak CO2 emissions in approximately 2030, avoided premature deaths from ozone reductions are 54 300 (95% confidence interval: 37 100-71 000) in China in 2030, nearly 60% of those from PM2.5. Total avoided premature deaths in South Korea, Japan, and the US are 1200 (900-1600), 3500 (2800-4300), and 1900 (1400-2500), respectively. Total avoided deaths in South Korea and Japan are dominated by reductions in PM2.5-related mortality, but ozone plays a more important role in the US. Similar to co-benefits for PM2.5 in China, co-benefits of China's policy for ozone and for both pollutants in those downwind countries also rise with increasing policy stringency.

In order to determine recent behaviors in atmospheric polycyclic aromatic hydrocarbon (PAH) concentrations at the west end of Japan and to reveal the causes of these behaviors, atmospheric PAH concentrations were measured in suburban and forest sites of Nagasaki, Japan from 2017 to 2021. The results showed that the total concentration of PAHs decreased considerably by 60% and 57% in suburban and forest sites, respectively, over this period. When analyzed by season, the rate of decrease in winter was markedly high. Therefore, the decreasing behavior in PAH concentrations in Nagasaki in recent years was considered to be mainly due to less PAHs originating from cold continental regions such as northern China. In particular, the reduction in coal and biomass combustion for winter heating in households, the efforts to improve air quality, and the limitation of economic activities in response to COVID-19 were likely responsible for the decrease in atmospheric PAH concentrations. In addition, although the PAH concentrations decreased, there was no significant change in the breakdown of the number of benzene rings in the PAH or in the attributes of their sources.

Columnar and ground-level aerosol optical properties co-located in space and time and retrieved from sun/sky photometer and nephelometer measurements, respectively, have been analyzed to investigate the impact of local and transboundary pollution, to analyze their relationships, and hence to contribute to the aerosol load characterization over the Central Mediterranean. The aerosol optical depth (AOD) at 440 nm, the Ångström exponent (Å) calculated from the AOD at 440 and 675 nm, and the asymmetry parameter ( g col ) at 440 nm represent the investigated columnar aerosol parameters. The scattering coefficient ( σ p ) at 450 nm, the scattering Ångström exponent (å) calculated from σ p at 450 and 635 nm, and the asymmetry parameter ( g ) at 450 nm are the corresponding ground-level parameters. It is shown that the columnar and ground-level aerosol properties were significantly and similarly affected by the main airflows identified with backtrajectory cluster analysis. The yearly averaged daily evolution of σ p , å, and g was fairly correlated to the one of the AOD, Å, and g col , respectively. These results indicate that the aerosol particles were on average characterized by similar yearly averaged optical properties up to the ground level. In particular, the yearly means of columnar and ground-level Ångström exponents, 1.3 ± 0.4 and 1.1 ± 0.4, respectively, which are close to one, reveal a coarse-mode aerosol contribution in addition to the fine-mode particle contribution up to the ground level. Hourly means, day-by-day, and seasonal daily patterns of ground-level parameters were, however, very weakly correlated with the corresponding columnar parameters. The large impact of the local meteorology on the daily evolution of the ground-level aerosol properties, which makes the impact of long-range transported particles less apparent, was mainly responsible for these last results. It has also been found that columnar Ångström exponents much smaller than one may not be linked to å values smaller than 1. This may occurs when coarse-mode particle plumes, advected at high altitudes, do not penetrate inside the planetary boundary layer. Ångström exponents smaller than 1 are due to a significant contribution of coarse-mode particles as dust particles. Therefore, it is shown that å represents one of the best parameters to infer the contribution of coarse-mode particles at the ground level. The daily evolution of the aerosol properties referring to working days (Monday to Friday) and Sunday and the weekly cycle have suggested that the aerosol source contributions varied during the weekends. In particular, the AOD was characterized by a negative weekly cycle (higher AOD values during the weekend than during the weekdays), the Sunday σ p daily mean was 11 % larger than the Monday value, and å reached the highest value on Sunday. The impact up to the ground level of the weekdays’ transboundary pollution, which reaches the monitoring site during the weekends, has likely contributed to these results.

The Chernobyl disaster, the Amoco Cadiz oil spill and the Colorado River dispute are examples of an activity conducted by one state which has serious adverse effects in the territory of another, or in global common areas. This book details the international rules and compensation procedures and is intended for use by governmental officials, international lawyers and jurists. It discusses existing laws on international liability and considers the underlying legal issues that require further development. It is one of the few books on the subject written from the perspective of a developing country with rapid economic and social development.