Exploring pollution control in transboundary watersheds under the perspective of ecological compensation based on aggregate game

Pollution control in inter-provincial river basins involves many complex subjects, so it is difficult to effectively implement ecological compensation policies. To clarify the interest relationship among pollution control subjects and stimulate their willingness to cooperate in collaborative governance, this paper builds a multi-agent coordinated pollution control model based on the theory of aggregate game; explores the change of equilibrium action of a single pollution control agent and multi-actors, symmetric, and asymmetric situations under the influence of synergistic benefits; and studies the incentive mechanism design to maintain the cooperation of various agents. The research results show that an increase in the number of upstream firms would lead to a reduction in the incentive effects of downstream government compensation and an increase in the likelihood of "free-riding" and "coordination failure." Synergy benefits vary positively with the degree of cooperation between government and enterprises, and higher synergy benefits can effectively compensate for the high transaction costs caused by multiple entities, alleviate the financial pressure on downstream governments, and increase the willingness of upstream and downstream entities to cooperate. In addition, focusing on wastewater reduction from core enterprises, such as heavy polluters can help improve the efficiency of regional emissions reduction, while having a catalytic effect on small enterprises.

How does the urban-rural income gap affect regional environmental pollution?--Re-examination based on the experience of cities at prefecture level and above in China

Based on the traditional "EKC" theory, this paper examines the impact of urban-rural income disparity on environmental pollution in Chinese cities above the prefecture level from 2005 to 2015 using nonlinear models and spatial correlation models and tests the mechanism of action from two perspectives: demand scale and human capital. The results show that the urban-rural income gap has an obvious "inverted U-shaped" trend on environmental pollution. Both demand size and human capital are the main mechanisms affecting the environmental pollution effect of the urban-rural income gap, and the marginal pollution effects of both are "negative first and then positive" as the urban-rural income gap widens. The pollution effects of the urban-rural income gap are significantly spatially correlated at both the national and regional scales. The strength of environmental regulation is an important factor affecting the urban-rural income gap and has a significant "U-shaped" effect on regional pollution through the urban-rural income gap.

The impact of three related emission industries on regional atmospheric chlorinated paraffins pollution

Identifying the contributions of various chlorinated paraffins (CPs) sources in the environment plays an important practical role in the prevention and control of the CPs contamination. However, little is known about how main CP-related emission industries affect the regional atmospheric characteristics of CPs, including CP products industry, metal working industry, and polyvinyl chloride (PVC) industry. In this study, 60 passive air samples were collected from five typical cities in Henan Province, China, which had serious CP pollution and different structures of CP-related emission industry. Short chain CPs (SCCPs) and medium chain CPs (MCCPs) were detected in all samples in concentrations ranging of 2.6-7.7 × 10² and 2.1-4.3 × 10² ng m^-3, respectively, which were higher than those in most reports. Moreover, Luoyang (LY) is different from other cities, showing a relatively severe MCCP contaminations. The CP pollution characteristics between different cities are obviously affected by the proportion of local CP-related industries. According to the results of cluster heatmaps, the local CP-related emission industrial structure had a greater impact on MCCPs pollution than SCCPs. Additionally, the contribution of metal working industry was beyond that of PVC production industry and CP products industry.

Temporal variations, regional contribution, and cluster analyses of ozone and NOx in a middle eastern megacity during summertime over 2017-2019

Particulate matter is usually regarded as the dominant pollutant in Tehran megacity in Iran. However, the number of ozone exceedance days significantly increased in recent years. This study analyzes simultaneous measurements of O₃ and NO_x (NO+NO₂) concentrations to improve our understanding of ozone evolution during the summers of 2017 to 2019. The k-means clustering technique was used to select five representative air quality monitoring sites in Tehran to capture O₃ and NO_x concentrations' variability. The findings show that all of the investigated sites failed to meet the ozone non-attainment criterion. The ozone weekend effect is seen in the study of weekday/weekend differences in 2017 and 2018, but not in 2019, which can be due to the shift in the ozone production regime. The summer mean variation analysis can also be used to deduce this regime change. In 2017, the O₃ and NO₂ summer mean variations suggest a holdback in the NO₂ upward trend and a reversal in the O₃ downward trend that had been in place since 2012. Air mass back trajectory clustering reveals that east and north-east air mass clusters have the most significant impact on Tehran's O₃ pollution and the highest regional contribution to O_X. The study of O_X against NO_x shows that the regional contribution to O_X increased from 2017 to 2018 and then decreased in 2019; however, the local contribution is the opposite. The diurnal analysis of the regional and local contributions to O_X indicated that O_X in Tehran might be primarily affected by pollutants from a short distance. The findings reveal critical changes in the behavior of O₃ in recent years, indicating that decision-makers in Tehran should reconsider air pollution control measures.

Effect of COVID-19 lockdown on regional pollution in Ireland

This study examines the regional impact of the COVID-19 lockdown restrictions on pollution in Ireland by comparing the 2020 measurements of ozone (O₃), nitrogen dioxide (NO₂), and particulate matter (PM) from monitoring stations around the country to the previous 3-year average. Results indicate that O₃ was 5.6% lower and 13.7% higher than previous years during the lockdown at rural and suburban sites, respectively. NO₂ decreased by 50.7% in urban areas, but increased slightly in agricultural regions, consistent with satellite observations. PM concentrations did not change significantly compared to previous years; however, a reduction in the signal variability in the smaller size particle measurements may be the result of different emission sources. The reduction in NO₂ likely increased the ratio of volatile organic compounds (VOCs) to NO_x (nitrogen oxides), creating a NO_x limited environment, which resulted in an initial increase in O₃ in suburban areas, and the lower than usual levels observed at rural sites. Meteorology showed higher than average wind speeds prior to lockdown, which likely acted to disperse PM and NO₂.

A seriously air pollution area affected by anthropogenic in the central China: temporal-spatial distribution and potential sources

This study used the officially released data by the Chinese air quality monitoring network to analyze the pollution characteristics of six air pollutants (PM_2.5, PM₁₀, SO₂, NO₂, CO, and O₃) for 29 cities in the Central Plains Economic Zone (CPEZ; China) in 2015. During 2015, serious particulate matter (PM) pollution often occurred, and the concentrations of PM_2.5 and PM₁₀ were 77 μg m^-3 and 128 μg m^-3, respectively. Air pollutants were at higher concentrations in the northern cities than those in the southern region of the CPEZ, and the correlation among the cities indicated that there was regional pollution in CPEZ. Generally, PM, SO₂, NO₂, and CO showed similar seasonal characteristics and the highest and lowest concentrations appeared in winter and summer, respectively. In addition, we used the HYSPLIT model and trajStat model to identify the potential source contribution function and concentration-weighted trajectory of Zhengzhou, the central city of CPEZ. More serious air pollution occurred when air masses were transported from the west of the CPEZ. Shaanxi Province, Hubei Province, Anhui Province and the northwest of the CPEZ were found to be the main exogenous sources of total PM with contributions of > 100 μg m^-3 PM_2.5 and > 180 μg m^-3 PM₁₀. Therefore, the concentrations of PM in 2015 at Zhengzhou were probably influenced by both long-distance transmission and local emissions.

Spatial agglomeration of new energy industries on the performance of regional pollution control through spatial econometric analysis

With the increasing prominence of China's energy security and environmental pollution issues, improving environmental control performance is significant for China to achieve a sustainable economy and environment. In this study, the impact of the spatial agglomeration of the new energy industry on the regional pollution control performance was considered in a spatial econometric model. From the two perspectives of technology patents and employees, the impact of the spatial agglomeration of the new energy industry was explored using the spatial panel data model. The research results show the existence of spatial correlation of the pollution control performance among regions. Moreover, the spatial agglomeration of relevant technology patents can have a negative effect and the spatial agglomeration of employees a positive effect on the improvement in regional pollution control performance. Then, policy recommendations to improve the regional pollution control performance are proposed based on the research results: establishing a regional environmental joint governance system, improving the diffusion mode of new energy technology patents, and quickly constructing a new energy industrial park.

Assessment of air pollution origin based on year-long parallel measurement of PM2.5 and PM10 at two suburban sites in Prague, Czech Republic

From 2nd April 2008 to 28th March 2009, a total 248 daily samples of the PM_2.5 and PM₁₀ were collected every sixth day parallel at two suburban sites (Libuš and Suchdol) located at the two opposite sides (south and north, respectively) of Prague, Czech Republic. The PM_2.5 samples were analyzed for ions by ion chromatography (IC), organic and elemental carbon (OC and EC) by OC/EC analyzer and PM₁₀ samples also for 56 elements by inductively coupled plasma-mass spectrometry (ICP-MS). The average annual PM_2.5 and PM₁₀ was 24.4 ± 13.0 μg m^-3 and 26.7 ± 15.1 μg m^-3, respectively, in Prague-Libuš, and 25.1 ± 22.1 μg m^-3 and 27.1 ± 23.2 μg m^-3, respectively, in Prague-Suchdol. Since the species forming large part of the aerosol mass were strongly correlated (Spearman's rank correlation coefficient r_s > 0.80), the variability of PM_2.5 and PM₁₀ concentration was mainly driven by the local meteorology or regional and/or long range transport. PM₁₀ mass closure was calculated based on analytical results with the average percentage of recalculated mass of 77 ± 19% in Prague-Libuš and 86 ± 16% in Prague-Suchdol. The most abundant groups in PM₁₀ at both sites during the four seasons were OM (Prague-Libuš 34% and Prague-Suchdol 37%) and SIA (Prague-Libuš 30% and Prague-Suchdol 34%). The Positive Matrix Factorization (PMF) was applied to the chemical composition of PM₁₀ from both sites (124 samples) together to determine its sources. The nine factors were assigned as: mixed factor secondary sulphate and biomass burning, secondary sulphate, traffic, secondary nitrate, road dust, residential heating, aged sea salt, industry and mixed factor road salt along with aged sea salt. According to the polar plots and ventilation index (VI) east/west classification analysis the sources were separated based on origin to four categories local, urban agglomeration, regional and long range transport (LRT). The mixed source secondary sulphate and biomass burning, residential heating and industry were common sources of local origin at both sites. Prague-Suchdol was influenced by traffic related pollution from the urban agglomeration more than Prague-Libuš where the traffic and road dust/salt were of local origin. The regional pollution by secondary sulphates and nitrate was also relevant at both sites along with long range transport of sea salt from North Atlantic Ocean, Norwegian Sea and North Sea. The contribution of the local sources to PM₁₀ was significant mainly at Prague-Libuš site. However, the sources of regional origin were also important and influence of urban agglomeration pollution to PM₁₀ is not negligible as well.

Temporal characterization and regional contribution to O3 and NOx at an urban and a suburban site in Nanjing, China

To improve our understanding of the interplay among local and regional photochemical pollutants in the typical city of the Yangtze River Delta (YRD) region, the concurrent observation of O3 and NOx concentrations at an urban and a suburban site in Nanjing during 2008 is presented. In general, the annual mean O3 concentration is 2.35ppbv lower in the downtown than at suburban due to higher NOx pollution levels correlated with heavy traffic. At both sites, O3 shows a distinct seasonality with the spring maximum and the winter minimum, while the minimum concentration of NOx appears in summertime. Besides the chemical processes of O3 sensitivity in the daytime and the NOx titration at night, meteorological conditions also play an essential role in these monthly and diurnal variations. The ozone weekend effect that can be attributed to the weekly routine of human activities is observed in the urban atmosphere of Nanjing as well, with O3 concentrations 2.09ppbv higher and NOx concentrations 6.20ppbv lower on weekends than on weekdays. The chemical coupling of NO, NO2 and O3 is investigated to show that the OX-component (O3 and NO2) partitioning point occurs at about 35ppbv for NOx, with O3 being the dominant form at lower levels and NO2 dominating at higher levels. And it is also discovered that the level of OX is made up of two contributions, including the regional contribution affected by regional background O3 level and the local contribution correlated with the level of primary pollution. The diurnal peak of regional contribution appears 2-5h after the peak of local contribution, implying that OX in Nanjing might prominently affected by the pollutants from a short distance. The highest regional contribution and the second highest local contribution lead to the spring peak of O3 observed in Nanjing, whereas the highest local contribution and the moderate regional contribution make the O3 concentrations in summer higher than those in autumn and winter. Our results reveal the important environment impacts from meteorological conditions and human activities in the YRD region, and can help to understand O3 pollution in these polluted areas by just using the conventional observations.

Urban rivers as hotspots of regional nitrogen pollution

Excess nitrogen inputs to terrestrial ecosystems via human activities have deteriorated water qualities on regional scales. Urban areas as settlements of over half global population, however, were usually not considered in the analysis of regional water pollution. Here, we used a 72-month monitoring data of water qualities in Hangzhou, China to test the role of urban rives in regional nitrogen pollution and how they response to the changes of human activities. Concentrations of ammonium nitrogen in urban rivers were 3-5 times higher than that in regional rivers. Urban rivers have become pools of reactive nitrogen and hotspots of regional pollution. Moreover, this river pollution is not being measured by current surface water monitoring networks that are designed to measure broader regional patterns, resulting in an underestimation of regional pollution. This is crucial to urban environment not only in China, but also in other countries, where urban rivers are seriously polluted.