Regional Emission Control Research Articles

Aerosol in global oceanic regions: Four-decade trends, spatial patterns, and policy implications

High aerosol loadings are observed not only in megacities on continents but also in oceanic regions like the Bohai Sea. This work provides a comprehensive analysis of the spatial and temporal variations in Aerosol Optical Depth (AOD) across different ocean regions worldwide over the past four decades, using remote sensing reanalysis data. The mean AOD value across all oceanic grids is approximately 0.112, with higher levels recorded in the Central Atlantic (~0.206), followed by the North Indian Ocean (~0.201), and the Western North Pacific (~0.197). A latitudinal analysis reveals that high AOD values are predominantly found in the Northern Hemisphere's oceanic regions, especially between latitudes 0° and 70° N. Except for the Gulf of California and Hudson Bay, AOD values in the other fourteen surveyed inland seas surpass the mean levels found at similar latitudes in oceanic regions. Among which, the Bohai Sea stands out as the most polluted oceanic region with AOD value of 0.35. Over the last four decades, AOD trends have revealed a significant decrease across about 89.5 % of global oceanic grids, while an increase in AOD is observed in low-latitude oceanic areas (30° S–30° N). Investigation into inland seas shows that nearly two-thirds have experienced a declining AOD trend, while sharply upward trends in AOD are primarily found in Asia. The Bohai Sea shows the largest increase in AOD, with an annual growth rate of 1.4 %. The turning-points of the AOD in each inland sea confirm the success of regional emission control policies initiated on the adjacent continents. To improve air quality in inland seas like the Bohai Sea, adjusting industrial layouts, such as relocating heavy industries from the surrounding coastal cities' proximities to areas near open seas, could significantly benefit public health.

Seasonal quantification of the inter-city transport of PM2.5 in the Yangtze River Delta region of China based on a source-oriented chemical transport model and the Michaelis-Menten equation

Regional transport plays a crucial role in the pollution of fine particulate matter (PM2.5) over the Yangtze River Delta region (YRD). A practical joint regional emission control strategy requires quantitative assessment of the contribution of regional transport. In this study, the contribution of inter-city transport to PM2.5 among the 41 cities in the YRD region were quantitatively estimated using a source-oriented chemical transport model, and then the relationship between the cumulative contribution of regional transport and the distance was examined using the Michaelis-Menten equation. The results show that the Michaelis-Menten equation is suitable to represent the relationship between the cumulative contribution and transport distance. The coefficient of determination (r2) of the fittings is greater than 0.9 in 71 % of the cases in the six subregions and four seasons in YRD. Two key parameters in the Michaelis-Menten eq. K1, indicating the maximum contribution of regional transport, and K2, indicating the distance to which the regional transport contribution reach half the maximum contribution, show substantial regional and seasonal variations. The average K1 is 73.6 %, with lower values observed in the northern part of the YRD and higher values in central Jiangsu. K2 is larger in northern Jiangsu, as well as central and southern Zhejiang. The local contribution in autumn and winter is lower than that in spring and summer in the northern part of the YRD. Particularly in northern Jiangsu, the local contribution reaches 90.4 % in summer but drops to 53.0 % in autumn and winter, illustrating significant impacts of regional transport to PM2.5 in autumn and winter in this area. K2 is larger on polluted days, compared to clean days, indicating greater contributions from regional transport to PM2.5 in YRD. The results can serve as a scientific foundation for implementing regional joint prevention and control measures in the YRD region.

Frequent haze events associated with transport and stagnation over the corridor between the North China Plain and Yangtze River Delta

Abstract. PM2.5 pollution is a major air quality issue that deteriorates human health, and numerous studies have focused on PM2.5 pollution in major regions such as the North China Plain (NCP) and Yangtze River Delta (YRD). However, the characteristics of PM2.5 concentrations and the associated formation mechanism in the transport corridor (referred to as SWLY) between the NCP and YRD are largely ignored. Based on observational data, we find that the number of PM2.5 pollution events in SWLY is comparable to that in the NCP, far exceeding that in the YRD, which is indicative of the severity of air pollution in this area. Utilizing a regional climate and air quality model, we isolate the effect of seesaw transport events, e.g., transport between the NCP and YRD, and atmospheric stagnation on the accumulation of PM2.5 over SWLY. Specifically, seesaw events and stagnation, comparable to each other, collectively account for an average of 67 % of pollution days, with PM2.5 exceeding 75 µg m−3, and this fraction (85 %) is even larger for severe haze events, with PM2.5 exceeding 150 µg m−3. Furthermore, the connection between seesaw transport and large-scale circulation is examined. The transregional transport of pollutants from the NCP to the YRD (YRD to NCP) is likely stimulated by positive (negative) to negative (positive) geopotential height anomalies at 500 hPa located in northern China. The health effect due to short-term PM2.5 exposure induced by the transregional transport and stagnation is investigated, yielding a total of 8634 (95 % CI: 6023–11 223) and 9496 (95 % CI: 6552–12 413) premature deaths, respectively, in SWLY during winter 2014–2019, which is as high as 9 % of the total premature deaths in China, even though SWLY takes up less than 1 % of China's area. While atmospheric stagnation is in general projected to occur more frequently under a warming climate, this study indicates the importance of regional emission control to alleviate PM2.5 pollution from seesaw transport and stagnation.

Predictions of air quality and challenges for eliminating air pollution during the 2022 Olympic Winter Games

Scientifically and efficiently ensuring good air quality for important events is an issue of concern to the government. In addition to analysis based on historical data, advanced prediction before an event is essential for the government having ample time to take effective actions to improve air quality during the event period. Taking “the 2022 Olympic Winter Games (OWG)” as a typical case, a chemical transport model coupled with a tracer-tagged module was used to evaluate the air quality and source apportionment of ambient pollutants in the OWG host cities under historical and predicted meteorological conditions. Driven by the downscaling of meteorological fields from an operational real-time climate forecast system, the potential ability of air quality forecasting three months ahead was investigated, which was meaningful for designing control strategies. Sensitive simulations indicated that under unfavorable meteorological conditions, such as those during February 2014, both Beijing and Zhangjiakou faced a high risk of experiencing haze episodes, even based on current anthropogenic emission intensity. The contribution of the joint prevention and control region to Beijing and Zhangjiakou would become larger under worse meteorological conditions, which favor heavy air pollution. The source apportionment results indicated that strengthened emission control in cities including Beijing, Zhangjiakou and south of Beijing (Baoding, Langfang, Tianjin, and Tangshan) is effective for reducing haze episodes in the host cities. There is still a long way to make accurate daily fine particulate matter predictions on a seasonal-scale in advance; however, it could capture the trends in air quality in host cities around the OWG period three months ahead. The comparison of observations and predictions confirmed and highlighted the role of regional emission controls on the realization of the “OWG blue”.

Optimizing emission control strategies for mitigating PM2.5 and O3 pollution: A case study in the Yangtze River Delta region of eastern China

Effective mitigation of fine particulate matter (PM2.5) and ozone (O3) pollution necessitates collaborative regional emission control of major pollutants. In this study, we propose an approach based on source-receptor relationships (SRRs) and a mathematical programming (MP) model to quantify the regional atmospheric environmental capacity (AEC) constrained by certain air quality goals for PM2.5 and O3. We apply this method to optimize emission control strategies addressing a springtime case of concurrent high PM2.5 and O3 pollution in the Yangtze River Delta (YRD) region of eastern China in May 2014. Our analysis of SRRs reveals that O3 pollution is more contributed by regional transport compared to PM2.5, thereby limiting the potential for meeting the O3 target through anthropogenic emission reductions. Imposing various constraints on air quality goals and upper limits of emission reduction ratios yields significant variations in potential control pathways specific to source sectors and regions. To effectively mitigate PM2.5 pollution, substantial reductions in sulfur dioxide (SO2) and primary PM2.5 emissions are required, whereas ammonia (NH3) control demonstrates less effectiveness. Differentiated and coordinated efforts in controlling nitrogen oxide (NOx) and volatile organic compounds (VOCs) emissions are necessary to simultaneously achieve the desired PM2.5 and O3 targets. Evaluation of potential control pathways further emphasizes the effectiveness of implementing control measures on major precursor emissions to reduce PM2.5. However, meeting the O3 target remains challenging due to the complex nonlinearity involved in O3 formation. To attain the air quality goals for PM2.5 (<50 μg m−3) and daily maximum 1-h average (MDA1) O3 (<160 μg m−3) across the entire YRD, the estimated AEC values for SO2, NOx, NH3, VOCs, and primary PM2.5 are approximately 8.3, 79.4, 102.7, 186.9, and 13.0 kt mon−1, respectively, with corresponding emission reduction ratios of 95.6%, 75.5%, 33.1%, 45.1%, and 85.5% at the regional level.

Economic aspects of assessment and marketing of carbon emissions by enterprises based on the principles of sustainable development

Purpose. To analyze the economic aspects of carbon emissions by industry and conduct a marketing assessment of the emissions trading system (ETS). To develop recommendations for the introduction of market mechanisms for regulating emissions. Methodology. Special and general methods of scientific knowledge are used: abstract-logical analysis to identify the predominant causes of greenhouse gas (GHG) generation; statistical methods of analysis to establish the correlation of capital investments and emissions; induction and deduction to identify complex management approaches to reducing harmful emissions; mathematical – for the formalization of the factors of the ETS market and their functional dependencies, necessary for the analysis of the market. Findings. A correlation between capital investments and emissions has been established, which confirms the long-term trend of implementing a strategic policy of enterprises to reduce emissions. The presence of sectoral differences in correlation coefficients indicated the need for differentiation of institutional support for industries as a tool for changing the export structure. The effects of Carbon Border Adjustments Mechanism (CBAM) influence on the economy of Ukraine are indicated. Recommendations for harmonizing issues regarding Ukraine’s obligations to reduce emissions are proposed. Measures to reduce risks for the economy during the introduction of the national ETS are proposed. Originality. Factors of the ETS market and their functional dependencies that are necessary for market analysis are presented mathematically. An equivalence function is proposed for the assessment of individual specific indicators of enterprises. The factors that determine prices and the amount of demand at the ETS market are stratified. Principles of this market are formulated. Practical value. It is proposed to introduce regional emission control laboratories and agree on the recognition of their certificates by Ukraine and the EU.

Large Modeling Uncertainty in Projecting Decadal Surface Ozone Changes Over City Clusters of China

AbstractClimate policies will affect future surface ozone pollution in China. Here, we simulate changes in summertime ozone across China by 2030 under four emission scenarios reflecting different levels of climate action. We also contrast results obtained with two different chemical mechanisms employed in the chemical transport model (WRF‐Chem). With emission reductions in ozone precursors introduced by climate policies, both mechanisms show promising ozone mitigation for most parts of China. However, they disagree starkly in China's three main city clusters, where one mechanism projects worsening ozone pollution by 2030 despite the emission reductions. We analyze possible drivers of this important discrepancy, in particular the role of varying ozone chemical regimes affecting its sensitivity to emission changes. We recommend an intercomparison project to examine this critical modeling uncertainty among other models/mechanisms, which would be invaluable for informing local and regional emission control strategies that are based on single‐model results.

Elucidating the Factors Governing the Interannual Variability of Ozone Concentrations During Fall 2015-2019 in Sanya, China

While ozone pollution has been a major air pollution concern in metropolitans in China, the characteristics and governing factors of ozone concentrations in Sanya remains unclear. In this study, we first analyze the interannual variability of ozone based on observational data in Sanya, and identify it is in general characterized by a peak ozone season in fall and minimal ozone season in summer. Meanwhile, the substantial ozone enhancement in 2019 compared to the previous three to four years over Sanya clearly stands out. To elucidate the possible governing factors, we design a few numerical experiments based on regional air quality model, and find that the modulation of meteorology is key to steering the interannual variability of ozone in fall in Sanya. The spatial evolution further indicates that the transport from upwind regions like Pearl River Delta region is crucial in stimulating the ozone accumulation in Sanya. In addition, ship emissions play important roles in further enhancing their ozone concentration, ranging from 7% -10% during 2015-2019. The findings in this study imply that whereas an overall low ozone concentration in Sanya, ozone exceedance may still occur in particular under unfavorable meteorological conditions together with the concomitant transport from other regions facing ozone pollution. It stresses the importance of regional emission control, including anthropogenic emissions and ship emissions, on improving air quality in Sanya.

Application of data assimilation technology in source apportionment of PM2.5 during winter haze episodes in the Beijing-Tianjin-Hebei region in China

Atmospheric fine particles (PM2.5) in the Beijing-Tianjin-Hebei region have a considerable impact on air quality. Quantitative analysis of PM2.5 transport within the boundary layer is still lacking. In this study, vertical observations from the lidar network were assimilated into the Community Multiscale Air Quality model. The integrated source apportionment method was used to investigate the contributions of PM2.5 in Beijing from January 10 to 18, 2018. After assimilation, the correlation coefficient values of the average diurnal vertical variation between the simulations and observations improved by 20.61%. The investigation of the regional transport at the different vertical layers indicated that: During the two pollution episodes, Beijing's local contribution was significant from the surface to 0.1 km, the maximum hourly mean contributions were 31.15 μg/m3 and 27.56 μg/m3, respectively. From 0.1 to 0.8 km, the local contribution was decreased to below 10 μg/m3, the contributions from the top 10 surrounding areas ranged from 9.51 μg/m3 (49.9%) to 20.42 μg/m3 (80.8%), which were 1.0–9.3 times greater than the local contribution. From 0.8 to 2.0 km, the local contribution decreased gradually, and the regional transport was mainly from Shanxi under prevailing wind fields. Based on lidar vertical observation data, our study revealed that the local contribution of Beijing played an important role in controlling the PM2.5 concentrations from the surface to 0.1 km, while the regional transport was considerable from 0.1 to 2.0 km, particularly from the severely polluted upwind region. It is critical to enhance regional joint emission control, especially during pollution episodes.

Mitigating ozone damage to ecosystem productivity through sectoral and regional emission controls: a case study in the Yangtze River Delta, China

The land ecosystems of China are estimated to provide an important sink for the increased atmospheric carbon dioxide (CO2), but are undermined by severe ozone (O3) pollution. Mitigation of O3 damage to ecosystems remains a challenge considering that O3 precursors are emitted from a wide range of anthropogenic sectors and O3 formations are also affected by regional transport. Here, we combine chemical transport and dynamic vegetation models to quantify the benefits of sectoral and regional emission controls for the recovery of gross primary productivity (GPP) in the Yangtze River Delta (YRD). For sectoral emission controls, the largest mitigation of O3 damage to GPP in YRD by 3.1 ± 0.4 and 2.2 ± 0.2 Gg[C] d−1 with 50% reductions in the emissions from industry and transportation sectors, respectively. For regional emission controls, reducing 50% anthropogenic emissions outside YRD can mitigate GPP losses by 18.6 ± 3.5 Gg[C] d−1, larger than the recovery of 10.1 ± 1.6 Gg[C] d−1 by the 50% reductions of anthropogenic emissions within YRD. Moreover, summer months, especially July are the best period for GPP recovery from anthropogenic emission controls. Our results highlight the importance of sectoral and regional emission controls to mitigate O3 damage to ecosystem productivities in YRD.

Unveiling the dipole synergic effect of biogenic and anthropogenic emissions on ozone concentrations

Biogenic emissions are widely known as important precursors of ozone, yet there is potentially a strong interaction and synergy between biogenic and anthropogenic emissions, including volatile organic compounds (VOCs) and nitrogen oxides (NOx), in modulating ozone formation. To a large extent, the synergy affects the effectiveness of anthropogenic emission control, thereby reshaping the O3-NOx-VOC empirical kinetic modeling approach (EKMA) diagram. Focusing on the ozone pollution period of June 2017 in the North China Plain, we design almost 500 numerical experiments using regional air quality model Community Multiscale Air Quality (CMAQ) that revealed an interesting synergic effect, defined as the contribution of biogenic emissions to ozone concentrations concomitant with a reduction in anthropogenic emissions. A quasi-EKMA diagram is constructed to delineate the contribution of biogenic emissions to ozone concentrations, indicative of a linearly amplified or nonlinearly weakened result associated with reductions in anthropogenic VOCs or NOx emissions, respectively, illustrating the dipole characteristics of the synergic effect. The reduced ozone contribution from biogenic emissions along with NOx emission reduction can be used to represent controllable biogenically induced ozone (BIO). Both the amplified and controllable BIO are tightly linked to both local emissions and regional transport, implicative of an essential role in joint regional emission control. In regard to ozone exceedance, the role of biogenic emissions may be even more important, in that its contribution is comparable to or even larger than that of anthropogenic emissions when associated with a reduction in anthropogenic emissions, which is clearly demonstrated based on the near carbon neutrality scenario shared socioeconomic pathway (SSP) 126. Meanwhile, the biogenic emissions may steer the modulation of anthropogenic emissions in the change rate of MDA8 ozone concentration. Therefore, the synergic effect of biogenic and anthropogenic emissions elucidated in this study should be carefully considered in future ozone pollution control.

Effectiveness of emission control in sensitive emission regions associated with local atmospheric circulation in O3 pollution reduction: A case study in the Beijing-Tianjin-Hebei region

Currently, mitigation of persistent severe O3 pollution is the key for further improving the air quality in the Beijing-Tianjin-Hebei (BTH) region, China. The source contributions and transboundary transport of O3 during pollution episodes are closely related to weather conditions. The effective reduction in emissions to control O3 pollution under typical local atmospheric circulation conditions highly correlated with continuous pollution processes in the North China Plain (NCP) is rarely reported. In this study, a sensitive area in the BTH region was identified based on the analysis of the diurnal evolution features of local atmospheric circulation and the distribution characteristics of anthropogenic emissions in the NCP region. Multiple emission reduction scenarios were designed to explore the impacts of hotspot anthropogenic emissions in this sensitive area on O3 pollution formation during a regional prolonged O3 pollution episode from 30 August to 6 September 2019. Compared to large-scale anthropogenic emission control across the NCP region, a smaller emission reduction and much larger O3DM (the daytime mean ozone concentration, from 10 a.m. to 5pm) reduction were obtained through emission control in the sensitive area. The results also indicated that anthropogenic emission hotspots in this sensitive area play a decisive role in O3 photochemical formation chemistry across the whole BTH region with high emissions. The actual impact of hotspot anthropogenic emissions originating in the BTH region was not limited to its locality but occurred within a certain wide range, with a relatively significant contribution to O3DM ranging from approximately 20-80 μg/m3 in most of the plain area, accounting for approximately 15%∼40% of O3DM. Among all anthropogenic sources, the industry is the most important contributor to O3 formation, and traffic is the second most important contributor. In terms of regional emission control, it is suggested that under extremely unfavorable weather conditions, the BTH government should focus on local emission reduction, particularly in the industrial source category, and it should simultaneously consider the synergistic impact between the industry and traffic to maximize the effectiveness of control policies to achieve long-term ozone reduction.

Influence of regional emission controls on the chemical composition, sources, and size distributions of submicron aerosols: Insights from the 2014 Nanjing Youth Olympic Games

High-intensity emission controls were implemented in Nanjing and in 8 surrounding cities to ensure good air quality during the 2014 summer Youth Olympic Games (YOG). An Aerodyne soot-particle aerosol mass spectrometer (SP-AMS) was deployed at a downwind site of downtown Nanjing to investigate the chemical composition, sources, and size distribution of submicron aerosols (PM1), in response to emission control policies. However, results show that emission controls played a negligible role in reducing PM1 concentration during the YOG period, yet primary precursors such as NOx and SO2 were decreased by 10–20%. Low wind speed, high relative humidity, and high ozone (O3) concentration likely play a significant role in the production and accumulation of the oxygenated organic aerosol (OOA) and the secondary inorganic aerosols (SIA) in summer Nanjing. We propose that long-term regional emission reduction could be a solution for future air pollution mitigation strategies in downwind cities of the YRD region, and that seasonal meteorological characteristics in a specific region should be considered before emission control policies are made.

Mechanism of haze pollution in summer and its difference with winter in the North China Plain

Heavy haze pollution usually occurs in winter. However, according to the enhanced atmospheric boundary layer (ABL) field experiments conducted in the North China Plain (NCP) from 17 June to 6 July 2019, heavy haze pollution may also occur in summer, although with a lower probability. Winter haze pollution is significantly affected by adverse boundary layer meteorological conditions, whereas our study shows different mechanisms of summer haze pollution from that of winter. In summer, PM2.5 is distributed uniformly as a thick layer at a lighter pollution level; however, the PM2.5 column content in summer exceeds that in winter, suggesting that the better air quality in summer is mainly due to improved diffusion conditions. In summer, even under haze conditions, the ABL can develop over 1000 m and has a large ventilation similar to clean periods, which indicates both favourable vertical diffusion conditions and advection capability of the summer ABL. Unlike in winter, the heavy haze pollution in summer is often caused by regional transport which is related to local circulation. To explore the influence of different scale systems on summer haze pollution, we applied the spectral analysis method to surface PM2.5 concentrations. Strong periodicity of PM2.5 concentrations is found in 4–9 d and 1 d, corresponding to the impacts of large-scale synoptic system changes and the ABL evolution, respectively. The influence of weather change is much stronger than that of the ABL evolution on PM2.5 concentrations in summer. The resulting changes in PM2.5 concentrations are approximately 45 μg/m3 and 15 μg/m3, respectively. There has been a consensus on the importance of emission control in winter. And this study shows that heavy haze pollution can also occur in summer and regional joint emission control should also be emphasized in summer.

Atmospheric ammonia and its effect on PM2.5 pollution in urban Chengdu, Sichuan Basin, China

Controlling ammonia (NH3) emissions has been proposed as a strategy to mitigate haze pollution. To explore the role of NH3 in haze pollution in Sichuan Basin, where agricultural activities are intense, hourly in situ data of NH3, as well as nitric acid and secondary inorganic aerosols (SIAs) were gathered in Chengdu from April 2017 to March 2018. We found that NH3 had an annual mean concentration of 9.7 ± 3.5 (mean ± standard deviation) μg m−3, and exhibited seasonal variations (spring > summer > autumn and winter) due to changes in emission sources and meteorological conditions (particularly temperature). Chengdu's atmosphere is generally NH3-sufficient, especially in the warm seasons, implying that the formation of SIAs is more sensitive to the availability of nitric acid. However, an NH3 “sufficient-to-deficient” transition was found to occur during winter pollution periods, and the frequency of NH3 deficiency increased with the aggravation of pollution. Under NH3-deficient conditions, the nitrogen oxidation ratio increased linearly with the increase in free NH3, implying that NH3 contributes appreciably to the formation of nitrate and thus to high PM2.5 loadings. No relationships of NH3 with fossil fuel combustion–related pollutants were found. The NH3 emissions from farmland and livestock waste in the suburbs of Chengdu and regional transport from west of Chengdu probably contribute to the occurrence of high PM2.5 loading in winter and spring, respectively. These results suggest that to achieve effective mitigation of PM2.5 in Chengdu, local and regional emission control of NH3 and NOx synergistically would be effective.

Assessment of Emission Reduction and Meteorological Change in PM2.5 and Transport Flux in Typical Cities Cluster during 2013–2017

Under the Air Pollution Prevention and Control Action Plan (APPCAP) implemented, China has witnessed an air quality change during the past five years, yet the main influence factors remain relatively unexplored. Taking the Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD) regions as typical cluster cities, the Weather Research Forecasting (WRF) and Comprehensive Air Quality Model with Extension (CAMx) were introduced to demonstrate the meteorological and emission contribution and PM2.5 flux distribution. The results showed that the PM2.5 concentration in BTH and YRD significantly declined with a descend ratio of −39.6% and −28.1%, respectively. For the meteorological contribution, those regions had a similar tendency with unfavorable conditions in 2013–2015 (contribution concentration 1.6–3.8 μg/m3 and 1.1–3.6 μg/m3) and favorable in 2016 (contribution concentration −1.5 μg/m3 and −0.2 μg/m3). Further, the absolute value of the net flux’s intensity was positively correlated with the degree of the favorable/unfavorable weather conditions. When it came to emission intensity, the total net inflow flux increased, and the outflow flux decreased significantly across the border with the emission increasing. In short: the aforementioned results confirmed the effectiveness of the regional joint emission control and provided scientific support for the proposed effective joint control measures.

Sustainable Risk Assessment of Resource Industry at Provincial Level in China

The development of China’s resource industry is facing great pressures from industrial structure adjustment and environmental restraints, and the sustainable risk of the provincial resource industry is different. Considering the development of the resource industry and environmental pressure, this article selects the panel data of 31 provinces from 2015 to 2019 to construct an index evaluation system with six dimensions: influence, induction, supply and demand safety, regional pollution emission, environment quality, and pollution control. The results showed that Shanxi, Anhui, Jiangsu, and Shanghai had the highest sustainable risk in the resource industry, while Heilongjiang, Jilin, Tianjin, Fujian, Jiangxi, Hunan, Guizhou, Sichuan, and Qinghai had the lowest sustainable risk. The resource industry model of all the provinces is divided into sustainable, industrial, ecological, and unsustainable. Finally, this article puts forward reasonable suggestions for the four scenarios and argues that the balanced development of the resource industry sector and environmental protection is conducive to reducing the sustainable risks of the resource industry.

Temporal and spatial characteristics of PM2.5 transport fluxes of typical inland and coastal cities in China

Local pollution and the cross-boundary transmission of pollutants between cities have an inevitable impact on the atmosphere. Quantitative assessments of the contribution of transport to pollution in inland and coastal cities are necessary for the implementation of practical, regional, and joint emission control strategies. In this study, the Comprehensive Air Quality Model (CAMx), together with the Weather Research and Forecasting model (WRF), was used to simulate the contributions to pollution of different cities in 2016. The monthly inflow, outflow, and net flux from the ground to the extended layers served as the three main indicators for the analysis of the interactions of PM2.5 transport between adjacent cities. Between inland and coastal cities, the magnitude of inflow and outflow are larger in the former than in the latter. The inflow flux in the inland cities (Beijing and Shijiazhuang) was 10.6 and 10.7 kt/day, respectively, while that in the coastal cities (Tianjin, Shanghai, Hefei, Nanjing, and Hangzhou) was 9.1, 3.3, 5.8, 4.4, and 3.7 kt/day, respectively. In terms of variation over the year, the strongest inflow in the BTH region occurred in April, followed by October, July, and January, while that in the coastal cities in YRD occurred in January, followed by October, April, and July. Therefore, based on the flux intensity calculations and the transport flux pathways, effective joint control measures can be provided with scientific support, and a better understanding of the evolutionary mechanism among inland and coastal cities can be acquired.

Air quality and source apportionment modeling of year 2017 ozone episodes in Albuquerque/Bernalillo County, New Mexico

ABSTRACT Albuquerque/Bernalillo County, New Mexico, is currently in attainment of the 2015 National Ambient Air Quality Standard (NAAQS) for ozone (70 ppb), but its ozone design values have increased in recent years. Air quality and source apportionment modeling with the Comprehensive Air Quality Model with Extensions (CAMx) was conducted for Albuquerque/Bernalillo County to develop a refined understanding of ozone source apportionment in the region, estimate ozone concentrations in the year 2025 based on projected changes in anthropogenic emissions, and evaluate the sensitivity of future ozone concentrations to various changes in local and non-local emissions. The study focused on two ozone episodes during June and July 2017 when 8-hr average ozone concentrations were greater than 70 ppb. Based on the modeling results, ozone during the June 2017 episode was found to be driven largely by contributions from non-local and regional emissions, whereas ozone during the July 2017 episode was driven more strongly by local emissions from within Albuquerque/Bernalillo County. On high ozone days, anthropogenic emissions from within Albuquerque/Bernalillo County contributed between 8% and 19% (6–14 ppb) of total ozone. Half of this local ozone contribution was from on-road mobile sources. Fire emissions contributed as much as 2 ppb of ozone on a given day. Contributions from large power plants in New Mexico were as large as 1 ppb on a given day but less than 0.5 ppb on most days. Modeled ozone concentrations in Albuquerque/Bernalillo County were also sensitive to emissions from oil and gas emissions in New Mexico. If projected emission reductions by 2025 materialize, these reductions could reduce future peak 8-hr average ozone concentrations by as much as 3–4% compared to 2017 values. Implications: The results of this study have important implications for air quality management in Albuquerque/Bernalillo County. Ozone in Albuquerque/Bernalillo County is the result of local and non-local emissions, is impacted by wildfires, and is sensitive to statewide oil and gas emissions. The magnitude of modeled contributions from anthropogenic emissions within Albuquerque/Bernalillo County is strongly influenced by meteorological conditions, transport pathways, and the presence of wildfire. This modeling is important for understanding the potential effectiveness of local emission controls in Albuquerque/Bernalillo County, and can serve as a basis for testing future regional and local emission control options.

Transport and boundary layer interaction contribution to extremely high surface ozone levels in eastern China.

Vertical measurements of ozone (O3) within the 3000-m lower troposphere were obtained using an O3 lidar to investigate the contribution of the interactions between the transport and boundary layer processes to the surface O3 levels in urban Shanghai, China during July 23-28, 2017. An extremely severe pollution episode with a maximum hourly O3 mixing ratio of 160.4ppb was observed. In addition to enhanced local photochemical production, both downward and advection transport in the lower troposphere may have played important roles in forming the pollution episode. The O3-rich air masses in the lower free troposphere primarily originated from central China and the northern Yangtze River Delta (YRD) region. The downward transport of O3 from the lower free troposphere may have an average contribution of up to 49.1% to the daytime (09:00-16:00 local time) surface O3 in urban Shanghai during the pollution episode (July 23-26, 2017). As for the advection transport, large amounts of O3 were transported outward from Shanghai in the planetary boundary layer under the influence of southeasterly winds during the field study. In this condition, the boundary-layer O3 that was transported downward from the free troposphere in Shanghai could be transported back to the northern YRD region and accumulated therein, leading to the occurrence of severe O3 pollution events over the whole YRD region. Our results indicate that effective regional emission control measures are urgently required to mitigate O3 pollution in the YRD region.