Air Pollution Prevention Research Articles

Estimation of PM2.5 Hourly Concentration in Sichuan Province Based on GTWR-XGBoost Model

Aerosol optical depths of satellites and meteorological factors have been widely used to estimate concentrations of surface particulate matter with an aerodynamic diameter ≤ 2.5 μm. Research on a high time resolution and high-precision PM2.5 concentration estimation method is of great significance for timely and accurate air quality prediction and air pollution prevention and mitigation. Himawari-8 AOD hour product and ERA5 meteorological reanalysis data were used as estimation variables, and a GTWR-XGBoost combined model was proposed to estimate hourly PM2.5 concentration in Sichuan Province. The results showed that:① the performance of the proposed combination model was better than that of the KNN, RF, AdaBoost, GTWR, GTWR-KNN, GTWR-RF, and GTWR-AdaBoost models in the full dataset; the fitting accuracy indexes R2, MAE, and RMSE were 0.96, 3.43 μg·m-3, and 5.52 μg·m-3, respectively; and the verification accuracy indexes R2, MAE, and RMSE were 0.9, 4.98 μg·m-3, and 7.92 μg·m-3, respectively. ② The model had a high goodness of fit (R2 of the whole dataset was 0.96, and R2 of different times ranged from 0.91 to 0.98) when applied to the estimation of PM2.5 concentration hour. It showed that the model had good time stability for hourly estimation and could provide accurate estimation information for regional air quality assessment. ③ In terms of time, the annual average PM2.5hourly concentration estimation showed an inverted U-shaped trend. It began to increase gradually at 09:00 am to a peak of 44.56 μg·m-3 at 11:00 and then gradually decreased. Moreover, the seasonal variation was very obvious, with winter>spring>autumn>summer. ④ In terms of spatial distribution, it showed the characteristics of high in the east and low in the west and a high degree of local pollution.

Impact assessment of air pollutants and greenhouse gases on urban heat wave events in the Beijing-Tianjin-Hebei region.

The production and quality of human life have been impacted by the extreme heat wave events caused by global warming and urbanization. This study analyzed the prevention of air pollution and the strategies of emission reduction based on decision trees (DT), random forests (RF), and extreme random trees (ERT). Additionally, we quantitatively investigated the contribution rate of atmospheric particulate pollutants and greenhouse gases to urban heat wave occurrences by combining numerical models and big data mining technology. This study focuses on changes in the urban environment and climate. The main findings of this study are as follows.The average concentrations of PM2.5 in the northeast of Beijing-Tianjin-Hebei in 2020 were 7.4%, 0.9%, and 9.6% lower than those in the corresponding years of 2017, 2018, and 2019, respectively. The carbon emissions in the Beijing-Tianjin-Hebei region showed an increasing trend during the previous 4years, which was consistent with the spatial distribution of PM2.5. In 2020, there were fewer urban heat waves, which was attributable to a reduction of 75.7% in emissions and an improvement of 24.3% in the prevention and management of air pollution. These results suggest that the government and environmental protection agencies need to pay attention to changes in the urban environment and climate to diminish the negative effects of heatwaves on the health and economic growth of the urban population.

EVALUATION AND ANALYSIS OF AMBIENT AIR QUALITY IN JIAOZUO CITY

Taking Jiaozuo agglomeration area as the research area, the environmental quality evaluation was carried out. The monthly and annual variation characteristics of 6 basic pollutants and 3 supplementary monitoring pollutants were analyzed by single factor index and ambient air quality index ( AQI ). The results showed that the AQI value of the average concentration in 2019-2021 reached the secondary standard. Compared with the air quality in 2019 and 2020, the single factor pollution index decreased year by year in 2021. The annual air quality index of 2020 and 2021 shows that the average value of AQI increases from October to the highest value in January of the second year, decreases from January to the lowest value in July and August, and the three supplementary monitoring pollutants all meet the evaluation criteria. The ambient air quality pollutants in the study area are mainly PM10 and PM2.5. It is necessary to take corresponding measures to prevent air pollution and provide scientific basis for atmospheric environmental governance.

Air pollution prevention in central China: Effects on particulate-bound PAHs from 2010 to 2018

Long-term trends in particulate-bound polycyclic aromatic hydrocarbon (PAH) concentrations in air in Zhengzhou (a severely polluted city in central China) between 2010 and 2018 were studied to assess the effectiveness of an air pollution prevention and control action plan (APPCAP) implemented in 2013. The PM2.5, sum of 16 PAHs (Σ16 PAHs), benzo[a]pyrene (BaP), and BaP toxic equivalent concentrations were high before 2013 but 41%, 77%, 77%, and 78% lower, respectively, after the APPCAP. The maximum daily Σ16 PAHs concentration between 2014 and 2018 was 338 ng/m3, 65% lower than the maximum of 961 ng/m3 between 2010 and 2013. The ratio between the Σ16 PAHs concentrations in winter and summer decreased over time and was 8.0 in 2011 and 1.5 in 2017. The most abundant PAH was benzo[b]fluoranthene, for which the 9-year mean concentration was 14 ± 21 ng/m3 (15% of the Σ16 PAHs concentration). The mean benzo[b]fluoranthene concentration decreased from 28 ± 27 ng/m3 before to 5 ± 4 ng/m3 after the APPCAP (an 83% decrease). The mean daily BaP concentrations were 0.1–62.8 ng/m3, and >56% exceeded the daily standard limit of 2.5 ng/m3 for air. The BaP concentration decreased from 10 ± 8 ng/m3 before to 2 ± 2 ng/m3 after the APPCAP (a 77% decrease). Diagnostic ratios and positive matrix factorization model results indicated that coal combustion and vehicle exhausts were important sources of PAHs throughout the study period, contributing >70% of the Σ16 PAHs concentrations. The APPCAP increased the relative contribution of vehicle exhausts from 29% to 35% but decreased the Σ16 PAHs concentration attributed to vehicle exhausts from 48 to 12 ng/m3. The PAH concentration attributed to vehicle exhausts decreased by 79% even though vehicle numbers strongly increased, indicating that pollution caused by vehicles was controlled well. The relative contribution of coal combustion remained stable but the PAH concentration attributed to coal combustion decreased from 68 ng/m3 before to 13 ng/m3 after the APPCAP. Vehicles made dominant contributions to the incremental lifetime cancer risk (ILCRs) before and after the APPCAP even though the APPCAP decreased the ILCRs by 78%. Coal combustion was the dominant source of PAHs but contributed only 12–15% of the ILCRs. The APPCAP decreased PAH emissions and changed the contributions of different sources of PAHs, and thus strongly affected the overall toxicity of PAHs to humans.

Regional differentiation in influencing factors of clean renewable energy consumption from the perspective of air pollution prevention and control

Global economic growth is now increasingly conflicting with the sustainable development strategy. In the context of ecological environmental preservation and air pollution prevention and control, this paper probes into the regional differentiation in the influencing factors of clean renewable energy consumption. First and foremost, a brief analysis of the status quo of clean renewable consumption in China was outputted, grounded on data on the input and output of 30 provinces and cities nationwide from 2010 to 2020. Then, national and regional models are built respectively in virtue of differential GMM, systematic GMM, and bias-corrected LSDV methods. Furthermore, efforts were invested in dissecting the working mechanism of the influencing factors and verifying the previous prediction resulting in applying the Tobit regression method. For every 1% increase in the green finance index, the clean renewable energy consumption rises by 0.882 accordingly, said the regression analysis results. Last but not least, it was concluded that the development level of green finance, internet advance, and technological progress significantly positively affected clean renewable energy consumption. While the industrial structure, the degree of openness, and the level of urbanization represented by the proportion of the secondary industry play hardly-seen impact.

Pathways toward PM2.5 air quality attainment and its CO2 mitigation co-benefits in China's northern cities by 2030

Rapid economic development and urbanization have left millions of people in urban areas vulnerable to the adverse effects of air pollution. Reducing serious PM2.5 pollution remains a major policy challenge for Chinese cities, such as the “2 + 26” Cities in the most polluted region of China, despite adopting various air pollution-control measures since 2017. In this study, we use a Greenhouse Gas and Air Pollution Interactions and Synergies model for the “2 + 26” Cities to explore feasible pathways for achieving the PM2.5 air quality annual standard (35 μg/m3) until 2030 by developing four future scenarios based on a 2017 emission inventory. The results show that by continuing the control policies from before 2020, including the Air Pollution Prevention and Control Action Plan from 2013 and the Three-Year Action Plan for Wining the Blue Sky Defense Battle from 2018, and implementing the policies likely to be proposed after 2020, the “2 + 26” Cities will not succeed in achieving the standard by 2030; furthermore, the amount of the population living below 35 μg/m3 will not exceed 12%. Nevertheless, by combining the best available technologies, the regional average PM2.5 concentration in the “2 + 26” Cities is 34 μg/m3 by 2030, attaining the target; moreover, more than half of the population will experience air quality that conforms to the standard. Under this scenario, emissions of primary PM2.5, SO2, NOx, NH3 and NMVOCs are estimated to decrease by 75%, 69%, 76%, 32% and 52%, respectively, in 2017–2030. The emission reductions under alternative scenarios vary widely across cities, indicating the need for differentiated control strategies among cities. Considering the predominant contributions to emissions and the lack of effective control measures, fuel conversion, off-road, agricultural and solvent use sectors should be paid more attention to enable further emission reductions in future. In addition, CO2 emission reduction co-benefits of implemented clean air action measures have been identified; however, the negative reduction effects of these measures should be given more attention (e.g., increased carbon emissions in the power sector from electrification of end-users).

Assessing the Prospects of a Landfill Gas Harvesting and Utilizing System with Taking into Account Climatic and Economic Factors

There are many technologies for converting waste to energy, including municipal solid waste, the degradation of which entails release of landfill gas. To prevent air pollution and further increase of the greenhouse effect, it is necessary to solve the problem of collecting and utilizing landfill gas, the components of which (methane and carbon dioxide) affect significantly the climate change. In the majority of cases, the environmental conditions in the Chelyabinsk region call for improvement, which in frequent cases is stemming from the problems related to landfills. Due to the long periods of time taken for municipal solid waste to degrade in a natural way and a constant growth of their volumes at landfills, it is necessary to assess the prospects of a system for collecting and utilizing the released landfill gas with taking into account climatic and economic factors, as well as the profitability of generating heat and electricity at landfills for which reclamation measures are planned.

Comprehensive performance evaluation of coordinated development of industrial economy and its air pollution control

Exploring coordinated pathways that can promote not only the sustainable development of the industrial economy but also air quality is of great significance for the prevention and control of air pollution in China. Currently, the joint development pathways of the industrial economy-environment nexus remain unclear and poorly evaluated. In this study, we proposed a comprehensive performance evaluation combining objective and subjective weighting to identify industrial enterprises' economic-environment nexus benefits. It would be one of the most important steps to explore the coordinated pathways. Based on data envelopment analysis (DEA), the proposed method integrated with the index integration was used to evaluate the comprehensive performances of 41 industrial sectors in China's 13th five-year plan (2016–2020). Evaluation results showed that the comprehensive performances of the economy-environment nexus of the industrial sectors varied significantly, with the five-year average comprehensive technical efficiency (TE) of 0.11–1. Overall, the best two performances were realized by the industries of equipment manufacturing and living consumption, whereas the worst one belonged to the industry of bulk raw materials, with average comprehensive TE values of 0.50, 0.43, and 0.19, respectively. The results of the quantitative evaluation were consistent with those of the qualitative analysis in terms of the developmental status of the industrial sectors. According to the analyses of pure technical efficiency and scale effect, the proposed method identified the industrial sectors with the highest developmental value and with the highest need to control air pollution. Compared with those of the original DEA model, the results of the proposed method showed pronounced differences in terms of the performances of industrial sectors with high energy consumption and high particulate matter (PM) emissions and with low energy consumption and low PM emissions. The proposed evaluation method combining the weighting was suitable for identifying the comprehensive performance of the industrial economy-environment nexus and provides the basis for the prevention and control of air pollution.

Revealing the impact of China's clean air policies on synergetic control of CO2 and air pollutant emissions: Evidence from Chinese cities

China is presently confronted with the intricate challenge of simultaneously mitigating air pollution and decelerating the pace of climate change. An integrated perspective to investigate the synergetic control of CO2 and air pollutant emissions is in an urgent need. Using data for 284 Chinese cities from 2009 to 2017, we introduced an indicator called coupling and coordination degree of CO2 and air pollutant emissions control (CCD) and found an upward and spatial agglomeration trend of CCD distribution during the research period. Then, this study posed a specific focus on the impact of China's Air Pollution Prevention and Control Action Plan (APPCAP). The DID model revealed that implementation of the APPCAP resulted in a 4.0% increase in CCD for cities with special emission limits, attributed to industrial structural adjustments and the promotion of technology innovation. Furthermore, we also identified positive spillover effects of the APPCAP on neighboring control group cities situated within 350 km of the treatment group cities, providing an explanation for the spatial agglomeration trend observed in CCD distribution. These findings hold significant implications for the synergetic control in China and underscored the potential benefits of industrial structural adjustments and technology innovation in mitigating environmental pollution.

Investigation of the Effect of Long-Term Exposure to Outdoor Air Pollution on Deaths in Konya with AirQ+ Software

Outdoor air pollution is one of the biggest environmental risks to public health and a problem that affects everyone in low-, middle- and high-income countries. Particulate matter (PM) is a common air pollutant consisting of a mixture of solid and liquid particles suspended in the air. PM2.5 and PM10 are the most common and are health related. The World Health Organization declared Particulate Matter (PM) as a carcinogen in 2013. The aim of this study was to calculate how much of the adult deaths aged 30 and over in Konya can be attributed to outdoor air pollution caused by PM2.5 pollutant. AirQ+ software was used to calculate the cases of deaths attributed to PM10 and PM2.5. The results show that 2163 premature deaths in 2017, 1582 in 2018 and 1278 in 2019 from long-term exposure to PM2.5 could be prevented if the PM2.5 concentration in the region does not exceed the recommended threshold of 10 µg/m3. Air pollution level is quite high in Konya. In the calculation made using AirQ+ software, the death rate attributable to air pollution in the population aged 30 and over was high, similar to previous studies in Turkey. The findings show that many premature deaths can be prevented by preventing air pollution.

Unraveling spatiotemporal patterns and multiple driving factors of surface ozone across China and its urban agglomerations management strategies

Since State Council launched the Action Plan for Air Pollution Prevention and Control in 2013, national concentration of fine particulate matter (PM2.5) has continued to decline in China, while surface ozone (O3) pollution shows an obvious rise. To identity hot regions and develop targeted policy, the spatiotemporal O3 variation and its population-weighted exposure features were analyzed in 337 cities across China, using autocorrelation analysis and grid exposure calculation. In the identified hot urban agglomerations, the correlation analysis and geographic weighted regression model (GWR) were used to study related meteorological factors and socioeconomic driving factors. O3 pollution and its human exposure were found to have significant spatial aggregation characteristics, showing a need for regional management policy. Beijing-Tianjin-Hebei Urban Agglomeration (BTH-UA), Central Plains Urban Agglomeration (CP-UA), and Yangtze River Delta Urban Agglomeration (YRD-UA) were identified as hot regions where O3 concentration exceeded 160 μg·m−3, exceedance rate was over 20% and population-weighted exposure risk was relatively high. Correlation analysis in the hot regions indicated high surface temperature, low relative humidity, and low wind speed were positive to O3 increase. Further, GWR results revealed that O3 in the majority of cities was positively related with population density (PD), the per capita GDP (Per_GDP), industrial soot emissions (ISE), industrial SO2 emissions (ISO2), and average annual concentration of inhaled fine particulate matter (PM10), and negatively related with total land area of administrative region (Administration) and area of green land (Green). From the regional driving factor difference, the targeted UA management policy was provided.

Health Benefit Evaluation for PM2.5 as Well as O3-8h Pollution Control in Chengdu, China from 2016 to 2020

Both particulate matter with aerodynamics of less than 2.5 (PM2.5) and ozone are the two main air pollutants in China, which seriously endanger human health. To estimate the adverse impacts of PM2.5 and ozone on human health during the implementation of air pollution prevention and control actions in Chengdu, both the generalized additive model and the nonlinear distribution lag model of epidemiology were adopted to explore the exposure-response relationship coefficients β of daily ozone 8h maximum concentration average (O3-8h), as well as that of PM2.5 on disease deaths in Chengdu from 2014 to 2016. On this basis, the environmental risk model and environmental value assessment model were both adopted to evaluate the health effects and health benefits in Chengdu from 2016 to 2020, respectively, with the assumption that PM2.5 and O3-8h concentration were reduced to specified air pollution control limits (35 μg·m-3 and 70 μg·m-3, respectively). The results showed 1 the annual concentration of PM2.5 presented gradually decreasing trends in Chengdu from 2016 to 2020. Specifically, ρ(PM2.5) from 63 μg·m-3 in 2016 decreased to 40.92 μg·m-3 in 2020. The average annual decline rate was approximately 9.8%. In contrast, the annual concentration of O3-8h from 155 μg·m-3 in 2016 increased to 169 μg·m-3 in 2020, and the increasing rate was approximately 2.4%. 2 Both PM2.5 and O3-8h had lag effects on three types of disease deaths. Under the maximum lag effect, the corresponding exposure-response relationship coefficients β of PM2.5were 0.0003600, 0.0005001, and 0.0009237 for all-cause, cardiovascular, and respiratory premature deaths, respectively, whereas the corresponding β of O3-8h were 0.0003103, 0.0006726, and 0.0007002, respectively. 3 If ρ(PM2.5) was reduced to the national secondary standard limit (35 μg·m-3), the corresponding number of health beneficiaries and economic benefits declined yearly. Specifically, the health beneficiary number of all-cause, cardiovascular, and respiratory disease deaths were reduced from 1128, 416, and 328 in 2016 to 229, 96, and 54 in 2020, respectively. There were a total number of 3314 avoidable premature deaths for all-cause diseases during the five years, resulting in a total health economic benefit of 7.66 billion yuan. 4 If we assume that ρ(O3-8h) was reduced to the concentration limit specified by the World Health Organization (70 μg·m-3), the corresponding number of health beneficiaries and economic benefits were increasing yearly. Specifically, the health beneficiaries' numbers of all-cause, cardiovascular, and respiratory disease deaths rose from 1919, 779, and 606 in 2016 to 2429, 1157, and 635 in 2020, respectively. The annual average growth rates of avoidable all-cause and cardiovascular mortality were 6.85% and 10.72%, respectively, which was higher than the annual average rise rate of ρ(O3-8h). There were 10790 total avoidable deaths from all-cause diseases during the five years, resulting in a total health economic benefit of 26.62 billion yuan. These findings indicate that PM2.5 pollution in Chengdu had been well controlled, whereas O3 pollution had become more severe and had become another key air pollutant threatening human health. Therefore, the synchronous control of PM2.5 and ozone should be implemented in the future.

Experimental and molecular dynamics simulation study of toluene absorption by nanofluids

It is well known that the emission of volatile organic compounds (VOCs) is a significant threat to human health and the ecological environment, and toluene is a typical representative of aromatic VOCs, whose elimination makes an important contribution to the prevention and control of air pollution. Absorption is the classical process to eliminate air pollutants, but the application of absorption is often constrained by absorbent and gas-liquid mass transfer. In recent years, process intensification has become an important development in the chemical industry, and nanotechnology can effectively reduce mass transfer resistance and improve gas-liquid mass transfer effectiveness. This work aims to evaluate the effect of adding nanoparticles on the gas-liquid mass transfer process. The effects of TiO2, Al2O3, and SiO2 nanoparticles on the removal of toluene by green solvent low transition temperature mixtures (LTTM) were investigated experimentally and theoretically. The mass transfer enhancement factors of the toluene absorption process were measured at different concentrations and sizes of TiO2, Al2O3, and SiO2 nanoparticles, absorption temperatures and number of cycles. Molecular dynamics (MD) simulations of the microscopic properties of LTTM and toluene were performed. Based on the MD simulation results, the toluene density distribution, interaction energy, radial distribution function, spatial distribution function, and self-diffusion coefficient were calculated, which helped to explain the absorption mechanism of toluene gas. The findings demonstrated that nanoparticles can alter the gas-liquid mass transfer process, and provided a method and theoretical reference for enhancing the toluene absorption process.

Assessment of Regional Differences in the Implementation of the Air Pollution Prevention and Control Action Plan in China.

Air pollution is still an important risk factor that endangers the health of Chinese people, leading the government to implement a series of policies to address air pollution. This study takes the Air Pollution Prevention and Control Action Plan (APPCAP) proposed in 2013 as the object and uses the combined data set of China's 2000-2019 economic panel data and PM2.5 remote sensing data to analyse the implementation effect of the policy by the multiperiod difference-in-differences method, considering regional heterogeneity. The results show that the implementation of the APPCAP significantly reduced the PM2.5 concentration in China, and the effect was stronger in the Yangtze River Delta region. Future governance policies should further consider local characteristics and determine pollution control goals and measures according to local conditions.

Identification and contribution of potential sources to atmospheric lead pollution in a typical megacity: Insights from isotope analysis and the Bayesian mixing model

Atmospheric particulate matter (PM) enriched with lead (Pb) has severe irreversible effects on human health. Therefore, identifying the contribution of Pb emission sources is essential for protecting the health of residents. Using the Pb isotopic tracer method, this study explored the seasonal characteristics and primary anthropogenic Pb sources for atmospheric PM in Tianjin in 2019. We calculated the contribution of Pb sources using the end-member and MixSIAR models. The results showed that Pb loaded in PM10 was more abundant in January than in July, and was strongly influenced by meteorological conditions and anthropogenic emissions. The primary Pb sources of the aerosol samples originated from coal combustion and vehicle and steel plant emissions, mainly originating from local Pb emission sources in Tianjin. The PM10-bond Pb in January was influenced by regional transportation and local sources. The MixSIAS model calculated the contribution of coal combustion as approximately 50 %. Compared with that in January, the contribution of coal combustion decreased by 9.6 % in July. Our results indicate that some of the benefits of phased-out leaded gasoline have been short-lived, whereas other industrial activities releasing Pb have increased. Furthermore, the results emphasise the practicability of the Pb isotope tracer source approach for identifying and distinguishing between different anthropogenic Pb inputs. Based on this study, scientific and effective air pollution prevention and control programs can be formulated to provide decision support for the guidance and control of air pollutant emissions.

Impact of Ship Emissions on Air Quality in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA): With a Particular Focus on the Role of Onshore Wind

Background: ship emissions have an adverse effect on air quality in coastal regions, and this effect can be exacerbated by onshore winds. Objectives and methods: to investigate the impact of ship emissions on air pollutant concentrations during the onshore wind period in a low-latitude region in China, this study applied the WRF/Chem model to simulate the contribution of ship emissions to PM2.5 and O3 by “zero-out” in 2018, in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). Results/findings: results show that the onshore winds facilitated the transport of ship-emitted pollutants to inland areas, causing the contribution of ship emissions to PM2.5 exceeding 4 μg/m3 to areas north of Guangzhou in April and west of the GBA in October. The impact of onshore winds on the ship contribution to the O3 concentration shows a bidirectional trend both spatially and monthly. The onshore winds raised the ship contribution to O3 concentrations in April by 1.54 μg/m3, while exacerbated the decreasing contribution in other months. In VOC-sensitive cities such as Foshan, onshore winds exacerbated the negative contribution of ship emissions to O3 concentrations; while in NOx-sensitive cities such as Huizhou, they enhanced the contribution of ship-induced O3. Novelty/Improvement: this paper fills a gap in the study of pollutants transportation characteristics from ship emissions under the influence of onshore winds in the GBA. Our results demonstrate the importance of considering meteorological conditions and atmospheric chemical mechanisms regarding the coastal air pollution prevention caused by ship emissions.

Identification of Key Production Factors in China's Environmental Protection Industry Based on Deep Learning

Analyzing from the micro level of the basic unit of environmental protection industry -- enterprise, this paper takes   relevant information of more than 8000 key enterprises in China's environmental protection industry from 2018 to 2020 as the big data training samples, and uses BP neural network method to identify the key production factors that have great impact on the output of the whole China's environmental protection industry and its main subdivisions. The results show that China's environmental protection industry is still in the growing stage in the current stage, with significant capital pulling, technological innovation driving, and management innovation also plays an important role. There are differences in the performance of water, air and solid waste in the environmental protection industry. In detail, R&D expenses from the government plays the most important role in water pollution prevention and control industry. Technology innovation plays the most important role in air pollution prevention and control industry. And staff play the most important role in solid waste treatment and resource recycling industry.

Robust Control of RSOC/Li-ion Battery Hybrid System Based on Modeling and Active Disturbance Rejection Technology

The application of new energy systems for industrial production to advance air pollution prevention and control has become an irreversible trend. This development includes hybrid systems consisting of reversible solid oxide cells (RSOC) and a Li-ion battery; however, at present the energy dispatching of such systems has an unstable factor in the form of poor heat/electricity/gas controllability. Therefore, the system studied in this paper uses the Li-ion battery as the energy supply/storage case, and uses the RSOC to supply power for the Li-ion battery charge or the Li-ion battery supply power to the RSOC for hydrogen production by water electrolysis. In this hybrid system, Li-ion battery thermoelectric safety and RSOC hydrogen production stability are extremely important. However, system operation involves the switching of multiple operating conditions, and the internal thermoelectric fluctuation mechanism is not yet clear. Therefore, in this paper we propose a separate control with a dual mode for hybrid systems. Active disturbance rejection control (ADRC) with a simple structure is used to achieve Li-ion battery module thermoelectric safety and control the hydrogen production/consumption of the RSOC module in the hybrid system. The results show that the required Li-ion battery thermoelectric safety and RSOC hydrogen consumption/production requirements can be met using the proposed controller, leading to a hybrid system with high stability control.

A survey on air pollutant PM2.5 prediction using random forest model

Background: One of the most critical contributors to air pollution is particulate matter (PM2.5) that its acute or chronic exposure causes serious health effects to human. Accurate forecasting of PM2.5 concentration is essential for air pollution control and prevention of health complications. A survey of the available scientific literature on random forest model for PM2.5 prediction is presented here. Methods: The scientific literature is extracted from Science Direct database based on a set of specified search criteria. The input features, data length, and evaluation parameters used in PM2.5 prediction were analyzed in this study. Results: The study shows that majority of the publications are aimed at the daily prediction of outdoor PM2.5. Most publications base their PM2.5 prediction on features aerosol optical depth (AOD) and boundary layer height (BLH). PM10 and NO2 are the main air pollutants employed in the PM2.5 estimation. Majority studies utilized input data lengths covering more than one year, and the effectiveness of prediction models are unaffected by the length of investigation. The coefficient of determination, R2 , is the primary evaluation parameter used in all publications. The majority of research study indicated R2 values greater than 0.85, demonstrating the reasonable dependability and efficiency of random forest regression-based PM2.5 prediction models. Conclusion: The study demonstrates that the publications use a variety of meteorological and geological features for PM2.5 estimation, depending on the context of the research as well as data accessibility. The findings demonstrate that it is hard to pinpoint the optimal model in any particular way.

A Two-Stage Hybrid Model for Determining the Scopes and Priorities of Joint Air Pollution Control

Due to the spillover nature of air pollution, the territorial separate governance mode is ineffective in combating pollution, making Joint Prevention and Control of Air Pollution (JPCAP) among multiple regions the only viable option. However, determining the appropriate scopes and priorities for JPCAP is known to be a challenging and significant issue. To address this, we propose a new two-stage hybrid model. In the first stage, making use of long-term, wide area monitoring data provided by the air pollution monitoring network, we propose a new method for subdividing large regions into sub-regions by using data mining techniques. In the second stage, we propose a comprehensive decision-making framework to evaluate the priorities of JPCAP sub-regions from three different perspectives, namely, the impact of a sub-region on the pollution level of the entire target region, as well as the urgency and elasticity of sub-regional air pollution control. A case study is conducted on 27 cities of the Yangtze River Delta region of China. The case study demonstrates the validity and practicality of the proposed two-stage hybrid model. This work provides a viable tool for the effective implementation of air pollution control in China and other regions of the world.