CO2 Emission Control Research Articles

The causative factors of environmental degradation in South Asia

Urbanization, economic growth, and intensity of electricity consumption are the important causative factors of environmental degradation in South Asia. The present study has revealed this while investigating the relationship between the level of CO2 emissions and important economic variables in the context of five South Asian countries. Panel data are used for this study over the period 1974–2017. Panel co-integration tests and the Panel Autoregressive Distributive Lag (PARDL) model are applied for empirical analysis. Robust results of the analysis indicate that urbanization, Gross Domestic Product (GDP) and the intensity of electricity consumption are contributing factors to carbon emissions. Based on the results of the Dumitrescu Hurlin Panel Causality test, it is concluded that there is a bi-directional causal link between urbanization and CO2 emissions and unidirectional causal links from GDP to CO2 emissions, from GDP to urbanization, and from the intensity of electricity consumption to urbanization. This study focuses on planned urbanization, eco-efficient income growth, and sensible use of electricity to control CO2 emissions in this region. Considering the nature of these developing economies in South Asia, collaborative measures and strategic planning are suggested on a regional basis to address the concerns in the above-mentioned areas that minimize carbon emissions and thereby aid sustainable development in this region.

Life Cycle Assessment of Battery Electric and Internal Combustion Engine Vehicles Considering the Impact of Electricity Generation Mix: A Case Study in China

Battery Electric Vehicles (BEVs) are considered to have higher energy efficiency and advantages to better control CO2 emissions compared to Internal Combustion Engine Vehicles (ICEVs). However, in the context that a large amount of thermal power is still used in developing countries, the CO2 emission reduction effectiveness of BEVs can be weakened or even counterproductive. To reveal the impact of the electricity generation mix on carbon emissions from vehicles, this paper compares the life cycle carbon emissions of BEVs with ICEVs considering the regional disparity of electricity generation mix in China. According to Life Cycle Assessment (LCA) analysis and regional electricity carbon intensity, this study demonstrates that BEVs in the region with high penetration of thermal power produce more CO2 emissions, while BEVs in the region with higher penetration of renewable energy have better environmental performance in carbon emission reduction. For instance, in the region with over 50% penetration of renewable energy, a BEV can reduce more CO2 (18.32 t) compared to an ICEV. Therefore, the regions with high carbon emissions from vehicles need to increase the proportion of renewable generation as a priority rather than promoting BEVs.

Comparison Between Tributary and Main Stream and Preliminary Influence Mechanism of CO2 Flux Across Water-air Interface in Wanzhou in the Three Gorges Reservoir Area

The main stream of the Three Gorges Reservoir area in Wanzhou and its tributary (the Pengxi River) were selected as a survey area to monitor the CO2 concentration. Twelve related indicators were selected during the blooming period from April to September 2019, which were divided into Climate factors, Water environment factors, Carbon source factors, Nutrient factors, and Sediment factors. These factors were considered for further discussion of the impact pathways and contribution to CO2 flux. The average CO2 fluxes of Gaoyang (the Pengxi River), Huangshi (the Pengxi River), and Wanzhou (the main stream) were (1.445±1.739), (3.118±2.963), and (2.899±1.144) mmol·(m2·h)-1, respectively, showing that Gaoyang < Wanzhou < Huangshi. The CO2 flux of tributary showed a large variation, while the main stream had a relatively small variation, which is a stable "source" of CO2. The main stream of the Yangtze River, as a hub for the transportation of biomass from land to sea, has higher carbon concentration and higher flow rate than its tributaries, which makes the CO2 flux of the main stream usually larger than that of the tributary. However, the difference in hydrological conditions result in spatial differences in CO2 flux at different points of the same tributary. Gaoyang is located in the reservoir bay, which is conducive to the growth of phytoplankton and the CO2 flux is lower; Huangshi is located in a river with a faster flow rate. The backwater support and backflow of the main stream make the CO2 flux significantly greater than that at Wanzhou. The effects of various indicators on the CO2 flux are also markedly different in the tributary and main stream. Temperature (T), DO, dissolved organic carbon (DOC), and dissolved inorganic carbon (DIC) have significant effects on CO2 fluxes in the tributary, while NH4+-N has a significant impact on CO2 fluxes in the main stream. Nutrient factors and carbon source factors contribute 32.37% and 27.25%, respectively, to CO2 flux, accounting for more than half of the total, followed by climate factors, water environment factors, and sediment factors, which contribute 18.81%, 13.49%, and 8.08%, respectively. Reservoir CO2 emission control can focus on controlling the eutrophication and carbon sources; phenomena such as global warming and sedimentation will also have a certain impact on the CO2 emission of reservoirs.

Exchange Rate Dynamics, Energy Consumption, and Sustainable Environment in Pakistan: New Evidence From Nonlinear ARDL Cointegration

Pakistan's local currency has been devalued during different exchange regimes, which may substantially affect energy consumption and CO2 emissions. Therefore, this study investigates the effects of exchange rate depreciation on Pakistan's CO2 emissions and energy consumption from 1990–2018. We apply the nonlinear autoregressive distributed lag (ARDL) cointegration approach for the empirical analysis and found that exchange rate depreciation increases CO2 emissions and energy consumption in both the short and long runs. These results suggest that currency devaluation has an expansionary effect which enhances economic growth at the cost of high energy consumption and CO2 emissions. Therefore, the government needs regulations along with an exchange rate policy to control CO2 emissions. Moreover, the government should search for alternate energy resources such as renewable energy resources that meet the country's energy needs and mitigate CO2 emissions.

Asymmetric impact of economic growth, financial development and energy consumption on CO2 emissions in Vietnam

This study aims to investigate the asymmetric effects of economic growth, financial development, and energy consumption on CO2 emissions in Vietnam over the period 1995–2020. By doing so, we employ Quantile on Quantile Regression introduced by Sim and Zhou (2015) and Granger Causality in different quantiles developed by Troster (2018). Our findings indicate that there is a positive influence of economic growth, financial development, and energy usage on CO2 emissions at most quantiles, which implies that these macroeconomic factors would increase CO2 emissions in this country. In addition, economic development requires more energy, resulting in a rise in environmental degradation is inevitable in the short run. Nevertheless, it is necessary for Vietnam to pay attention to enhancing the use of clean energy and controlling CO2 emissions in order to achieve sustainable development. Furthermore, financial policies are able to support the development of renewable energy and contribute to reducing CO2 emissions. The Vietnamese government should develop a rough, transparent, and relatively stable policy mechanism in the long run, including emission benchmark, tax incentives and other incentives to encourage private investment and foreign direct investment participating in the process of technological innovation, clean energy and renewable energy.

Evaluation of a new low-cost CO2 trapper material for the biodiesel fuelled diesel engine

The main greenhouse gases which confer global warming and green house effects to the Earth are Carbon Dioxide (CO2), Methane, Nitrous Oxide (NOx) and Water Vapor. In these greenhouse gases CO2 content is vast in the atmosphere. CO2 emissions are caused due to the burning of fossil fuels like petrol, diesel, natural gas, etc. for electrical power supply, mobility and industrial applications. Hence it has become a requisite to avoid further add of CO2 emissions on to atmosphere and to control global warming and green house effects. The most important cause for natural disasters and changes in climatic conditions is because of CO2 emissions. There are many sources that emit CO2 but most comes from automobiles which is about 65 % while comparing it with other sources. To diminish and manage the control of CO2 emission to the atmosphere from automobiles, theoretical approach and practical experiments of adsorption of CO2 were conducted and analyzed. Charcoal is one among the best adsorption materials because of its huge porous value and capture capacity. This new cost-efficient CO2 absorber has been tested under various load conditions on 5.2 kW diesel engine fueled with Jatropha Biodiesel (BD) Blend. CO2 emissions were adsorbed up to 70 % for the CCS3 material for full load condition.

Experimental Investigation to Utilize Adsorption and Absorption Technique to Reduce CO2 Emissions in Diesel Engine Exhaust Using Amine Solutions

Due to the increased demand for global transportation needs, a long-range diesel engine is considered an important prime mover to fulfill the transportation demand. The major problem addressed by the diesel engines is it liberates harmful emissions and it also increases global warming. CO2 is considered an important greenhouse gas and it has to be controlled by diesel engines. In this research, extensive experimental work is done to identify a suitable solution to control CO2 emissions. For five different mole concentrations (0.1 to 0.5), three types of amino solutions (L-alanine, L-aspartic acid, and L-arginine) were prepared. By passing diesel exhaust through each solution, CO2 absorption is investigated. For CO2 absorption, an appropriate CO2 control system is built and tested. The tests were carried out in a diesel engine which is a naturally aspirated single-cylinder engine with a water-cooled system. It was possible to obtain an effective CO2 reduction of up to 90%, as well as a simultaneous reduction in HC and CO.

Énergie renouvelable, croissance économique et attenuation des émissions de dioxyde de carbone dans les pays de l'UEMOA

L'efficacité des énergies renouvelables pour assurer la croissance économique et la qualité de l'environnement devient un sujet important dans la littérature économique, étant donné que les énergies fossiles majoritairement utilisées et menacées par le risque d'épuisement entraînent une augmentation des émissions de gaz à effet de serre. L'objectif de ce papier est d'analyser l'effet de la consommation des énergies renouvelables sur la croissance économique et les émissions de dioxyde de carbone dans les pays de l'UEMOA. Pour ce faire, nous utilisons les fonctions de croissance et d'environnement avec une investigation empirique basée sur une régression linéaire en données de panel constituées des pays de l'UEMOA sur la période 1990 à 2015. Les résultats des estimations par la méthode de Pooled Mean Group développée par Pesaran et alii (1999) montrent principalement qu'à long terme, l'utilisation des énergies renouvelables contribue significativement à promouvoir la croissance économique et à atténuer la dégradation de l'environnement à travers la réduction des émissions de carbone. A cet effet, les décideurs politiques devraient orienter la politique énergétique de l'union vers un mix-énergétique dominé par la production et la consommation d'énergie renouvelable ; tout en mettant en place une politique de contrôle des émissions de CO2.

Development of Active CO2 Emission Control for Diesel Engine Exhaust Using Amine-Based Adsorption and Absorption Technique

Diesel-powered transportation is considered an efficient method of transportation; this sees the increase in the demand for the diesel engine. But diesel engines are considered to be one of the largest contributors to environmental pollution. The automobile sector accounts for the second-largest source for increasing CO2 emission globally. In this experiment, a suitable postcombustion treatment to control CO2 emission from IC engine exhaust is developed and tested. This work focuses to control CO2 emission by using the chemical adsorbent technique in diesel engine exhaust. An amine-based liquid is used to adsorb the CO2 molecules first and absorb over the amines from the diesel engine exhaust. Three types of amino solutions (L-alanine, L-aspartic acid, and L-arginine) were prepared for 0.3 mole concentrations, and the CO2 absorption investigation is performed in each solution by passing the diesel exhaust. A suitable CO2 adsorption trap is developed and tested for CO2 absorption. The experiments were performed in a single-cylinder diesel engine under variable load conditions. The eddy current dynamometer is used to apply appropriate loads on the engine based on the settings. The AVL DIGAS analyzer was used to measure the CO2, HC, and CO emissions. An uncertainty analysis is carried out on the experimental results to minimize the errors in the results. The effective CO2 reduction was achieved up to 85%, and simultaneous reduction of HC and CO was also observed.

TRIBUTAÇÃO DO CARBONO NA AMÉRICA LATINA E PERSPECTIVAS PARA O BRASIL

This paper presents an analysis of carbon taxation, that is, the taxation of greenhouse gas emissions, in Latin American countries. This research aims to draw a parallel between foreign and Brazilian legislation, to promote the discussion on the use of economic mechanisms to control CO2 emissions in the country. For its realization, bibliographical and documental research was carried out, as well as the study of the specific legislation of the countries that instituted such taxation in their legal systems. Mexico, some of its states, Chile, Colombia, and Argentina tax carbon in some way. Despite not being the only market mechanism or policy to control and reduce GHG emissions, carbon taxation is shown to be the most viable market mechanism for developing countries, given its low complexity and implementation costs.

Study on CO2 Emission Characteristics of China VI Heavy Duty Diesel Engine

CO2 emission control is of great urgency, and the decrease of heavy-duty diesel engines’ CO2 emission is one of the significant methods to reduce CO2 emission. This paper uses a full-flow constantvolume dilution sampling system to experiment on the China VI heavy-duty diesel engine in order to measure CO2 emissions under WHTC and WHSC cycles and different loads, with studying the instantaneous emissions characteristics of CO2, post-processing effects on CO2 emissions, influence factors of CO2 emissions. The study found that the CO2 emissions before the post-treatment of the WHSC cycle are 37% higher than that of the WHTC cycle, while emissions of CO2 are 3.45% higher than that before post-treatment. Simultaneously, cold start increases the CO2 emissions of the heavy-duty diesel engines by more than 1%. Post-treatment still increases the CO2 emissions of heavy-duty diesel engines by 3.5%. In addition, CO2 emissions have different trends with power at different speeds. CO2 emissions get an incremental within 600rpm and 900rpm, which gradually becomes slower until it reaches the peak, as engine power increases; the CO2 emissions initially increase, followed by a decrease, and then continue to increase within 1000rpm and 1400rpm; the CO2 emissions are almost not affected by the speed within 1500rpm and 1900rpm.

Comprehensive study on the effect of CO2 on coal pyrolysis at fast heating rate

Oxy-fuel combustion is considered one of the most effective CO2 emission control technologies, and CO2 has a very important effect on coal pyrolysis. A novel Concentrating Photothermal Thermogravimetric Analyzer was developed to study the effect of CO2 on coal pyrolysis at fast heating rate of 1000 °C/min. Coal conversion characteristics, kinetics and structural evolution of coal/char were analyzed comprehensively and quantitatively. The average mass loss rates at 1000 °C/min under various CO2 atmospheres were about two orders of magnitude higher than those at 10 °C/min. The activation energies calculated by the best-fitted D3 model were 34.52–36.22 kJ/mol under various CO2 atmospheres. CO2 inhibited functional groups transformation, aromatization rate within 500 °C and formation of stable radicals, but promoted coal aromatization at relatively higher temperature and induced gasification.

Adsorption studies of carbon dioxide and anionic dye on green adsorbent

As a consequence of the use of obsolete coal and oil and manufacturing techniques, pollution levels are rising, posing a significant threat to the environment and public health. As a result, nearby is a pressing essential to investigate actual CO2 emission and dye removal controls. Though, the achievement of this approach dependent particular on the use of low-cost adsorbent with high CO2 discrimination and high adsorption bulk. In this study, date seed active carbon (DSAC) for capturing CO2 was made using a two-step technique with KOH as the activation and varied carbonization rates. The properties of surface area on carbonization rate were investigated. The DSAC was subjected to BET, XRD, IR, and SEM examination. The researchers discovered that the micro-porous geometry has a significant impact on the adsorption efficiency of DSAC. The greatest CO2 adsorption of 3.7 mmol/g was attained under optimal circumstances of calcination temperature 700 °C, adsorption temperature 0 °C, and pressure 1 bar. Furthermore, activated carbon with a carbonization temperature of 700 °C has a high selectivity for CO2 over N2, indicating that it has a promising future in CO2 capture applications. Langmuir, Henry, Temkin, Toth, Dubbin, Harkin-Jura, Redlich Peterson, Elovich, and Josene models showed the greatest fit for any empirical sorption process that predicted heterogeneous surface characteristics of DSAC. Factors include beginning pH, catalyst loading, contact time, and temperatures have all been explored in order to determine appropriate adsorption parameters of acid yellow 99 (AY99) from aqueous systems. The isotherm of Langmuir was found to be an excellent match for the experimental data. The pseudo-second-order rate expression was utilized to characterize the dye uptake mechanism. Energy of adsorption activation was also determined to be 14 kJ/mol, suggesting chemisorption as the mode of adsorption. At varying temperatures, thermodynamic limitations such as ΔGo, ΔHo, and ΔSo were established. It was endothermic and unexpected, according to the adsorption thermodynamic characteristics. The findings of the research project are presented in form of chemical activation processes for date seeds produced adsorbents for capturing carbon dioxide and AY99 adsorption.

Analysis of the combustion mechanism of diesel surrogate fuel under CO2/O2 atmosphere

Closed-cycle diesel engine (CCDE) can effectively control CO2 emissions and reduce the greenhouse gas effect, but diesel fuel combustion under an atmosphere with CO2 has the problem of misfire and unclear mechanism. In order to study the CO2 impact on diesel combustion under the CO2/O2 atmosphere, a quantum chemical (QC) model of diesel surrogate fuel (DSF) is proposed, which takes into account the CO2 pyrolysis effect (CO2⇆CO+12O2) and the new reaction of OH radical generation from pyrolysis products (CO+O2+H∙→CO2+OH∙). Firstly, the active sites of the DSF molecules are predicted by average local ionization energy (ALIE) and electrostatic potential (ESP). New chemical reaction paths are obtained using ab initio theory and density functional theory combined with thermodynamic combination algorithm. The QC model is then established by sensitivity analysis and simplification of the mechanism and computational fluid dynamics (CFD) simulation of constant volume combustion chamber (CVCC.) Secondly, the CVCC experiment bench and visualization system are set up. The flame propagation at different times (1.5 ms, 1.9 ms, 2.3 ms, 2.7 ms, 3.1 ms and 3.5 ms) are captured by high-speed cameras under four different CO2 concentrations (air condition, 50%CO2 + 50%O2, 43%CO2 + 57%O2 and 35%CO2 + 65%O2). Finally, the comparison between experiment and model shows that the QC model is suitable for studying combustion characteristics of diesel fuel under CO2/O2 atmosphere. Under maximum CO2 concentration (50%CO2 + 50%O2), The maximum errors of flame combustion limit length (FCLL) and Flame longitudinal section area (FLSA) are 8.54% and 4.94%, respectively. In addition, the CO2 pyrolysis reaction and the new reaction of generating OH radicals indicate that the CO2 chemical effect can promote the combustion of diesel fuel under CO2/O2 atmosphere.

Analysis of CO2 Emissions in the Whole Production Process of Coal-Fired Power Plant

The linear programming (LP) model has been used to identify a cost-effective strategy for reducing CO2 emissions in power plants considering coal washing, pollutant removal, and carbon capture processes, thus CO2 emissions in different production processes can be obtained. The direct emissions (combustion emissions and desulfurization emissions) and indirect emissions (pollutant removal, coal washing, and carbon capture) of CO2 were all considered in the LP model. Three planning periods were set with different CO2 emission control desirability to simulate CO2 emissions of the different reduction requirements. The results can reflect the CO2 emissions across the whole production process of a coal-fired power plant overall. The simulation results showed that for a coal-fired power plant containing two 1000 MW ultra super-critical sets, when the desirability was 0.9, the CO2 total emissions were 2.15, 1.84, and 1.59 million tons for the three planning periods. The research results suggest that the methodology of LP combined with fuzzy desirability function is applicable to represent the whole production process of industry sectors such as coal-fired power plants. The government policy makers could predict CO2 emissions by this method and use the results as a reference to conduct effective industrial and energy structure adjustment.

Development of poly(ethylene glycol) diacrylate membrane for facilitated CO2/N2 separation

Carbon dioxide (CO2) is responsible for approximately 80% of greenhouse gases emission that is the main source to global climate change causing notable environmental impacts. Poly (ethylene glycol) diacrylate (PEGDA) have polar PEG repeating units, which provide a strong affinity towards carbon dioxide (CO2) molecules has been blended with 3-aminopropyltrimethoxysilane (APTMS) to synthesize membrane for CO2/nitrogen (N2) separation. The new synthesized membrane is studied for potential applications in gas separation and to be implemented in control CO2 emission. APTMS is also used to delay the diffusion between polymer and solvent. In this study, concentration of polymer of PEGDA and casting solvent of APTMS in terms of mol ratio from a range of 0.9:1.1 to 1.3:0.7 is discussed. Based on the results, PEGDA membrane shows best gas separation performance at mol ratio of PEGDA to APTMS of 1:1 where the permeance for both CO2/N2, and CO2/N2 selectivity are 75.21±0.15 GPU, 22.95±0.05 GPU and 3.28±0.12, respectively. An optimal aminosilane/polymer reaction ratio benefits the gas separation performance of the membrane due to the affinity of the membrane towards CO2 and formation of different membrane surface morphology.

Remarkable CO2 photoreduction activity using TiO2 nanotube arrays under favorable photothermal conditions driven by concentrated solar light

The photoreduction of carbon dioxide (CO2) to solar fuels is meaningful in many fields relevant to CO2 emission control, solar energy conversion and storage, carbon-neutral fuel production, CO2 conversion, and carbon cycle closure. The CO2 photoreduction on TiO2 nanotube arrays using concentrated sunlight under favorable photothermal conditions is considered in this work. TiO2 is a typical catalyst for the process while the reaction rate is still kept at rather poor level, partly because of the mild reaction conditions employed. In this study, the TiO2 photocatalyst was shaped as nanotube arrays and the current process limitations were tackled by raising the incident light intensity and reaction temperature by using concentrating solar light (concentration ratio between 200 and 800), while jointly increasing the achievable H2O and CO2 partial pressure. The results showed that the rate of CO2 photoreduction on the TiO2 nanotube array was increased by hundred times. The use of concentrated solar light heightens the hydrocarbons production rate to thousand μmol g−1 h−1 and enriches hydrocarbons products to CH4, C2H4, and C2H6. The favorable effects on enhancing the catalyst performance were ascribed to the intensification of reaction conditions. This noticeable breakthrough may represent an important step forward in the deployment of CO2 photoreduction technologies.

Identification of on-road vehicle CO2 emission pattern in China: A study based on a high-resolution emission inventory

As the country with the largest anthropogenic CO2 emission, China is greatly influential on fighting with climate change. However, CO2 emitted from on-road vehicles in China is a barrier to its carbon neutral due to the inevitable increase trend of vehicle quantity. Thus, to meet the requirement of refined policy-making for vehicular CO2 abatement, we calculated the CO2 emissions from 37 vehicular types and 3 fuel categories across 339 cities in China through the bottom-up method, and developed a national vehicular CO2 emission inventory in a high spatial resolution (1 km × 1 km). Additionally, machine learnings were conducted to the inventory for the emission pattern identification. It was found that the total vehicular CO2 emission in 2019 was 1090 million tons, and 77.1% of CO2 was emitted by vehicles of light-duty gasoline vehicle (LDGV) and heavy-duty diesel truck (HDDT). In addition, for the grids accompanying CO2 emissions, 75% of vehicular CO2 emissions were contributed by 15% of grids (hot grids). Furthermore, results of machine learning showed that LDGVs mainly distributed in economically advanced regions of which vehicular structures were relatively simple, while HDDTs were widely applied on the national scale. Based on the results above, two measures were proposed: (1) Electric cars have to be strongly promoted in hot grids for the LDGV replacement. (2) Long-distance freight tool replacements are urgently required in the national wide. Our study provided a studying base for further investigations on decarbonization and a new insight of China's vehicular CO2 emission controls.

Many-objective optimization of energy conservation and emission reduction in China’s cement industry

Industrial Energy Conservation and Emission Reduction (ECER) management is challenging due to the large number of objectives involved, and the complex synergies/conflicts amongst them. Most studies do not quantify these synergies/conflicts, resulting in high dimension ECER management problems. This study builds a 10-objective problem to optimize 5 heavy metals (Cd, Hg, Pb, As, Cr) and 5 conventional ECER-objectives (economic cost, energy, CO2, PM and NOx) in China’s cement industry. First, NSGA-III is used to calculate optimal objective values under technology application constraints. Second, synergies/conflicts amongst objectives are quantified using Spearman’s correlation. Finally, TOPSIS, Conservation Supply Curves and Quadrant methods are used to generate optimal ECER management policies. Results show that: (1) Optimal solutions are reliable as reflected by algorithm verification metrics – Error rate, Spacing metric and Hypervolume indicator; (2) The 10-objective problem is reduced to a 4-objective problem based on synergies. The four main-objectives are economic cost, energy consumption, CO2 and PM emission control. Therefore, ECER policies should focus on these objectives since optimizing them will synergistically improve all other objectives; (3) The average reduction potential for HMs and conventional objectives is 20% and 25% respectively, with an increase in economic cost of about 44–83 CNY/t; (4) From 72-ECER strategies assessed, 11-key strategies have better economic and environmental performances. They are mostly circular economy strategies utilizing industrial wastes, indicating that ECER policies should shift from traditional end-of-pipe approaches to a more circular economy approach. In sum, the proposed methodology can reduce the complexity of many-objective ECER management through a synergic control.

The role of solar energy and eco-innovation in reducing environmental degradation in China: Evidence from QARDL approach.

In the past decade, researchers have shifted their interests to explore different ways to mitigate environmental degradation. In that context, the present study explores the role of solar energy and eco-innovation in reducing environmental degradation in China. The study utilized data for the period 1990-2018 and applied the latest available econometric technique, a quantile autoregressive distributed lag model, to determine the impacts of solar energy and eco-innovation on improving China's environmental quality. According to the empirical results, in the long term, solar energy is negatively and significantly associated with CO2 emissions at higher quantiles. Eco-innovation has proven to be the most important channel to mitigate CO2 emissions in China. Eco-innovation is exerting a negative and significant influence on CO2 emissions at all quantiles in the long term. In addition, the population size is causing CO2 emissions to surge significantly at lower quantiles. The empirical analysis reveals that per capita income (PI) is positively associated with CO2 emissions at all quantiles, but it is significant only at higher quantiles in China. We found evidence of unidirectional causality for eco-innovation to CO2 emissions and solar energy to CO2 emissions. However, for population and CO2 emissions, per capita income, and CO2 emissions, we found bidirectional causality. As indicated by our empirical results, solar energy and eco-innovation are the two most effective channels to control CO2 emissions in China. Therefore, policies based on the promotion of eco-innovation and the initiation of new solar energy projects can control emissions and improve environmental quality in China. Integr Environ Assess Manag 2022;18:555-571. © 2021 SETAC.