Search

In recent years, clean air policies have led to reductions in air pollution across China. Alongside this, emerging carbon neutrality (CN) policies that aim to address the impacts of climate change may also deliver air quality (AQ) co-benefits or climate penalties. Different CN policies will lead to different changes in volatile organic compound (VOC), NO x and particulate matter (PM) emissions, which will in turn impact the photochemical production of secondary pollutants such as ozone (O 3). It is currently unclear how different combinations of AQ and CN policies may impact in situ O 3 production across China in the future. A detailed chemical box model incorporating the Master Chemical Mechanism was developed to investigate the impact of combined AQ and CN policies on O 3 formation in Beijing. The Multi-resolution Emission Inventory model for Climate and air pollution research (MEIC) and the Dynamic Projection model for Emissions in China (DPEC) were used to estimate future pollutant mixing ratios, relative to ambient observations of 35 VOCs, NO x , CO and aerosol surface area (ASA) during the APHH-Beijing 2017 summer campaign. The most ambitious policy scenario, "Ambitious Pollution 1.5D Goals", led to the largest reduction in O 3 production by 2060 but was not the most impactful scenario for reducing O 3 production between 2030–2045. Larger reductions were observed under the "Ambitious Pollution Neutral Goals" policy, which focuses on achieving net zero by 2060. O 3 production was found to be most sensitive to changes in the OLE2 group of VOCs (alkenes where kOH>7×104 ppm -1 min -1 ; a 5 % increase in OLE2 increased simulated O 3 production by 1.12 %). However, reducing less reactive but higher concentration species in Beijing (such as short-chain alkanes) led to larger reductions in O 3 production under all scenarios. O 3 production was not sensitive to changes in ASA, with a 69 % decrease in ASA leading to a change of <1 % in O 3. However, doubling biogenic VOCs in the model further increased O 3 production in 2060 under all future scenarios by up to 18 %, indicating that the influence of future climate-induced changes in biogenic emissions may have a significant impact on in situ O 3 formation in Beijing. This study highlights that the emission trajectories of certain specific VOCs are highly influential in determining possible future O 3 air quality effects that may arise from increasing ambient temperatures and decarbonisation in Beijing. [ABSTRACT FROM AUTHOR]

The greenhouse effect of atmospheric pollution is globally concerning. China is transitioning to market-driven emission reduction from policy-driven efforts. In 2021, key power industry emitters were included in the national carbon trading market. However, many companies lack willingness and understanding of carbon assets, hindering progress. Research on power companies in Beijing, a political and carbon market pilot region, is valuable. This study obtained data on the participation of Beijing's power generation companies in the carbon market and the construction of their carbon management systems during the first compliance period through the distribution of surveys. The findings revealed that the implementation and preparation of carbon inventory, Chinese Certified Emission Reduction (CCER) development, the allocation of carbon management personnel, and training are key factors influencing the actual effectiveness of carbon management within companies. Based on the survey results and the impact pathways, this study outlines the preparatory work, system content, and construction steps for power companies to build a carbon management system. It summarizes five key areas of work for power companies in managing carbon assets: carbon inventory, carbon management personnel and mechanisms, carbon trading, carbon emission reduction, and carbon finance. This provides guidance to help power companies fulfill their obligations smoothly, add value to their carbon assets, and achieve low-carbon development goals. Additionally, it offers a reference for other industry enterprises that are about to enter carbon trading. [ABSTRACT FROM AUTHOR]

High contents of reactive nitrogen components aggravate air pollution and could also impact ecosystem structures and functioning across the terrestrial–aquatic–marine continuum. However, the long-term historical trends and future predictions of reactive nitrogen components at the global scale still remain highly uncertain. In our study, field observations, satellite products, model outputs, and many other covariates were integrated into the multi-stage machine-learning model to capture the global patterns of reactive nitrogen components during 2000–2019. In order to decrease the estimate uncertainties in the future scenarios, the constructed reactive nitrogen component dataset for the historical period was utilised as the constraint to calibrate the CMIP6 dataset in four scenarios. The results suggested that the cross-validation (CV) R2 values of four species showed satisfying performance (R2>0.55). The concentrations of estimated reactive nitrogen components in China experienced persistent increases during 2000–2013, while they suffered drastic decreases from 2013, except for NH3. This might be associated with the impact of clean-air policies. However, in Europe and the United States, these compounds have remained relatively stable since 2000. In the future scenarios, SSP3-7.0 (traditional-energy scenario) and SSP1-2.6 (carbon neutrality scenario) showed the highest and lowest reactive nitrogen component concentrations, respectively. Although the reactive nitrogen concentrations in some heavy-pollution scenarios (SSP3-7.0) also experienced decreases during 2020–2100, SSP1-2.6 and SSP2-4.5 (middle-emission scenario) still showed more rapidly decreasing trends. Our results emphasise the need for carbon neutrality pathways to reduce global atmospheric N pollution. [ABSTRACT FROM AUTHOR]

A scientific assessment of the synergistic effect of the low-carbon city pilot policy in reducing air pollution and carbon emissions is needed to promote carbon peak and carbon neutrality. This study applied the Spatial Durbin Model-Difference in Difference technique to investigate the synergistic effect of air pollution and carbon emission reduction through the implementation of the low-carbon city pilot policy. The main results are as follows. (1) A spatial phenomenon was observed, in which there was a coexistence of urban carbon emissions and air pollution agglomerations. The spatial characteristics of the "symbiotic" carbon emissions and air pollution agglomerations were revealed. (2) The low-carbon city policy significantly reduced CO2, SO2, and PM2.5 concentrations, and the effect of the "co-governance" of air pollution and carbon emission reduction was obvious. (3) There was a clear regional heterogeneity in the synergistic effect of air pollution and carbon emission reduction in low-carbon cities. A stronger incentive effect was apparent in central and western cities, resource-based cities, and key environmental protection cities. (4) To achieve a synergistic governance "sharing" situation, the transmission mechanism of the low-carbon city pilot policy was the reduction of total energy consumption, the promotion of industrial restructuring, the optimization of the factor endowment structure, and the continuous improvement of the urban transport structure and green innovation. Our results not only help advance the research on synergistic reduction of air pollution and carbon emissions, but also can be of interest to low-carbon city policy makers in China. [ABSTRACT FROM AUTHOR]