Cost-benefits analysis of ultra-low emissions standard on air quality and health impact in thermal power plants in China

Synergistic effects of air pollutants and CO2 at Chinese thermal power plants based on real-monitored data

The thermal power industry is a major anthropogenic source of emissions in China, significantly contributing to the release of carbon dioxide (CO2) and air pollutants. This study evaluated emission reduction potential under various scenarios by establishing the latest, real-monitored, and unit-level emissions database of particulate matter (PM), sulfur dioxide (SO2), nitrogen oxide (NOx), and CO2 for Chinese thermal power industry during 2021-2023. The results indicate that, during 2022-2023, the concentrations of PM, SO2, NOx, and CO2 decreased by 1.40 %, 0.83 %, 0.94 %, and 36.93 %, respectively. However, these reductions were insufficient to offset the impact of increased fuel consumption, leading to a rise in emissions of PM, SO2, NOx, and CO2 by 21.42 %, 13.43 %, 17.49 %, and 5.28 %, respectively. In 2023, the national average Synergy Indices for CO2-PM, CO2-SO2, and CO2-NOx were only 0.02, 0.01, and 0.01, indicating weak synergistic effects between CO2 and air pollutant. This low coordination level is mainly caused by the continued implementation of separate and uncoordinated management frameworks for carbon and air pollutants in most provinces. Furthermore, clean energy substitution was identified as the most effective measure for emission reduction, with potential decreases of 66.45 %, 70.16 %, 70.43 %, and 9.80 % for PM, SO2, NOx, and CO2, respectively. This study provides a practical roadmap for the development of synergistic mitigation policies and offers valuable insights for other countries, such as India, in addressing climate change challenges within the energy sector.

Assessment of sulfate and nitrate variations in China during 19902020: Insights into source contributions and formation pathways

Sulfate (SO42-) and nitrate (NO3-) are two critical constituents of fine particulate matter (PM2.5), significantly impacting air quality and public health. This study provides a comprehensive assessment of spatial and temporal variations in SO42- and NO3- levels across China from 1990 to 2020 by using a revised Community Multiscale Air Quality Modeling System (CMAQ), focusing on elucidating insights into source contributions and formation pathways. The results reveal that NO3- pollution has become increasingly significant, with its concentrations surpassing those of SO42- in most regions of China since 2017. Industrial emissions were identified as the primary contributors to SO42- levels, accounting for 40.2 %57.5 % in Beijing-Tianjin-Hebei region (BTH), 51.0 %76.6 % in Yangtze River Delta (YRD), 46.8 %68.2 % in Pearl River Delta (PRD), 38.9 %62.8 % in Sichuan Basin (SCB), and 36.1 %58.8 % in Fenwei Plain (FWP). For NO3-, industrial emissions were predominant in BTH (27.7 %33.1 %) and YRD (31.0 %33.6 %), while transportation emissions were the major source in PRD (26.4 %36.3 %), in SCB and FWP, contributions from these sectors were comparable. The formation pathways of SO42- exhibited distinct regional variations: overall, primary emission of SO42- was the predominant pathway in BTH (23.7 %47.3 %) and YRD (24.1 %30.5 %), heterogeneous reaction dominated in SCB (23.2 %55.5 %) and FWP (20.5 %48.9 %), and aqueous-phase oxidation reaction of SO2 by H2O2 was the leading formation pathway in PRD (23.6 %32.8 %). In contrast, the formation pathways of NO3- demonstrated consistency across all regions, with combined gas-phase oxidation reaction of NO2 by OH and the heterogeneous reaction of N2O5 accounting for over 90 % of its production. This study highlights the need for targeted air quality management strategies that account for regional variations in source contributions and prioritize the reduction of key oxidants driving secondary aerosol formation. The findings could offer valuable insights for policymakers developing effective measures to mitigate air pollution.

The effect of coal-fired power plants on ambient air quality in Mpumalanga province, South Africa, 2014-2018

Several coal-fired power plants (CFPPs) were built in South Africa, mainly in the central Mpumalanga Province, due to an increase in the demand for Eskom, the national power utility, to keep up with socio-economic growth. The CFPPs, of which 90% are owned by Eskom, generate a significant share of the country's electricity but contribute to the air pollution experienced in the country. The paper discusses sulphur dioxide (SO2), nitrogen dioxide (NO2) and particulate matter of size less than 10 micrometre (μm) in diameter (PM10), using data from 2014 to 2018. The statistics revealed higher PM10 concentrations during winter than in summer and spring at the Kriel and Komati sites; associated with the higher contribution of domestic burning. The study's results could influence legislation and policies and help to understand the source of poor ambient air quality by assessing the three pollutants within the area of the selected power plants.

Exosomal miR-129-2-3p promotes airway epithelial barrier disruption in PM2.5-aggravated asthma

Particulate matter 2.5 (PM2.5) exposure is intricately linked to asthma exacerbations. Damage to the airway epithelial barrier function serves as an initiating factor for asthma attacks and worsening symptoms. In recent years, numerous exosomal microRNAs (miRNAs) have emerged as potential biomarkers for diagnosing asthma. However, the mechanisms by which PM2.5-induced exosomes exacerbate asthma remain unclear. This study aims to investigate the role of exosomal miR-129-2-3p in regulating airway epithelial cell barrier function, its potential targets, and signaling pathways involved in PM2.5-induced aggravation of asthma. In this study, miR-129-2-3p is highly expressed in plasma exosomes from patients with asthma, mouse lung tissue and plasma exosomes, and exosomes produced by PM2.5-stimulated 16HBE cells. Moreover, the exposure level of PM2.5 is positively correlated with exosomal miR-129-2-3p in plasma in patients with asthma. As the concentration of PM2.5 increases, the synthesis of connexin (ZO-1, occludin, and E-cadherin) is gradually weakened, while the content of inflammatory factors (IL-6, IL-8, and TNF-α) is notably upregulated in PM2.5 exacerbated asthmatic mice. PM2.5-induced exosomes can decrease the level of connexin, enhance cell permeability and promote the secretion of inflammatory factors in 16HBE cells. TIAM1, a specific target gene for miR-129-2-3p, regulates the synthesis of connexin. Exosomal miR-129-2-3p exacerbates airway epithelial barrier dysfunction by targeted inhibition of the TIAM1/RAC1/PAK1 signaling pathway in PM2.5 aggravated asthma. In contrast, blocking miR-129-2-3p may be an alternative approach to therapeutic intervention in asthma.

Identifying Key Sources for Air Pollution and CO2 Emission Co-control in China

China is confronting the dual challenges of air pollution and climate change, mandating the co-control of air pollutants and CO2 emissions from their shared sources. Here we identify key sources for co-control that prioritize the mitigation of PM2.5-related health burdens, given the homogeneous impacts of CO2 emissions from various sources. By applying an integrated analysis framework that consists of a detailed emission inventory, a chemical transport model, a multisource fused dataset, and epidemiological concentration-response functions, we systematically evaluate the contribution of emissions from 390 sources (30 provinces and 13 socioeconomic sectors) to PM2.5-related health impacts and CO2 emissions, as well as the marginal health benefits of CO2 abatement across China. The estimated source-specific contributions exhibit substantial disparities, with the marginal benefits varying by 3 orders of magnitude. The rural residential, transportation, metal, and power and heating sectors emerge as pivotal sources for co-control, with regard to their relatively large marginal benefits or the sectoral total benefits. In addition, populous and heavily industrialized provinces such as Shandong and Henan are identified as the key regions for co-control. Our study highlights the significance of incorporating health benefits into formulating air pollution and carbon co-control strategies for improving the overall social welfare.