An evaluation of China’s carbon emission reduction policies on urban transport system

Climate change has become one of the hottest issues in international law. As the world’s second-largest greenhouse gas emission sector, the transport sector, especially the urban traffic system, is facing much more pressure to reduce its aggregate emissions. This article begins with a theoretical examination of the system theory, takes the cobenefit concept as a methodological guide and discusses various urban traffic emission reduction policies such as travel demand management, vehicles policies, fuel policies, road policies and comprehensive management policies of the urban transport system. It argues that holistic policy reform is the most important means of promoting CO2 emission reduction effectively in urban traffic system. It is unrealistic to only implement one type of policy to achieve CO2 emission reduction targets in urban traffic system; a policy mix will arguably be of great significance to achieve and sustain emission reduction. Therefore, the promotion and perfection of policy system of CO2 emission reduction in urban traffic system and the intensification of policy innovation should be deemed a strategic choice to effectively realize CO2 emission reduction targets in urban traffic system, while promoting the sustainable development of the urban traffic system, the city and the economy.Keywords: Urban transport system, greenhouse gas emission reduction, policy summarizing

Carbon Mitigation Pathway Evaluation and Environmental Benefit Analysis of Mitigation Technologies in China’s Petrochemical and Chemical Industry

International audienceThe co-benefits of mitigation technology in China’s petrochemical and chemical industry have not been evaluated, although they are deemed valuable for the cost-benefit analysis of carbon mitigation. On this basis, this study evaluates the carbon mitigation effects and environmental co-benefits of mitigation technologies that have been long ignored in China’s petrochemical and chemical industry. In addition, this study also fills the gap of provincial research in chemical industry. A bottom-up energy model and marginal abatement cost curves are constructed for each sector. The study is based on national and provincial levels to provide quantitative reference for the mitigation technologies. Results show that, among 18 technologies in the chemical industry, waste heat utilization and technological process transformation technologies have the highest marginal abatement benefits. Technologies in the petrochemical industry with the largest marginal abatement social benefit typically exists in three categories: efficiency improvement technology, waste heat utilization technology, and coating technology. At the national level, 8039 and 5105 premature deaths are effectively avoided by the promotion of chemical and petrochemical mitigation technologies, respectively. Monetary value of health impact in these two industries are 7.0 billion and 5.5 billion RMB, respectively. At the provincial level, coal gasification multi-generation gas turbine power generation technology, a technological process transformation technology, performs well in Shaanxi province with 122 million RMB of total social benefit

Dual-Responsive Carbon Dots for Tumor Extracellular Microenvironment Triggered Targeting and Enhanced Anticancer Drug Delivery

In this work, pH/redox dual-responsive carbon dots (CDs-RGD-Pt­(IV)-PEG) were fabricated for tumor extracellular microenvironment triggered targeting and enhanced anticancer drug delivery. The system consists of fluorescent carbon dots as imaging-guided drug nanocarriers, cisplatin­(IV) as prodrug, and RGD peptide as active targeting ligand, which is covered by monomethoxypolyethylene glycol (mPEG) through tumor extracellular pH (6.5–6.8) responsive benzoic-imine bond. The drug nanocarriers could be tracked by multicolor fluorescence of carbon dots. After the hydrolysis of benzoic-imine bond at the tumor extracellular pH to expose the inner targeting RGD peptide, the drug nanocarriers showed effective uptake by cancer cells through RGD-integrin α_<i>v</i>β₃ (ligand–receptor) interaction. Upon the internalization, the loaded cisplatin­(IV) prodrug was reduced to cytotoxic cisplatin in reductive cytosol of cancer cells to exhibit therapeutic effects. Confocal imaging, flow cytometry, and cell viability assays using CDs-RGD-Pt­(IV)-PEG were performed to reveal the enhanced uptake and better therapeutic efficiency to cancer cells with high integrin α_<i>v</i>β₃ expression at tumor extracellular pH than that in physiological condition. The developed CDs-RGD-Pt­(IV)-PEG offers a new strategy to provide safe and effective therapeutic agents based on carbon dots for promising cancer therapy

The Benefits of the Clean Heating Plan on Air Quality in the Beijing&ndash;Tianjin&ndash;Hebei Region

Coal-to-gas/electricity conversion (hereafter referred to as CTGC/CTEC) as the core project of a clean heating campaign has been widely adopted to replace and reduce the combustion of residential coal in Northern China since 2017. In this study, simulations based on the WRF-Chem model were carried out to quantitatively assess the impacts of the CTGC/CTEC project on air quality in the Beijing&ndash;Tianjin&ndash;Hebei (BTH) region. It was found that the CTGC/CTEC projects exert a remarkable effect on improving the air quality in the BTH region, especially in the plain area. The maximum decrease in the concentrations of PM2.5 and PM10 averaged during January can reach 30 and 40 &mu;g/m3, respectively. In addition, the spillover effects due to CTGC/CTEC projects are rather small; that is, the local reduced emissions tend to provide more benefit to the local air quality but less for its surrounding regions. It is also noteworthy that the effects due to meteorological condition changes are comparable with, or even larger, than those due to CTGC/CTEC projects, which are not spatially uniform for the BTH region among various cities. Overall, these results not only demonstrate the effectiveness of CTGC/CTEC projects on air-quality improvement in the BTH region, but also indicate the importance of meteorological conditions in modulating the local air quality. To sustain better air quality in the future, residential coal replacement, all over China, can be further promoted. In addition, continued policy refinement can be essential for the nationwide implementation of clean heating projects

Charge-Convertible Carbon Dots for Imaging-Guided Drug Delivery with Enhanced <i>in Vivo</i> Cancer Therapeutic Efficiency

Carbon dots (CDs) are remarkable nanocarriers due to their promising optical and biocompatible capabilities. However, their practical applicability in cancer therapeutics is limited by their insensitive surface properties to complicated tumor microenvironment <i>in vivo</i>. Herein, a tumor extracellular microenvironment-responsive drug nanocarrier based on cisplatin­(IV) prodrug-loaded charge-convertible CDs (CDs–Pt­(IV)@PEG-(PAH/DMMA)) was developed for imaging-guided drug delivery. An anionic polymer with dimethylmaleic acid (PEG-(PAH/DMMA)) on the fabricated CDs–Pt­(IV)@PEG-(PAH/DMMA) could undergo intriguing charge conversion to a cationic polymer in mildly acidic tumor extracellular microenvironment (pH ∼ 6.8), leading to strong electrostatic repulsion and release of positive CDs–Pt­(IV). Importantly, positively charged nanocarrier displays high affinity to negatively charged cancer cell membrane, which results in enhanced internalization and effective activation of cisplatin­(IV) prodrug in the reductive cytosol. The <i>in vitro</i> experimental results confirmed that this promising charge-convertible nanocarrier possesses better therapeutic efficiency under tumor extracellular microenvironment than normal physiological condition and noncharge-convertible nanocarrier. The <i>in vivo</i> experiments further demonstrated high tumor-inhibition efficacy and low side effects of the charge-convertible CDs, proving its capability as a smart drug nanocarrier with enhanced therapeutic effects. The present work provides a strategy to promote potential clinical application of CDs in the cancer treatment