• Energy Research
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Aromatic hydrocarbons (AHs) are both hazardous air pollutants and important precursors to ozone and secondary organic aerosols. Here we investigated 14 C6-C9 AHs at one urban, one suburban and two rural sites in the Pearl River Delta region during November-December 2009. The ratios of individual aromatics to acetylene were compared among these contrasting sites to indicate their difference in source contributions from solvent use and vehicle emissions. Ratios of toluene to benzene (T/B) in urban (1.8) and suburban (1.6) were near that of vehicle emissions. Higher T/B of 2.5 at the rural site downwind the industry zones reflected substantial contribution of solvent use while T/B of 0.8 at the upwind rural site reflected the impact of biomass burning. Source apportionment by positive matrix factorization (PMF) revealed that solvent use, vehicle exhaust and biomass burning altogether accounted for 89-94% of observed AHs. Vehicle exhaust was the major source for benzene with a share of 43-70% and biomass burning in particular contributed 30% to benzene in the upwind rural site; toluene, C8-aromatics and C9-aromatics, however, were mainly from solvent use, with contribution percentages of 47-59%, 52-59% and 41-64%, respectively.

AbstractBecause of its low level of energy consumption and the small scale of its industrial development, the Tibet Autonomous Region has historically been excluded from China's reported energy statistics, including those regarding CO2 emissions. In this paper, we estimate Tibet's energy consumption using limited online documents, and we calculate the 2014 energy‐related and process‐related CO2 emissions of Tibet and its seven prefecture‐level administrative divisions for the first time. Our results show that 5.52 million tons of CO2 were emitted in Tibet in 2014; 33% of these emissions are associated with cement production. Tibet's emissions per capita amounted to 1.74 tons in 2014, which is substantially lower than the national average, although Tibet's emission intensity is relatively high at 0.60 tons per thousand yuan in 2014. Among Tibet's seven prefecture‐level administrative divisions, Lhasa City and Shannan Region are the two largest CO2 contributors and have the highest per capita emissions and emission intensities. The Nagqu and Nyingchi regions emit little CO2 due to their farming/pasturing‐dominated economies. This quantitative measure of Tibet's regional CO2 emissions provides solid data support for Tibet's actions on climate change and emission reductions.

Urban heat islands (UHIs) are an important issue in urban sustainability, and the standardized calculation of surface urban heat island (SUHI) intensity has been a common concern of researchers in the past. In this study, we used the administrative borders (AB) method and an optimized simplified urban-extent (OSUE) algorithm to calculate the surface urban heat island intensity from 2001 to 2017 for 36 major cities in mainland China by using Moderate Resolution Imaging Spectroradiometer (MODIS) images. The spatiotemporal differences between these two methods were analyzed from the perspectives of the regional and national patterns and the daily, monthly, and annual trends. Regardless of the spatial or temporal scale, the calculation results of these two methods showed extremely similar patterns, especially for the daytime. However, when the calculated SUHI intensities were investigated through a regression analysis with multiple driving factors, we found that, although natural conditions were the main drivers for both methods, the anthropogenic factors obtained from statistical data (population and gross domestic product) were more correlated with the SUHI intensity from the AB method. This trend was probably caused by the spatial extent of the statistical data, which aligned more closely with the rural extent in the AB method. This study not only explores the standardization of the calculation of urban heat intensity but also provides insights into the relationship between urban development and the SUHI.

Low carbon transformation plays an important role in promoting the energy production and consumption revolution. Currently, the power sector of China still faces a series of challenges, such as the overcapacity of coal-fired power, the renewable energy consumption, the new constraints of carbon-emissions, and fragmented power planning. This study develops a multi-objective optimization model to predict the future trend of China power structure by 2035. The key factors such as network, power, load and storage are taken into account. Besides, the technical feasibility, economic rationality and social acceptable constraints are also fully considered. Through planning and optimization, the premise of low carbon transformation is to ensure the continuity of existing policies for removing inefficient assets, and the core is to develop and utilize non-fossil energy on a large scale. Specifically, the capacity of coal-fired power will be attained in the peak in 2025, and the factor will also transfer from main power supplier to main power and energy supplier. Before 2025, the clean replacement of incremental power installation will be completed. In 2035, 92% of new investment comes from non-fossil energy. The economy and competitiveness of wind power and PV (Photovoltaic) power generation are continuously increasing. By 2020, the coal-fired power and the wind power in eastern of China will be parity firstly. In 2025, the cost of PV and wind power will be the same. Furthermore, the evaluation dimension of modern power system with clean, low-carbon, safety and high efficiency are innovatively constructed, and the index system target of 2035 is quantitatively analyzed and prospected.

The solid by-product from power plant fueled with municipal solid waste and coal was used as a raw material to synthesize zeolite by fusion-hydrothermal process in order to effectively use this type of waste material. The effects of treatment conditions, including NaOH/ash ratio, operating temperature and hydrothermal reaction time, were investigated, and the product was applied to simulated wastewater treatment. The optimal conditions for zeolite X synthesis were: NaOH/ash ratio=1.2:1, fusion temperature=550 degrees C, crystallization time=6-10 h and crystallization temperature=90 degrees C. In the synthesis process, it was found that zeolite X tended to transform into zeolite HS when NaOH/ash ratio was 1.8 or higher, crystallization time was 14-18 h, operating temperature was 130 degrees C or higher. The CEC value, BET surface area and pore volume for the synthesized product at optimal conditions were 250 cmol kg(-1), 249 m(2) g(-1) and 0.46 cm(3) g(-1) respectively, higher than coal fly ash based zeolite. Furthermore, when applied to Zn(2+) contaminated wastewater treatment, the synthesized product presented larger adsorption capacity and bond energy than coal fly ash based zeolite, and the adsorption isotherm data could be well described by Langmuir and Freundlich isotherm models. These results demonstrated that the special type of co-combustion ash from power plant is suitable for synthesizing high quality zeolite, and the products are suitable for heavy metal removal from wastewater.

Carbonaceous aerosols (CAs) scatter and absorb incident solar radiation in the atmosphere, thereby influencing the regional climate and hydrological cycle, particularly in the Third Pole (TP). Here, we present the characteristics of CAs at 19 observation stations from the Atmospheric Pollution and Cryospheric Change network to obtain a deep understanding of pollutant status in the TP. The organic carbon (OC) and elemental carbon (EC) concentrations decreased noticeably inwards from outside to inland of the TP, consistent with their emission load and also affected by transport process and meteorological condition. Urban areas, such as Kathmandu, Karachi, and Mardan, exhibited extremely high OC and EC concentrations, with low and high values occurring in the monsoon and non-monsoon seasons, respectively. However, remote regions inland the TP (e.g., Nam Co and Ngari) demonstrated much lower OC and EC concentrations. Different seasonal variations were observed between the southern and northern parts of the TP, suggesting differences in the patterns of pollutant sources and in distance from the sources between the two regions. In addition to the influence of long-range transported pollutants from the Indo-Gangetic Plain (IGP), the TP was affected by local emissions (e.g., biomass burning). The OC/EC ratio also suggested that biomass burning was prevalent in the center TP, whereas the marginal sites (e.g., Jomsom, Dhunche, and Laohugou) were affected by fossil fuel combustion from the up-wind regions. The mass absorption cross-section of EC (MACEC) at 632 nm ranged from 6.56 to 14.7 m2 g-1, with an increasing trend from outside to inland of the TP. Urban areas had low MACEC values because such regions were mainly affected by local fresh emissions. In addition, large amount of brown carbon can decrease the MACEC values in cities of South Asia. Remote sites had high MACEC values because of the coating enhancement of aerosols. Influenced by emission, transport process, and weather condition, the CA concentrations and MACEC presented decreasing and increasing trends, respectively, from outside to inland of the TP.

Abstract The transport sector has become an important source of urban greenhouse gas (GHG) and air pollutant emissions, with the continuous growth of transportation demand. The co-benefits of reducing GHG and air pollutant emissions in the transport sector are receiving more and more attention. Taking Guangzhou as the case study city, this study quantitatively analyzed the co-benefits of reducing CO2 and air pollutant emissions under the sustainable scenario in the transport sector by developing a quantitative analysis model based on the Long-range Energy Alternatives Planning (LEAP) framework. The co-benefits quantitative parameter and the co-benefits radar chart analysis method are used to identify and evaluate the generated co-benefits, and then the co-benefits generated by implementing the sustainable measures are discussed. The results show that adjusting transport modes and increasing the application of electricity are the two most effective measures for achieving the co-benefits of reducing CO2 and air pollutant emissions in the Guangzhou transport sector. Thus, these two measures are highly preferential for mitigating CO2 and air pollutant emissions. In addition, increasing the application of biofuel and hydrogen energy also has good co-benefits. However, increasing the application of Liquefied Natural Gas (LNG) has poor co-benefits. Promoting the utilization of LNG intercity buses, trucks, and cargo ships will lead to emission increases of CO and HC compared to the current policy scenario, and small emission reductions of CO2 and other air pollutants. Therefore, to promote the utilization of LNG vehicles and ships, it is necessary to cooperate with the use of air pollutant end removal devices and high-pressure direct injection (HPDI) gas engines.

Recycling the arsenic-rich biomass of Pteris vittata is a critical problem during phytoremediation primarily because of the low value and high risk of arsenic-rich biomass. Nevertheless, extracts of P. vittata have been found to have a variety of bio-activities (e.g., anti-oxidation, anti-cancer, and anti-bacterial) and abundant valuable bio-active compositions (e.g., flavonoids), which might present a new solution for the recycling of P. vittata harvests. This work demonstrated a pilot-scale experiment to extract and purify the phenolic compounds from 1 t of arsenic-rich P. vittata biomass. Result showed that 47.9 kg of phenolic-rich extract with a potential value of US$908.66-8345.14 was obtained. This extract showed no acute oral toxicities (LD50 > 10 g/kg), no skin irritation, and no chronic risks in the long-term skin contact exposure pathways. All of the wastes from production have been recycled and safely disposed with low cost (US$28.44), and the cost may be further reduced. The calculated benefits from this method showed a potential to provide 995-53,050 US$/hm2 per year to a phytoremediation project. Therefore, this strategy could address the issue of expensive phytoremediation.