Carbon In Beijing Research Articles

Does decarbonization policy decrease disease risks from black carbon in Beijing, China? A comparison study

Epidemiology studies evaluating the health effect of the decarbonization policy in Beijing, China are limited. This time series study sought to examine the health effectiveness of BC and PM2.5 in Beijing, a formerly heavily polluted city. Therefore, the objectives of this article were (1) to evaluate the modification effects of temperature on the health effects of black carbon (BC) and fine particles (PM2.5) in Beijing. (2) to compare the health effects of BC and PM2.5 pre- and post-implementation of decarbonization policy. Bivariate Response Surface Model and Generalised Additive Model were used to analyze the modification effects. Comparison analysis was conducted pre- and post-implementation of decarbonization policy. The results indicated that (i) Post-implementation, reductions were noted in non-accidental diseases (RR = 1.064 per 10 μg/m3), circulatory diseases (RR = 1.068 per 10 μg/m3) and respiratory diseases (RR = 1.148 per 10 μg/m3) related to BC; this was especially pronounced on cold days. (ii) Greater reductions in risk of non-accidental, circulatory and respiratory deaths (D-value: 0.134 versus 0.002, 0.180 versus 0.003, 0.176 versus 0.002) were noted for BC than for PM2.5. (iii) Higher risks of the impact of BC on respiratory diseases were observed in females than in males. In conclusion, a stronger correlation existed between BC and mortality on cold days than moderately cold days in Beijing. Furthermore, compared with PM2.5, BC posed a greater disease risk and the effectiveness of the decarbonization policy was more obvious.

Effect of Two Exogenous Organic Acids on the Excitation Effect of Soil Organic Carbon in Beijing, China

Significance: The study of the effects and pathways of catechol and pyrogallic acid on soil organic carbon mineralization has a positive effect on mastering soil carbon transformation. Methods and objectives: In this study, we took 0–20 cm soil from Pinus tabulaeformis forest as an object to investigate the effects of catechol and pyrogallic acid with different concentrations on soil organic carbon mineralization through a 60-day mineralization incubation test. The soil active carbon content and changes in soil microbial diversity and community composition were analyzed by using single exponential fitting, quantitative PCR, and high-throughput sequencing to explore the influencing mechanisms of catechol and pyrogallic acid on soil organic carbon excitation. Results: Catechol and pyrogallic acid had the effect of enhancing the soil organic carbon mineralization and soil active carbon content, and the higher the concentration, the stronger the enhancement effect. Catechol reduced the Ace index, Chao1 index, and Shannon index of bacteria and fungi, and further changed the relative abundance of two dominant groups (Proteobacteria and Acidobacteriota) in bacteria and Basidiomycota in fungi at high concentrations. There was no obvious regularity in the effects of pyrogallic acid on bacteria and fungi, but the Ace index and Chao1 index of bacteria underwent drastic and disordered changes. Conclusions: Catechol and pyrogallic acid can trigger positive excitation of the soil organic carbon through two pathways: increasing the soil active carbon content and modulating soil microorganisms, but the way they modulate soil microorganisms are different. Catechol regulates soil microorganisms by reducing the number, richness, and evenness of the bacteria and fungi species, as well as the community composition, while the way pyrogallic acid regulates only closely relates to the changes in the number, richness, and evenness of bacteria species.

Sources of Black Carbon in Beijing, China

Sources of Black Carbon in Beijing, China

Variation, sources and historical trend of black carbon in Beijing, China based on ground observation and MERRA-2 reanalysis data

Based on the ground-measurements and MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, Version 2) reanalysis data, the temporal-spatial variation of black carbon (BC) in Beijing and the affecting factors were investigated. According to the ground-measured BC concentration in November months of 2014, 2015 and 2016, the before-heating period in November 2014 showed the lowest BC concentration as a result of the efficient emission controls for the Asia-Pacific Economic Cooperation (APEC) meeting. Except for November 2014, the BC mass concentration during the heating periods was notably lower than the before-heating periods in November 2015 and 2016. Wind speed and relative humidity appeared to be two important meteorological parameters affecting BC pollution. The MERRA-2 BC concentration was validated through comparison with the continuous ground BC measurements in 2015 and 2016, affirming its reliability in demonstrating the large scale and long term variations of the ground BC concentration. The MERRA-2 BC spatial distribution, the potential source regions determined by concentration weighted trajectory (CWT) analysis, and the regional emission inventories were combined to reveal the potential source regions and source types of BC in Beijing. Transportation emission in Beijing and residential emissions in the neighboring regions such as Hebei appeared to be important sources of BC in Beijing. According to the historical trends of MERRA-2 BC concentration and typical fossil fuel consumption (1980–2017), local coal and coke are no longer the major factor affecting the BC concentration, instead, liquid fuels such as gasoline, kerosene, and diesel may highly contribute to the BC pollution in Beijing in recent years. Regional transport of BC may have also contributed to the loading of BC in Beijing. Open biomass burning may be a non-negligible factor for the short-term variation of BC in the atmosphere.

Important fossil source contribution to brown carbon in Beijing during winter

Organic aerosol (OA) constitutes a substantial fraction of fine particles and affects both human health and climate. It is becoming clear that OA absorbs light substantially (hence termed Brown Carbon, BrC), adding uncertainties to global aerosol radiative forcing estimations. The few current radiative-transfer and chemical-transport models that include BrC primarily consider sources from biogenic and biomass combustion. However, radiocarbon fingerprinting here clearly indicates that light-absorbing organic carbon in winter Beijing, the capital of China, is mainly due to fossil sources, which contribute the largest part to organic carbon (OC, 67 ± 3%) and its sub-constituents (water-soluble OC, WSOC: 54 ± 4%, and water-insoluble OC, WIOC: 73 ± 3%). The dual-isotope (Δ14C/δ13C) signatures, organic molecular tracers and Beijing-tailored emission inventory identify that this fossil source is primarily from coal combustion activities in winter, especially from the residential sector. Source testing on Chinese residential coal combustion provides direct evidence that intensive coal combustion could contribute to increased light-absorptivity of ambient BrC in Beijing winter. Coal combustion is an important source to BrC in regions such as northern China, especially during the winter season. Future modeling of OA radiative forcing should consider the importance of both biomass and fossil sources.

A research about Beijing's carbon emissions based on the IPSO‐BP model

The problem of CO2 emissions, as an important factor of air pollution, attracts broad attention. For the purpose of pollution prevention, this paper would establish a reasonable model to study Beijing's impacting factors of carbon emissions and carry out future forecast. This paper use the non‐inertia weight coefficient and particle mutation particle swarm optimization (PSO) algorithm to optimize the initial connection weights and thresholds of the traditional BP neural network, and establish a BP neural network model based on the improved PSO. Through empirical analysis of carbon emissions and its driven factors in Beijing city from 1978 to 2012, IPSO‐BP is found to be a good method to make carbon emissions' forecast as it can improve the global optimization ability of traditional IPSO and BP algorithm. The results also can contribute to the local government's policy related decision‐making to make control of carbon emissions. © 2016 American Institute of Chemical Engineers Environ Prog, 36: 428–434, 2017

Spatial variation in the ecological relationships among the components of Beijing's carbon metabolic system

In this paper, we construct a spatially explicit model of carbon metabolism for the flows of carbon among the components of an urban area. We used the model to identify spatial heterogeneity in the ecological relationships within a carbon metabolic network. We combined land-use and cover type maps for Beijing from 1990 to 2010 with empirical coefficients and socioeconomic data to quantify the flows. We used utility analysis to determine the ecological relationships between the components of the system and analyzed their changes during urban development. We used ArcGIS to analyze their spatial variation. We found that the positive utilities in Beijing decreased over time and that negative relationships mostly outweighed positive relationships after 2000. The main ecological relationships were distributed throughout the entire urban area before 2000; subsequently, exploitation, control, and mutualism relationships became concentrated in the southeast, leaving competition relationships to dominate the northwest. Mutualism relationships were most common for natural components, but were not stable because they were easily disturbed by urban expansion. Transportation and industrial land and urban land were the most important contributors to exploitation and control relationships and may be important indicators of spatial adjustment. Increasing competition relationships unbalanced the carbon metabolism, and limitations on the area of land available for development and on the water resources led to increasingly serious competition. The results provide an objective basis for planning adjustments to Beijing's land-use patterns to improve its carbon metabolism and reduce carbon emission.

Source Apportionment of Elemental Carbon in Beijing, China: Insights from Radiocarbon and Organic Marker Measurements.

Elemental carbon (EC) or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In this study, radiocarbon ((14)C) based source apportionment is used to distinguish between fossil fuel and biomass burning sources of EC isolated from aerosol filter samples collected in Beijing from June 2010 to May 2011. The (14)C results demonstrate that EC is consistently dominated by fossil-fuel combustion throughout the whole year with a mean contribution of 79% ± 6% (ranging from 70% to 91%), though EC has a higher mean and peak concentrations in the cold season. The seasonal molecular pattern of hopanes (i.e., a class of organic markers mainly emitted during the combustion of different fossil fuels) indicates that traffic-related emissions are the most important fossil source in the warm period and coal combustion emissions are significantly increased in the cold season. By combining (14)C based source apportionment results and picene (i.e., an organic marker for coal emissions) concentrations, relative contributions from coal (mainly from residential bituminous coal) and vehicle to EC in the cold period were estimated as 25 ± 4% and 50 ± 7%, respectively, whereas the coal combustion contribution was negligible or very small in the warm period.

Chemical characteristics and light-absorbing property of water-soluble organic carbon in Beijing: Biomass burning contributions

Emissions from biomass burning contribute significantly to water-soluble organic carbon (WSOC) and light-absorbing organic carbon (brown carbon). Ambient atmospheric samples were collected at an urban site in Beijing during winter and summer, along with source samples from residential crop straw burning. Carbonaceous aerosol species, including organic carbon (OC), elemental carbon (EC), WSOC and multiple saccharides as well as water-soluble potassium (K+) in PM2.5 (fine particulate matter with size less than 2.5 μm) were measured. Chemical signatures of atmospheric aerosols in Beijing during winter and summer days with significant biomass burning influence were identified. Meanwhile, light absorption by WSOC was measured and quantitatively compared to EC at ground level. The results from this study indicated that levoglucosan exhibited consistently high concentrations (209 ± 145 ng m−3) in winter. Ratios of levoglucosan/mannosan (L/M) and levoglucosan/galacosan (L/G) indicated that residential biofuel use is an important source of biomass burning aerosol in winter in Beijing. Light absorption coefficient per unit ambient WSOC mass calculated at 365 nm is approximately 1.54 ± 0.16 m2 g−1 in winter and 0.73 ± 0.15 m2 g−1 in summer. Biomass burning derived WSOC accounted for 23 ± 7% and 16 ± 7% of total WSOC mass, and contributed to 17 ± 4% and 19 ± 5% of total WSOC light absorption in winter and summer, respectively. It is noteworthy that, up to 30% of total WSOC light absorption was attributed to biomass burning in significant biomass-burning-impacted summer day. Near-surface light absorption (over the range 300–400 nm) by WSOC was about ∼40% of that by EC in winter and ∼25% in summer.

Analyzing spatial patterns of urban carbon metabolism: A case study in Beijing, China

Analyzing the spatial pattern of a city's carbon metabolism can provide insights into the spatial adjustments required to mitigate the greenhouse effect. Using GIS software and empirical coefficients, we analyzed the spatial distribution of Beijing's carbon metabolism in 5 years (1990, 1995, 2000, 2005, and 2008), and analyzed both temporal and spatial changes in this pattern. Our results highlight the importance of the expansion of built-up areas in defining the patterns of Beijing's carbon metabolism, and let us explore options for changing these patterns. Carbon emission was high in the highly urbanized southeastern parts of the city and low in the less-urbanized northwestern parts, whereas carbon sequestration showed the opposite pattern (low in southeastern parts and high in northwestern parts). During the study period, carbon sequestration only offset 2.4% of carbon emission, indicating a serious imbalance of the city's carbon metabolism. The city's core built-up area expanded along eight axes, and its form fluctuated between simpler and more complex. From a small-scale perspective, the spatial pattern mainly showed expansion and aggregation of patches with high carbon emission and shrinkage and fragmentation of patches with high carbon sequestration. These results provide insights that will guide the development of more effective management of the spatial patterns of carbon emission and sequestration.

Global Bang for the Buck: Cutting Black Carbon and Methane Benefits Both Health and Climate

Black carbon and methane have both been implicated in climate change. They also pose more direct human health threats, with black carbon constituting one component of fine particulate matter (PM2.5) and methane acting as a precursor of ground-level ozone. An international team of researchers analyzed 14 control measures for human-caused emissions of black carbon and methane to investigate health benefits that might occur in tandem with actions to help mitigate climate change in the next 20–40 years [EHP 120(6):831–839; Anenberg et al.]. Black carbon and methane are attractive climate-change mitigation targets because they are relatively short-lived in the atmosphere compared with carbon dioxide, with emission restrictions leading to fairly rapid benefits. Some of the primary sources of methane are fossil-fuel extraction, landfills, livestock, rice production, and wastewater treatment. Among major sources of black carbon are many types of incomplete combustion, including that tied to transportation, industry, housing, and burning of biomass. The 14 measures target sources such as fossil-fuel operations, vehicle emissions, landfill gas, sewage, agriculture, brick kilns, and biomass-fueled cook stoves. Using published emissions scenarios as a basis for their calculations, the investigators estimate that if all 14 measures were fully implemented by 2030, average global population-weighted surface concentrations of PM2.5 could be reduced by 23–34% and ozone could drop 7–17% within the same period. That could prevent anywhere from 640,000 to 4,900,000 premature deaths annually, or about 1–7% of all deaths estimated to occur with the projected global population of 8.4 billion. The estimated health benefits would be due almost entirely to the black carbon control measures—with their attendant reductions in PM2.5, organic carbon, and non-methane ozone precursors—and would occur mostly in Asia and portions of Africa. Climate-change mitigation effects could have their own health benefits, although the authors didn’t attempt to calculate these. The authors accounted for just outdoor exposures from biomass-fueled cook stoves, not the well-documented health benefits of avoided indoor exposures; adding that information with a geographically appropriate distribution likely would substantially increase the number of avoided premature deaths. The researchers used two atmospheric models, each of which predicted substantially different air-quality responses to the 14 measures and incorporated a wide range of data from numerous epidemiological studies as factors in their equations. Uncertainties and variations in the models and data suggest the number of averted premature deaths could be substantially higher or lower. The researchers didn’t address the difficulties or costs of implementing the 14 measures but did note that some related efforts are already under way on many continents, including adoption of European vehicle-emission standards and reductions in cook-stove emissions in some developing countries.

Mass absorption efficiency of elemental carbon and water-soluble organic carbon in Beijing, China

Abstract. The mass absorption efficiency (MAE) of elemental carbon (EC) in Beijing was quantified using a thermal-optical carbon analyzer. The MAE measured at 632 nm was 8.45±1.71 and 9.41±1.92 m2 g−1 during winter and summer respectively. The daily variation of MAE was found to coincide with the abundance of organic carbon (OC), especially the OC to EC ratio, perhaps due to the enhancement by coating with organic aerosol (especially secondary organic aerosol, SOA) or the artifacts resulting from the redistribution of liquid-like organic particles during the filter-based absorption measurements. Using a converting approach that accounts for the discrepancy caused by measurements methods of both light absorption and EC concentration, previously published MAE values were converted to the equivalent-MAE, which is the estimated value if using the same measurement methods as used in this study. The equivalent-MAE was found to be much lower in the regions heavily impacted by biomass burning (e.g., below 2.7 m2 g−1 for two Indian cities). Results from source samples (including diesel exhaust samples and biomass smoke samples) also demonstrated that emissions from biomass burning would decrease the MAE of EC. Moreover, optical properties of water-soluble organic carbon (WSOC) in Beijing were presented. Light absorption by WSOC exhibited strong wavelength (λ) dependence such that absorption varied approximately as λ−7, which was characteristic of the brown carbon spectra. The MAE of WSOC (measured at 365 nm) was 1.79±0.24 and 0.71±0.20 m2 g−1 during winter and summer respectively. The large discrepancy between the MAE of WSOC during winter and summer was attributed to the difference in the precursors of SOA such that anthropogenic volatile organic compounds (AVOCs) should be more important as the precursors of SOA in winter. The MAE of WSOC in Beijing was much higher than results from the southeastern United States which were obtained using the same method as used in this study, perhaps due to the stronger emissions of biomass burning in China.