Reduced carbon emission estimates from fossil fuel combustion and cement production in China.

Nearly three-quarters of the growth in global carbon emissions from the burning of fossil fuels and cement production between 2010 and 2012 occurred in China. Yet estimates of Chinese emissions remain subject to large uncertainty; inventories of China's total fossil fuel carbon emissions in 2008 differ by 0.3 gigatonnes of carbon, or 15 per cent. The primary sources of this uncertainty are conflicting estimates of energy consumption and emission factors, the latter being uncertain because of very few actual measurements representative of the mix of Chinese fuels. Here we re-evaluate China's carbon emissions using updated and harmonized energy consumption and clinker production data and two new and comprehensive sets of measured emission factors for Chinese coal. We find that total energy consumption in China was 10 per cent higher in 2000-2012 than the value reported by China's national statistics, that emission factors for Chinese coal are on average 40 per cent lower than the default values recommended by the Intergovernmental Panel on Climate Change, and that emissions from China's cement production are 45 per cent less than recent estimates. Altogether, our revised estimate of China's CO2 emissions from fossil fuel combustion and cement production is 2.49 gigatonnes of carbon (2 standard deviations = ±7.3 per cent) in 2013, which is 14 per cent lower than the emissions reported by other prominent inventories. Over the full period 2000 to 2013, our revised estimates are 2.9 gigatonnes of carbon less than previous estimates of China's cumulative carbon emissions. Our findings suggest that overestimation of China's emissions in 2000-2013 may be larger than China's estimated total forest sink in 1990-2007 (2.66 gigatonnes of carbon) or China's land carbon sink in 2000-2009 (2.6 gigatonnes of carbon).

The geographical distribution of fossil fuels unused when limiting global warming to 2 °C.

Policy makers have generally agreed that the average global temperature rise caused by greenhouse gas emissions should not exceed 2 °C above the average global temperature of pre-industrial times. It has been estimated that to have at least a 50 per cent chance of keeping warming below 2 °C throughout the twenty-first century, the cumulative carbon emissions between 2011 and 2050 need to be limited to around 1,100 gigatonnes of carbon dioxide (Gt CO2). However, the greenhouse gas emissions contained in present estimates of global fossil fuel reserves are around three times higher than this, and so the unabated use of all current fossil fuel reserves is incompatible with a warming limit of 2 °C. Here we use a single integrated assessment model that contains estimates of the quantities, locations and nature of the world's oil, gas and coal reserves and resources, and which is shown to be consistent with a wide variety of modelling approaches with different assumptions, to explore the implications of this emissions limit for fossil fuel production in different regions. Our results suggest that, globally, a third of oil reserves, half of gas reserves and over 80 per cent of current coal reserves should remain unused from 2010 to 2050 in order to meet the target of 2 °C. We show that development of resources in the Arctic and any increase in unconventional oil production are incommensurate with efforts to limit average global warming to 2 °C. Our results show that policy makers' instincts to exploit rapidly and completely their territorial fossil fuels are, in aggregate, inconsistent with their commitments to this temperature limit. Implementation of this policy commitment would also render unnecessary continued substantial expenditure on fossil fuel exploration, because any new discoveries could not lead to increased aggregate production.

Lung cancer risk by geologic coal deposits: A case-control study of female never-smokers from Xuanwei and Fuyuan, China.

Coal types vary around the world because of geochemical differences in their source deposits; however, the influence of coal emissions from different deposits on human health remains unexplored. To address this issue, we conducted the first study of the relationship between coal use from various deposits and lung cancer risk in Xuanwei and Fuyuan, counties in China where lung cancer rates are among the highest in the world among female never-smokers due to use of bituminous ("smoky") coal for heating and cooking. We conducted a population-based case-control study of 1031 lung cancer cases and 493 controls among never-smoking women in Xuanwei and Fuyuan. Logistic regression models were used to estimate associations between coal use from various deposits across the lifecourse and lung cancer risk. There was substantial heterogeneity in risks by coal deposit (p = 7.8E-05). Compared to non-smoky coal users, risks by smoky coal deposit ranged from OR = 7.49 (95% CI: 3.43-16.38) to OR = 33.40 (95% CI: 13.07-85.34). Further, women born into homes that used smoky coal and subsequently changed to non-smoky coal had a higher risk (OR = 10.83 (95% CI: 4.61-25.46)) than women born into homes that used non-smoky coal and changed to smoky coal (OR = 4.74 (95% CI: 2.03-11.04, pdifference = 0.04)). Our study demonstrates that various sources of coal have considerably different impact on lung cancer in this population and suggests that early-life exposure to carcinogenic emissions may exert substantial influence on health risks later in life. These factors should be considered when evaluating the health risks posed by exposure to coal combustion emissions.

Ecological study on solid fuel use and pneumonia in young children: A worldwide association.

BACKGROUND AND OBJECTIVE: Pneumonia constitutes one of the major causes of worldwide mortality in young children. Poverty has been traditionally assigned as the underlying factor accounting for these trends. However, the independent role of solid fuel use yielding biomass pollution on pneumonia rates among young children has not been extensively examined. METHODS: Independent socio-economic variables, and the percentage of solid fuel use, tobacco consumption, improved water access source and sanitation facilities were extracted for each country from the available public databases. Multivariate regression analyses were performed to assess potential associations between these recognized risk factors and country pneumonia incidence in young children <5 years of age. RESULTS: Multivariate linear regression analyses yielded two models that accounted for approximately 87% of the variance, and included solid fuel use, tobacco consumption, sanitation access, measles immunization, life expectancy, access to electricity and the Human Development Index (HDI) as being independently associated with the number of annual pneumonia cases per child <5 years of age. CONCLUSION: In this ecological study, current country rates of pneumonia among young children are independently associated with the use of solid fuels. We postulate that interventions aimed at reducing indoor solid fuel biomass pollution through implementation of efficient stoves will translate into meaningful decreases in child mortality and morbidity.

Exposure to cooking fuels and birth weight in Lanzhou, China: a birth cohort study.

BACKGROUND: Early studies have suggested that biomass cooking fuels were associated with increased risk of low birth weight (LBW). However it is unclear if this reduced birth weight was due to prematurity or intrauterine growth restriction (IUGR). METHODS: In order to understand the relationship between various cooking fuels and risk of LBW and small for gestational age (SGA), we analyzed data from a birth cohort study conducted in Lanzhou, China which included 9,895 singleton live births. RESULTS: Compared to mothers using gas as cooking fuel, significant reductions in birth weight were observed for mothers using coal (weight difference = 73.31 g, 95 % CI: 26.86, 119.77) and biomass (weight difference = 87.84 g, 95 % CI: 10.76, 164.46). Using biomass as cooking fuel was associated with more than two-fold increased risk of LBW (OR = 2.51, 95 % CI: 1.26, 5.01), and the risk was mainly seen among preterm births (OR = 3.43, 95 % CI: 1.21, 9.74). No significant associations with LBW were observed among mothers using coal or electromagnetic stoves for cooking. CONCLUSIONS: These findings suggest that exposure to biomass during pregnancy is associated with risk of LBW, and the effect of biomass on LBW may be primarily due to prematurity rather than IUGR.

Material flow analysis of fossil fuels in China during 2000-2010.

Since the relationship between the supply and demand of fossil fuels is on edge in the long run, the contradiction between the economic growth and limited resources will hinder the sustainable development of the Chinese society. This paper aims to analyze the input of fossil fuels in China during 2000-2010 via the material flow analysis (MFA) that takes hidden flows into account. With coal, oil, and natural gas quantified by MFA, three indexes, consumption and supply ratio (C/S ratio), resource consumption intensity (RCI), and fossil fuels productivity (FFP), are proposed to reflect the interactions between population, GDP, and fossil fuels. The results indicated that in the past 11 years, China's requirement for fossil fuels has been increasing continuously because of the growing mine productivity in domestic areas, which also leads to a single energy consumption structure as well as excessive dependence on the domestic exploitation. It is advisable to control the fossil fuels consumption by energy recycling and new energy facilities' popularization in order to lead a sustainable access to nonrenewable resources and decrease the soaring carbon emissions.

Characteristics of fundamental combustion and NOx emission using various rank coals.

Eight types of coals of different rank were selected and their fundamental combustion characteristics were examined along with the conversion of volatile nitrogen (N) to nitrogen oxides (NOx)/fuel N to NOx. The activation energy, onset temperature, and burnout temperature were obtained from the differential thermogravimetry curve and Arrhenius plot, which were derived through thermo-gravimetric analysis. In addition, to derive the combustion of volatile N to NOx/fuel N to NOx, the coal sample, which was pretreated at various temperatures, was burned, and the results were compared with previously derived fundamental combustion characteristics. The authors' experimental results confirmed that coal rank was highly correlated with the combustion of volatile N to NOx/fuel N to NOx.

Modeling the dynamic Nexus among coal consumption, pollutant emissions and real income: empirical evidence from South Africa.

This study explores the interaction among coal consumption, pollutant emissions, and real income for South Africa in a multivariate setting. To achieve this objective, annual frequency data spanning from 1965 to 2017 is used for analysis. A series of econometrics tests were conducted ranging from stationarity and non-stationarity tests for unit root properties of the variables under consideration. Empirical evidence finds support for the inverted U-shaped pattern between energy consumption and environmental degradation in South Africa. The Toda-Yamamoto Granger causality test shows a feedback causality between economic growth and carbon dioxide emissions, as well as between GDP and coal consumption. All these highlighted findings have inherent environmental implications. Based on these outcomes, policy directions such as diversification of the South Africa energy mix to renewables and cleaner energy sources and also the adoption of carbon capturing and storage techniques were suggested to engender a cleaner and friendlier environment.

Purification, characterization, and coal depolymerizing activity of lignin peroxidase from Gloeophyllum sepiarium MTCC-1170.

Lignin peroxidase from the liquid culture filtrate of Gloeophyllum sepiarium MTCC-1170 has been purified to homogeneity. The molecular weight of the purified enzyme was 42 kDa as determined by SDS-PAGE. The K(m) values were 54 and 76 microM for veratryl alcohol and H2O2, respectively. The pH and temperature optima were 2.5 and 25 degrees C, respectively. Depolymerization of coal by the fungal strain has been demonstrated using humic acid as a model of coal. Depolymerization of humic acid by the purified lignin peroxidase has been shown by the decrease in absorbance at 450 nm and increase in absorbance at 360 nm in presence of H2O2. Depolymerization of humic acid by the purified enzyme has also been demonstrated by the decrease in the viscosity with time of the reaction solution containing humic acid, H2O2, and the purified lignin peroxidase. The influence of NaCl and NaN3 and inhibitory effects of various metal chelating agents on the lignin peroxidase activity were studied.

Association between coal consumption and urbanization in a coal-based region: a multivariate path analysis.

This study examines causal relationship between urbanization and coal consumption. By taking Shanxi Province, China, as a typical case area, a multivariate path analysis model is used to seek for the key driving factors of coal consumption throughout its urbanization during the period of 1978 to 2014. The result indicates that the key factors are urban household disposable income and residential area per capita, which are closely related to urban construction and household lifestyle. It is expected that the study may inform better policies on coal consumption reduction and energy structure improvement.

Village energy survey reveals missing rural raw coal in northern China: Significance in science and policy.

Burning coal for winter heating has been considered a major contributor to northern China's winter haze, with the district heating boilers holding the balance. However a decade of intensive efforts on district heating boilers brought few improvements to northern China's winter air quality, arousing a speculation that the household heating stoves mainly in rural area rather than the district heating boilers mainly in urban area dominate coal emissions in winter. This implies an extreme underestimation of rural household coal consumption by the China Energy Statistical Yearbooks (CESYs), although direct evidence supporting this speculation is lacking. A village energy survey campaign was launched to gather the firsthand information on household coal consumption in the rural areas of two cities, Baoding (in Hebei province) and Beijing (the capital of China). The survey data show that the rural raw coal consumption in Baoding (5.04 × 103 kt) was approximately 6.5 times the value listed in the official CESY 2013 and exceeded the rural total of whole Hebei Province (4668 kt), revealing a huge amount of raw coal missing from the current statistical system. More importantly, rural emissions of particulate matter (PM) and SO2 from raw coal, which had never been included in widely distributing environmental statistical reports, were found higher than those from industrial and urban household sectors in the two cities in 2013, which highlights the importance of rural coal burning in creating northern China's heavy haze and helps to explain why a number of modeling predictions on ambient pollutant concentrations based on normal emission inventories were more bias-prone in winter season than in other seasons. We therefore recommend placing greater emphasis on the "missing" rural raw coal to help China in its long-term ambition to achieve clean air in the context of rapid economic development.

Domestic solid fuel combustion in an adult population in Nigeria: A cross sectional analysis of association with respiratory symptoms, quality of life and lung function.

BACKGROUND AND OBJECTIVES: We examined the association of respiratory symptoms, health status, and lung function with the use of solid fuel (wood, charcoal, coal or crop residue) for cooking or heating in a predominantly non-smoking population. METHODS: Using the protocol of the Burden of Obstructive Lung Diseases (BOLD) initiative, we collected representative population data using questionnaires and spirometry tests. We categorized solid fuel use into 'never user', 'ex user' and 'current user' based on responses to the survey. We developed regression models to evaluate the relation between use of solid fuel and the prevalence of respiratory symptoms, quality of life and lung function adjusting for confounding variables. RESULTS: Out of 1147 respondents with complete information on domestic fuel type, 33% were 'never-users', 19% were 'ex-users' while 48% reported current use of solid fuel for domestic cooking and/or indoor heating. Compared with never-users, current solid fuel users were more likely to report cough (OR: 1.7, 95% CI: 1.0, 2.9), cough or phlegm (OR: 1.6, 95% CI: 1.0, 2.5) and the association was stronger among women (OR: 3.0, 95% CI: 1.3, 7.1 and OR: 2.3, 95% CI: 1.1, 5.2, respectively). Current solid fuel users also had lower mental health status (coefficient: ?1.5, 95% CI: ?2.8, - 0.2) compared with the group of never-users. Current or previous domestic use of solid fuels for cooking or heating was not associated with higher prevalence of chronic airflow obstruction (FEV1/FVC < LLN). CONCLUSIONS: Using solid fuel for domestic cooking or heating was associated with a higher risk of cough or phlegm and a lower mental quality of life. However we found no significant effect in the prevalence of chronic airflow obstruction in Ife, Nigeria.