Household Heating Research Articles

An explainable artificial intelligence framework for risk prediction of COPD in smokers

BackgroundSince the inconspicuous nature of early signs associated with Chronic Obstructive Pulmonary Disease (COPD), individuals often remain unidentified, leading to suboptimal opportunities for timely prevention and treatment. The purpose of this study was to create an explainable artificial intelligence framework combining data preprocessing methods, machine learning methods, and model interpretability methods to identify people at high risk of COPD in the smoking population and to provide a reasonable interpretation of model predictions.MethodsThe data comprised questionnaire information, physical examination data and results of pulmonary function tests before and after bronchodilatation. First, the factorial analysis for mixed data (FAMD), Boruta and NRSBoundary-SMOTE resampling methods were used to solve the missing data, high dimensionality and category imbalance problems. Then, seven classification models (CatBoost, NGBoost, XGBoost, LightGBM, random forest, SVM and logistic regression) were applied to model the risk level, and the best machine learning (ML) model’s decisions were explained using the Shapley additive explanations (SHAP) method and partial dependence plot (PDP).ResultsIn the smoking population, age and 14 other variables were significant factors for predicting COPD. The CatBoost, random forest, and logistic regression models performed reasonably well in unbalanced datasets. CatBoost with NRSBoundary-SMOTE had the best classification performance in balanced datasets when composite indicators (the AUC, F1-score, and G-mean) were used as model comparison criteria. Age, COPD Assessment Test (CAT) score, gross annual income, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), anhelation, respiratory disease, central obesity, use of polluting fuel for household heating, region, use of polluting fuel for household cooking, and wheezing were important factors for predicting COPD in the smoking population.ConclusionThis study combined feature screening methods, unbalanced data processing methods, and advanced machine learning methods to enable early identification of COPD risk groups in the smoking population. COPD risk factors in the smoking population were identified using SHAP and PDP, with the goal of providing theoretical support for targeted screening strategies and smoking population self-management strategies.

Impact of NO2 emissions from household heating systems with wall-mounted gas stoves on indoor and ambient air quality in Chinese urban areas

Nitrogen dioxide (NO2) has been discussed as a typical indoor pollutant for decades. As an increasingly popular heating method, household heating system (HHS) with wall-mounted natural gas stoves has led to a continuous increase in the emission of NO2. The absence of legal regulations and strict limits for NO2 emissions from wall-mounted gas stoves has led to a significant exceedance of indoor NO2 concentrations beyond the permissible value. However, this issue is rarely taken into consideration. In this study, we present the first report on NO2 emissions from wall-mounted gas stoves for household heating and their impact on indoor and ambient air quality in Chinese urban areas based on in-situ measurements and numerical simulations. On heating days, the observed indoor NO2 concentration is within 80-200 μg/m3, much higher than the outdoor atmospheric concentration. With a low emission grade of the wall-mounted gas stoves, it is estimated that >10 % of residents in a typical residential building area are exposed to a high NO2 concentration of >200 μg/m3, and >50 % of residents are exposed to a concentration of >80 μg/m3. In addition, the indoor NO2 concentration shows an obvious non-uniform distribution with the floor in residential buildings. The NO2 emission from residential natural gas heating also shows an obvious impact on the microenvironment around buildings, which is primarily determined by the emission grade of the stoves. The findings highlight that HHS has become a non-negligible source of indoor NO2 pollution in China. It is urgently necessary to formulate NO2 emission limit standards for wall-mounted gas stoves in Chinese urban areas and upgrade traditional natural gas heaters with efficient emission reduction technologies.

Private benefits from ambient air pollution reduction policies: Evidence from the household heating stove replacement program in Chile

We estimate the key private benefits from a program to improve ambient air quality during winter in central Chile by replacing inefficient wood-fired home heating stoves with more efficient pellet stoves. We are interested in the private benefits to households, because they represent additional value of the program and likely drive adoption. Combining electronic stove surface temperature and air pollution monitoring with household surveys, we estimate the effects of adoption on household fuel expenditures, indoor temperatures and indoor air pollution concentrations (PM2.5) when the stoves are in use. We also explore heterogeneous effects of the program by income group and energy poverty status. Our results suggest that, after controlling for observable characteristics of individuals and dwellings, users of pellet stoves on average enjoy 14 % lower indoor PM2.5 concentrations during hours in which stoves are in use compared with those who use traditional stoves during the same periods of time. Lower-income and energy-poor households receive much greater than average improvements in indoor air pollution than those with higher-incomes, driving the overall estimate and indicating that the program is progressive in this dimension. The improved heating stove has significantly higher operating costs, however, and we find that these costs are most salient for low-income and energy-poor households.

Potential of V2O5-WO3/TiO2 catalyst usage as the secondary measure for household heating combustion unit

The active substance used in oxidation honeycomb catalysts determined for real flue gas purification usually consists of precious metals such as platinum or palladium, while the most common is the mixture of the two mentioned elements, however high prices and limited availability of these elements encourages producers for the search for new, equally or better effective alternatives. In this study V2O5-WO3/TiO2 honeycomb catalyst was tested during the combustion test with commonly sold manually loaded stove. The catalyst was installed in the flue gas duct at the stove outlet. The experimental comparison of the flue gas composition at the catalyst inlet and at the catalyst outlet was performed. Flue gas sampling took place for whole combustion periods. Relatively high conversion rates by catalyst of CO (up to 87.1%), C3H8 (up to 61.3%) and TSP (up to 17.7%) were reached, which meant that the limit values of Commission regulation for mentioned kind of equipment were met during four, not only one period (in case of non-use of the catalyst). The V2O5-WO3/TiO2 catalyst has a great potential as the secondary emission control device for achieving low mass concentration of the certain pollutants in the flue gas.

Low-cost sensors and Machine Learning aid in identifying environmental factors affecting particulate matter emitted by household heating

Poland continues to rely heavily on coal and fossil fuels for household heating, despite efforts to reduce Particulate Matter (PM) levels. The availability of reliable air quality data is essential for policymakers, environmentalists, and citizens to advocate for cleaner energy sources. However, Polish air quality monitoring is challenging due to the limited coverage of reference stations and outdated equipment. Here, we report the results of a study on the spatio-temporal variability of Particulate Matter in Legionowo, Poland, using residents’ network of low-cost sensors. Along with identifying the hotspots of household-emitted PM, (1) we propose a data quality assurance scheme for PM sensors, (2) suggest an approach for estimating the Relative Humidity-induced uncertainty in the sensors without co-location with reference instruments, and (3) develop an interpretable Machine Learning (ML) model, a Generalized Additive Model (RMSE = 6.16 μg m−3, and R2 = 0.88), for unveiling the underlying relations between PM2.5 levels and other environmental parameters. The results in Legionowo suggest that as air temperature and wind speed increase by 1 °C and 1 km h−1, PM2.5 would respectively decrease by 0.26 μg m−3 and 0.14 μg m−3 while PM2.5 increases by 0.03 μg m−3 as RH increases by 1%.

Characterising personal, household, and community PM2.5 exposure in one urban and two rural communities in China

BackgroundCooking and heating in households contribute importantly to air pollution exposure worldwide. However, there is insufficient investigation of measured fine particulate matter (PM2.5) exposure levels, variability, seasonality, and inter-spatial dynamics associated with these behaviours. MethodsWe undertook parallel measurements of personal, household (kitchen and living room), and community PM2.5 in summer (May–September 2017) and winter (November 2017-Janauary 2018) in 477 participants from one urban and two rural communities in China. After stringent data cleaning, there were 67,326–80,980 person-hours (ntotal = 441; nsummer = 384; nwinter = 364; 307 had repeated PM2.5 data in both seasons) of processed data per microenvironment. Age- and sex-adjusted geometric means of PM2.5 were calculated by key participant characteristics, overall and by season. Spearman correlation coefficients between PM2.5 levels across different microenvironments were computed. FindingsOverall, 26.4 % reported use of solid fuel for both cooking and heating. Solid fuel users had 92 % higher personal and kitchen 24-h average PM2.5 exposure than clean fuel users. Similarly, they also had a greater increase (83 % vs 26 %) in personal and household PM2.5 from summer to winter, whereas community levels of PM2.5 were 2–4 times higher in winter across different fuel categories. Compared with clean fuel users, solid fuel users had markedly higher weighted annual average PM2.5 exposure at personal (78.2 [95 % CI 71.6–85.3] μg/m3 vs 41.6 [37.3–46.5] μg/m3), kitchen (102.4 [90.4–116.0] μg/m3 vs 52.3 [44.8–61.2] μg/m3) and living room (62.1 [57.3–67.3] μg/m3 vs 41.0 [37.1–45.3] μg/m3) microenvironments. There was a remarkable diurnal variability in PM2.5 exposure among the participants, with 5-min moving average from 10 μg/m3 to 700–1200 μg/m3 across different microenvironments. Personal PM2.5 was moderately correlated with living room (Spearman r: 0.64–0.66) and kitchen (0.52–0.59) levels, but only weakly correlated with community levels, especially in summer (0.15–0.34) and among solid fuel users (0.11–0.31). ConclusionSolid fuel use for cooking and heating was associated with substantially higher personal and household PM2.5 exposure than clean fuel users. Household PM2.5 appeared a better proxy of personal exposure than community PM2.5.

Residential combustion of coal: Effect of the fuel and combustion stage on emissions

Worldwide coal is still used for household heating purposes not only because it is available and cheap but also due to behavioural issues. Regional variability in fuels and combustion appliances make accurate emission estimates from this source hard to achieve. In the present study, gaseous (CO, VOCs, SO2 and NOX) and particulate matter (TSP) emission factors (EFs) were determined for Spanish household coal combustion covering three commercial coals and distinct combustion stages and mimicking usage patterns in real households. TSP samples were analysed to determine water-soluble inorganic ions, metal(loid)s, and organic and elemental carbon (OC and EC). Additionally, the morphology of the emitted particles was also characterised.CO (3.43–169 g kg−1), NOX (1.29–6.00 g kg−1) and SO2 (8.96–22.3 g kg−1) EFs showed no trend regarding the combustion stage or coal type tested. On the other hand, VOC, TSP and EC EFs were higher for the ignition/devolatilisation combustion stage, regardless of the fuel tested. TSP EFs (0.085–1.08 g kg−1) increased with increasing coal volatile matter while the opposite trend was recorded for VOC emissions (0.045–3.39 gC kg−1).TSP carbonaceous matter was dominated by EC while OC represented a small fraction of the particulate mass emitted (less than 8 %wt.). Inorganic compounds composed an important fraction of the TSP samples. Sulphate particulate mass fractions (8.66–22.9 %wt.) appeared to increase with coal S-content. Coal combustion released particles with diverse morphologies, including silicate-rich particles, ferro- and glassy-spheres. This study provides novel emission factors to update emission inventories of residential coal combustion. Additionally, detailed chemical profiles were obtained for source apportionment.

Estimating the joint effect of household solid fuel use and social isolation on depression among middle-aged and older adults in China

BackgroundHousehold solid fuel use and social isolation are reported to increase the risk of depressive symptoms, but their joint effect has not yet been examined. This study aimed to explore the separate and joint effects of household solid fuel use and social isolation on depression. MethodsWe used data from the latest four waves (2011–2018) of the China Health and Retirement Longitudinal Study (CHARLS). Depression was defined as a score of ≥12 using the Center for Epidemiologic Studies Depression Scale (CES-D 10). Cox proportional hazards models were applied to explore the separate and joint associations of household solid fuel use and social isolation with incident depression. ResultsDuring the seven-year follow-up, 2793 (30.25 %) out of the 9232 participants were identified with depressive symptoms. Solid fuel use for household heating or cooking was significantly associated with more hazards of depressive symptoms after adjusting for potential confounders (cooking: HR = 1.280, 95 % CI = 1.175–1.394; heating: HR = 1.142, 95 % CI = 1.054–1.238). High social isolation at baseline was also a significant predictor of incident depressive symptoms (HR = 1.139, 95 % CI = 1.053–1.231). Participants exposed to both solid fuel use and high social isolation were found to have higher hazards of experiencing depressive symptoms than those exposed to none or only one of these two risk factors (heating: HR for ‘solid fuel use + high social isolation’=1.308 versus HR for other groups = 1–1.185; cooking: HR for ‘solid fuel use + high social isolation’ = 1.430 versus HR for other groups = 1–1.255). ConclusionHousehold solid fuel use and social isolation were separately and jointly associated with higher risks of incident depression. Appropriate interventions to reduce solid fuel use and social isolation are recommended to improve the psychological health among middle-aged and older adults in China.

Inequalities across cooling and heating in households: Energy equity gaps

Understanding the degree of energy limiting behavior in low-income and vulnerable households is vital to eradicating energy poverty and associated negative health effects. We estimate the outdoor temperatures at which households turn on and off their electricity-based cooling and heating units under a cold climate in northern Illinois, USA (N = 418,255 for cooling; N = 22,628 for electric heating). We find that the cooling energy equity gap between low and high income groups is 3 °F (1.7 °C), while the electric-based heating energy equity gap is 6 °F (3.3 °C). The pattern of energy limiting behavior is found to be different between the cooling season and the heating season. Our metrics contribute to the policy design of home energy bill and weatherization assistance programs to identify vulnerable households in a cold climate: Among low-to-middle-income households, our metric identifies 19,001 households (20%) in the cooling sector and 1,290 households (24%) in the heating sector who may be neglected by the traditional income-based energy poverty measure. We also find that households living in black-majority census block groups have a cooling gap that is 17% wider than households living in white-majority census block groups. Policy design should focus on addressing the income inequality and other systematic inequalities that have impacted Black American households.

Techno-economic analysis of residential building heating strategies for cost-effective upgrades in European cities

The energy crisis in Europe requires cost-effective evaluations of residential heating strategies to reduce costs and mitigate greenhouse gas emissions. This research studied different heating systems in China and Europe. Based on heating energy surveys, simulation models were developed and further expanded for European cities. Monte Carlo analyses were conducted to understand the heating demand and utility costs in Rome, Madrid, and Athens. The sensitivity analysis found that electrifying heating systems with heat pumps can reduce household heating costs and mitigate European cities' dependence on natural gas. However, the high upfront investment may hinder the cost-effective deployment of high-performance heat pump systems. Building envelope retrofits can also provide plausible energy savings despite relatively long payback periods. Financial incentive analyses were conducted to quantify how fiscal measures can improve technologies' techno-economic performance. Finally, the paper provided policy recommendations on future building cost-effective retrofits and heating electrification in Europe.

Winter-time pollution in Central European cities shifts the 208Pb/207Pb isotope ratio of atmospheric PM2.5 to higher values: Implications for lead source apportionment

Atmospheric lead pollution has adverse health effects on humans. Identification of anthropogenic Pb sources is thus crucial for understanding of pollution-related risks and for formulation of efficient abatement strategies. We analyzed concentrations and isotope ratios of Pb in fine air-borne particulate matter (PM2.5) in three Central European cities. Aerosol sampling in 12-h intervals was performed during summer and winter in Hradec Králové, Olomouc and Brno, regional centers of highly industrialized Czech Republic, each with a population of more than 90 thousand. Lead analysis was complemented with concentration measurements of Zn, Cu, Cd, As, Sb, and S. Trace element and PM2.5 concentrations were higher in winter than in summer in all studied cities, on average by 47%. The overall mean concentration of PM2.5 in urban air was 21 μg m−3, similar to that in Bern (Switzerland) and Vienna (Austria). Across the sites, 206Pb/207Pb ratios ranged from 1.142 to 1.178 in summer and from 1.143 to 1.173 in winter. The mean 206Pb/207Pb ratios were statistically indistinguishable in all three studied cities (1.165 in Hradec Králové, 1.163 in Olomouc, and 1.160 in Brno). In the 206Pb/207Pb vs.208Pb/207Pb graph, Pb isotope composition of summer samples formed a straight line, whereas Pb isotope composition of winter samples was shifted toward higher 208Pb/207Pb ratios. A Pb isotope inventory of regional pollution sources indicated that winter-time Pb pollution was not caused solely by household heating and increased electricity production in coal-burning power plants. Recycling of industrial Pb originating from Variscan ores and waste incineration could have shifted the 208Pb/207Pb ratio of PM2.5 to higher values, however, such sources do not emit more Pb in winter than in summer. Remobilization of legacy alkyl-Pb from gasoline additives and Pb emissions from current unleaded gasoline and diesel could have shifted both Pb isotope ratios to lower values.

The Intersection of Fuel and Transport Policy in Scotland: A Review of Policy, Definitions and Metrics

This paper is a literature review of fuel and transport poverty in the U.K. with a focus on contextualising this challenge in Scotland. Building on the discussion in the literature, we see that the objective of policy interventions should be to provide a mechanism for identifying vulnerable households. First, we analyse the definitions of fuel, energy, and transport poverty and observe that definitions in policy have been used to limit the scope of the issue to make it more easily addressable. In contrast, academic research points out that fuel poverty should not only encompass all energy use, including household heating, but that transport poverty should be considered under the same umbrella as the drivers overlap. We then consider the indicators used to measure fuel and transport poverty, finding that the thresholds set are arbitrary and only measure one of many possible drivers, namely expenditure. Through an analysis of the drivers, it is clear that both fuel and transport poverty are complex multidimensional challenges requiring a combination of indicators to allow the policy to accurately identify vulnerable households.

Thermoacoustic heat pump utilizing medium/low-grade heat sources for domestic building heating

Thermoacoustic heat pumps are a promising heating technology that utilizes medium/low-grade heat to reduce reliance on electricity. This study proposes a single direct-coupled configuration for a thermoacoustic heat pump, aimed at minimizing system complexity and making it suitable for domestic applications. Numerical investigations were conducted under typical household heating conditions, including performance analysis, exergy loss evaluation, and axial distribution of key parameters. Results show that the proposed thermoacoustic heat pump achieves a heating capacity of 5.7 kW and a coefficient of performance of 1.4, with a heating temperature of 300 °C and a heat-sink temperature of 55 °C. A comparison with existing absorption heat pumps reveals favorable adaptability for large temperature lift applications. A case study conducted in Finland over an annual cycle analyzes the economic and environmental performance of the system, identifying two distinct modes based on the driving heat source: medium temperature (≥250 °C) and low temperature (<250 °C), both of which exhibit favorable heating performance. When the thermoacoustic heat pump is driven by waste heat, energy savings of 20.1 MWh/year, emission reductions of 4143 kgCO2/year, and total environmental cost savings of 1629 €/year are obtained. These results demonstrate the potential of the proposed thermoacoustic heat pump as a cost-effective and environmentally friendly option for domestic building heating using medium/low-grade heat sources.

Light absorption properties of brown carbon aerosol after following the switch from coal to natural gas policy in China: A case study of winter particulate matter over Xi'an, northwestern China

To control haze pollution, the Xi'an city in northwestern China replaced coal by natural gas in industrial and household heating at the end of 2017. Following this change we studied here the light absorption properties of brown carbon (BrC)in atmospheric particulate matter (PM2.5) over Xi'an in 2018. PM2.5 samples were collected from November 15 to December 25, 2018, and the light absorption properties of brown carbon in methanol-soluble organic carbon (MSOC) and water-soluble organic carbon (WSOC) were analyzed. Compared to a previous study from the coal combustion period, the mass absorption efficiency (MAE) increased in the sampling period while the radiation-forced absorption fraction of brown carbon relative to elemental carbon reduced, indicating that the light-absorbing capacity and efficiency of brown carbon has improved. Furthermore, highly positive linear relationships (r > 0.80) occur between the absorption coefficient and typical products of biomass burning and vehicle emission, except for coal combustion (r = 0.57). Additionally, an estimation from the positive matrix factorization and multivariable linear regression model results showed that biomass burning, motor vehicle emission, and secondary source took up approximately 89.53% of AbsWSOC,365. The contribution of coal combustion to light absorption BrC was the lowest (7.36% for AbsMSOC,365 and 10.24% for AbsWSOC,365) in our study, which differs from previous studies in Xi'an. Therefore, the emission source of bulk coal combustion has a relatively small influence on the light absorption of BrC in Xi'an.

Clean and low-carbon heating in the building sector of China: 10-Year development review and policy implications

Space heating in China relies heavily on fossil fuels that cause heavy air pollution and greenhouse gas emissions. The clean heating policy began in 2013 to improve air quality and is now expanding to clean and low-carbon heating (CLCH) for the 2030 carbon dioxide peaking targets. However, few studies have focused on the transformation of China's heating sector over the past decade. The heating areas in China are categorized into urban areas in Northern China, town areas in Northern China, rural areas in Northern China, and regions in Southern China. Six types of CLCH technologies with the highest potential and prospects were reviewed and summarized. In northern urban and town areas, waste heat utilization could help achieve zero-carbon district heating. However, energy-efficient and affordable distributed (household) heating technologies should be promoted in rural and southern areas. In addition, the energy-efficient retrofit of buildings is crucial for reducing heating energy demand and should be given priority. This review provides an overview of CLCH development in China and can be used as a reference for other countries to develop heating strategies.

Energy efficiency of an electric boiler with indirect surface resistive heating of the heat carrier

Introduction. The share of energy for heating of households makes up to 80 % of the total energy consumption. Works on increase of energy efficiency of HVAC equipment make the biggest contribution to reduction of manmade impact on the environment. Power-to-Heat technology — electric boilers used for heating with water systems with radiators and low-temperature heating devices of the “warm floor” type. The research of energy efficiency of the wall mounted electric boiler equipped with the heat generator of indirect surface resistive heating of the heat carrier is presented.&#x0D; &#x0D; Materials and methods. The object of the research is an electric boiler ARDERIA E24, with a nominal capacity of 24 kWh, equipped with a circulation pump, an expansion tank with a volume of 6 L, a group of hydraulic safety and heat carrier recharge. Control of the capacity of the boiler is carried out on semistors with cooling radiators located on the reverse line of the circulation circuit. The boiler is equipped with an electric heat generator with indirect resistor surface heating of the heat carrier.&#x0D; &#x0D; Results. The studied electric heat generators have high specific volumetric power equal to 9.3 kWh/dm3. The average specific power of tubular electric heaters is 25.1 watts/cm2. The coefficient of energy efficiency of the boiler is 0.986. The hydraulic resistance of the unit is 1.25 meters of water column at a flow rate of 1.0 m3/h.&#x0D; &#x0D; Conclusions. The application of the electric heat generator design consisting of a cast aluminum block with tubular heating elements placed inside and a spiral coolant circulation pipe showed high energy efficiency with coefficients of 0.98–0.986 in the modulation range of heat output. The heat output modulation factor of the electric boiler is 12 (2–24 kW). The energy intensity of the heat generator design is 9.3 kWh/dm3, which is significantly higher than traditional heat generation units with “wet” heating elements. The boiler’s heat output control system eliminates the possibility of the temperature rising above 88 °C on the inner heating medium circulation pipe surface.

Much More Than Firewood: Woody Plants in Household Well-Being Among Rural Communities in Argentina

The use of firewood as an energetic resource in various rural regions of the world is essential for the satisfaction of basic human needs. However, the role of firewood in domestic life and its link to household well-being and food sovereignty have been poorly addressed. In order to investigate these aspects, an ethnobotanical study was carried out in three socio-environmental systems of Argentina ( Chaco, Pampa, and Patagonia). Quantitative and qualitative data were gathered and analyzed. A total of 78 firewood species were recorded. The main use of firewood is for household heating, followed by food preparation and cooking, and lastly for starting and producing home fires. In total 21 firewood species are preferred over others for their various qualities and biophysical attributes, thus becoming of great cultural importance. From different examples and testimonies, we gather that the link between peoples and firewood transcends the mere utilitarian sphere, giving rise to aspects related to the symbolic, emotional, affective, and culinary, among others. These aspects contribute to the well-being of households and communities. In this way, the different firewood species become central in the domestic sphere, not only in terms of their combustion power, but also because of their importance in social, cultural and food life.

Impacts of end-use electrification on air quality and CO2 emissions in China's northern cities in 2030

Urban activities such as transportation and household heating and cooking, contribute to current air pollution and climate change. Electrification policies such as the transition to electric vehicles and the substitution of household coal with electricity, have been implemented at unprecedented levels in the “2 + 26” Cities (i.e., Beijing, Tianjin and 26 other cities in northern China), to reduce air pollutants and CO2 emissions at the point of use. We employed the Greenhouse gas and Air pollution Interactions and Synergies model to evaluate the impact of vehicle/residential electrification on air quality and CO2 emissions from 2017 to 2030. Contribution of the end-use sector depends on its relative importance to the emissions of each pollutant and the ability of each sector to reduce their emissions through electrification. Accordingly, electrifying the residential sector improved the air quality in the cities of Shijiazhuang, Xingtai and Baoding, while electrifying the transportation sector generated more local benefits in Beijing and Tianjin. The combination of fleet electrification and coal-to-electricity could reduce the annual mean PM2.5 concentration by 2.0 μg/m3 (4.4%) throughout the “2 + 26” Cities in 2030. Moreover, more rapid decarbonization of the power sector is needed to maximize the synergies between air quality and climate goals.

Gaseous and particulate emissions from the combustion of hard and soft wood for household heating: Influence of boiler type and heat output

Comparison of gaseous and particulate emissions from the combustion of hard (beech) and soft (spruce) wood in four types (old and modern) boilers used for household/residential heating was studied. The boilers were run with three different heat outputs, i.e. nominal (85–100%) and two reduced outputs (60–70% and 35–45%), to cover the expected usage of these boilers in real households during different outdoor air winter temperatures. Gaseous emission factors (CO2, CO, NOx, OGC – organic gaseous compounds), particulate pollutants (n-alkanes and polycyclic aromatic hydrocarbons) and particulate organic markers (monosaccharide anhydrides, methoxyphenols and diterpenoids) were determined. In general, modern-type boilers emitted lower amounts of products of incomplete combustion than those old-type boilers. The emission factors (EFs) of total suspended particles varied between 562 and 2150 mg kg−1 (beech logs, the oldest-type boiler), and 69.1 and 118 mg kg−1 (spruce pellets, the modern-type boiler). The trends between the heat outputs of boilers and the EFs of particulate organic compounds/markers were observed for all boilers (especially the automatic boiler) with some exceptions and mostly increased with a decreasing output of boilers. The ratios levoglucosan/mannosan varied in the range of 13.4–18.6 for the combustion of beech, and 2.11–4.16 for the combustion of spruce.

Does the energy efficiency of buildings bring price premiums? Evidence from urban micro-level energy data

Energy efficient buildings can facilitate the achievement of sustainable development goals. However, higher investment costs are not conducive to the development of energy efficient buildings. It is not clear whether the energy efficiency of buildings (EEBs) bring price premiums that could offset the incremental costs of adopting green practice. In this paper, a data envelopment analysis (DEA) model is constructed that takes into account the differences in regional and urban size to measure the EEBs in 54 cities of China during 2007–2018. We evaluate the influence of EEBs on price premiums by using fixed effects regression. We then adopt a moderated mediation model to explore the impact of industrial structure and the regional economic development level on this premium effect. The empirical results show that the cities’ EEBs is gradually improving, due to the fact that the level of technical progress in residential construction is rising. A 1% increase in house energy efficiency causes price premiums of 0.583%. Moreover, this premium effect is more obvious in cities with a high proportion of tertiary industries and economically developed areas. Considering energy consumption in household heating, the housing prices expectations were pulled down in heating cities, while the situation was reversed in non-heating cities. This study provides companies and governments with scientific evidence to promote EEBs.