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[Display omitted] • Sorting strategies based on source, physical and chemical properties were compared. • The gasification efficiency of sorted RMSW was 40.89% higher than that of unsorted. • The yield of syngas can be increased by 37.14% after waste sorting. • The emission of CO 2 can be reduced by 81 t·per year after waste sorting. • Elemental composition based sorting method benefited to efficient gasification. Gasification is a promising way to convert residual municipal solid waste (RMSW) to high-valued syngas. Waste sorting is helpful to alleviate the heterogeneity problem of waste on gasification. This paper aimed to search for an optimal sorting strategy and evaluate the influence of waste sorting on downstream gasification. A sorting strategy based on elemental composition was proposed and compared with common source and density based strategies. The results validated the enhancement of waste sorting on RMSW gasification, where the elemental composition based strategy showed optimal gasification. The yield of syngas, cold gas efficiency, the lower heating value of syngas and H 2 /CO were increased by 37.14 %, 38.95 %, 2.18 % and 8.81 %, respectively. It also showed a good effect on the improvement of air gasification compared with the literature, especially for H 2 /CO. This paper also discussed the economic and environmental potential of the elemental composition based sorting method. The waste sorting can help increase 29,250 RMB/year and reduce CO 2 emission by 81 t/year. This method has potential for industrial application. It is suggested that further fast elemental composition characterization technologies and intelligent sorting equipment can be developed. Limitations and future perspectives were discussed from gasification simulation models, more energy utilization technologies, the underlying logic of waste sorting and sustainability evaluation. It is hoped that this work can provide insightful fundamentals to their applications in RMSW sorting, thus benefiting resource recovery and circular economy. [ABSTRACT FROM AUTHOR]

• Environmental life cycle impacts are assessed for current and future heating. • Electric air source heat pumps are the lowest-impact option to decarbonise heating. • Boilers using H 2 from natural gas with carbon capture cannot achieve Net Zero. • Boilers using hydrogen from electrolysis have the highest impacts in 17 categories. • The proposed 2050 Net Zero heating mixes reduce GHG emissions by 84–94% per kWh. Heating and hot water within buildings account for almost a quarter of global energy consumption. Approximately 90% of this heat is derived directly from the combustion of fossil fuels, primarily natural gas, leading to the unabated emission of carbon dioxide. This paper assesses the environmental sustainability of a range of heating technologies and scenarios on a life cycle basis. The major technologies considered are natural gas boilers, air source heat pumps, hydrogen boilers and direct electric heaters. The scenarios use the UK as an example due to its status as a major economy with a legally-binding net-zero carbon target for 2050; they consider plausible future electricity and natural gas mixes, including the potential growth of domestic shale gas. The environmental impacts are estimated using ReCiPe 2016. Current gas boilers have a climate change impact of 220 g CO 2 eq./kWh of heat, which could fall to 64 g CO 2 eq./kWh for boilers fuelled by hydrogen derived from natural gas with carbon capture. Heat from electric air source heat pumps or hydrogen from electrolysis can achieve net zero with a decarbonised electricity mix, but electrolysis has the highest energy demand of all options which leads to the highest impacts across 17 of the 19 categories. Despite their high carbon emissions, gas boilers remain the lowest impact option across 12 categories as they avoid the impacts related to electricity generation, including metal depletion, toxicities and eutrophication. By 2050, the best performing scenario sees the climate change impact of the heating mix fall by 95%; this is achieved by prioritising electric air source heat pumps without hydrofluorocarbon refrigerants, alongside demand reduction. The results show that, if infrastructure and financial challenges can be overcome, there are several viable decarbonisation strategies for heating, with heat pumps offering the most environmentally sustainable option of those considered here. However, increased renewable electricity demand may worsen some environmental impacts compared to natural gas boilers. [ABSTRACT FROM AUTHOR]