大气细颗粒物中环境持久性自由基的分子特征与形成机理的研究

Aerosol-bound organic radicals,including environmentally persistent free radicals(EPFRs),are key components that affect climate,air quality,and human health.While putative structures have been proposed,the molecular characteristics of EPFRs remain unknown.Here,we report a surrogate method to characterize EPFRs in real ambient samples using mass spectrometry.The method identifies chemically relevant oxygenated polycyclic aromatic hydrocarbons(OxPAH)that interconvert with oxygen-centered EPFR(OC-EPFR).We found OxPAH compounds most relevant to OC-EPFRs are structurally rich and diverse quinones,whose diversity is strongly associated with OC-EPFR levels.Both atmospheric oxidation and combustion contributed to OC-EPFR formation.Redundancy analysis and photochemical aging model show pyrolytic sources generated more oxidized OC-EPFRs than photolytic sources.Our study reveals the detailed molecular characteristics of OC-EPFRs and shows that oxidation states can be used to identify the origins of OC-EPFRs,offering a way to track the development and evolution of aerosol particles in the environment.

Electrochromism-induced adaptive fresh air pre-handling system for building energy saving

Building fresh air supply needs to meet certain regulations and fit people’s ever-growing indoor air quality de-mand.However,fresh air handling requires huge energy consumption that goes against the goal of net-zero energy buildings.Thus,in this work,an adaptive fresh air pre-handling system is designed to reduce the cool-ing and heating loads of HVAC system.The sky-facing surface of the system uses electrochromic mechanism to manipulate the optical properties and thus make full use of solar energy(solar heating)and deep space cold source(radiative cooling)by switching between heating and cooling modes.In the cooling mode,the sky-facing surface shows a transmittance of down to zero,while the reflectance is high at 0.89 on average.In the heating mode,the electrochromic glass is highly transparent,allowing the sunlight to reach the solar heat absorber.To obtain the energy-saving potential under different climates,six cities were selected from various climate regions in China.Results show that the adaptive fresh air pre-handling system can be effective in up to 55.4%time of a year.The maximum energy-saving ratios for medium office,warehouse,and single-family house can reach up to 11.52%,26.62%,and 18.29%,respectively.In addition,the system shows multi-climate adaptability and broad application scenarios,making it a potential solution to building energy saving.

Daily and annual performance analyses of the BIPV/T system in typical cities of Sudan

In this paper,a numerical study is carried out to investigate the performance of a coupled BIPV/T-AHU system in Sudan.A mathematical model was utilzed,Matab Simulink was used to do simul ation.Results showed good agreement with experimental data from the literature.The problem studied in this paper is reducing the energy required for heating in winter(preheating BIPV/T)and avoiding the high photovoltaic cell temperature in summer.We compare the energy consumption with and without BIPV/T-AHU in different cities in Sudan.The results showed that utilizing the exhaust air to cool the photovoltaic cell could reduce the PV/T cell temperature in the range(9-12)℃,which can increase the eletrical power output in a range of(12-21.44)W/m^(2).In winter,utilization of the preheating BIPV/T system can decrease the heating load in Wadi Halfa in the range of(6-107.1%).Damazein does not need a high heating power in the daytime for the ait conditioning system depending on the local climate,so the heat energy produced by the system can be used for drying,desiccant cooling,or heating water,with increasing the eletrice power produced by cooling PV/T cells.The results indicated a great posibility to use the BIPV 1 T system under the studied conditions,in addition,this study provides important information for the application of the BIPV/T system in these areas.