Junfeng Liu

Peking University | PKU · College of Urban and Environmental Sciences

Phasing out coal is essential for climate mitigation but can result in job losses. Although growing literature has reported green job opportunities (e.g., solar technicians) as a potential solution to the displacement of coal sector workers, the extent to which green jobs are easily accessible, regarding co-location and skill requirements, remains...

Land-use change (LUC) is ranked as the second anthropogenic source of climate change after fossil fuel burning and yields negative albedo-induced radiative forcing (ARF). This cooling effect has been assessed using low spatiotemporally resolved LUC datasets derived from historical statistical data with large uncertainties. Herein, we implement a sa...

Improving electrification feasibility is essential for reducing emissions from non-electric energy sources, thereby enhancing air quality and public health. Concurrently, climate mitigation actions, such as carbon pricing policies, have significant potential to alleviate increasing carbon dioxide (CO2) and other co-emitted air pollutants. However,...

Poor dispersibility of carbon nanotubes greatly hinders their practical applications. Herein, a long‐term stable dispersion of multiwalled carbon nanotubes (MWCNTs) in peroxydisulfate (PDS) is achieved. MWCNTs at 40 mg L⁻¹ are completely dispersed by PDS upon ultrasonication (US/PDS) within 64 min and a stable dispersion is maintained at least 20 d...

The benefits and costs of carbon pricing policies (CPPs) are not equally distributed across regions, and the specific CPP options would inevitably affect their ancillary benefits and costs and how they are distributed across different regions. This brings up challenging and ongoing questions within CPPs—how policymakers weigh the overall efficiency...

Building a low-carbon energy system is particularly essential to address global climate change and regional air pollution. Focusing on China, this study integrated a power system decision model into a computable general equilibrium (CGE) model to comprehensively explore the low-carbon transition, environmental benefits, and economic costs of a comb...

To greatly enhance the unsatisfactory Au(III) sorption performance (2280 mg/g) by the material designed in our previous work, we ingeniously fabricated a nano-sized and uniform molybdenum composite (MoCOM) using a...

Associations between tropospheric ozone (O3) and climate variations have been extensively investigated worldwide. However, given the lack of historical O3 monitoring data, the knowledge gaps regarding the influences of climate variations on long-term O3 trends in China remain. The present study used a tropospheric O3 dataset from the summers of 199...

Following a series of actions in China, the annual mean fine particle (PM 2.5 ) concentrations have considerably reduced since 2013. However, in some cities, the PM 2.5 concentrations exceed the national ambient air quality standard of 35 μg/m ³ . Herein, we evaluated the historical trends of PM 2.5 from 2014 to 2022 in mainland China and found con...

Outdoor air pollution causes millions of premature deaths annually worldwide. Sulfate is a major component of particulate pollution. Winter sulfate observations in China show both high concentrations and an accumulation mode with a modal size >1 μm. However, we find that this observed size distribution cannot be simulated using classical gaseous an...

The impacts of climate change on wildfires have been studied extensively. Along with declining emissions from fossil fuel combustion due to anthropogenic emission control, black carbon (BC) released from wildfires is expected to contribute a more significant portion to its atmospheric burden. However, from a global perspective, little is known abou...

Associations between tropospheric ozone (O3) and climate variations have been extensively investigated worldwide. However, given the lack of historical O3 monitoring data, the knowledge gaps regarding the influences of climate variations on long-term O3 trends in China remain. The present study used a unique tropospheric O3 dataset from the summer...

Black carbon (BC) plays a vital role in Arctic warming. Extensive investigations have been conducted to elucidate the source-receptor relationships of BC between the Arctic and mid-/high-latitude sources. However, it is unclear to what extent source relocation under globalization could disturb Arctic BC contamination and climate forcing from anthro...

To synthesize a novel magnetic nanomaterial for effective Au(III) recovery from the aqueous phase with excellent capability, superior selectivity, one-step reduction and ease of separation after loading Au(III) still remains a huge challenge. In this study, a magnetic nanomaterial (γ-Fe2O3@PDA-NAM) with a core–shell structure was synthesized for ef...

The city of Lhasa is located in the central Tibetan Plateau and is the most densely populated area. As the first continuous monitoring of atmospheric mercury (Hg) species in a city in the Tibetan Plateau, our monitoring in Lhasa showed that the concentrations of gaseous elemental Hg (GEM), gaseous oxidized Hg (GOM), and particle-bound Hg (PBM) duri...

In this study, electrospinning technique was used to synthesize a novel cost-effective fiber mat chitosan-glutaraldehyde-thiourea (CS-Glu-Th) with superior maximum sorption capacity, sorption rate, and selectivity. The sorption results showed that CS-Glu-Th performed perfectly at both low and high concentrations of Au(III), with the maximum sorptio...

Carbon, the human’s most reliable fuel type in the past, must be neutralized in this century towards the Paris Agreement temperature goals. Solar power is widely believed a key fossil fuel substitute, but suffers from the needs of large space occupation and huge energy storage for peak shaving. Here we propose a solar network circumnavigating the g...

Heavy metals with opposite charges (e.g., arsenic and lead) generally have opposite environmental behaviors. Nano-enabled strategies to concurrently inhibit their accumulation in crops remain elusive. Here, nano-TiO2 with anatase (NAT)...

Lhasa City is located in the central Tibetan Plateau and is the most densely populated area. As the first continuous monitoring of atmospheric mercury (Hg) species in a city on the Tibetan Plateau, our monitoring in Lhasa showed that the concentrations of gaseous elemental Hg (GEM), gaseous oxidized Hg (GOM), and particle-bound Hg (PBM) during subs...

Freight transport has become increasingly important regarding CO2 and air pollutant emissions in China but has rarely been assessed using consumption-based methods. Based on the multi-regional input-output tables of China, in this work, we use structural path analysis (SPA) to link interprovincial trade-related freight turnover to responsible secto...

Sulfate is a major atmospheric pollutant and radiative forcing (RF) factor that influences air quality, cloud microphysics, and climate. Therefore, a better evaluation of sulfate concentrations and RF patterns is essential for policy‐making and the management of air pollution and climate change. This study comprehensively estimates the global distr...

International freight transport associated with global trade generates significant CO2 emissions, which are expected to increase with further globalization. The reduction of these emissions will require international and interregional collaboration. However, which trading partners are responsible for freight transport carbon footprints throughout g...

Urban traffic pollution, which is strongly influenced by the complex urban morphology, has posed a great threat to human health. In this study, we performed a high-resolution simulation of traffic pollution in a typical city block in Baoding, China, based on the Parallelized Large-eddy simulation Model (PALM), to examine the distribution patterns o...

Increasing worldwide demand for beef products promotes international beef trade. Cattle raising and beef products as significant sources of methane (CH4) emissions have received widespread concerns. However, the factors driving CH4 emissions embodied in the global beef trade have not been quantified. Here, we evaluate international beef trade-induc...

The high-speed rail (HSR) network in China has experienced rapid development since the 2000s. In 2016, the State Council of the People's Republic of China issued a revised version of the “Mid- and Long-term Railway Network Plan”, detailing the expansion of the railway network and construction of an HSR system. In the future, the HSR construction ef...

Diesel-fueled ships have long been considered to contribute a marginal fraction of the global methane (CH4) emission budget compared to liquified natural gas (LNG)-fueled ships. Here, based on real-world measurements, we find that a specific yet-overlooked group of diesel-fueled ships–the old small fishing vessels (OSFVs)–is associated with high le...

Air quality management is a complex project involving the coordination of multiple sectors and has been identified as an important strategy for food security. However, little is known about how pollutant emissions from each sector affect agriculture. Each sector emits different precursors, resulting in varying impacts of their pollutants and aeroso...

Urbanization perturbs air pollutants from a dynamic and thermodynamic perspective, which has inspired extensive investigations in China due to rapid urban land expansion in the past four decades. However, knowledge gaps remain in the long-term and nationwide responses to air pollutants to urbanization. The evolution of tropospheric ozone associated...

North China is among the most polluted regions in the country, and human exposure to PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 μm) in this region has led to severe health consequences. The region has also benefited the most from emission reductions in recent years. It is of interest to understand to what extent and throug...

Carbon dots (CDs) have a great potential in biological applications due to their excellent fluorescent properties, low cytotoxicity, and biocompatibility. However, whether they can promote photosynthesis of plant by in...

Coriander (Coriandrum sativum L.) seedlings were cultivated in 50% Hoagland’s nutrient solution amended with carbon dots (CDs) at different concentrations (0, 10, 20, 30 and 40 mg/L) for 7 days...

Industry relocation under globalization has altered the origins and strength of emission sources of many air pollutants. We develop global emission inventories of polycyclic aromatic hydrocarbons (PAHs) embodied in the production and consumption of goods and services. We implement these inventories within a global atmospheric transport model and si...

Significance Mercury is a globally ubiquitous pollutant that is harmful to humans and animals. Most mercury entering the environment is released from anthropogenic sources and then stored for some period in soils and water bodies before potentially being remobilized, which greatly facilitates its global distribution. Although the ocean is recognize...

A portable emission sampling system was used to perform on-site measurements of the emission factors (EFs; quantities of pollutants emitted per unit of energy consumed) of 29 polycyclic aromatic hydrocarbons (PAHs) for five types of marine vessels using light diesel in Hainan Province, China. Both gaseous- and particulate-phase PAHs from vessel emi...

Sulfur dioxide (SO2) is a major atmospheric pollutant and precursor of sulfate aerosols, which influences air quality, cloud microphysics, and climate. Therefore, better understanding the conversion of SO2 to sulfate is essential to simulate and predict sulfur compounds more accurately. This study evaluates the effects of in-cloud aqueous-phase che...

Exposure to air pollution by burning solid fuels (such as coal) for residential cooking and heating in China has caused significant health impacts in the past. The government has implemented measures to replace coal with relatively clean energy sources (e.g., natural gas). However, the scale and scope of health benefits associated with such energy...

Rural residential energy switching from solid fuels to electricity and natural gas has resulted in substantial health benefits in China. Here, we quantitatively estimated the environmental and health benefits of stove upgrading, energy switching, and the interaction of stove upgrading and energy switching in rural mainland China during the period o...

A low-temperature plasma device was developed to introduce N-containing moieties into biochar type CS-300 to improve ciprofloxacin removal. The sorption capacity of ciprofloxacin by the treated biochars was 2.61-4.26 times that of CS-300, and the mechanisms were explained by X-ray photoelectron spectroscopy and site energy distribution analysis. Th...

The bioaccumulation of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), known as dioxins, in fatty meat is one of primary pathways entry into the human body, but levels of human exposure to dioxins in fatty meat subject to global trade are unknown. We show high dioxin estimated dietary intake (EDI) via pork consumption in Europe, the United Stat...

High resolution urban wind field simulations are limited in small simulation domain, short simulation period, or stable boundary conditions due to the high computational requirements. To address these limitations, non-intrusive reduced order models (NIROMs) are developed in this study and first realized the prediction of high-resolution 3D wind fie...

Plain Language Summary Vertical exchange of an air pollutant between the atmospheric boundary layer (ABL) and free atmosphere has been a major concern for the transfer of the pollutant out of the ABL. The secondary circulation (SC) provides one of the pathways for the vertical mixing of air pollutants. Following the classical SC formation mechanism...

Ground-level ozone is detrimental to human and vegetation health. The ground-level ozone concentration in China has been increasing in recent years. It is necessary to take actions to mitigate ozone pollution. Identifying the variability of ozone concentration is significant for developing an optimal mitigation strategy. In this study, complex empi...

Atmospheric black carbon (BC) concentrations are governed by both emissions and meteorological conditions. Distinguishing these effects enables quantification of the effectiveness of emission mitigation actions by excluding meteorological effects. Here, we develop reduced-form models in both direct (RFDMs) and inverse (RFIMs) modes to estimate ambi...

To stop the spread of COVID-19 (2019 novel coronavirus), China placed lockdown on social activities across China since mid-January 2020. The government actions significantly affected emissions of atmospheric pollutants and unintentionally created a nationwide emission reduction scenario. In order to assess the impacts of COVID-19 on fine particular...

Sulfur dioxide (SO2) is a major atmospheric pollutant and precursor of sulfate aerosols, which influences air quality, cloud microphysics and climate. Therefore, better understanding the conversion of SO2 to sulfate is essential to simulate and predict sulfur compounds more accurately. This study evaluates the effects of in-cloud aqueous-phase chem...

Plain Language Summary Black carbon originated from incomplete combustion can endanger human health and contaminate the environment. The light‐absorbing nature of black carbon is of vital importance to regional and global climate. Emissions from agriculture sources consist of large portion of black carbon particles, especially in India with intensi...

Air pollution is a major environmental issue in China and imposes severe health burdens on Chinese citizens. Consequently, China has deployed a series of control measures to mitigate fine particulate matter (PM2.5). However, the extent to which these measures have been effective is obscured by the existence of confounding meteorological effects. He...

Traffic pollution threatens both human health and climate stability. The Chinese government issued the “Mid- and Long-term Railway Network Plan” and the “National Highway Network Plan (2013-2030)” in 2004 and 2013, respectively, aiming at building a national railway network and a national highway network with reasonable layout, wide coverage and ec...

To address the problem that urban wind field simulations are limited by high computational requirements, a supervised machine learning framework for the non-intrusive model order reduction of urban airflow is proposed to provide fast predictions with dynamic boundary conditions. An integrated atmospheric modeling system is established by coupling t...

The identified components of fine particulate matter with dynamic diameters less than 2.5 μm (PM2.5) suggests the remarkable increase in Cl⁻ in PM2.5 during autumn and winter over North China. Anthropogenic chlorine emissions, including those from biomass burning, coal combustion and biofuel burning, are the main sources of Cl⁻, which could potenti...

Residential heating using solid fuels contributes significantly to air pollution and has subsequent health impacts in China. To mitigate emissions, a clean heating campaign (CHC-1) covering 28 municipalities has been implemented. Although only a single penetration rate was initially planned by CHC-1 for all municipalities, outcomes in the different...

Residential contribution to air pollution–associated health impacts is critical, but inadequately addressed because of data gaps. Here, we fully model the effects of residential energy use on emissions, outdoor and indoor PM2.5 concentrations, exposure, and premature deaths using updated energy data. We show that the residential sector contributed...

Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous organic contaminants which poses an adverse health impact on environment and humans. This study assesses the PAHs environmental contamination and associated lung cancer risk attributable to interprovincial trade in goods and services in China. Virtual trade driven PAHs flow mainly fr...

The possible application of TiO2 nanoparticles (nano-TiO2) to alleviate arsenic bioaccumulation in rice seedlings and such a functioning with their crystalline structure were investigated. Specifically, nano-TiO2 with anatase and rutile structures and the bulk TiO2 at 0, 10, 100, and 1000 mg/L were amended to the hydroponic exposure systems with ar...

Many studies have examined changes in soil microbial community structure and composition by carbon nanomaterials (CNMs). Few, however, have investigated their impact on microbial community functions. This study explored how fullerene (C60) and multi-walled carbon nanotubes (M50) altered functionality of an agricultural soil microbial community (Arc...

The trade liberalization of Environmental Goods (EG), through as Environmental Goods Agreement (EGA), is crucial in low carbon electricity technology diffusion. However, there is a big gap of the EG definition lists and the integrated effectiveness analysis of EGA. This paper analyses the effects of the trade liberalization of EG based on macroecon...

China's environmental protection tax (EPT) has been implemented since the beginning of 2018 to control environmental issues (e.g., air pollution). The current EPT law indicates that tax revenues are given to provincial governments without return. However, tax revenue redistribution is the key to achieving a so‐called “double dividend”; that is, an...

Abstract. Wind farms have been found to alter local and regional meteorology and climate. Here, we show that multiple large-scale wind farms might disturb air quality forecasts and affect PM_2.5 air pollution. We explore the impact of large-scale wind farms on PM_2.5 concentrations and forecasts in the Northern China Plain in wi...

Serious haze pollution (e.g., PM2.5, particulate matter with aerodynamic diameters less than 2.5 μm) and increased ground-level ozone are severe air quality issues in China. In Beijing-Tianjin-Hebei and the surrounding areas (denoted as BTH&SA), although recently the particulate matter pollution appeared to be under control due to stringent polluti...

Urban air pollution features large spatial and temporal variations due to the high heterogeneity in emissions and ventilation conditions, which render the pollutant distributions in complex urban terrains difficult to measure. Current urban air pollution models are not able to simulate pollutant dispersion and distribution at a low computational co...

Polycyclic aromatic hydrocarbons (PAHs) are formed by the incomplete combustion of fossil fuels and forest or biomass burning. PAHs undergo long-range atmospheric transport, as evidenced by in situ observations across the Arctic. However, monitored atmospheric concentrations of PAHs indicate that ambient PAH levels in the Arctic do not follow the d...

The short-term health effects of ozone (O3) have highlighted the need for high-temporal-resolution O3 observations to accurately assess human exposure to O3. Here, we performed 20-s resolution observations of O3 precursors and meteorological factors to train a random forest model capable of accurately predicting O3 concentrations. Our model perform...

To improve air quality, China has been increasing the stringency of national emission standards for industrial sectors. However, from the projected air quality and associated health impacts it is not known if the updated emission limits have been completely followed. Here, we develop emission inventories based on the emission limits at different st...

Since triphenyl phosphate (TPhP) elicits both anti-estrogenic activity via blocking estrogen receptor (ER) and estrogenic activity by elevating 17β-estradiol (17β-E2) synthesis, its adverse effects on female reproduction is uncertain. In this study, we exposed Japanese medaka to TPhP at 131, 363, and 1773 ng/L for 100 days following hatching. TPhP...