Publications by authors named "Shu Tao"

464 Publications

Substantial leakage into indoor air from on-site solid fuel combustion in chimney stoves.

Environ Pollut 2021 Sep 10;291:118138. Epub 2021 Sep 10.

Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China; School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, China.

Exposure to household air pollution (HAP) from solid fuel use (SFU) causes millions of premature deaths globally. Direct leakage from stoves into indoor air is believed to be the main cause of severe HAP. However, previous laboratory-based measurements reported leakage of minimal fractions from wood fuel combustion. Using a newly developed measurement method, on-site measurements were conducted to quantitatively evaluate the leakage of gases and particulate matter from different fuel-stove combinations. The fraction of indoor leakage to the total emission (F) of the measured air pollutants varied from 23 ± 11% to 40 ± 16% for different pollutants and fuel-stove combinations, and these were significantly higher than previously lab-based results. Fuel differences overwhelmed stove differences in influencing F values, with higher values from biomass burning than from coal combustion. The particles had higher F values than gases. Fugitive emission rates (ERs) were log-normally distributed, and biomass burning had higher ERs than coal burning. Indoor PM (fine particulate matter) and CO (carbon monoxide) concentrations measured during the burning period increased by nearly 1-2 orders of magnitude compared to concentrations before or after burning, confirming substantially high indoor leakage from fuel combustion in cookstoves. High fugitive emissions in indoor cookstoves quantified from the present on-site measurements effectively explain the high HAP levels observed in rural SFU households, and call for interventions to improve indoor air quality.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.envpol.2021.118138DOI Listing
September 2021

The wheat AGL6-like MADS-box gene is a master regulator for floral organ identity and a target for spikelet meristem development manipulation.

Plant Biotechnol J 2021 Sep 6. Epub 2021 Sep 6.

National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.

The AGAMOUS-LIKE6 (AGL6)-like genes are ancient MADS-box genes and are functionally studied in a few model plants. The knowledge of these genes in wheat remains limited. Here, by studying a "double homoeolog mutant" of the AGL6 gene in tetraploid wheat, we showed that AGL6 was required for the development of all four whorls of floral organs with dosage dependent effect on floret fertility. Yeast two-hybrid analyses detected interactions of AGL6 with all classes of MADS-box proteins in the ABCDE model for floral organ development. AGL6 was found to interact with several additional proteins, including the G protein β and γ (DEP1) subunits. Analysis of the DEP1-B mutant showed significant reduction in spikelet number per spike in tetraploid wheat, while over-expression of AGL6 in common wheat increased the spikelet number per spike and hence the grain number per spike. RNA-seq analysis identified the regulation of several meristem activity genes by AGL6, such as FUL2 and TaMADS55. Our work therefore extensively updated the wheat ABCDE model and proposed an alternative approach to improve wheat grain yield by manipulating the AGL6 gene.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/pbi.13696DOI Listing
September 2021

A critical review of pollutant emission factors from fuel combustion in home stoves.

Environ Int 2021 Aug 23;157:106841. Epub 2021 Aug 23.

School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

A large population does not have access to modern household energy and relies on solid fuels such as coal and biomass fuels. Burning of these solid fuels in low-efficiency home stoves produces high amounts of multiple air pollutants, causing severe air pollution and adverse health outcomes. In evaluating impacts on human health and climate, it is critical to understand the formation and emission processes of air pollutants from these combustion sources. Air pollutant emission factors (EFs) from indoor solid fuel combustion usually highly vary among different testing protocols, fuel-stove systems, sampling and analysis instruments, and environmental conditions. In this critical review, we focus on the latest developments in pollutant emission factor studies, with emphases on the difference between lab and field studies, fugitive emission quantification, and factors that contribute to variabilities in EFs. Field studies are expected to provide more realistic EFs for emission inventories since lab studies typically do not simulate real-world burning conditions well. However, the latter has considerable advantages in evaluating formation mechanisms and variational influencing factors in observed pollutant EFs. One main challenge in field emission measurement is the suitable emission sampling system. Reasons for the field and lab differences have yet to be fully elucidated, and operator behavior can have a significant impact on such differences. Fuel properties and stove designs affect emissions, and the variations are complexly affected by several factors. Stove classification is a challenge in the comparison of EF results from different studies. Lab- and field-based methods for quantifying fugitive emissions, as an important contributor to indoor air pollution, have been developed, and priority work is to develop a database covering different fuel-stove combinations. Studies on the dynamics of the combustion process and evolution of air pollutant formation and emissions are scarce, and these factors should be an important aspect of future work.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.envint.2021.106841DOI Listing
August 2021

Field-based measurements of major air pollutant emissions from typical porcelain kiln in China.

Environ Pollut 2021 Jul 19;288:117810. Epub 2021 Jul 19.

Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China.

China has been famous for its porcelains for millennia, and the combustion processes of porcelain production emit substantial amounts of air pollutants, which have not been well understood. This study provided firsthand data of air pollutant emissions from biomass porcelain kilns. The emission factor of PM was 0.95 ± 1.23 g/kg during the entire combustion cycle, lower than that of biomass burning in residential stoves and coal burning in brick kilns, attributed to the removal effects of the long-distance transport in dragon kilns. The temporal trend of particle pollutants, including particulate matters (PMs) and particulate polycyclic aromatic hydrocarbons (PAHs) (low at ignition phase and high at the end) again indicated the removal effects of the special structure, while gaseous pollutants, such as gaseous PAHs, exhibited the opposite result. The GWC was estimated as 1.4 × 10 and 0.5 × 10 kg COe/yr for the scenarios in which 50% and 100% of the wood was renewable, respectively. The GWC of dragon kilns is nearly equal to that of 745 households using wood-fueled stoves. These results indicate the necessity of pollution controls for biomass porcelain kilns to estimate the emission inventory and climate change.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.envpol.2021.117810DOI Listing
July 2021

Direct and Inverse Reduced-Form Models for Reciprocal Calculation of BC Emissions and Atmospheric Concentrations.

Environ Sci Technol 2021 08 23;55(15):10300-10309. Epub 2021 Jul 23.

College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes, Sino-French Institute for Earth System Science, Peking University, Beijing 100871, China.

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 ambient BC concentrations. The models were developed based on outputs from multiyear simulations under three conditional scenarios with realistic or fixed emissions and meteorological conditions. We established a set of probabilistic functions (PFs) to quantify the meteorological influences. A significant two-way linear relationship between multiyear annual emissions and mean ambient BC concentrations was revealed at the grid cell scale. The correlation between them was more significant at grid cells with high emission densities. The concentrations and emissions at a given grid cell are also significantly correlated with emissions and concentrations of the surrounding areas, respectively, although to a lesser extent. These dependences are anisotropic depending on the prevailing winds and source regions. The meteorologically induced variation at the monthly scale was significantly higher than that at the annual scale. Of the major meteorological parameters, wind vectors, temperature, and relative humidity were found to most significantly affect variation in ambient BC concentrations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.est.1c02174DOI Listing
August 2021

Mass Absorption Efficiency of Black Carbon from Residential Solid Fuel Combustion and Its Association with Carbonaceous Fractions.

Environ Sci Technol 2021 08 16;55(15):10662-10671. Epub 2021 Jul 16.

Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, People's Republic of China.

Black carbon (BC) emissions, derived primarily from incomplete fuel combustion, significantly affect the global and regional climate. Mass absorption efficiency (MAE) is one important parameter in evaluating the climate impacts of BC. Here, values and variabilities in the MAE of BC (MAE) from real-world residential emissions were investigated from a field campaign covering 163 burning events for different fuel-stove combinations. MAE (average: 12 ± 5 m/g) was normally distributed and varied greatly by 2 orders of magnitude. Statistically significant differences in MAE were found for various fuels, while no significant differences were observed among different stoves. The fuel difference explained 72 ± 7% of the MAE variation. MAE did not correlate with the modified combustion efficiency but positively correlated with the ratio of organic carbon (OC) to elemental carbon (EC) and negatively correlated with char-EC. The OC/EC ratio was not always lower in coal emissions in comparison to biomass burning emissions. Coal- and biomass-burning emissions had different profiles of carbon fractions. Char-EC, OC, OC/EC, and char-EC/soot-EC can explain 68.7% of the MAE variation, providing the potential for predicting MAE from the carbon fractions, since they are more commonly measured and available.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.est.1c02689DOI Listing
August 2021

Water-induced release of recalcitrant polycyclic aromatic hydrocarbons from soil organic matter during microwave-assisted solvent extraction.

Environ Pollut 2021 Sep 3;284:117493. Epub 2021 Jun 3.

College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes, Sino-French Institute for Earth System Science, Peking University, Beijing, 100871, China.

Polycyclic aromatic hydrocarbons (PAHs) in soil can be recalcitrant to solvent extraction after aging. We showed in this study that mixing a small amount of water in the extracting solvent during microwave-assisted extraction (MAE) can release recalcitrant PAHs, resulting in significant improvement in the analyzed concentrations. The improvement factor (F) for the total of 16 priority PAHs (∑PAH16) listed by the United States Environmental Protection Agency was 1.44-1.55 for field soils. By comparing the F values for different soil organic components, we demonstrated that the recalcitrant PAHs were primarily associated with biochar, humic acid (HA), and humin (HM), with the F values for ∑PAH16 of 1.94, 6.62, and 4.59, respectively. The results showed that the recalcitrant PAHs comprised a sequestered fraction and a desorption-limited fraction. NMR spectra showed that water worked alone at elevated temperature to promote hydrolysis of biochar and destroy the macromolecular structure, thus causing the release of the otherwise sequestered PAHs during MAE. The substantial reduction in F values for HA and HM after demineralization indicated sequestration of PAHs in organic-mineral complexes, which can be destroyed by hot water treatment. The release of the sequestered fraction was nonselective and independent of compound hydrophobicity. In comparison, the release of the desorption-limited fraction was positively affected by the hydrophobicity of PAHs and was facilitated by the presence of water in the extracting solvent. The results of this study provide important insights into the sequestration and release of recalcitrant PAHs in soil.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.envpol.2021.117493DOI Listing
September 2021

Contributions of internal emissions to peaks and incremental indoor PM in rural coal use households.

Environ Pollut 2021 Jul 9;288:117753. Epub 2021 Jul 9.

Key Lab for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China. Electronic address:

Indoor air quality is critically important to the human as people spend most time indoors. Indoor PM is related to the outdoor levels, but more directly influenced by internal sources. Severe household air pollution from solid fuel use has been recognized as one major risk for human health especailly in rural area, however, the issue is significantly overlooked in most national air quality controls and intervention policies. Here, by using low-cost sensors, indoor PM in rural homes burning coals was monitored for ~4 months and analyzed for its temporal dynamics, distributions, relationship with outdoor PM, and quantitative contributions of internal sources. A bimodal distribution of indoor PM was identified and the bimodal characteristic was more significant at the finer time resolution. The bimodal distribution maxima were corresponding to the emissions from strong internal sources and the influence of outdoor PM, respectively. Indoor PM was found to be correlated with the outdoor PM, even though indoor coal combustion for heating was thought to be predominant source of indoor PM. The indoor-outdoor relationship differed significantly between the heating and non-heating seasons. Impacts of typical indoor sources like cooking, heating associated with coal use, and smoking were quantitatively analyzed based on the highly time-resolved PM. Estimated contribution of outdoor PM to the indoor PM was ~48% during the non-heating period, but decreased to about 32% during the heating period. The contribution of indoor heating burning coals comprised up to 47% of the indoor PM during the heating period, while the other indoor sources contributed to ~20%. The study, based on a relatively long-term timely resolved PM data from a large number of rural households, provided informative results on temporal dynamics of indoor PM and quantitative contributions of internal sources, promoting scientific understanding on sources and impacts of household air pollution.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.envpol.2021.117753DOI Listing
July 2021

Unsupervised PM anomalies in China induced by the COVID-19 epidemic.

Sci Total Environ 2021 Nov 1;795:148807. Epub 2021 Jul 1.

Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China. Electronic address:

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 matter (PM) levels, we developed a "conditional variational autoencoder" (CVAE) algorithm based on the deep learning to discern unsupervised PM anomalies in Chines cities during the COVID-19 epidemic. We show that the timeline of changes in number of cities with unsupervised PM anomalies is consistent with the timeline of WHO's response to COVID-19. Using unsupervised PM anomaly as a time node, we examine changes in PM before and after the time node to assess the response of PM to the COVID-19 lockdown. The rate of decrease of PM around the time node in northern China is 3.5 times faster than southern China, and decreasing PM levels in southern China is 3.5 times of that in northern China. Results were also compared with anomalous PM occurring in Chinese's Spring Festival from 2017 to 2019, PM anomalies during around Chinese New Year in 2020 differ significantly from 2017 to 2019. We demonstrate that this method could be used to detect the response of air quality to sudden changes in social activities.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2021.148807DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8247192PMC
November 2021

Bone mesenchymal stem cell-derived exosome-loaded injectable hydrogel for minimally invasive treatment of spinal cord injury.

Nanomedicine (Lond) 2021 08 30;16(18):1567-1579. Epub 2021 Jun 30.

Department of Spine Surgery, South China Hospital, Health Science Center, Shenzhen University, Shenzhen, 518116, China.

Bone mesenchymal stem cell-derived exosomes (Exos) have been shown to exert therapeutic effects in spinal cord injury (SCI). In this study, we aimed to apply bioengineering approaches to promote Exo retention and their sustained release for SCI repair. 3D gelatin methacrylate hydrogel (GelMA) was used as a transplanted Exo delivery system (GelMA-Exos). The viability, proliferation, and differentiation of neural stem cells cultured on hydrogel were assessed. Further, GelMA-Exos was injected into the damaged lesions to assess its repair potential. GelMA hydrogel enhanced the retention of Exos, which promoted the neuronal differentiation and extension . Furthermore, GelMA-Exos promoted neurogenesis and attenuated glial scars in the damaged lesions. The injectable Exo-loaded 3D hydrogel induced neurological functional recovery post SCI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2217/nnm-2021-0025DOI Listing
August 2021

Updated Global Black Carbon Emissions from 1960 to 2017: Improvements, Trends, and Drivers.

Environ Sci Technol 2021 06 7;55(12):7869-7879. Epub 2021 Jun 7.

College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes, Sino-French Institute for Earth System Science, Peking University, Beijing 100871, China.

Accurate estimation of black carbon (BC) emissions is essential for assessing the health and climate impact of this pollutant. Past emission inventories were associated with high uncertainty due to data limitations, and recent information has provided a unique updating opportunity. Moreover, understanding the drivers that cause temporal emission changes is of research value. Here, we update the global BC emission estimates using new data on the activities and emission factors (EFs). The new inventory covers 73 detailed sources at 0.1° × 0.1° spatial resolution and monthly temporal resolution from 1960 to 2017. The estimated annual emissions were 32% higher than the average of several previous inventories, which was primarily due to field-measured EFs for residential stoves and differentiated EFs for motor vehicles. In addition, the updated emissions show an inverse U-shaped temporal trend, which was mainly driven by the interaction between the positive effects of population growth, per capita energy consumption, and vehicle fleet and the negative effects of residential energy switching, stove upgrading, phasing out of beehive coke ovens, and reduced EFs for vehicles and industrial processes. Urbanization caused a significant increase in urban emissions accompanied by a more significant decline in rural emissions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.est.1c03117DOI Listing
June 2021

Insights into the horizontal and vertical profiles of microplastics in a river emptying into the sea affected by intensive anthropogenic activities in Northern China.

Sci Total Environ 2021 Jul 19;779:146589. Epub 2021 Mar 19.

Key Laboratory for Earth Surface and Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China. Electronic address:

Studies focused only on surface water may underestimate microplastic abundance in aquatic environments. This was the first survey to investigate the vertical (surface, intermediate, and bottom waters) distribution and composition of microplastics (MPs) in the water columns and surface sediments collected from an urban seagoing river in northern China. Microplastic abundance in the water columns ranged from 5.6 to 31.4 items∙L and from 2141 to 10,035 items∙kg dry weight (dw) in the surface sediments. Polyethylene dominated throughout the water columns to the surface sediments, in which low- and high-density polyethylene (LDPE and HDPE) were dominant in the water columns and surface sediments, respectively. The dominant shape of MPs was fibers/lines in both the water column and the surface sediment samples. Different from the estimations, the average abundance of MPs in the surface and intermediate waters was significantly lower (p < 0.01) than that in the bottom water, which may be due to the resuspension of small-sized MPs in the bottom water. As the MPs size increased, their vertical distributions in the water columns were more affected by the water depth. The results showed that MPs were detained in the water columns of river system, and the high concentrations of MPs in the bottom water could not be neglected.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2021.146589DOI Listing
July 2021

Enantioselective Cross-couplings between Halide Derivatives and Organometallics by Using Iron and Cobalt Catalysts: Formation of C-C Bonds.

Chemistry 2021 Aug 24;27(43):11021-11029. Epub 2021 Jun 24.

Molecular, Macromolecular Chemistry and Materials ESPCI Paris, PSL University, 10 rue Vauquelin, 75005, Paris, France.

This review highlights the recent achievements of iron- and cobalt-catalyzed enantioselective cross-couplings of halide derivatives with organometallic reagents for the construction of C-C bonds. Synthetic applications of enantioselective cross-couplings to natural products and biologically active compounds are also covered showing the power of these cross-couplings in organic synthesis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/chem.202101363DOI Listing
August 2021

The pH-Responsive Transcription Factors YlRim101 and Mhy1 Regulate Alkaline pH-Induced Filamentation in the Dimorphic Yeast Yarrowia lipolytica.

mSphere 2021 05 19;6(3). Epub 2021 May 19.

Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan, China

Environmental pH influences cell growth and differentiation. In the dimorphic yeast , neutral-alkaline pH strongly induces the yeast-to-filament transition. However, the regulatory mechanism that governs alkaline pH-induced filamentation has been unclear. Here, we show that the pH-responsive transcription factor Rim101 (YlRim101) is a major regulator of alkaline-induced filamentation, since the deletion of Yl severely impaired filamentation at alkaline pH, whereas the constitutively active Yl mutant mildly induced filamentation at acidic pH. YlRim101 controls the expression of the majority of alkaline-regulated cell wall protein genes. One of these, the cell surface glycosidase gene Yl, plays a critical role in growth, cell wall function, and filamentation at alkaline pH. This finding suggests that YlRim101 promotes filamentation at alkaline pH via controlling the expression of these genes. We also show that, in addition to YlRim101, the Msn2/Msn4-like transcription factor Mhy1 is highly upregulated at alkaline pH and is essential for filamentation. However, unlike YlRim101, which specifically regulates alkaline-induced filamentation, Mhy1 regulates both alkaline- and glucose-induced filamentation, since the deletion of abolished them both, whereas the overexpression of induced strong filamentation irrespective of the pH or the presence of glucose. Finally, we show that YlRim101 and Mhy1 positively coregulate seven cell wall protein genes at alkaline pH, including Yl and five cell surface adhesin-like genes, three of which appear to promote filamentation. Together, these results reveal a conserved role of YlRim101 and a novel role of Mhy1 in the regulation of alkaline-induced filamentation in The regulatory mechanism that governs pH-regulated filamentation is not clear in dimorphic fungi except in Here, we investigated the regulation of alkaline pH-induced filamentation in , a dimorphic yeast distantly related to Our results show that the transcription factor YlRim101 and the Msn2/Msn4-like transcription factor Mhy1 are the major regulators that promote filamentation at alkaline pH. They control the expression of a number of cell wall protein genes important for cell wall organization and filamentation. Our results suggest that the Rim101/PacC homologs play a conserved role in pH-regulated filamentation in dimorphic fungi.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/mSphere.00179-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8265631PMC
May 2021

Coal Is Dirty, but Where It Is Burned Especially Matters.

Environ Sci Technol 2021 06 12;55(11):7316-7326. Epub 2021 May 12.

College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes, Sino-French Institute for Earth System Science, Peking University, Beijing 100871, China.

Coal abatement actions for pollution reduction often target total coal consumption. The health impacts of coal uses, however, vary extensively among sectors. Here, we modeled the sectorial contributions of coal uses to emissions, outdoor and indoor PM (particulate matter with an aerodynamic diameter of less than 2.5 mm) concentrations, exposures, and health outcomes in China from 1970 to 2014. We show that in 2014, residential coal accounted for 2.9% of total energy use but 34% of premature deaths associated with PM exposure, showing that effects were magnified substantially along the causal path. The number of premature deaths attributed to unit coal consumption in the residential sector was 40 times higher than that in the power and industrial sectors. Emissions of primary PM were more important than secondary aerosol precursors in terms of health consequences, and indoor exposure accounted for 97% and 91% of total premature deaths attributable to PM from coal combustion in 1974 and 2014, respectively. Our assessment raises a critical challenge in the switching of residential coal uses to effectively mitigate PM exposure in the Chinese population.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.est.1c01148DOI Listing
June 2021

Emission factors of environmentally persistent free radicals in PM from rural residential solid fuels combusted in a traditional stove.

Sci Total Environ 2021 Jun 6;773:145151. Epub 2021 Feb 6.

Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, United States.

Emission factors (EFs) are crucial for establishing emission inventory and subsequent health risk assessment of pollutants. However, the EFs of environmentally persistent free radicals (EPFRs) in PM have not been well investigated. We measured EPFRs in PM from burning of different solid fuels in a traditional stove widely used in rural China and calculated the EFs of EPFRs (EF). The characteristics of EPFRs varied greatly with PM depending on the feedstock, and the EF of crop residue, firewood and bitumite was 2.13 ± 1.04, 1.40 ± 0.76 and 1.08 ± 0.39 (10 spins·kg), respectively. The estimated results of EPFRs emission associated with PM showed that the crop residue was the main contributor to the top four provinces with high EPFRs emissions in China in 2010. A wide range (0.03-4.89 cig·person·day) of equivalent cigarette number converted by inhaling EPFRs in PM was observed. Provinces with higher equivalent cigarette number were mainly agricultural provinces, because the rural residents tend to use readily available fuels. Additionally, EPFRs in collected PM during 2 - month photoaging were more stable in particles with higher organic carbon contents. Our findings provided a new insight into the risk assessment of PM from different sources by taking EPFRs into consideration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2021.145151DOI Listing
June 2021

A Live-Attenuated Zika Virus Vaccine with High Production Capacity Confers Effective Protection in Neonatal Mice.

J Virol 2021 06 24;95(14):e0038321. Epub 2021 Jun 24.

State Key Laboratories of Respiratory Diseases, Guangdong-Hong Kong-Macao Joint Laboratory of Infectious Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.

Zika virus (ZIKV) infection during pregnancy has been linked to congenital abnormalities, such as microcephaly in infants. An efficacious vaccine is desirable for preventing the potential recurrence of ZIKV epidemic. Here, we report the generation of an attenuated ZIKV (rGZ02a) that has sharply decreased virulence in mice but grows to high titers in Vero cells, a widely approved cell line for manufacturing human vaccines. Compared to the wild-type ZIKV (GZ02) and a plasmid-launched rGZ02p, rGZ02a has 3 unique amino acid alterations in the envelope (E, S304F), nonstructural protein 1 (NS1, R103K), and NS5 (W637R). rGZ02a is more sensitive to type I interferon than GZ02 and rGZ02p, and causes no severe neurological disorders in either wild-type neonatal C57BL/6 mice or type I interferon receptor knockout () C57BL/6 mice. Immunization with rGZ02a elicits robust inhibitory antibody responses with a certain long-term durability. Neonates born to the immunized dams are effectively protected against ZIKV-caused neurological disorders and brain damage. rGZ02a as a booster vaccine greatly improves the protective immunity primed by Ad2-prME, an adenovirus-vectored vaccine expressing ZIKV prM and E proteins. Our results illustrate that rGZ02a-induced maternal immunity can be transferred to the neonates and confer effective protection. Hence, rGZ02a may be developed as an alternative live-attenuated vaccine and warrants further evaluation. Zika virus (ZIKV), a mosquito-borne flavivirus that has caused global outbreaks since 2013, is associated with severe neurological disorders, such as Guillian-Barré syndrome in adults and microcephaly in infants. The ZIKV epidemic has gradually subsided, but a safe and effective vaccine is still desirable to prevent its potential recurrence, especially in countries of endemicity with competent mosquito vectors. Here, we describe a novel live-attenuated ZIKV, rGZ02a, that carries 3 unique amino acid alterations compared to the wild-type GZ02 and a plasmid-launched rGZ02p. The growth capacity of rGZ02a is comparable to GZ02 in Vero cells, but the pathogenicity is significantly attenuated in two mice models. Immunization with rGZ02a elicits robust inhibitory antibody responses in the dams and effectively protects their offspring against ZIKV disease. Importantly, in a heterologous prime-boost regimen, rGZ02a effectively boosts the protective immunity primed by an adenovirus-vectored vaccine. Thus, rGZ02a is a promising candidate for a live-attenuated ZIKV vaccine.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.00383-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8223925PMC
June 2021

The contributions of individual countries and regions to the global radiative forcing.

Proc Natl Acad Sci U S A 2021 Apr;118(15)

Sino-French Institute for Earth System Science, Ministry of Education Key Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

Knowing the historical relative contribution of greenhouse gases (GHGs) and short-lived climate forcers (SLCFs) to global radiative forcing (RF) at the regional level can help understand how future GHGs emission reductions and associated or independent reductions in SLCFs will affect the ultimate purpose of the Paris Agreement. In this study, we use a compact Earth system model to quantify the global RF and attribute global RF to individual countries and regions. As our evaluation, the United States, the first 15 European Union members, and China are the top three contributors, accounting for 21.9 ± 3.1%, 13.7 ± 1.6%, and 8.6 ± 7.0% of global RF in 2014, respectively. We also find a contrast between developed countries where GHGs dominate the RF and developing countries where SLCFs including aerosols and ozone are more dominant. In developing countries, negative RF caused by aerosols largely masks the positive RF from GHGs. As developing countries take measures to improve the air quality, their negative contributions from aerosols will likely be reduced in the future, which will in turn enhance global warming. This underlines the importance of reducing GHG emissions in parallel to avoid any detrimental consequences from air quality policies.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1073/pnas.2018211118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8054000PMC
April 2021

Spatiotemporal variations and source identification of atmospheric nitrated and oxygenated polycyclic aromatic hydrocarbons in the coastal cities of the Bohai and Yellow Seas in northern China.

Chemosphere 2021 Sep 12;279:130565. Epub 2021 Apr 12.

Key Laboratory for Earth Surface and Processes, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China. Electronic address:

Gaseous and particulate nitrated polycyclic aromatic hydrocarbons (NPAHs, 12 species) and oxygenated polycyclic aromatic hydrocarbons (OPAHs, 4 species) in seven coastal cities of the Bohai and Yellow Seas were determined throughout the year. The annual arithmetical mean concentrations of ΣNPAH and ΣOPAH were 737 ± 475 pg/m and 35.3 ± 26.8 ng/m. NPAHs and OPAHs existed mainly in the gaseous phase, accounted for 88.5% and 95.2% of the total concentrations. Air concentrations of ΣNPAH and ΣOPAH in the coastal cities of the Yellow Sea were significantly lower (p < 0.05) than those of the Bohai Sea. Air concentrations of ΣNPAH and ΣOPAH were significantly higher (p < 0.01) in winter than in summer. Strong secondary formation of atmospheric NPAHs and OPAHs occurred in all of the studied cities. The sequence of annual contribution of the emission sources of airborne NPAHs determined by positive matrix factorization was traffic exhaust > combustion of solid fuels (coal and biomass) > secondary formation, while for OPAHs, it was combustion of solid fuels > secondary formation > traffic exhaust. The combustion of solid fuels served as the main source of NPAHs and OPAHs in winter, while secondary formation was the predominant source in summer. Interregional transport may exert an important effect on the local atmospheric NPAHs and OPAHs by potential source contribution function analysis. The estimated incremental lifetime cancer risk (ILCR) due to inhalation exposure to specific NPAHs ranged from 2.9 × 10 to 6.2 × 10 (median at 4.8 × 10) was mainly attributed to exposure before the age of 16.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2021.130565DOI Listing
September 2021

Intermediate Volatile Organic Compound Emissions from Residential Solid Fuel Combustion Based on Field Measurements in Rural China.

Environ Sci Technol 2021 05 2;55(9):5689-5700. Epub 2021 Apr 2.

Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

Residential solid fuel combustion (RSFC) is a key cause of air pollution in China. In these serial studies, field measurements of RSFC from 166 rural households in eastern China were conducted to update the database of emission factors (EFs) and chemical profiles of gaseous and particulate organic pollutants, and the present study focuses on the intermediate volatile organic compounds (IVOCs), which are precursors of secondary organic aerosol (SOA). The results show that the averaged EFs of IVOCs (EF) for crop straw, fuelwood, and coal are 550.7 ± 397.9, 416.1 ± 249.5, and 361.9 ± 308.0 mg/kg, respectively, which are among the EF of gasoline vehicle, diesel vehicle, non-road machinery, and heavy fuel oil vessel, and are significantly affected by fuel, stove, and combustion efficiency. The percentages of normal alkanes (-alkanes), branched alkanes (-alkanes), polycyclic aromatic hydrocarbons (PAHs), and unresolved complex mixture from RSFC are 3.5 ± 1.6, 8.0 ± 3.7, 17.6 ± 6.7, and 70.9 ± 8.1%, respectively, and the compositions are featured by lower b-alkanes and higher PAHs than those of vehicle sources. The proportions of some individual n-alkanes and PAHs (such as -C--C, naphthalene, and its alkyl substituents) can be used as indicators to differentiate RSFC from vehicle sources, while methoxyphenols can be used to distinguish biomass burning from coal combustion. Based on China's energy statistics, the total IVOC emissions from RSFC in 2014 were 175.9 Gg. These data will help to update the IVOC emission inventory and improve the estimates of SOA production in China.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.est.0c07908DOI Listing
May 2021

Organochlorine Pesticide Ban Facilitated Reproductive Recovery of Chinese Striped Hamsters.

Environ Sci Technol 2021 05 2;55(9):6140-6149. Epub 2021 Apr 2.

State Key Laboratory of Integrated Management on Pest Insects and Rodents in Agriculture, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.

Organochlorine pesticides (OCPs) have been used worldwide on an enormous scale over the last century but are banned globally due to environmental persistence and ecotoxicity in recent decades. The long-term effects of OCP ban for agricultural use in China since 1983 on the reproductive health of small terrestrial mammals have never been evaluated in the field. We examined the residue dynamics of OCPs and the reproductive performance of Chinese striped hamsters () in North China Plain during 1983-2010 and concluded that the exposure levels of OCPs in hamsters drastically decreased from 2900 ± 740 to 25.2 ± 6.88 ng/g with an average half-life of 5.08 yrs, coinciding with the observed reproductive recovery of hamsters. The population-based reproductive performance of hamsters was significantly and negatively associated with OCP exposure levels after adjusting the contributions from climate and population density factors, indicating that the ban of OCPs has facilitated the reproductive recovery of hamsters by up to 81% contribution. Our findings suggest that the OCP ban is effective to restore reproduction of small terrestrial mammals. Integration of population biology and environmental science is essential to assess the impacts of persistent organic pollutants on ecological safety and biodiversity loss under accelerated global change.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.est.1c00167DOI Listing
May 2021

Mucosal Priming with a Recombinant Influenza A Virus-Vectored Vaccine Elicits T-Cell and Antibody Responses to HIV-1 in Mice.

J Virol 2021 05 24;95(12). Epub 2021 May 24.

State Key Laboratory of Respiratory Diseases, Guangdong Laboratory of Computational Biomedicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China

Recombinant influenza A viral (IAV) vectors are potential to stimulate systemic and mucosal immunity, but the packaging capacity is limited and only one or a few epitopes can be carried. Here, we report the generation of a replication-competent IAV vector that carries a full-length HIV-1 gene linked to the 5'-terminal coding region of the neuraminidase segment via a protease cleavage sequence (IAV-p24). IAV-p24 was successfully rescued and stably propagated, and P24 protein was efficiently expressed in infected mammalian cells. In BALB/c mice, IAV-p24 showed attenuated pathogenicity compared to that of the parental A/PR/8/34 (H1N1) virus. An intranasal inoculation with IAV-p24 elicited moderate HIV-specific cell-mediated immune (CMI) responses in the airway and vaginal tracts and in the spleen, and an intranasal boost with a replication-incompetent adenovirus type 2 vector expressing the HIV-1 gene (Ad2-gag) greatly improved these responses. Importantly, compared to an Ad2-gag prime plus IAV-p24 boost regimen, the IAV-p24 prime plus Ad2-gag boost regimen had a greater efficacy in eliciting HIV-specific CMI responses. P24-specific CD8 T cells and antibodies were robustly provoked both systemically and in mucosal sites and showed long-term durability, revealing that IAV-p24 may be used as a mucosa-targeted priming vaccine. Our results illustrate that IAV-p24 is able to prime systemic and mucosal immunity against HIV-1 and warrants further evaluation in nonhuman primates. An effective HIV-1 vaccine remains elusive despite nearly 40 years of research. CD8 T cells and protective antibodies may both be desirable for preventing HIV-1 infection in susceptible mucosal sites. Recombinant influenza A virus (IAV) vector has the potential to stimulate these immune responses, but the packaging capacity is extremely limited. Here, we describe a replication-competent IAV vector expressing the HIV-1 gene (IAV-p24). Unlike most other IAV vectors that carried one or several antigenic epitopes, IAV-p24 stably expressed the full-length P24 protein, which contains multiple epitopes and is highly conserved among all known HIV-1 sequences. Compared to the parental A/PR/8/34 (H1N1) virus, IAV-p24 showed an attenuated pathogenicity in BALB/c mice. When combined with an adenovirus vector expressing the HIV-1 gene, IAV-p24 was able to prime P24-specific systemic and mucosal immune responses. IAV-p24 as an alternative priming vaccine against HIV-1 warrants further evaluation in nonhuman primates.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1128/JVI.00059-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8315921PMC
May 2021

Bioaccessibility and public health risk of heavy Metal(loid)s in the airborne particulate matter of four cities in northern China.

Chemosphere 2021 Aug 19;277:130312. Epub 2021 Mar 19.

MOE Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

Atmospheric coarse particulate matter (PM) enriched with heavy metal(loid)s could pose potentially significant health risk to humans, while accurate health risk assessment calls for characterization of their bioaccessibility, besides the total contents. The health risk of major toxic heavy metal(loid)s in the PM from four large cities in northern China via inhalation was investigated based on their total contents and bioaccessibility. The annual mean concentrations of PM-bound Zn, As, Pb, and Mn in the atmosphere of the four cities were 650, 305, 227, and 177 ng⋅m, respectively. The levels of heavy metal(loid)s in the PM were generally higher in winter but lower in summer in all four cities, which resulted primarily from the emissions associated with coal combustion for district and household heating and the unfavorable meteorological conditions in winter. The bioaccessibility of heavy metal(loid)s in the PM ranged from 0.9 to 48.7%, following the general order of Mn > Co > Ni > Cd > Cu > As > Cr > Zn > Pb. Based on their total contents in the PM, most heavy metal(loid)s posed significant public health risk via inhalation exposure in the four cities. However, after accounting for the bioaccessibility of metal(loid)s, the non-carcinogenic risk of most metal(loid)s was negligible, except for As in the PM of Jinzhong, while only the carcinogenic risk posed by Cr and As in the PM exceeded the acceptable level. These findings demonstrate the importance of characterizing the bioaccessibility of airborne PM-bound heavy metal(loid)s in health risk assessment and could guide the on-going efforts on reducing the public health risk of PM in northern China.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.chemosphere.2021.130312DOI Listing
August 2021

Spatially Resolved Emission Factors to Reduce Uncertainties in Air Pollutant Emission Estimates from the Residential Sector.

Environ Sci Technol 2021 04 15;55(8):4483-4493. Epub 2021 Mar 15.

Laboratory for Earth Surface Process, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

The residential sector is a major source of air pollutant emission inventory uncertainties. A nationwide field emission measurement campaign was conducted in rural China to evaluate the variabilities of realistic emission factors (EFs) from indoor solid fuel combustion. For a total of 1313 burning events, the overall average EFs (±standard deviation) of PM were 8.93 ± 6.95 and 7.33 ± 9.01 g/kg for biomass and coals, respectively, and 89.3 ± 51.2 and 114 ± 87 g/kg for CO. Higher EFs were found from burning of uncompressed straws, while lower EFs were found from processed biomass pellets, coal briquettes, and relatively clean anthracite coals. Modified combustion efficiency was found to be the most significant factor associated with variations in CO EFs, whereas for PM, fuel and stove differences determined its variations. Weak correlations between PM and CO indicated high uncertainties in using CO as a surrogate for PM. EFs accurately fit log-normal distributions, and obvious spatial heterogeneity was observed attributed to different fuel-stove combinations across the country. Emission estimation variabilities, which are determined by the interquartile ranges divided by the median values, were notably reduced when spatially resolved EFs were adopted in the inventory.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.est.0c08568DOI Listing
April 2021

Learning Burnout: Evaluating the Role of Social Support in Medical Students.

Front Psychol 2021 22;12:625506. Epub 2021 Feb 22.

School of Medicine and Health Management, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

Burnout is a stress-induced syndrome considered to be closely related to work. Although social support could relief burnout syndrome, its effect on learning burnout in medical students remains unclear. The objectives of the study are to evaluate the association between learning burnout and social support in Chinese medical students. A cross-sectional online survey was distributed to students who participated in online learning in a medical college in Wuhan during the COVID-19 epidemic. We used the Lian version of the Maslach Burnout Inventory (MBI) to assess learning burnout and the Social Support Rating Scale (SSRS) to assess social support. Chi-square tests were used to analyze factors associated with burnout. Independent -test and multiple logistic regression were explored to analyze the relationship between social support and burnout. A total of 684 students have completed the survey (response rate: 30.9%), of which 315 (46.12%) met standard criteria for learning burnout. Multiple logistic regression analysis has revealed that seniors, low family income and low social support were significant predictors of learning burnout (χ = 41.983, < 0.001). After adjusting for the grade and family income, there was a significant and relevant association between social support and learning burnout (OR = 0.937; 95% CI: 0.905-0.970; < 0.001). Learning burnout was highly prevalent in medical students at our college. Senior students and low family income might be risk factors for learning burnout. Social support, especially subjective support and utilization of support might play a protective role in reducing the risk of learning burnout.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpsyg.2021.625506DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7937700PMC
February 2021

Nerve recognition in percutaneous transforaminal endoscopic discectomy using convolutional neural network.

Med Phys 2021 May 1;48(5):2279-2288. Epub 2021 Apr 1.

Biomedical Information Engineering Lab, The University of Aizu, Aizu-Wakamatsu City, Fukushima, 965-8580, Japan.

Purpose: Percutaneous transforaminal endoscopic discectomy (PTED) is one of the most common minimally invasive surgery methods used in clinic in recent years. In this study, we developed a computer-aided detection system (CADS) based on convolutional neural network (CNN) to automatically recognize nerve and dura mater images under PTED surgery.

Methods: We collected surgical videos from 65 patients with lumbar disc herniation who underwent PTED; we then converted the videos into images, and randomly divided some images into a training dataset, a validation dataset, test dataset. The training dataset and validation dataset were composed of 10 454 images containing nerve and dura mater from 50 randomly selected patients; test dataset contained 12 000 images from the remaining 15 patients.

Results: The results showed that sensitivity, specificity, and accuracy reached 90.90%, 93.68%, and 92.29%, respectively. CADS could recognize the nerve and dura mater with no significant difference (P > 0.05) between each patient in test dataset. In comparison with clinicians of different levels, the performance of CADS was lower than that of a spinal endoscopist, but significantly higher than that of general surgeons. With the assistance of CADS, the performance of the general surgeons approached that of the spinal endoscopist.

Conclusions: CNN can recognize well nerve and dura mater images in PTED surgery, and can help general surgeons to improve their ability to recognize tissues during the operation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mp.14822DOI Listing
May 2021

Xenobiotics Targeting Cardiolipin Metabolism to Promote Thrombosis in Zebrafish.

Environ Sci Technol 2021 03 25;55(6):3855-3866. Epub 2021 Feb 25.

Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

Exposure to environmental pollutants is an important factor contributing to the development and severity of thrombosis. However, the important physiological molecules in the thrombotic processes affected by environmental exposures remain unknown. In this study, we show that exposure to environmental chemicals disrupts the equilibrium of cardiolipins (CLs), and directing CL synthesis promotes thrombosis. Using an untargeted metabolomics approach, approximately 3030 molecules were detected in zebrafish embryos exposed to 11 environmental chemicals and automatically clustered into a network. Interconnectivity among CLs and linoleates or isoxanthopterin was discovered through the highly consistent variations in the coregulated metabolites in the network. The chemical exposure resulted in significant upregulation of CLs through influencing the enzymatic activities of phospholipase A, cardiolipin synthase, and lysocardiolipin acyltransferase. Consequently, metabolic disorders of CLs affected the levels of anticardiolipin antibodies, disrupted the homeostasis between platelet thromboxane A and endothelial prostacyclin, and promoted thrombotic events including heart ischemia and tachycardia. Our study thus reveals the common molecular mechanisms underlying the CL-induced thrombosis targeted by environmental exposures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.est.0c08068DOI Listing
March 2021

Evaluation of PAHs in edible parts of vegetables and their human health risks in Jinzhong City, Shanxi Province, China: A multimedia modeling approach.

Sci Total Environ 2021 Jun 4;773:145076. Epub 2021 Feb 4.

Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China. Electronic address:

Knowledge of the origins of polycyclic aromatic hydrocarbon (PAH) in vegetables is essential to reduce human health risks induced by dietary exposure. The current study developed a vegetation-advanced multimedia model, SESAMe-Veg, to identify the major uptake pathway of 15 priority PAHs in vegetables and assess the PAHs in edible parts of cabbages and carrots in Jinzhong City, Shanxi Province, China. The model was well evaluated against site- and plant-specific measurements. Edible parts exhibited lower PAH concentrations than the other parts for both vegetables. The estimated concentrations of ΣPAH15 were 79 ng/g in cabbage shoots and 83 ng/g in carrot roots. Higher concentrations were estimated in shoots of the leafy vegetable than in roots of the root vegetable for most PAHs. Although air-shoot is the major transport pathway, 98% was deposition of particles, which was attached outside and could be removed relatively easily by washing. Soils might be the origin of PAHs inside vegetables, especially for lighter PAHs. PYR was more likely to be stored in roots than other congeners. The translocation of PAHs inside vegetables was negligible. Adulthood dietary exposure to local vegetables probably caused a high health risk; however, contributions from consuming cabbages and especially carrots were low. Females generally exhibited slightly higher risks than males of exposure to PAHs in local vegetables. Considering the dominant role of particle deposition, carefully vegetable washing before ingestion could reduce this risk. This study has provided a functional tool to evaluate vegetable contamination by PAHs. CAPSULE: A vegetation-advanced multimedia model of PAHs in different parts of vegetables and other environmental media was developed to evaluate the potential health risk to local populations of different sexes and ages via vegetable ingestion.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2021.145076DOI Listing
June 2021

Emissions of particulate PAHs from solid fuel combustion in indoor cookstoves.

Sci Total Environ 2021 Jun 26;771:145411. Epub 2021 Jan 26.

Laboratory of Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing 100871, China.

Residential solid fuel combustion is a major emission source of PAHs (polycyclic aromatic hydrocarbons) in most developing countries, including China; however, accurate estimates of PAH emissions are often challenged by limited real-world emission factors (EFs) under field conditions, which can hardly be repeated in laboratory-controlled tests. In this study, a series of field measurements was conducted to determine the emissions of 28 PAHs from different fuel-stove combinations. A total of 14 fuel-stove combinations were studied. The total EFs of 28 PAHs (EF), on the basis of fuel mass, ranged from 20.7 to 535 mg/kg, with relatively lower EFs for coal than for biomass. Biomass burning in gasifier stoves had lower PAH EFs and fewer toxic PAH species than biomass burning in traditional brick stoves. Fuel type was a significant factor affecting PAH emissions, while stove difference had a relatively smaller influence. Much higher EFs were found from these field tests than from the idealized laboratory tests, which indicated significant underestimation in inventories based on the laboratory-based EFs. Biomass and coal had different profiles, with larger intra-fuel variations in coal than those in biomass. Highly variable values of some, though not all, commonly used isomer ratios indicated substantial biases in source apportionment relying on single or simple ratios without correction, and the MCE was found to be significantly corrected with some ratios.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2021.145411DOI Listing
June 2021

Temporal and spatial variation of PM in indoor air monitored by low-cost sensors.

Sci Total Environ 2021 May 22;770:145304. Epub 2021 Jan 22.

College of Urban and Environmental Sciences, Laboratory for Earth Surface Processes, Sino-French Institute for Earth System Science, Peking University, Beijing 100871, China. Electronic address:

Indoor air pollution has significant adverse health impacts, but its spatiotemporal variations and source contributions are not well quantified. In this study, we used low-cost sensors to measure PM concentrations in a typical apartment in Beijing. The measurements were conducted at 15 indoor sites and one outdoor site on 1-minute temporal resolution (convert to 10-minute averages for data analysis) from March 14 to 24, 2020. Based on these highly spatially-and temporally-resolved data, we characterized spatiotemporal variations and source contributions of indoor PM in this apartment. It was found that indoor particulate matter predominantly originates from outdoor infiltration and cooking emissions with the latter contributing more fine particles. Indoor PM concentrations were found to be correlated with ambient levels but were generally lower than those outdoors with an average I/O of 0.85. The predominant indoor source was cooking, leading to occasional high spikes. The variations observed in most rooms lagged behind those measured outdoors and in the studied kitchen. Differences between rooms were found to depend on pathway distances from sources. On average, outdoor sources contributed 36% of indoor PM, varying extensively over time and among rooms. From observed PM concentrations at the indoor sites, source strengths, and pathway distances, a multivariate regression model was developed to predict spatiotemporal variations of PM. The model explains 79% of the observed variation and can be used to dynamically simulate PM concentrations at any site indoors. The model's simplicity suggests the potential for regional-scale application for indoor air quality modeling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.scitotenv.2021.145304DOI Listing
May 2021
-->