The clutch size,incubation behavior of Reeves’s Pheasant(Syrmaticus reevesii) and their responses to ambient temperature and precipitation

Weather conditions play a pivotal role in embryo development and parental incubation costs,potentially impacting the clutch size and incubation behavior of birds.Understanding these effects is crucial for bird conservation.Reeves’ s Pheasant(Syrmaticus reevesii) is a threatened species endemic to China,which is characterized by female-only incubation.However,there is a lack of information regarding the impact of weather conditions on clutch size and incubation behavior in this species.Using satellite tracking,we tracked 27 wild female Reeves’ s Pheasants from 2020 to 2023 in Hubei Province,China.We explored their clutch size and incubation behavior,as well as their responses to ambient temperature and precipitation.Clutch size averaged 7.75 ±1.36,had an association with average ambient temperature and average daily precipitation during the egglaying period,and was potentially linked to female breeding attempts.Throughout the incubation period,females took an average of 0.73 ±0.46 recesses every 24 h,with an average recess duration of 100.80 ±73.37 min and an average nest attendance of 92.98 ±5.27%.They showed a unimodal recess pattern in which nest departures peaked primarily between 13:00 and 16:00.Furthermore,females rarely left nests when daily precipitation was high.Recess duration and nest attendance were influenced by the interaction between daily mean ambient temperature and daily precipitation,as well as day of incubation.Additionally,there was a positive correlation between clutch size and recess duration.These results contribute valuable insights into the lifehistory features of this endangered species.

Low ambient temperature and air pollution are associated with hospitalization incidence of coronary artery disease:Insights from a cross-sectional study in Northeast China

Background:Previous studies have established a link between fluctuations in climate and increased mortality due to coronary artery disease(CAD).However,there remains a need to explore and clarify the evidence for associations between meteorological changes and hospitalization incidences related to CAD and its subtypes,especially in cold regions.This study aimed to systematically investigate the relationship between exposure to meteorological changes,air pollutants,and hospitalization for CAD in cold regions.Methods:We conducted a cross-sectional study using hospitalization records of 86,483 CAD patients between January 1,2009,and December 31,2019.Poisson regression analysis,based on generalized additive models,was applied to estimating the influence of hospitalization for CAD.Results:Significant associations were found between low ambient temperature[-10℃,RR=1.65;95%CI:(1.28-2.13)]and the incidence of hospitalization for CAD within a lag of 0-14 days.Furthermore,O_(3)[95.50μg/m^(3),RR=12;95%CI:(1.03-1.21)]and NO_(2)[48.70μg/m^(3),RR=1.0895%CI:(1.01-1.15)]levels were identified as primary air pollutants affecting the incidence of CAD,ST-segment-elevation myocardial infarction(STEMI),and non-STEMI(NSTEMI)within the same lag period.Furthermore,O_(3)[95.50μg/m^(3),RR=1.12;95%CI:(1.03-1.21)]and NO_(2)[48.70μg/m^(3),RR=1.0895%CI:(1.01-1.15)]levels were identified as primary air pollutants affecting the incidence of CAD,ST-segment-elevation myocardial infarction(STEMI),and non-STEMI(NSTEMI)within the same lag period.The effect curve of CAD hospitalization incidence significantly increased at lag days 2 and 4 when NO_(2)and O_(3)concentrations were higher,with a pronounced effect at 7 days,dissipating by lag 14 days.No significant associations were observed between exposure to PM,SO_(2),air pressure,humidity,or wind speed and hospitalization incidences due to CAD and its subtypes.Conclusion:Our findings suggest a positive correlation between short-term exposure to low ambient temperatures or air pollutants(O_(3)and NO_(2))and hospitalizations for CAD,STEMI,and NSTEMI.These results could aid the development of effective preparedness strategies for frequent extreme weather events and support clinical and public health practices aimed at reducing the disease burden associated with current and future abnormal weather events.

The impact of low ambient temperature on cardiovascular health

Extreme weather events and climate change have witnessed a substantial increase in recent years,leading to heightened concerns.The rise in abnormal ambient temperatures,both in intensity and frequency,directly and indirectly impacts cardiovascular health.While the impact of high ambient temperatures on cardiovascular response is a common concern in the context of global warming,the significance of low temperatures cannot be overlooked.The challenges posed by low temperatures contribute to increased cardiovascular morbidity and mortality,posing a significant threat to global public health.This review aims to provide an overview of the relationship between low ambient temperature and cardiovascular health,encompassing the burden of cardiovascular outcomes and underlying mechanisms.Additionally,the review explores strategies for cold adaptation and cardioprotection.We posit that to optimize cold adaptation strategies,future research should delve deeper into the underlying mechanisms of cardiovascular health in response to low ambient temperature exposure.

Influence of Ambient Temperature on the Thermal Safety of Fireworks Products in Civil Aviation Transportation

Fireworks products are energy-containing materials and are hazardous during production,storage,transportation,and use.By analyzing the range of civil aviation ground ambient temperature and civil aviation cabin ambient temperature in storage and ground operation as well as establishing a spontaneous combustion mathematical model for cylindrical fireworks products based on the spontaneous combustion theory,we identified the critical temperature for spontaneous combustion of a single spray and analyzed the thermal safety of fireworks products under the civil aviation ambient temperature by example to provide theoretical support for the feasibility study of transporting fireworks products by civil aviation.

Evaluation of the Influence of Ambient Temperature on the Performance of the Trans-Amadi Gas Turbine Plant

This paper examines the effects of ambient temperature on the Trans-Amadi gas turbine power station Phase II. The investigation took thirteen (13) months (January 2012 to January 2013) during which plant data were monitored and operational Logsheets like turbine logsheets, plant—auxiliaries’ logsheets and generator logsheets were studied. The gas turbine (GT) that was under investigation was GT-2: MS5001 Nuovopignone with designed installed capacity of 25.0 Megawatts (MW). The result of the study shows that a 1℃ rise of the ambient temperature is responsible for the following: 0% - 0.12% decrease in the power output, 0% - 0.12% increase in the power differential, 0% - 1.17% decrease in the thermal efficiency, 0% - 27.18% increase in the heat rate and 0% - 3.57% increase in the specific fuel consumption. An ambient temperature of 30℃ is found to yield minimal fuel consumption.

Targeting PPARαin low ambient temperature exposure-induced cardiac dysfunction and remodeling

The present study demonstrates that the down-regulation of peroxisome proliferator-activated receptor-α(PPARα)results in chronic low ambient temperature(LT)exposure-induced cardiac dysfunction and remodeling,emphasizing the therapeutic potential of PPARαactivation strategies(e.g.,fenofibrate treatment)in LT-associated cardiac injury.

Synthesis of hierarchical transition metal oxyhydroxides in aqueous solution at ambient temperature and their application as OER electrocatalysts

First-row(3 d)transition metal oxyhydroxides have attracted increasing attention due to their various advantages.Although investigating the oxidation mechanism and processing such materials into hierarchical architectures are greatly desired for their further development,it remains unclear how the oxidation state change occurs,and efforts to produce hierarchical oxyhydroxides in compliance with high ecological and economic standards have progressed slowly.Here,we describe a facile one-step coprecipitation route for the preparation of hierarchical CoOOH,NiOOH and MnOOH,which involves the diffusion of NH_(3)originating from ammonium hydroxide solution into an aqueous solution containing metal ion salts and K_(2)S_(2)O_(8).Comprehensive characterizations by scanning electron microscope,transmission electron microscopy,X-ray diffraction analysis,X-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy and in situ p H measurement demonstrated that K_(2)S_(2)O_(8)induces the oxidation state change of metal ion species after the start of hydrolysis.Meanwhile,it was found that,benefiting from the OH–concentration gradient created by the NH_(3)diffusion method and the suitable growth environment provided by the presence of K_(2)S_(2)O_(8)(high nucleation rate and secondary nucleation),the formation of hierarchical oxyhydroxide structures can be realized in aqueous solution at ambient temperature without the use of heat energy and additional structure-directing agents.The hierarchical CoOOH structures are performed as the electrocatalysts for the oxygen evolution reaction in alkaline media,which exhibit good activity with an overpotential of 320 m V at 10 m A cm^(-2)and a low Tafel slope of 59.6 m V dec^(–1),outperforming many congeneric electrocatalysts.Overall,our study not only provides important insights to understand the formation mechanism of hierarchical oxyhydroxides,but also opens up new opportunities for the preparation of hierarchical oxyhydroxides via a facile,green and low-cost method.

Incubation strategies of the Black-necked Crane(Grus nigricollis) in relation to ambient temperature and time of day

Background: The behavior of cranes reflects many of their survival strategies, but little has been known of the incubation strategies of cranes, in which both parents share incubation duties, in response to cold temperatures in alpine environments. The lack of information may restrict the effective conservation of the threatened Black-necked Crane(Grus nigricollis), a biparental bird nesting in high elevation wetlands.Methods: We directly observed and used infrared video cameras from 2014 to 2015 to study the incubation behavior and quantitatively measured the frequency and details of egg turning behavior in the Black-necked Crane at the Yanchiwan National Nature Reserve in western Gansu Province, China.Results: At lower ambient temperatures in the morning, crane parents spent more time on the nest with less recess frequency and prolonged on-bout duration, while at higher temperatures around noon, the parents had more frequent recesses from incubation and shorter periods between nest exchanges. They adjusted the amount of time incubating by varying the recess frequency and the length of on-bout duration. Mean nest attendance and egg turning frequency of females were significantly higher than those of the males. The nest attendance and on-bout duration of females showed a significantly negative relationship with those of males. The two parents responded differently to the change of temperature. Females spent more time on the nest at lower morning temperatures, while males increased their time on the nest at higher temperatures after noon. Higher incubation recess frequency and egg turning frequency were observed at noon, probably because parents spent more time foraging, taking advantage of the lower egg cooling rate.Conclusion: Both Black-necked Crane parents in the alpine environment adjusted their behavior in response to the thermal requirements of eggs and the weather conditions experienced. Our findings demonstrate that parents of this species incubated in different but complementary ways and efficiently enhanced egg care in a dynamic environment, so as to maximize benefits from the warm portion of the day and the intense solar radiation while minimizing the cost of rewarming eggs and the risks of cooling eggs.

Transporting Mammalian Cells at Ambient Temperature:A Viable Alternative to Dry Ice

The most common method of shipping cells between institutes and companies is sending them frozen, usually treated with anti-freeze solution (most commonly DMSO because it is less toxic than many alternatives), and then packaging them in dry ice for shipment. However many countries place restrictions on dry ice shipments. An alternative to shipping frozen cell vials is to send flasks of growing cells in media. This also has problems because cells in media have limited viability and the flasks can leak. Here we report on an alternative method for shipping viable cells at ambient temperature without dry ice or in media filled flasks. In this study we report on the development and properties of HemSol?. This is an inexpensive, eco-friendly and protects cell integrity at ambient temperature while maintaining viability. We have previously shown that HemSol? protects platelet and RBC function in cold storage and circulating tumor cells up to 6 days. Therefore we wanted to know if HemSol? could also be used to transport live cells. Since HemSol? is a liquid, we experimented with encasing the cells with HemSol? and gelatin so as to prevent dry ice shipment of cells and circumvent the shipping of cells in media. We performed mock shipping experiments where cells were stored in HemSol? gel kept at room temperature on a lab benchtop and cells stored in dry ice was also kept on lab benchtop for up to 2 days. After the mock shipping period, we analyzed cells for their functions. Our results show that cells in HemSol? gel have greater than 95% viability and restored biological functions in 2 hours, whereas, cells shipped in dry ice required more than 24 hours to recover and needed media change to remove the DMSO.

Impact of UVB Solar Radiation on Ambient Temperature for Kuwait Desert Climate

This study examines the correlation between solar UVB and different weather parameters in Kuwait climate. To achieve that purpose, an experimental outdoor facility is designed and set up at the College of Technological Studies, Kuwait for regular monitoring of solar global radiation, UVB radiation and ambient temperature in Kuwait from beginning of January 1st 2014 until the end of December 2019. Outcomes reveal that the change of solar UVB as well as global radiation through the whole day inaugurate the same behavior for the recorded data in clear day times. Statistical analysis is carried out to obtain a correlation linking UVB radiation and both ambient temperature and global solar radiation. Regression analysis of the current work shows that there is a solid correlation among UVB radiation and both ambient temperature and global solar radiation, especially for intermediate to small global solar radiation ranges. In addition, UV index is evaluated for various months at all day times. It is important to record that UV index with the maximum values is attained in May-August months through midday period. Also, UV index values do not surpass the accepted extreme value which is higher than 9 during any time of the study period.

Design Optimization and Operating Performance of S-CO_(2) Brayton Cycle under Fluctuating Ambient Temperature and Diverse Power Demand Scenarios

The supercritical CO_(2)(S-CO_(2)) Brayton cycle is expected to replace steam cycle in the application of solar power tower system due to the attractive potential to improve efficiency and reduce costs.Since the concentrated solar power plant with thermal energy storage is usually located in drought area and used to provide a dispatchable power output,the S-CO_(2) Brayton cycle has to operate under fluctuating ambient temperature and diverse power demand scenarios.In addition,the cycle design condition will directly affect the off-design performance.In this work,the combined effects of design condition,and distributions of ambient temperature and power demand on the cycle operating performance are analyzed,and the off-design performance maps are proposed for the first time.A cycle design method with feedback mechanism of operating performance under varied ambient temperature and power demand is introduced innovatively.Results show that the low design value of compressor inlet temperature is not conductive to efficient operation under low loads and sufficient output under high ambient temperatures.The average yearly efficiency is most affected by the average power demand,while the load cover factor is significantly influenced by the average ambient temperature.With multi-objective optimization,the optimal solution of designed compressor inlet temperature is close to the minimum value of35℃ in Delingha with low ambient temperature,while reaches 44.15℃ in Daggett under the scenario of high ambient temperature,low average power demand,long duration and large value of peak load during the peak temperature period.If the cycle designed with compressor inlet temperature of 35℃ instead of 44.15℃ in Daggett under light industry power demand,the reduction of load cover factor will reach 0.027,but the average yearly efficiency can barely be improved.

Evaluating the short-term effect of ambient temperature on non-fatal outdoor falls and road traffic injuries among children and adolescents in China: a time-stratified case-crossover study

studies have suggested that non-optimal temperatures may increase the risk of injury,epidemiological studies focusing on the association between temperature and non-fatal injury among children and adolescents are limited.Therefore,we investigated the short-term effect of ambient temperature on non-fatal falls and road traffic injuries(RTIs)among students across Jiangsu Province,China.Meteorological data and records of non-fatal outdoor injuries due to falls and RTIs among students aged 6–17 were collected during 2018–2020.We performed a time-stratified case-crossover analysis with a distributed lag nonlinear model to examine the effect of ambient temperature on the risk of injury.Individual meteorological exposure was estimated based on the address of the selected school.We also performed stratified analyses by sex,age,and area.A total of 57322 and 5455 cases of falls and RTIs were collected,respectively.We observed inverted U-shaped curves for temperatureinjury associations,with maximum risk temperatures at 18℃(48th of daily mean temperature distribution)for falls and 22℃(67th of daily mean temperature distribution)for RTIs.The corresponding odds ratios(95%confidence intervals)were 2.193(2.011,2.391)and 3.038(1.988,4.644)for falls and RTIs,respectively.Notably,there was a significant age-dependent trend in which the temperature effect on falls was greater in older students(P-trend<0.05).This study suggests a ignificant association between ambient temperature and students’outdoor falls and RTIs.Our findings may help advance tailored strategies to reduce the incidence of outdoor falls and RTIs in children and adolescents.

Numerical study on the influence of initial ambient temperature on the aerodynamic heating in the tube train system

The evacuated tube transportation has great potential in the future because of its advantages of energy saving and environmental protection.The train runs in the closed tube at ultra-high speed.The heat quantity generated by aerodynamic heating is not easy to spread to external environment and then accumulates in the tube,inducing the ambient temperature in the tube to rise gradually.In this paper,a three-dimensional geometric model and the Shear Stress Transport(SST)κ-ωturbulence model are used to study the influence of initial ambient temperature on the structure of the flow field in the tube.Simulation results show that when the train runs at transonic speed,the supersonic flow region with low temperature and low-pressure is produced in the wake.The structure of the flow field of the wake will change with the initial ambient temperature.And the higher the initial ambient temperature is,the shorter the low temperature region in the wake will be.The larger temperature difference caused by the low temperature region may increase the temperature stress of the tube and affect the equipment inside the tube.Consequently,the temperature inside the tube can be maintained at a reasonable value to reduce the influence of the low temperature region in the wake on the system.

Cardiac-specific knockout of ET_(A)receptor mitigates low ambient temperature-induced cardiac hypertrophy and contractile dysfunction

Cold exposure is associated with oxidative stress and cardiac dysfunction.The endothelin(ET)system,which plays a key role in myocardial homeostasis,may participate in cold exposure-induced cardiovascular dysfunction.This study was designed to examine the role of ET-1 in cold stress-induced cardiac geometric and contractile responses.Wild-type(WT)and ETA receptor knockout(ETAKO)mice were assigned to normal or cold exposure(48C)environment for 2 and 5 weeks prior to evaluation of cardiac geometry,contractile,and intracellular Ca21 properties.Levels of the temperature sensor transient receptor potential vanilloid(TRPV1),mitochondrial proteins for biogenesis and oxidative phosphorylation,including UCP2,HSP90,and PGC1a were evaluated.Cold stress triggered cardiac hypertrophy,depressed myocardial contractile capacity,including fractional shortening,peak shortening,and maximal velocity of shortening/relengthening,reduced intracellular Ca21 release,prolonged intracellular Ca21 decay and relengthening duration,generation of ROS and superoxide,as well as apoptosis,the effects of which were blunted by ETAKO.Western blotting revealed downregulated TRPV1 and PGC1a as well as upregulated UCP2 and activation of GSK3b,GATA4,and CREB in cold-stressed WT mouse hearts,which were obliterated by ETAKO.Levels of HSP90,an essential regulator for thermotolerance,were unchanged.The TRPV1 agonist SA13353 attenuated whereas TRPV1 antagonist capsazepine mimicked cold stress-or ET-1-induced cardiac anomalies.The GSK3b inhibitor SB216763 ablated cold stress-induced cardiac contractile(but not remodeling)changes and ET-1-induced TRPV1 downregulation.These data suggest that ETAKO protects against cold exposure-induced cardiac remodeling and dysfunction mediated through TRPV1 and mitochondrial function.

First order dynamics approaching of broiler chicken deep body temperature response to step changes in ambient temperature

Traditional environmental control methods for poultry housing which rely solely on environmental factors fall short in meeting thermal and physiological needs of the animals.New methods are needed that factor in the physiological needs and responses of the animals in order to maximize well-being of the animals and minimize heat stress.Deep body temperature(DBT)has been shown in the literature to be a strong indicator of heat stress,therefore studies are needed that help us gain a deeper understanding of the relationship between this variable and environmental conditions.The aim of this study was to identify the order of the dynamic response of poultry DBT to large step changes in ambient temperature(AT).Temperature steps had to be big enough to take the chickens out of their homeothermic zone.A total of 46 DBT/AT data sets with 23 upward AT steps and 23 downward AT steps were obtained using a biotelemetry system,and involving three chickens.DBT responses of individual chickens to step changes in AT were found to have a 0.88 average Pearson correlation suggesting consistency in chickens’responses to the same stimuli(p<0.0005).The data indicated that DBT responses to AT followed a first order behavior in most cases with an average time constant of 1.6 h,and the curve fitting method was used to validate this observation.There was a 0.88 average correlation between DBT model and measured data(p<0.0005).These results indicate statistical significance in the data used and the model derived from it.In conclusion,it is reasonable to assume that the dynamic response of poultry DBT to large step changes in ambient temperature follows a first order model.Although further studies are needed to more fully derive the model,this study provided a stepping-stone towards gaining a better understanding of the relationship between DBT and AT,therefore taking us one step closer towards making optimal management and risk assessment decisions that are based on physiological needs of the chickens.

Ambient Temperature is A Strong Selective Factor Influencing Human Development and Immunity

Solar energy,which is essential for the origin and evolution of all life forms on Earth,can be objectively recorded through attributes such as climatic ambient temperature(CAT),ultraviolet radiation(UVR),and sunlight duration(SD).These attributes have specific geographical variations and may cause different adaptation traits.However,the adaptation profile of each attribute and the selective role of solar energy as a whole during human evolution remain elusive.Here,we performed a genome-wide adaptation study with respect to CAT,UVR,and SD using the Human Genome Diversity Project-Centre Etude Polymorphism Humain(HGDP-CEPH)panel data.We singled out CAT as the most important driving force with the highest number of adaptive loci(6 SNPs at the genome-wide 1×10^(-7)level;401 at the suggestive 1×10^(-5)level).Five of the six genomewide significant adaptation SNPs were successfully replicated in an independent Chinese population(N=1395).The corresponding 316 CAT adaptation genes were mostly involved in development and immunity.In addition,265(84%)genes were related to at least one genome-wide association study(GWAS)-mapped human trait,being significantly enriched in anthropometric loci such as those associated with body mass index(χ^(2);P<0.005),immunity,metabolic syndrome,and cancer(χ^(2);P<0.05).For these adaptive SNPs,balancing selection was evident in Euro-Asians,whereas obvious positive and/or purifying selection was observed in Africans.Taken together,our study indicates that CAT is the most important attribute of solar energy that has driven genetic adaptation in development and immunity among global human populations.It also supports the non-neutral hypothesis for the origin of disease-predisposition alleles in common diseases.

Fluorescent light enhanced graphitic carbon nitride/ceria with ultralow-content platinum catalyst for oxidative decomposition of formaldehyde at ambient temperature

The complete decomposition of formaldehyde(HCHO) at ambient temperature is the most potential strategy for HCHO elimination from indoor environment.Herein,extra low content of Pt nanoparticles(0.025 wt%)supported on water-solubility carbon nitride/ceria(Pt/gC_(3)N_(4)@CeO_(2)) was prepared for gaseous HCHO removal at ambient temperature in a simulated indoor environment.Fluorescent light(8 W) illumination could visibly boost the complete decomposition of HCHO into CO_(2) over Pt/gC_(3)N_(4)@CeO_(2).The cooperative effect in the distinct heterostructure and plenty of surface reactive oxygen species contribute primarily to the enhanced catalytic performance of Pt/g-C_(3)N_(4)@CeO_(2).Moreover,the possible mechanism of HCHO oxidation over Pt/g-C_(3)N_(4)@CeO_(2) assisted by the fluorescent light irradiation was proposed based on the physicochemical and optical characterization as well as the result of in situ diffuse reflectance infrared Fourier transform spectra.This work might shed some light on the potential application of the versatile catalysts for ambient-temperature catalytic decomposition of HCHO by making full use of the indoor energies.

Highly Efficient and Well-controlled Ambient Temperature Raft Polymerization Under Visible Light Radiation

1 Results A range of well-defined polymers and their corresponding block copolymers were synthesized via ambient temperature RAFT polymerization under environmentally friendly visible light radiation,using a (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO) photo-initiator[1].The results indicated that the photolysis of chain transfer agent (CTA) functionalities was significantly suppressed under visible light radiation,thus exerting well control over RAFT process,leading to a remarkably living beh...

Improving tree health assessment accuracy at low temperatures:considering the effect of trunk ice content on electrical resistance and stress wave tomography

Accurate decay detection and health assessment of trees at low temperatures is an important issue for forest management and ecology in cold areas.Low temperature ice formation on tree health assessment is unknown.Because electric resistance tomography and stress wave tomography are two widely used methods for the detection of tree decay,this study investigated the effect of ice content on trunk electrical resistance and stress wave velocity to improve tree health assessment accuracy.Moisture content,trunk electrical resistance and stress wave velocity using time domain reflectometry were carried out on Larix gmelinii and Populus simonii.Ice content is based on moisture content data.The ice content of both species showed a trend of increasing and then decreasing.This was opposite with ambient temperatures.With the decrease of temperatures,daily average ice content increased,but the range narrowed gradually and both electrical resistance and stress wave velocity increased.Both increased rapidly near 0℃,mainly caused by ice formation(phase change and freezing of free water)in live trees.In addition,both are positively correlated with ice content.The results suggest that ice content should be considered for improving the accuracy of tree decay detection and health evaluation using electric resistance tomography and stress wave velocity methods under low temperatures.

Influence of ambient temperature on the CO_(2)emitted of light-duty vehicle

Because of global warming,people have paid more attention to greenhouse gas emitted by vehicles.To quantify the impact of temperature on vehicle CO_(2)emissions,this study was conducted using the world light vehicle test cycle on two light-duty E10 gasoline vehicles a ambient temperatures of-10,0,23,and 40℃,and found that CO_(2)emission factors of Vehicle1 in the low-speed phase were 22.07%and 20.22%higher than those of Vehicle 2 at cold star and hot start under-10℃.The reason was vehicle 1 had a larger displacement and more friction pairs than vehicle 2.There was the highest CO_(2)emission at the low-speed phase due to low average speed,frequent acceleration,and deceleration.The CO_(2)temperature factor and the ambient temperature had a strong linear correlation(R2=0.99).According to CO_(2)temperature factors and their relationships,CO_(2)emission factors of other ambien temperatures could be calculated when the CO_(2)emission factor of 23℃was obtained,and the method also could be used to obtain the CO_(2)temperature factors of different vehicles.To separate the effect of load setting and temperature variation on CO_(2)emission quantitatively a method was proposed.And results showed that the load setting was dominant for the CO_(2)emission variation.Compared with 23℃,the CO_(2)emission for vehicle 1 caused by load setting variation were 62.83 and 47.42 g/km,respectively at-10 and 0℃,while those fo vehicle 2 were 45.01 and 35.63 g/km,respectively.