Estimation and Spatio-temporal Patterns of Carbon Emissions from Grassland Fires in Inner Mongolia,China

Grassland fires results in carbon emissions,which directly affects the carbon cycle of ecosystems and the carbon balance.The grassland area of Inner Mongolia accounts for 22%of the total grassland area in China,and many fires occur in the area every year.However,there are few models for estimation of carbon emissions from grassland fires.Accurate estimation of direct carbon emissions from grassland fires is critical to quantifying the contribution of grassland fires to the regional balance of atmospheric carbon.In this study,the regression equations for aboveground biomass(AGB)of grassland in growing season and MODIS NDVI(Normalized Difference Vegetation Index)were established through field experiments,then AGB during Nov.–Apr.were retrieved based on that in Oct.and decline rate,finally surface fuel load was obtained for whole year.Based on controlled combustion experiments of different grassland types in Inner Mongolia,the carbon emission rate of grassland fires for each grassland type were determined,then carbon emission was estimated using proposed method and carbon emission rate.Results revealed that annual average surface fuel load of grasslands in Inner Mongolia during 2000–2016 was approximately 1.1978×1012 kg.The total area of grassland which was burned in the Inner Mongolia region over the 17-year period was 5298.75 km2,with the annual average area of 311.69 km2.The spatial distribution of grassland surface fuel loads is characterized by decreasing from northeast to southwest in Inner Mongolia.The total carbon emissions from grassland fires amounted to 2.24×107 kg with an annual average of 1.32×106 for the study area.The areas with most carbon emissions were mainly concentrated in Old Barag Banner and New Barag Right Banner and on the right side of the Oroqin Autonomous Banner.The spatial characteristics of carbon emission depend on the location of grassland fire,mainly in the northeast of Inner Mongolia include Hulunbuir City,Hinggan League,Xilin Gol League and Ulanqab City.The area and spatial location of grassland fires can directly affect the total amount and spatial distribution of carbon emissions.This study provides a reference for estimating carbon emissions from steppe fires.The model and framework for estimation of carbon emissions from grassland fires established can provide a reference value for estimation of carbon emissions from grassland fires in other regions.

Determination of Particulate Matter Emissions from Cattle Feedlots Using Wind-Trax and the Flux-Gradient Technique

Large commercial cattle feedlots are significant sources of particulate matter (PM) emissions. This research compared WindTrax and the flux-gradient technique in estimating emissions of PM with aerodynamic diameter < 10 μm (PM10) from cattle feedlots. Meteorological conditions were measured and PM10 concentrations were profiled vertically (i.e., 2.0 to 7.62 m) at a large commercial beef cattle feedlot in Kansas from May through September 2011. Results show that between the two methods evaluated, WindTrax was least sensitive to changes in heights and number of heights used in the emission estimation, with calculated PM10 emission rates varying by up to 18% only. On the other hand, PM10 emission rates produced by the flux-gradient technique varied by almost 56% when changing either heights and/or number of heights in emission calculation. Both methods were sensitive to height settings, with their respective PM10 emission rates higher when the lowest height setting (2.0 m) was included. Calculating PM10 emission rates with the 7.62-m height led to lower estimates for the flux-gradient technique but no significant change in estimates was observed for WindTrax. As demonstrated in this study, for the flux-gradient technique, settings for the lowest and highest heights were the most critical in emission estimation;exclusion of other heights in between showed only to 2% to 6% change in calculated PM10 emission rates. In general, the higher PM10 emission rates were obtained with the flux-gradient technique. However, eliminating the lowest height (2.0 m) in the calculation and, at the same time, using a specific set of formulations for the flux-gradient technique made its calculated PM10 emission rates slightly lower (but not significantly different) than those from WindTrax.

Estimation of Traffic Induced Pollution in Palestine

Traffic sector presents a major contributor to air pollution in Palestine. This has been maximized as Israeli closure of major roads resulted in major congestion in most of Palestinian cities in West Bank, which causes high emissions of exhaust gases, such as carbon monoxide （CO）. nitrogen oxides （NOx）. particulate matters （PM）, volatile organic compounds （VOCs） and sulphur dioxide （SO2）. In order that traffic induced pollution can be assessed in Palestine. in this paper, an approach is presented by which the traffic emissions can be estimated relying on the emission factors as input together with vehicle types, annual traveled distance, etc.. The outcomes cover the emission from the various types of vehicles in West Bank.

Spatiotemporal distribution,environmental risk and carbon emission reduction potential of livestock manure in Shaanxi Province,China

Shaanxi is a leading province in animal husbandry(AH)in China.However,the lack of provincial information on the characteristics and utilization potential of livestock manure(LM)hinders crucial management decisions.Therefore,we investigated the spatiotemporal distribution,availability and biogas potential of LM in Shaanxi,and examine the carbon emission reduction potential of AH.There has been a 1.26-fold increase in LM quantities in Shaanxi over the past 35 years,reaching 4635.6×10^(4)t by 2021.LM was mainly concentrated in northern Shaanxi and the eastern part of Hanzhong.Cattle and pig manure were the primary sources of LM,with the average LM land-load of 14.57 t·ha^(−1)in 2021.While the overall AH in Shaanxi has not exceeded the environmental capacity,the actual scales of AH in Ankang and Hanzhong have already surpassed the respective environmental capacities,posing a higher risk of N and P pollutions.In 2021,the estimated biogas energy potential of LM was 1.2×10^(11)MJ.From 2012 to 2021,the average carbon emission reduction potential in Shaanxi was 22%,with an average potential scale of 10%.The results of this research provide valuable data and policy recommendations for promoting the intensive use of LM and reducing carbon emissions in Shaanxi.

Modelling and Simulation of tile 50 MWe CFBC Boiler

A general mathematical model of CFBC boiler by taking the 50 MWe Tsinghua CFBC boiler as the object is established. The model has some distinguished feature.Firstly,in order to describe the CFBC precisely, emphasis is paid to tak t the broad size distribution of feeding coal and bed inventory into consideration. Secondly, the employingiof cell model makes it possible to show the distribution of any interested variable inside furnace.Thirdly ,since partial aspects such as hydrodynamics,devolatilisation of coal, combustion of char and the formation and reduction of harmful substances are considered in detail, therefore the emission at the outlet of the furnace can be estimated. By using the model, simulation is carried out to predict the performance of the 50 MWe Tsinghua CFBC boiler for both design and off-design operation. The results are useful for designers and possible improvement of desian.

Modelling air change rate of naturally ventilated dairy buildings using response surface methodology and numerical simulation

The air change rate(ACR)of naturally ventilated dairy buildings(NVDBs)plays an important part in the design and control of the ventilation system,as well as in the estimation of the gaseous emission rate.The objectives of this research were to model the ACR based on a quantitative investigation of the relationship between the ACR and its potential influencing factors,including the opening ratio(r),the building length to width ratio(a),the wind speed(U),and the wind direction(0).The investigations were performed using the response surface methodology integrated with the Box-Behnken design and Computational Fluid Dynamics(CFD)simulations.Three response surface models of the ACR of NVDBs were established for three opening ratio ranges of 5%-42.5%,42.5%-80%,and 5%-80%,respectively.It was found that the selection of the opening ratio range had almost no effect on the developed response surface models.The results showed that the ACR of NVDBs was not influenced by a,but was significantly affected by r,U,6,and interaction effects between every two of the three factors.The highest ACR was 6.7 s^(-1),6.0 s^(-1),and 4.0 s^(-1)when 0,U,and r was at their respective medium value while the rest parameters were at the highest values,indicating that the r played an important role in the value of ACR.It was concluded that in the prediction of the ACR of a building,the influences of both individual and interactional effects of 0,U,and r should be considered.