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1.
Dilution of indoor air contaminants with less contaminated outdoor air is the most common strategy for control of indoor air quality. Unfortunately this strategy frequently imposes a substantial energy burden. If the contaminants are associated with occupants and their activities, a ventilation control system based on the carbon dioxide level in the controlled space is shown to relieve this energy burden. A test was carried out in the Fridley, MN, Junior High School Music Department to obtain air quality, energy, and subjective response data on an Automatic Variable Ventilation System. A control system with both CO 2 and temperature inputs was devised to control the use of outdoor air. Infiltration measurements lead to a quantitative measure of ventil3tion efficiency. This in turn led to recommendations for air circulation patterns in rooms. The measured ventilation efficiency enabled energy and CO 2 models to fit measured data. Energy savings of approximately 20% were found for this application. Subjective response of the occupants also was measured. A special questionnaire, subjected to statistical analysis, showed that the subjects felt warmer with increased CO 2 in the room air. 相似文献
2.
Reaction of CO 2 with LiOH requires the presence of water in an amount sufficient to produce monohydrate thium hydroxide (LiOH · H 2O) prior to or simultaneously with the CO 2 reaction. For a given CO 2 content in the air stream at any given temperature, there is a corresponding humidity of the feed stream which results in maximum CO 2 absorption efficiency. Two commercially available LiOH granules with different porosities and water contents were studied. The combined effects of temperature and humidity on CO 2 absorption patterns and CO 2 absorption capacities were observed. Results showed that temperature and water content of the air stream did change the CO 2 absorption pattern and the CO 2 absorption capacity for LiOH absorbent.When the relative humidity in the air stream is below 14%, anhydrous LiOH has a higher CO 2 absorption capacity at higher temperatures. However, above 40% relative, lower temperatures are favored. Partially hydrated LiOH granules have a higher CO 2 absorptions capacity at lower temperatures at all relative humidities in the air stream except 14%. 相似文献
3.
A subcommittee of the Nordic Committee for Building Codes has released guidelines for building regulations regarding indoor air quality, especially concerning ventilation. The main features of the guidelines, such as acceptable outdoor air quality for ventilation and minimum outdoor air flows for dwellings and offices, are presented and discussed. Mechanical ventilation is, in principle, required in all buildings including dwellings, due to the requirement of a minimum outdoor air change of 0.5 h −1 and the normal highly airtight nature of new buildings. The guidelines are a basis for designing energy-efficient buildings while maintaining an indoor air quality which provides acceptable comfort and does not impair health. 相似文献
4.
The air quality in a newly built preschool was investigated in a longitudinal study. Typical air contaminants emanating from building materials were determined, their variation over time (0–18 months) was measured, and the influence of the ventilation system (81%–91% recirculation of return air) on contaminant concentrations was studied. Volatile organic compounds were sampled by adsorption on porous polymer, analysed by a GC/FID system, and identified by MS. A spatial build-up in concentration (ppb or μg/m 3 levels) is evident for all the organic compounds, as well as for CO 2, from the outdoor air, through the ventilation system, and through the rooms to the exhaust air. The longitudinal comparison over time shows that all the organic compounds decline in concentration mainly within the first 6 months of occupancy: 1-butanol 4–14 times, toluene and pentanal + hexanal 2–4 times, while formaldehyde remained at a constant low level of 90 ppb (110 μg/m 3). It is difficult to believe that the problems of poor air quality in 100 preschools in Stockholm are caused by the organic compounds alone unless interactions occur. A preschool building needs to be gassed off during the first 6 months after its construction with no recirculation of return air allowed (outdoor air rate approx 4–5 ach). During at least 1–2 additional years, it is desired that the recirculation rate of return air is restricted, perhaps to 50%. 相似文献
5.
Buildings contribute almost half of the world's carbon dioxide (CO 2) emissions. Energy and water consumption are some of the largest and fastest growing pressures on the global environment. The use of energy is mainly attributed to the heating and cooling of buildings. The type of materials used in the construction of buildings plays a significant role in the life-cycle emissions of each dwelling. Changing the material use in the construction of an existing building and adding insulation could have a major impact on energy use and the environment of the building in its entire life cycle. This paper investigates the amount of exergy savings and the decrease in CO 2 emissions resulting from the refurbishing of an existing building in Ljubljana. This study results from the growing awareness that in the choice of building materials, the designer must consider not only the requirements of the owner and occupier of the building, but also the resulting energy savings, the resource base and the effects of the manufacturing and processing of building materials on the environment. The exergy efficiency of the material use is calculated and the environmental impact assessment of energy and material use is accounted for. 相似文献
6.
Sixteen existing multi-family buildings (94 apartments) in Finland and 20 (96 apartments) in Lithuania were investigated prior to their renovation in order to develop and test out a common protocol for the indoor environmental quality (IEQ) assessment, and to assess the potential for improving IEQ along with energy efficiency. Baseline data on buildings, as well as data on temperature (T), relative humidity (RH), carbon dioxide (CO 2), carbon monoxide (CO), particulate matter (PM), nitrogen dioxide (NO 2), formaldehyde, volatile organic compounds (VOCs), radon, and microbial content in settled dust were collected from each apartment. In addition, questionnaire data regarding housing quality and health were collected from the occupants. The results indicated that most measured IEQ parameters were within recommended limits. However, different baselines in each country were observed especially for parameters related to thermal conditions and ventilation. Different baselines were also observed for the respondents' satisfaction with their residence and indoor air quality, as well as their behavior related to indoor environment. In this paper, we present some evidence for the potential in improving IEQ along with energy efficiency in the current building stock, followed by discussion of possible IEQ indicators and development of the assessment protocol. 相似文献
7.
The historic development of the scientific interest in monitoring CO 2 in the atmosphere is the subject of this article. Particular emphasis is placed upon activities initiated by the USA in the 1950s which led to the establishment of the Mauna Loa Observatory and further developed into the existing world-wide monitoring system for air constituents and air pollution operated under the auspices of the World Meteorological Organization, a major contributer to the Global Environmental Monitoring System of the UN Environment Programme. Recent studies on the feasibility of monitoring the background level of CO 2 at stations throughout the world have indicated considerable difficulties resulting from the influences of the biosphere. These problems have led WMO to adopt new criteria for CO 2 monitoring station locations which are presented in a discussion of future needs and plans for global monitoring of CO 2 in the atmosphere. 相似文献
8.
Upon arrival on Earth, the reduced carbon pool split into a series of compartments: core, mantle, crust, hydrosphere, atmosphere, biosphere.This distribution pattern is caused by the ability of carbon to adjust structurally to a wide range of pressure and temperature, and to form simple and complex molecules with oxygen, hydrogen and nitrogen. Transformation also involved oxidation of carbon to CO 2 which is mediated at depth by minerals, such as magnetite, and by water vapor above critical temperature. Guided by mineral-organic interactions, simple carbon compounds evolved in near surface environments towards physiologically interesting biochemicals. Life, as an autocatalytic system, is considered an outgrowth of such a development.This article discusses environmental parameters that control the CO 2 system, past and present. Mantle and crustal evolution is the dynamo recharging the CO 2 in sea and air; the present rate of CO 2 release from the magma is 0.05 × 10 15 g C per year. Due to the enormous buffer capacity of the chemical system ocean, such rates are too small to seriously effect the level of CO 2 in our atmosphere. In the light of geological field data and stable isotope work, it is concluded that the CO 2 content in the atmosphere has remained fairly uniform since early Precambrian time; CO 2 should thus have had little impact on paleoclimate. In contrast, the massive discharge of man-made CO 2 into our atmosphere may have serious consequences for climate, environment and society in the years to come. 相似文献
9.
The influence of long-term exposure of model plantations at elevated atmospheric CO 2 (550 ppm) on soil respiration under natural conditions has been studied using an automated Free-Air CO 2 Enrichment (FACE) system at the Hokkaido University, Japan. In the course of the experiment, an attempt has been made to
simulate the effect of forthcoming climate change on the process of CO 2 emission from different soil types. 相似文献
10.
The building sector has been regarded as a potential sector where there is large capacity to reduce the climate change effect. This study has proposed solutions to mitigate environmental impacts and achieve low CO 2 emission from residential sector. Therefore, full life cycle assessment (LCA) has been run to assess the CO 2 emission and its effect on the atmosphere and climate change. Based on the result, timber scheme is the best choice due to releasing less CO 2 emissions to the atmosphere. However, house builders in Malaysia have almost completely neglected timber as a building material, with timber use as building components reduced to 5%. In this study, LCA Software was used to assess CO 2 emissions from different wall construction. The alternative building scheme has been made by reinforce steel stud, wooden beam and timber wall (S8) to improve the scheme deficiency while releasing less CO 2 emissions compared to other schemes. Therefore, S8 has a decreased CO 2 effect by 85% less than precast concrete frame and 90% less than brick over their lifetime. (S8) increased the load bearing compared to conventional timber beam. Thus, new scheme S8 could be replaced by current scheme and promote more adjustable scheme for Malaysian housing. 相似文献
11.
Is emission intensity of carbon dioxide (CO 2) spatially correlated? What determines the CO 2 intensity at a provincial level? More importantly, what climate and economic policy decisions should the China’s central and local governments make to reduce the CO 2 intensity and prevent the environmental pollution given that China has been the largest emitter of CO 2? We aim to address these questions in this study by applying a dynamic spatial system generalized method of moment technique. Our analysis suggests that provinces are influenced by their neighbours. In addition, CO 2 intensities are relatively higher in the western and middle areas, and that the spatial agglomeration effect of the provincial CO 2 intensity is obvious. Our analysis also shows that CO 2 intensity is nonlinearly related to gross domestic product, positively associated with secondary-sector share and foreign direct investment, and negatively associated with population size. Important policy implications are drawn on reducing carbon intensity. 相似文献
12.
ABSTRACTThe biogas constituting majorly CH 4 and CO 2 has been produced by Ca(OH) 2 pre-treated wheat straw with pre-digested cow dung. Some of the key thermodynamic parameters like specific heat capacity, density and heating capacity of the biogas produced have also been calculated per day as well as throughout the hydraulic retention time. The governing equations of biogas with appropriate phase and interfacial conditions describing the physics of the biogas have been derived. The control volume approach has been used to predict the total volume (ml) of biogas, CH 4 and CO 2 throughout the experiment and on the daily basis. The effects of feedstock, temperature and pressure on the production of biogas, CH 4 and CO 2 in anaerobic digestion have also been studied. The average number of molar fraction and conversion ratio of CH 4 and CO 2 are correlated with number of carbon atoms available in feedstock. Numerical calculations by using developed model and Modified Gompertz model have shown proficient agreement with the experimental observations. 相似文献
13.
This paper summarized the study carried out in Krakow, Poland in 1975-76 on the estimated local air pollution as measured by carbon isotopes and total sulphur measurement in plants. Good correlation was found between δ 14C value and the total sulphur (measured by radionuclide excited X-ray fluorescence) in beech leaves collected in the late summer, indicating the common source of both pollutants. Sampling and measurement of σ 13C in atmospheric CO 2 has shown that σ 3C can be used as a pollution indicator only in the winter period when no fluctuations exist ddue to plant respiration. A method of CO 2 sampling using molecular sieve proved to be feasible for instantaneous sampling with no isotope fractionation. The highest pollution by fossil CO 2 was measured in winter (12.8% excess. During spring and summer the average contribution of fossil CO 2 was 4.5 to 5.6%. 相似文献
14.
Carbon dioxide fluxes from the surface of coarse woody debris (CWD) have been measured in Korean pine forests of the southern Sikhote-Alin mountain range. The seasonal dynamics of oxidative conversion of CWD carbon have been evaluated, and average values of the CO 2 emission rate have been determined for CWD fragments of three tree species at different stages of decomposition. The degree of decomposition is an important factor of spatial variation in CO 2 emission rate, and temporal variation in this parameter is adequately described by an exponential function of both CWD temperature and air temperature ( R2 = 0.65–0.75). 相似文献
15.
Abstract In this paper, using the input-output model, the author first calculated the CO 2 emissions embodied in exports of China in 2002 and 2007. Then, the author empirically analyzed problems existing in the composition of exported products and analyzed its possible reasons. The research results of this paper are as follows: Since China’s entry into WTO, the CO 2 emissions embodied in exports of China have been increasing rapidly; the value of exported products of high-carbon emissions industries accounts for a relatively higher proportion to China’s total exports value because China’s carbon intensive products have a certain competitive advantage. Additionally, this paper has put forward relevant suggestions based on these results. 相似文献
16.
The Pechelbronn oilfield (Rhine Graben, France), where mining activity ended in the 1960s, has been used for waste disposal for twenty years. Since the wastes are varied, work is underway to identify the discharged materials and their derivatives, as well as to locate and quantify potential discharge sites. Two major goals were assigned to the present work. The first was to identify or refine the location of hidden structures that could facilitate gas emanation up to the surface, by studying soil gas concentrations (mainly 222Rn, CO 2, CH 4 and helium) and carbon isotope ratios in the CO 2 phase. The second was devoted to examining, from a health and safety viewpoint, if the use of the oilfield as a waste disposal site might have led to enhanced or modified gas emanation throughout the area.It appeared that CO 2 and 222Rn evolution in the whole area were similar, except near some of the faults and fractures that are known through surface mapping and underground observations. These 222Rn and CO 2 anomalies made it possible to highlight more emissive zones that are either related to main faults or to secondary fractures acting as migration pathways. In that sense, the CO 2 phase can be used to evaluate 222Rn activities distant from tectonic structures but can lead to erroneous evaluations near to gas migration pathways. Dumping of wastes, as well as oil residues, did not appear to have a strong influence on soil gaseous species and emanation. Similarly, enhanced gas migration due to underground galleries and exploitation wells has not been established. Carbon isotope ratios suggested a balance of biological phenomena, despite the high CO 2 contents reached. Other monitored gaseous species (N 2, Ar, H 2 and alkanes), when detected, always showed amounts close to those found subsurface and/or in atmospheric gases. 相似文献
17.
The income inequality-economy link has been argued by researchers a long time. But the impact of income inequality on environmental pollution is a new investigation topic for developing countries. Turkey is well known as an emerging economy which has a high level of income inequality and CO2 emissions. Therefore, this paper concentrates on the income inequality-CO2 emissions link in Turkish economy by applying a nonlinear analysis. This paper integrates economic growth and financial development to the CO2 emissions specification over the period of 1987–2019. We employ the nonlinear autoregressive distributed lag approach to explore the long-run nonlinear linkages between the series. Our findings reveal an asymmetric cointegration among variables. Positive and negative income inequality shocks positively affect CO2 emissions implying that positive and negative shocks of income inequality enhance CO2 emissions in the long run. Negative economic growth shocks decrease CO2 emissions, while positive shocks to financial development increase CO2 emissions in the long run. We provide important policy suggestions that might be useful to the policymakers to decrease CO2 emissions in Turkey. 相似文献
18.
Abstract This paper proposes to use DEA models with undesirable outputs to construct the Malmquist index that can be use to investigate the dynamic changes of CO 2 emission performance. With the index, the authors have measured the CO 2 emission performance of 28 provinces and autonomous regions in China from 1996 to 2007; with the convergence theory and panel data regression model, the authors analyze the regional differences and the influencing factors. It is found that the performance of CO 2 emissions in China has been continuously improved mainly due to the technological progress, and the average improvement rate is 3.25%, with a cumulative improvement rate of 40.86%. In addition, the CO 2 emission performance varies across four regions. As a whole, the performance score of eastern China is the highest. The northeastern and central China has relatively lower performance scores, and the western China is relatively backward. The regional differences are decreasing, and the performance of CO 2 emissions is convergent. The influence of some factors on the performance of CO 2 emissions is significant, such as the level of economic development, the level of industrial structure, energy intensity, and ownership structure. The influence of some factors, such as opening-up to the outside world, on the performance of CO 2 emissions is not significant. 相似文献
19.
With the economic development, China has become the largest CO 2 emissions country. China’s power industry CO 2 emissions accounted for about 50% of total CO 2 emissions. Therefore, exploring major drivers of CO 2 emissions is critical to mitigating its CO 2 emissions in power industry. Many studies considered the time series model to analyze the national influences factors of CO 2 emissions. But this paper focuses on regional differences in CO 2 emissions and adopts panel data models to explore the major impact factors of CO 2 emissions in the power industry at the regional and provincial perspectives. The results indicate economic growth level plays a dominant role in reducing CO 2 emissions. The power-consuming efficiency on the demand side has large potential to mitigate CO 2 emissions, but its influences are different in three regions. The impacts of the electric power structure on CO 2 emissions decline from the eastern region to the central and western regions. The influence of urbanization and industrialization also has significant regional differences. Therefore, the governments should consider the influencing factors and regional differences and formulate appropriate policies to decrease CO 2 emissions in the power industry. 相似文献
20.
This study was performed to investigate the concentration of PM 10 and PM 2.5 inside trains and platforms on subway lines 1, 2, 4 and 5 in Seoul, KOREA. PM 10, PM 2.5, carbon dioxide (CO 2) and carbon monoxide (CO) were monitored using real-time monitoring instruments in the afternoons (between 13:00 and 16:00). The concentrations of PM 10 and PM 2.5 inside trains were significantly higher than those measured on platforms and in ambient air reported by the Korea Ministry of Environment (Korea MOE). This study found that PM 10 levels inside subway lines 1, 2 and 4 exceeded the Korea indoor air quality (Korea IAQ) standard of 150 μg/m 3. The average percentage that exceeded the PM 10 standard was 83.3% on line 1, 37.9% on line 2 and 63.1% on line 4, respectively. PM 2.5 concentration ranged from 77.7 μg/m 3 to 158.2 μg/m 3, which were found to be much higher than the ambient air PM 2.5 standard promulgated by United States Environmental Protection Agency (US-EPA) (24 h arithmetic mean: 65 μg/m 3). The reason for interior PM 10 and PM 2.5 being higher than those on platforms is due to subway trains in Korea not having mechanical ventilation systems to supply fresh air inside the train. This assumption was supported by the CO 2 concentration results monitored in tube of subway that ranged from 1153 ppm to 3377 ppm. The percentage of PM 2.5 in PM 10 was 86.2% on platforms, 81.7% inside trains, 80.2% underground and 90.2% at ground track. These results indicated that fine particles (PM 2.5) accounted for most of PM 10 and polluted subway air. GLM statistical analysis indicated that two factors related to monitoring locations (underground and ground or inside trains and on platforms) significantly influence PM 10 ( p < 0.001, R2 = 0.230) and PM 2.5 concentrations ( p < 0.001, R2 = 0.172). Correlation analysis indicated that PM 10, PM 2.5, CO 2 and CO were significantly correlated at p < 0.01 although correlation coefficients were different. The highest coefficient was 0.884 for the relationship between PM 10 and PM 2.5. 相似文献
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