Carbon monoxide and air pollution from automobile emissions in New York City

Local business-day traffic determines the diurnal carbon monoxide concentrations at individual sites in Manhattan. Concentrations during the day can be predicted from readings taken in early morning.     

Soil as a sink for atmospheric carbon monoxide

The rate of carbon monoxide oxidation by soil increased with increasing carbon monoxide concentration in the gas phase, in line with Michaelis-Menten kinetics. Rates of carbon monoxide oxidation were determined for 20 soils at 0 degrees , 10 degrees , 20 degrees , and 30 degrees C. The observed oxidation rates were used to calculate a global soil uptake rate of atmospheric carbon monoxide of 4.1 x 10(14) grams per year, which is slightly less than the amount of carbon monoxide believed to be produced annually as a result of fossil fuel combustion.     

Normal atmosphere: large radical and formaldehyde concentrations predicted

A steady-state model of the normal (unpolluted) surface atmosphere predicts a daytime concentration of hydroxyl, hydroperoxyl, and methylperoxyl radicals approaching 5 x 10(8)molecules per cubic centimeter and a formaldehyde concentration of 5 x 10(10) molecules per cubic centimeter or 2 parts per billion. A radical chain reaction is proposed for the rapid removal of carbon monoxide, leading to a carbon monoxide lifetime as low as 0.2 year in the surface atmosphere.     

Carbon monoxide balance in nature

Consideration of the steady-state equations for stable carbon monoxide and for radioactive carbon monoxide in the troposphere leads to the conclusion that carbon monoxide is produced at a rate of 5x10(15) grams per year, a value some 25 times greater than the rate of carbon monoxide production from combustion. The concomitant residence time for carbon monoxide is 0.1 year, in agreement with a previous estimate of Weinstock. Hydroxyl radicals are shown to account for both the production of this large amount of carbon monoxide by methane oxidation and for its removal by carbon monoxide oxidation. The average concentration of hydroxyl radicals in the troposphere required to achieve this effect is 2.3x10(6) molecules per cubic centimeter, with a daytime concentration of twice that. Levy and McConnell, McElroy, and Wofsy have deduced concentrations of hydroxyl radicals in the troposphere of the same magnitude from purely photochemical considerations, in support of this model.     

Venus upper atmosphere neutral gas composition: first observations of the diurnal variations

Measurements of the composition, temperature, and diurnal variations of the major neutral constituents in the thermosphere of Venus are being made with a quadrupole mass spectrometer on the Pioneer Venus orbiter. Concentrations of carbon dioxide, carbon monoxide, molecular nitrogen, atomic oxygen, and helium are presented, in addition to an empirical model of the data. The concentrations of the heavy gases, carbon dioxide, carbon monoxide, and molecular nitrogen, rapidly decrease from the evening terminator toward the nightside; the concentration of atomic oxygen remains nearly constant and the helium concentration increases, an indication of a nightside bulge. The kinetic temperature inferred from scale heights drops rapidly from 230 K at the terminator to 130 K at a solar zenith angle of 120 degrees , and to 112 K at the antisolar point.     

Soil: a natural sink for carbon monoxide

A potting soil mixture depleted carbon monoxide in a test atmosphere from a concentration of 120 parts per million to near zero within 3 hours. Maximum activity occurred at 30 degrees C. Steam sterilization of the soil, the addition of antibiotics or 10 percent (by weight) saline solution, and anaerobic conditions all prevented carbon monoxide uptake. Sterilized soil inoculated with nonsterile soil acquired activity with time. Samples of various natural soils differed in their ability to remove carbon monoxide from the air. Acidic soils with a high content of organic matter were generally the most active. The soil's ability to remove carbon monoxide from the atmosphere is ascribed to the activity of soil micro-organisms.     

城市行道树对道路空间CO浓度的影响

针对福州市、厦门市以小叶榕、高山榕、羊蹄甲、樟树、凤凰木、芒果为行道树的主干道路进行CO浓度、小气候、车流量的同步测定与分析。结果表明,不同树种对大气中CO浓度水平的影响呈极其显著关系;道路中央CO浓度与车流量有较大的相关性,树下CO浓度与车流量的相关性减小;行道树在一定程度上降低了大气中的CO浓度;福州市4种行道树降低CO浓度从大到小顺序为芒果,樟树,小叶榕,羊蹄甲;厦门市4种行道树降低大气中CO浓度从大到小顺序为凤凰木,芒果,高山榕,羊蹄甲。     

Corrections in the pioneer venus sounder probe gas chromatographic analysis of the lower venus atmosphere

Misidentification of two peaks from the Pioneer Venus sounder probe gas chromatograph (SPGC), also formerly known as the LGC, gave rise to quantitative errors in the abundances of oxygen, argon, and carbon monoxide. The argon abundance is estimated at 67 parts per million and that of carbon monoxide at 20 parts per million. At this time, no estimates for the oxygen abundance can be made.     

恒定环境条件下西洋参叶片光合作用的日变化

为了探索西洋参叶片光合作用日变化的内在因素，以人工气候葙内培养的西洋参为材料．对1日中叶片光合作用的变化及某些生理生化指标进行了测定。结果表明：在恒定环境条件下西洋参叶片光合作用日变化表现下午低于上午的日变化规律．即呈日下降变化．日下降范围为15％--20％。1日中叶片气孔导度和蒸腾作用也呈下降变化，但气孔导度日下降百分率大于蒸腾作用的日下降率．气孔导度的日下降百分率与光合日下降百分率基本一致。蒸腾作用和水分利用效率的日下降百分率低于光合日下降百分率。胞间CO2浓度下午呈上升变化趋势，说明光合日下降属于非气孔限制作用。西洋参叶片光合速率与比叶重及叶片淀粉含量均呈现出极显著负相关关系，叶片光合产物的积累是发生光合日下降现象的重要原因之一。     

淮河流域农田生态系统碳通量变化特征

利用涡度相关技术对安徽寿县冬小麦／水稻农田碳通量进行连续观测,结果显示：日变化呈典型的u型曲线,峰值均出现在11：00左右;CO2的月均日变化差异显著,6、10月以正值为主,农田生态系统表现为碳源,4、8月对CO2的吸收最为强烈;春、夏季CO2通量的日变化也呈现出典型的u型曲线,但是秋、冬季的碳通量日较差较小。COz通量各季的日总量表现为春季〉夏季〉冬季〉秋季,四季均为碳汇,春夏两季的碳汇能力明显强于秋冬季。     

Carboxyhemoglobin elevation after exposure to dichloromethane

Inhalation of dichloromethane vapor in concentrations of 500 to 1000 parts per million for 1 to 2 hours promptly initiated the formation of significant quantities of carbon monoxide in human subjects. The evidence suggests that carbon monoxide may be a metabolite of dichloromethane and, that exposure to concentrations of dichloromethane below the industrial threshold limit values may result in the formation of carbon monoxide in amounts that exceed the allowable limits.     

Carbon Monoxide in the Earth's Atmosphere: Increasing Trend

The results of an analysis of more than 60,000 atmospheric measurements of carbon monoxide taken over 3(1/2) years at Cape Meares, Oregon (45 degrees N, 125 degrees W), indicate that the background concentration of this gas is increasing. The rate of increase, although uncertain, is about 6 percent per year on average. Human activities are the likely cause of a substantial portion of this observed increase; however, because of the short atmospheric lifetime of carbon monoxide and the relatively few years of observations, fluctuations of sources and sinks related to the natural variability of climate may have affected the observed trend. Increased carbon monoxide may deplete tropospheric hydroxyl radicals, slowing down the removal of dozens of man-made and anthropogenic trace gases and thus indirectly affecting the earth's climate and possibly the stratospheric ozone layer.     

Diurnal variation of stratospheric chlorine monoxide: a critical test of chlorine chemistry in the ozone layer

This article reports measurements of the column density of stratospheric chlorine monoxide and presents a complete diurnal record of its variation (with 2-hour resolution) obtained from ground-based observations of a millimeter-wave spectral line at 278 gigahertz. Observations were carried out during October and December 1982 from Mauna Kea, Hawaii. The results reported here indicate that the mixing ratio and column density of chlorine monoxide above 30 kilometers during the daytime are approximately 20 percent lower than model predictions based on 2.1 parts per billion of total stratospheric chlorine. The observed day-to-night variation of chlorine monoxide is, however, in good agreement with recent model predictions, confirms the existence of a nighttime reservoir for chlorine, and verifies the predicted general rate of its storage and retrieval. From this evidence, it appears that the chlorine chemistry above 30 kilometers is close to being understood in current stratospheric models. Models based on this chemistry and measured reaction rates predict a reduction in the total stratospheric ozone content in the range of 3 to 5 percent in the final steady state for an otherwise unperturbed atmosphere, although the percentage decrease in the upper stratosphere is much higher.     

Air pollution: sensitive detection of ten pollutant gases by carbon monoxide and carbon dioxide lasers

Detection sensitivities of a few parts per billion for ten gaseous pollutants have been evaluated by measuring the strength of the absorption of infrared radiation from carbon monoxide and carbon dioxide lasers. Ethylene concentrations as small as 5 parts per billion have been detected in air. The measured absorption strengths indicate that in mixtures of pollutants, such as nitrogen dioxide and water vapor, the sensitivity is reduced by overlapping absorption bands. However, calculations indicate that it should be possible to detect nitrogen dioxide concentrations of 0.01 part per million in the presence of water vapor concentrations of 105 parts per million.     

Carbon, carbides, and methane in an apollo 12 sample

Total carbon in the Apollo 12 sample 12023 fines was 110 micrograms per gram of sample with a carbon isotopic abundance delta(13)C (relative to the Pee Dee belemnite standard) of +12 per mil. Hydrolysis of the fines with deuterium chloride yielded undeuterated methane along with deuterated hydrocarbons, thus confirming the presence of 7 to 21 micrograms of carbon per gram of sample as carbide and about 2 micrograms of carbon per gram of sample as indigenous methane. After vacuum pyrolysis of the fines to 1100 degrees C the following gases were detected in the relative abundance: carbon monoxide carbon dioxide methane. Variations of the delta(13)C value with the pyrolysis temperature indicated the presence of carbon with more than one range of isotopic values. The observed delta(13)C value of +14 per mil for lunar carbide is much higher than that of carbide in meteorites. These results suggest that lunar carbide is either indigenous to the moon or a meteoritic contribution that has been highly fractionated isotopically.     

Organogenic elements and compounds in surface samples from the sea of tranquillity

Organogenic elements, mainly carbon, nitrogen, phosphorus, and sulfur are present in the particulate material and in a breccia rock from Tranquillity Base in amounts ranging from 5 to 4200 parts per million. The major compounds of carbon released by heating are carbon monoxide and carbon dioxide; the former predominates. Small amounts of other compounds of carbon have also been observed. Sulfur can be released as hydrogen sulfide by treatment with acid. The carbon isotopic delta(13L)C values are definitely nonterrestrial (+ 13 to + 18.5 per mil).     

绥芬河国家森林公园生态因子效应分析

对绥芬河国家森林公园典型样地及绥芬河市区典型对照样地的空气负离子密度、温度、湿度、二氧化碳体积分数和噪音进行了测量,并分析了森林公园与市区样地中各生态因子的日变化规律,比较了森林公园与市区、森林公园内典型样地间的空气负离子密度、温度、湿度、二氧化碳体积分数及噪音在监测时段的发生量。结果表明,森林公园与市区样地的温度、湿度日变化规律基本一致。森林公园和市区的空气负离子密度、二氧化碳体积分数和环境噪音具有各自的日变化规律。绥芬河国家森林公园空气质量和生态效益整体上高于市区。     

Dynamics of carbon monoxide binding by heme proteins

Rebinding of carbon monoxide to myoglobin and to cytochrome P-450 after removal by a light flash occurs down to 50 degrees K for myoglobin and 25 degrees K for cytochrome P-450 in glycerol-water solution. Above 240 degrees K the reaction is second order; between 240 degrees and 200 degrees K the rebinding becomes exponential and independent of the carbon monoxide concentration. Below 150 degrees K the reaction follows a power law and is approximately 10(3) times faster for cytochrome P-450 than for myoglobin.     

Volcanic gases in the april 1979 soufriere eruption

Six gas samples from the 17 April 1979 Soufriere eruption plume were analyzed for carbonyl sulfide, carbon disulfide, carbon monoxide, carbon dioxide, methane, nitrous oxide, fluorocarbon-11, fluorocarbon-12, methyl chloroform, and carbon tetrachloride. Only carbon monoxide, carbon dioxide, carbonyl sulfide, and carbon disulfide were found to have increased mixing ratios as compared with those in clean tropospheric air, but the increases were not sufficient to contribute greatly to the global budgets of these four components.     

Heterogeneous catalysis: effect of an alternating electric field

Oxidation of carbon monoxide was studcied in a static reactor at 123 degrees +/- 1 degrees C, wtith NiO as catalyst. An alternating electric field of about 22,000 volts per centimeter, peak to peak, was applied normal to the catalytic Surfaces. The rate of oxidation was thereby enhanced by a factor of 6 at 100 cycles per second, with maximum enhancement at between 100 and 200 cycles per second.