The global carbon cycle and possible disturbances due to man's interventions

Global atmospheric CO₂ concentration has increased since the beginning of reliable monitoring in 1958 at a mean rate of about 0.9 ppm CO₂/yr. Now, atmospheric CO₂ concentration is at 330 ppm. From about 1860 up to 1974, man's intervention in the global carbon cycle caused a likely increase of 76.6 × 10¹⁵ gC, corresponding to 36 ppm CO₂ in the atmosphere, if a preindustrial content of 294 ppm CO₂ or 625.3 × 10¹⁵ g C is adopted to be valid. A further rise of atmospheric CO₂ seems to be inevitable and probably will be responsible for a climatic warming in the next several decades; therefore, a global examination of carbon reservoirs and carbon fluxes has been undertaken to determine their storage capacity for excess carbon which orginated mainly from burning fossil fuels and from land clearing. During 1860–1974 about 136 × 10¹⁵ g C have ben emitted into the atmosphere by fossil fuel combustion and cement production. At present, the emission rate is about 5 × 10¹⁵ g C/yr. The worldwide examination of carbon release, primarily by deforestation and soil cultivation since 1860, is estimated to be about 120 × 10¹⁵ g C. The net transfer of carbon to the atmosphere owing to man's interference with the biosphere is now believed to be about 2.4 × 10¹⁵ g C/yr. An oceanic uptake of roughly 179 × 10¹⁵ g C since 1860 is open to discussion. According to the chemical buffering of sea surface water only about 35.5 × 10¹⁵ g C could have been absorbed. It is argued, however, that oceanic circulations might have been more effective in removing atmospheric excess carbon of anthropogenic origin.     

Effect of cigarette smoking on residential NO2 levels

Two studies evaluating the levels and sources of nitrogen dioxide in approximately 90 employee homes in the Richmond area with continuous sampling during the weeks of August 5, 1980, and February 9, 1981, were performed using samplers in the living room, bedroom, kitchen, and outdoors. Additional data were collected concerning appliance usage, heating/cooling plant, ventilation and cigarette smoking. Results were analyzed using BMDP routines. The largest contributor to NO₂ concentration was found to be gas-fired kitchen appliances. The mean kitchen level for homes with gas appliances during the winter study was 188 μg/m³. Excluding participants with gas kitchens, incremental influence due to cigarette smoking was detected. The 7-day, 3-room average level of NO₂ in the homes of nonsmokers and smokers without gas-fired appliances was 12 and 15 μg/m³, respectively, in the summer. The corresponding winter values were 19 and 22 μg/m³. Furthermore, the individual levels of NO₂ in the homes of smokers were generally below both the adjacent outdoor level and the National Ambient Air Quality Standard limit for annual exposure.     

Seasonal variation in outdoor,indoor, and personal air pollution exposures of women using wood stoves in the Tibetan Plateau: Baseline assessment for an energy intervention study

Cooking and heating with coal and biomass is the main source of household air pollution in China and a leading contributor to disease burden. As part of a baseline assessment for a household energy intervention program, we enrolled 205 adult women cooking with biomass fuels in Sichuan, China and measured their 48-h personal exposure to fine particulate matter (PM_2.5) and carbon monoxide (CO) in winter and summer. We also measured the indoor 48-h PM_2.5 concentrations in their homes and conducted outdoor PM_2.5 measurements during 101 (74) days in summer (winter). Indoor concentrations of CO and nitrogen oxides (NO, NO₂) were measured over 48-h in a subset of ~ 80 homes. Women's geometric mean 48-h exposure to PM_2.5 was 80 μg/m³ (95% CI: 74, 87) in summer and twice as high in winter (169 μg/m³ (95% CI: 150, 190), with similar seasonal trends for indoor PM_2.5 concentrations (winter: 252 μg/m³; 95% CI: 215, 295; summer: 101 μg/m³; 95% CI: 91, 112). We found a moderately strong relationship between indoor PM_2.5 and CO (r = 0.60, 95% CI: 0.46, 0.72), and a weak correlation between personal PM_2.5 and CO (r = 0.41, 95% CI: − 0.02, 0.71). NO₂/NO ratios were higher in summer (range: 0.01 to 0.68) than in winter (range: 0 to 0.11), suggesting outdoor formation of NO₂ via reaction of NO with ozone is a more important source of NO₂ than biomass combustion indoors. The predictors of women's personal exposure to PM_2.5 differed by season. In winter, our results show that primary heating with a low-polluting fuel (i.e., electric stove or wood-charcoal) and more frequent kitchen ventilation could reduce personal PM_2.5 exposures. In summer, primary use of a gaseous fuel or electricity for cooking and reducing exposure to outdoor PM_2.5 would likely have the greatest impacts on personal PM_2.5 exposure.     

Characteristics of PM10, PM2.5, CO2 and CO monitored in interiors and platforms of subway train in Seoul, Korea

This study was performed to investigate the concentration of PM₁₀ and PM_2.5 inside trains and platforms on subway lines 1, 2, 4 and 5 in Seoul, KOREA. PM₁₀, PM_2.5, carbon dioxide (CO₂) and carbon monoxide (CO) were monitored using real-time monitoring instruments in the afternoons (between 13:00 and 16:00). The concentrations of PM₁₀ 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 PM₁₀ levels inside subway lines 1, 2 and 4 exceeded the Korea indoor air quality (Korea IAQ) standard of 150 μg/m³. The average percentage that exceeded the PM₁₀ 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/m³ to 158.2 μg/m³, 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/m³). The reason for interior PM₁₀ 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 CO₂ concentration results monitored in tube of subway that ranged from 1153 ppm to 3377 ppm. The percentage of PM_2.5 in PM₁₀ 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 PM₁₀ 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 PM₁₀ (p < 0.001, R² = 0.230) and PM_2.5 concentrations (p < 0.001, R² = 0.172). Correlation analysis indicated that PM₁₀, PM_2.5, CO₂ and CO were significantly correlated at p < 0.01 although correlation coefficients were different. The highest coefficient was 0.884 for the relationship between PM₁₀ and PM_2.5.     

A CO2-controlled ventilation system

For buildings in which the emissions from people is the main source of pollution, the number of people is the limiting factor for air ventilation. When such buildings are not used at full capacity, the ventilation, and consequently the energy consumption, is unnecessarily high. A great deal of the energy could be saved if the ventilation system could be developed to adjust the air flow to the actual requirements. One possible system would allow the amount of CO₂ in the exhaust air to control the ventilation rate. To study if this principle is practicable and economic, a CO₂ indicator has been installed in an office building in Helsinki. The mixture of exterior air and recirculated air is adjusted so that the amount of CO₂ during working hours is kept on ca 700 ppm (μL/L). The equipment was used during winter 1981-82, and the variation of CO₂ and the exterior air flow has been registered. The proportion of CO₂ has also been measured locally in order to study occasional variations that may occur. The proportion of other pollutants in the room air has been studied simultaneously with a gas chromatograph. Different types of CO₂ indicators were used to study the efficiency of the control system. The successful results indicate that the system can be used in new constructions, as well as in existing buildings.     

Soil Respiration and Carbon Storage of an Acrisol Under Forest and different Cultivations in rio de Janeiro State, Brazil

Soil respiration rates of a clay-loam textured Acrisol under different uses (Atlantic forest, manioc, horticulture and pasture) from Rio de Janeiro State were measured. The relationship between carbon dioxide (CO₂) emissions and soil physico-chemical properties were investigated. Rates of CO₂ emission of two sites (Atlantic forest and horticulture) were also evaluated in different seasons in 1997 and 1998. In the forest site, monthly means of measured respiration rates showed good correlation with soil temperature in the range 19.6–24.1°C (r² = 0.89). In the horticulture site, no change was observed with soil moisture alone, in the range 3.0–13.2 wt%. In the horticulture soil, even when the surface soil was very dry, respiration rates increased in the hot, wetter summer but remained higher than the mean flux from forest soil. The CO₂ emission flux of the Acrisol under different use showed good correlation with soil temperature (r² = 0.72) and moisture (r² = 0.61).     

Seasonal and spatial variability of Po,U and Pu levels in the river catchment area assessed by application of neural-network based classification

The present study deals with the application of self-organizing maps (SOM) in order to model, classify and interpret seasonal and spatial variability of ²¹⁰Po, ²³⁸U and ^239+240Pu levels in the Vistula river basin. The data set represents concentration values for 3 alpha emitters (²¹⁰Po, ²³⁸U and ^239+240Pu) measured in surface water samples collected at 19 different sampling locations (8 in major Vistula stream while 11 in right or left Vistula tributaries) during four seasons (winter, spring, summer and autumn) in the framework of a one-year quality monitoring study. The advantages of an SOM algorithm, its classification and visualization ability for environmental data sets, are stressed. The neural-network based classification made it possible to reveal specific patterns related to both seasonal and spatial variability. In the middle and upper part of Vistula catchment as well as in the right-shore tributaries, concentrations of ²¹⁰Po and ²³⁸U during summer and winter are the lowest. Concentrations of ²¹⁰Po and ²³⁸U increase significantly during spring and autumn in the Vistula river catchment, especially in the delta of Vistula river. High concentration of anthropogenic originated ^239+240Pu indicates “site-specific” character of pollution in two large left-shore tributaries located in the middle part of the Vistula drainage area. Efficient classification of sampling locations could lead to an optimization of river radiochemical sampling networks and to a better tracing of natural and anthropogenic changes along Vistula river stream.     

CO2 dispersion around two PWR nuclear power plants in Brazil

Atmospheric air samples were taken within 3 km from power plants encompassing five different distances and wind directions. Samples were taken between 2002 and 2005 aiming to evaluate the environmental ¹⁴C enrichment due to the operation of Brazilian nuclear power plants. The sampling system consisted of a pump connected to a trapping column filled with a 3 M NaOH solution. The trapped CO₂ was analyzed for ¹⁴C by using a single stage accelerator mass spectrometry (SSAMS).     

Chemical characteristics of precipitation and wet deposition of major ions in Liaozhong County of Liaoning Province,Northeast China

The chemical characteristics of precipitation were analyzed based on the chemical composition of principal ionic within acid rain（from February 2007 to January 2008）of Liaozhong Meteorological Station located in Malong Village in Liaozhong County of Northeast China,meteorological conditions on the corresponding period ground,and variation of several air pollutants concentration.The results indicated that:（1）The precipitation average pH value of all samples was4.76;the frequency of acid rain during the observation period was 70.7%;the frequency was 82.8%in summer and autumn.（2）In the chemical composition of precipitation,the primary anions were SO₄^2-and NO₃^-;the primary cations were NH₄⁺and Ca²⁺.（3）All concentration of anions was higher in summer and winter,but relatively low in spring and autumn.This showed that the relationship between regional rainfall acidification and pollution was not significant.（4）Rainwater acidity and nearly floor gaseous pollution concentration were different from each other,and pH and NO_x,CO,NO₂ and O₃concentrations showed significant negative correlation,but was not obvious with SO₂ concentration.However,the pH and alkaline pollutants,such as particulate,was positively correlative.     

Drugs of abuse and benzodiazepines in the Madrid Region (Central Spain): Seasonal variation in river waters,occurrence in tap water and potential environmental and human risk

This work analyzes the seasonal variation (winter and summer) of ten drugs of abuse, six metabolites and three benzodiazepines in surface waters from the Jarama and Manzanares Rivers in the Madrid Region, the most densely populated area in Spain. The occurrence of these compounds in tap water in this region is also investigated and a preliminary human health risk characterization performed for those substances found in tap water. Finally, a screening level risk assessment that combines the measured environmental concentrations (MECs) with dose–response data to estimate Hazard Quotients (HQs) for the compounds studied is also presented.The results of this study show the presence of fourteen out of the nineteen compounds analyzed in winter and twelve of them in summer. The most ubiquitous compounds, with a frequency of detection of 100% in both seasons, were the cocaine metabolite benzoylecgonine (BE), the amphetamine-type stimulant (ATS) ephedrine (EPH), the opioid methadone (METH), the METH metabolite 2-ethylene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and the three benzodiazepines investigated, namely alprazolam (ALP), diazepam (DIA) and lorazepam (LOR). The highest concentrations observed corresponded to EPH (1020 ng L^− 1 in winter and 250 ng L^− 1 in summer). The only compounds not detected in both seasons were heroin (HER) and its metabolite 6-acetylmorphine (6ACM), lysergic acid diethylamide (LSD) and its metabolite 2-oxo-3-hydroxy-LSD (O-H-LSD), and Δ⁹-tetrahydrocannabinol (THC). In terms of overall concentration, all sampling points presented higher concentrations in winter than in summer. Statistical analyses performed to gather evidence concerning occasional seasonal differences in the concentrations of individual substances between summer and winter showed statistically significantly higher concentrations (p < 0.05) of BE, EPH and the opioid morphine (MOR) in winter than in summer. Two out of the nineteen compounds studied, namely cocaine (CO) and EPH, were detected in tap water from one sampling point at concentrations of 1.61 and 0.29 ng L^− 1, respectively. The preliminary human health risk characterization showed that no toxic effects could be expected at the detected concentration level in tap water.The screening level risk assessment showed that MOR, EDDP and the THC metabolite 11-nor-9-carboxy-Δ⁹-tetrahydrocannabinol (THC-COOH) were present in at least one of the sampling sites in a concentration leading to a Hazard Quotient (HQ) value between 1.0 and 10.0, thus indicating some possible adverse effects. The cumulative HQ or Toxic units (TUs) calculated for each of the groups studied showed that opioids and cannabinoids were present at concentrations high enough to potentially generate some adverse effects on at least one sampling point.     

Movement towards a low carbon emitted environment: a test of some factors in Malaysia

There exists a high global concern in different nations on environmental sustainability especially at the focal stage of increased economic growth and development process due to high level of environmental degradation and pollution. The major aim of this study was to empirically examine how to minimise carbon emissions (CO₂) in Malaysia which are mainly caused by energy production, fossil fuel consumption, population density and economic growth. The study adopted the method of autoregressive distributed lag bound testing approach to analyse the data for the period 1971–2011. The study found that economic growth in Malaysia has a direct relationship with CO₂ emissions in both the short run and the long run. Similarly, there is a positive relationship between fossil fuel consumption and CO₂ emissions over the same period. Population density was found to have positive impacts on CO₂ emissions. Contrarily, the relationship between the activities of energy production and pollution is negative in the long run. The study recommends that a targeted GDP growth rate should be set with the consideration to avoid more environmental pollution. In addition, the positive impact of fossil fuel consumption on the environmental pollution implies that there is a need to make and implement policies that will encourage the use of public transportation system more than private transportations. That is, the unnecessary use of private vehicles should be discouraged in order to reduce the extent of fossil fuel consumption.     

A quantitative integrated assessment of pollution prevention achieved by Integrated Pollution Prevention Control licensing

This paper presents an innovative, quantitative assessment of pollution avoidance attributable to environmental regulation enforced through integrated licensing, using Ireland's pharmaceutical-manufacturing sector as a case study. Emissions data reported by pharmaceutical installations were aggregated into a pollution trend using an Environmental Emissions Index (EEI) based on Lifecycle Assessment methodologies. Complete sectoral emissions data from 2001 to 2007 were extrapolated back to 1995, based on available data. Production volume data were used to derive a sectoral production index, and determine ‘no-improvement’ emission trends, whilst questionnaire responses from 20 industry representatives were used to quantify the contribution of integrated licensing to emission avoidance relative to these trends. Between 2001 and 2007, there was a 40% absolute reduction in direct pollution from 27 core installations, and 45% pollution avoidance relative to hypothetical ‘no-improvement’ pollution. It was estimated that environmental regulation avoided 20% of ‘no-improvement’ pollution, in addition to 25% avoidance under business-as-usual. For specific emissions, avoidance ranged from 14% and 30 kt a^− 1 for CO₂ to 88% and 598 t a^− 1 for SO_x. Between 1995 and 2007, there was a 59% absolute reduction in direct pollution, and 76% pollution avoidance. Pollution avoidance was dominated by reductions in emissions of VOCs, SO_x and NO_x to air, and emissions of heavy metals to water. Pollution avoidance of 35% was attributed to integrated licensing, ranging from between 8% and 2.9 t a^− 1 for phosphorus emissions to water to 49% and 3143 t a^− 1 for SO_x emissions to air. Environmental regulation enforced through integrated licensing has been the major driver of substantial pollution avoidance achieved by Ireland's pharmaceutical sector — through emission limit values associated with Best Available Techniques, emissions monitoring and reporting requirements, and performance targets specified in environmental management plans. This compliant sector offers a positive, but not necessarily typical, case study of IPPC effectiveness.     

Investigation of volatile organic compounds and phthalates present in the cabin air of used private cars

The presence of selected volatile organic compounds (VOCs) including aromatic, aliphatic compounds and low molecular weight carbonyls, and a target set of phthalates were investigated in the interior of 23 used private cars during the summer and winter. VOC concentrations often exceeded levels typically found in residential indoor air, e.g. benzene concentrations reached values of up to 149.1 µg m^− 3. Overall concentrations were 40% higher in summer, with temperatures inside the cars reaching up to 70 °C. The most frequently detected phthalates were di-n-butyl-phthalate and bis-(2-ethylhexyl) phthalate in concentrations ranging from 196 to 3656 ng m^− 3.     

Persistence of radon-222 flux during monsoon at a geothermal zone in Nepal

The Syabru-Bensi hydrothermal zone, Langtang region (Nepal), is characterized by high radon-222 and CO₂ discharge. Seasonal variations of gas fluxes were studied on a reference transect in a newly discovered gas discharge zone. Radon-222 and CO₂ fluxes were measured with the accumulation chamber technique, coupled with the scintillation flask method for radon. In the reference transect, fluxes reach exceptional mean values, as high as 8700 ± 1500 g m⁻² d⁻¹ for CO₂ and 3400 ± 100 × 10⁻³ Bq m⁻² s⁻¹ for radon. Gases fluxes were measured in September 2007 during the monsoon and during the dry winter season, in December 2007 to January 2008 and in December 2008 to January 2009. Contrary to expectations, radon and its carrier gas fluxes were similar during both seasons. The integrated flux along this transect was approximately the same for radon, with a small increase of 11 ± 4% during the wet season, whereas it was reduced by 38 ± 5% during the monsoon for CO₂. In order to account for the persistence of the high gas emissions during monsoon, watering experiments have been performed at selected radon measurement points. After watering, radon flux decreased within 5 min by a factor of 2–7 depending on the point. Subsequently, it returned to its original value, firstly, by an initial partial recovery within 3–4 h, followed by a slow relaxation, lasting around 10 h and possibly superimposed by diurnal variations. Monsoon, in this part of the Himalayas, proceeds generally by brutal rainfall events separated by two- or three-day lapses. Thus, the recovery ability shown in the watering experiments accounts for the observed long-term persistence of gas discharge. This persistence is an important asset for long-term monitoring, for example to study possible temporal variations associated with stress accumulation and release.     

Interactions between diesel emissions and gaseous copollutants in photochemical air pollution: Some health implications

A complete assessment of the health effects of diesel emissions must take into account the possible chemical transformations (and associated biological impacts) of particulate organic matter (POM) due to reactions with the many gaseous copollutants which have now been unambiguously demonstrated to be present in atmospheres burdened by photochemical air pollution. These copollutants include the “trace” species, nitric (HNO₃) and nitrous (HONO) acids, the nitrate radical (NO₃), formaldehyde (H₂CO) and formic acid (HCOOH), as well as the criteria pollutants, ozone (O₃) and nitrogen dioxide (NO₂). Techniques for establishing the atmospheric concentrations of the trace pollutants (and their spatial and temporal variations) are briefly described, and we present results of investigations into the reactions of polycyclic aromatic hydrocarbons (PAH) coated on filters and exposed to ambient concentrations of O₃ and NO₂. Environmental health implications of these results are discussed and include the potential for sampling “artifacts” and their possible effects on the correlation (or lack thereof) between ambient PAH levels and urban lung cancer rates, as well as the problems associated with understanding the appropriate POM “dose” to be employed in animal testing and assessments of impacts on human health.     

The effect of tropopause height on the content of radioactive debris in surface atmosphere

The effect of tropopause height on the content of ¹³⁷Cs and total beta activity in surface atmosphere was considered for the period of intensive nuclear weapon tests, from 1968–1971. The activity of ¹³⁷Cs in monthly air filter samples was measured by gamma spectrometry and total beta activity was determined by 2π proportional counters. The results were correlated with data on tropopause height. The results indicate that the movement of radioactive debris from the stratosphere into the troposphere occurs simultaneously with the changes in tropopause height. The content of long lived radionuclides in the troposphere follows the changes with a certain delay due to meteorological conditions in surface air and due to the location of sampling.     

High resolution exposure modelling of heat and air pollution and the impact on mortality

BackgroundElevated temperature and air pollution have been associated with increased mortality. Exposure to heat and air pollution, as well as the density of vulnerable groups varies within cities. The objective was to investigate the extent of neighbourhood differences in mortality risk due to heat and air pollution in a city with a temperate maritime climate.MethodsA case-crossover design was used to study associations between heat, air pollution and mortality. Different thermal indicators and air pollutants (PM₁₀, NO₂, O₃) were reconstructed at high spatial resolution to improve exposure classification. Daily exposures were linked to individual mortality cases over a 15 year period.ResultsSignificant interaction between maximum air temperature (Ta_max) and PM₁₀ was observed. During “summer smog” days (Ta_max > 25 °C and PM₁₀ > 50 μg/m³), the mortality risk at lag 2 was 7% higher compared to the reference (Ta_max 15 °C and PM₁₀ 15 μg/m³). Persons above age 85 living alone were at highest risk.ConclusionWe found significant synergistic effects of high temperatures and air pollution on mortality. Single living elderly were the most vulnerable group. Due to spatial differences in temperature and air pollution, mortality risks varied substantially between neighbourhoods, with a difference up to 7%.     

Land use and energy scenarios affecting the global carbon cycle

Past increase of atmospheric CO₂ involves significant contributions from both fossil and biospheric sources. The latter are controversial, partly because these CO₂ releases may be balanced by accelerated regrowth following clearing of some forests, while others were being converted to agricultural or other nonforest land. A simulation model was used to reconstruct changes since 1860 and project four hypothetical future scenarios of CO₂ injection to 2460. Nineteen compartments and their exchanges of carbon were considered. Areal extents of tropical forests, other wooded ecosystems, and nonforests were incorporated into the model. Rapidly and slowly exchanging pools of carbon per unit area were projected by integrating income-loss differential equations numerically. Estimated cumulative releases of CO₂ from fossil fuels (plus cement) near 120 Pg of carbon (1 Pg = 10¹⁵ g) from 1860 to 1970 were assumed to equal the prompt plus delayed releases due to forest clearing. Limits of exploitable forest area and biomass were evaluated and found to contribute much less future CO₂ than usable fossil fuels. Ultimate release from the latter (7500±2500 Pg C) could increase atmospheric CO₂ manyfold: doubling the assumed 1860 levels as early as (1) the year 2032 for assumed early fossil-use scenarios and (2) the year 2045 for late fossil-use scenarios. Depending on the poorly known parametes that were programmed to constrain the organic production rates, cumulative storage, and the response of plants and soils to enhanced atmospheric CO₂, biospheric storage might reach higher levels for all scenarios than the estimates given here. However, maximizing such storage in real life would require much closer understanding and wiser management of ecosystems than history has shown.     

A study of effects of ambient urban air pollution using personal samplers; a preliminary report

Air pollution has been associated with an increased incidence of respiratory disease. However, significant differences may exist between air pollution levels measured at conventional fixed monitoring stations and actual levels inhaled by a subject. Furthermore, studies of effects of air pollution might best be done using asthmatics as study subjects, since they have irritable airways. This is a preliminary report of a study using a control and asthmatic group in which effects of air pollution are assessed by sympton and medication diaries and simple pulmonary function tests. Air pollution exposure is measured using a small portable sampler for particulates, SO₂ and NO₂; these samplers are carried by the subject (“personal”) and are situated inside and outside the home. Levels obtained are compared to data obtained from the same type of sampler located at a fixed monitoring station. Preliminary analysis of the data shows that the levels of pollutants are low and there are significant differences between the four air pollution measurements, with weak correlations among the various measurements. In this preliminary report, change in pulmonary function during the day correlates only with personal NO₂ measurements. This suggests the need for estimating air pollution exposure using “personal” samplers, when investigating health effects.     

The Potential of Soil Carbon Sequestration Through Improved Management Practices in Norway

The study was conducted to assess the potential of Norwegian agricultural ecosystems to sequester carbon (C) based on the data from some long-term agronomic and land use experiments. The total emission of CO₂ in Norway in 1998 was 41.4 million metric ton (MMT), of which agriculture contributed only 0.157 MMT, or <0.4% of the total emissions. With regards to methane (CH₄) and nitrous oxide (N₂O) gases, however, agricultural activities contributed 32.5% and 51.3% of their respective emissions in Norway. The soil organic carbon (SOC) losses associated with accelerated soil erosion in Norway are estimated at 0.475 MMTC yr^–1. Land use changes and soil/crop management practices with potential for SOC sequestration include conservation tillage methods, judicious use of fertilizers and manures, use of crop residues, diverse crop rotations, and erosion control measures. The potential for SOC sequestration is 0.146 MMTC yr^–1 for adopting conservation tillage, 0.011–0.035 MMTC yr^–1 for crop residue management, 0.026 MMTC yr^–1 for judicious use of mineral fertilizer, 0.016–0.135 MMTC yr^–1 for manure application, and 0.036 MMTC yr^–1 for adopting crop rotations. The overall potential of these practices for SOC sequestration ranges from 0.591 to 1.022 MMTC yr^–1 with an average value of 0.806 MMTC yr^–1. Of the total potential, 59% is due to adoption of erosion control measures, 5.8% to restoration of peat lands, 21% to conversion to conservation tillage and residue management, and 14% to adoption of improved cropping systems. Enhancing SOC sequestration and improving soil quality, through adoption of judicious land use and improved system of soil and crop management, are prudent strategies for sustainable management of soil, water and environment resources.Readers should send their comments on this paper to: bhaskarn ath@aol.com within 3 months of publication of this issue.