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Distribution of volatile organic compounds in Madrid (Spain) Полный текст
1999
Pérez-Pastor, Rosa María | García-Alonso, Susana | Cabezas, Alberto José Quejido
From November 1995 to October 1996, airborne concentrations of VOCs were measured in the Madrid area to study the organic pollution in general, and the correlation between different pollutants in relation to such parameters as location and season. Mean concentrations for up to 90 compounds were measured at four test sites, including both urban and suburban areas.At the urban sites, maximum concentrations occurred in the autumn and winter, whereas minimum concentrations were reached in summer and spring. Similar changes were obtained for the lesscontaminated site located in the SE of the city, whereas a different pattern was found at the site in the NW of the city due to meteorological aspects. Mean levels of hydrocarbons in Madrid were quite similar to those found in other European cities.Chemometrical techniques were applied to the set of data in order to assess the influence of such factors as traffic, temperature and seasonal variations on the VOC levels.
Показать больше [+] Меньше [-]The variation of street air levels of PAH and other mutagenic PAC in relation to regulations of traffic emissions and the impact of atmospheric processes Полный текст
1999
Nielsen, Torben | Feilberg, Anders | Binderup, Mona-Lise
The occurrence of particle associated PAH and other mutagenic PAC was determined in 1996 in the street air of Copenhagen. In addition, particle extracts were tested for mutagenicity. The measurements were compared with previous measurements in 1992/1993. The levels had decreased in this period. The decrease was caused by an implementation of light diesel fuels for buses and the exchange of older petrol-driven passenger cars with catalystequipped new ones. About 65% of the reduction was caused by the application of the light diesel fuels. Under special conditions, chemical processes in the atmosphere produced many more mutagens than the direct emissions. The concentrations of S-PAC and N-PAC were 10 times lower than those of PAH, while the levels of oxy-PAH were in the same order of magnitude as those of PAH. Benzanthrone, an oxy-PAH, is proposed to be formed in the atmosphere in addition to direct emissions. Benzo(a)pyrene, often applied as an air quality criteria indicator, was photochemically degraded in the atmosphere. A strong increase in the mutagenic activities was observed to coincide with a depletion of benzo(a)pyrene.
Показать больше [+] Меньше [-]Measurements of selected PCBs in open urban ambient air of Madrid (Spain) : First results Полный текст
1999
García-Alonso, Susana | Pérez-Pastor, Rosa María | Sevillano-Castaño, María Luisa
The focus of this study was to characterize the concentration levels of selected PCBs and compare them to compiled data in order to contribute to the international database. The sampling site is located in the outskirts of Madrid and can be considered an open urban area. 32 samples of air were taken from February 1998 to June 1998 by using a high volume air sampler. Glass fiber filters and polyurethane foam (PUF) were used to collect the paniculate and gas phase material, respectively.PUF plugs were Soxhlet extracted and filters were ultrasonically extracted by using pesticide-grade hexane and dichloromethane, respectively. The cleanup procedure was carried out on a florisil column with hexane and hexane/dichloromethane as elution solvents.GC/MS in a selected ion monitoring mode was used for quantification and 29 selected PCBs congeners were analyzed.
Показать больше [+] Меньше [-]Assessing the effects of international emissions reduction scenarios to combat the acidification of freshwaters in Great Britain with the First-order Acidity Balance (FAB) model and the Hull Acid Rain Model (HARM)
1999
Curtis, C.J. | Whyatt, J.D. | Metcalfe, S.E. | Allott, T.E.H. | Harriman, R.
Effect-based control strategies: what do we need in the future?
1999
Grennfelt, P.
How are results from critical load calculations reflected in lake water chemistry?
1999
Wilander, A. (SLU, Uppsala (Sweden))
Investigation of the uncertainties and assumptions in the Simple Mass Balance equation for acidity critical loads
1999
Hall, J. | Hornung, M. | Kennedy, F. | Langan, S. | Reynolds, B. | Aherne, J.
The link between the exceedance of acidity critical loads for freshwaters and biological damage: a re-interpretation
1999
Curtis, C.J. (ECRC, London (UK)) | Reynolds, B. | Allott, T.E.H. | Harriman, R.
Aluminum biogeochemistry in two Czech catchments with contrasting lithology subject to chronic acidic deposition
1999
Kram, P. | Hruska, J. (Czech Geological Survey, Prague (Czech Republic)) | Driscoll, C.T. | Johnson, C.E.
Can the division sum (Ca + K + Mg divided by Al) ratio be used as a predictive tool for estimating forest damages?
1999
Goeransson, A. (SLU, Uppsala (Sweden))