Open AccessFinding regions of influence on SO<sub>2</sub> and SO<sup>=</sup><sub>4</sub> daily concentration measurements at four sites in Spain
Author(s) -
E. Hernández,
António Rua,
R. H. Méndez,
Luis Gimeno
Publication year - 1996
Publication title -
annales geophysicae
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.522
H-Index - 93
eISSN - 1432-0576
pISSN - 0992-7689
DOI - 10.1007/s00585-996-0853-5
Subject(s) - homogeneous , homogeneity (statistics) , pollution , environmental science , pollutant , atmospheric sciences , air quality index , air pollution , aerosol , meteorology , statistics , mathematics , geography , physics , chemistry , ecology , organic chemistry , combinatorics , biology
Contamination by the pollutants SO2and SO=4 was analyzed for the 1989–1992 period at fourregional stations in Spain under the auspices of the EMEP-BAPMON program. Theevolution of the time series of the daily pollution has also been assessed, andhigh mean concentrations at La Cartuja and Logroño observed, with values of 3.8and 4.5 μg m–3 for SO2, respectively. Maximumannual concentrations were recorded in 1989, when SO2 reached valuesof 6.24, 5.39, 5.71, and 9.30 μg m–3 for the stations of LaCartuja, San Pablo de los Montes, Roquetas, and Logroño, respectively. Thiswork attempts to establish a relationship between the concentrations of thepollutants – both SO2 gas and SO=4 aerosol –and the zones of emission or persistence of these long-range transportedpollutants. In this way, those regions showing a greater impact on the airquality in each season have been determined. To achieve this, the trajectoriesof the air masses carrying away the pollution to each of the receiving stationswere considered and followed by a sectorial analysis. Nonparametric statisticalmethods were implemented to contrast the chemical homogeneity among thedifferent sectors. The criterion that several homogeneous sectors form achemically homogeneous region was used. To improve this sectorial analysis, wehave proposed a new technique based on the Potential-Source-ContributionFunction (PSCF). Starting out from a set of specified regions, considered to bechemically homogeneous domains, it is possible to determine the likelihood thatan air mass with particular characteristics (e.g., that a value of the dailyconcentration higher than the mean recorded at the station has been obtained)will arrive at a given station after having crossed one of the previouslydefined regions. Using this technique, it is possible to determine the sourceregions through which the air masses circulate and bring high pollutionconcentrations to the studied stations. Thanks to the PSCF, these statisticalmethods offer, through a sectorial analysis, the possibility to pass from aqualitative to a more quantitative view