Analysis of Air Quality Parameters in Csongrád County
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ACTA CLIMATOLOGICA ET CHOROLOGICA Universitatis Szegediensis, Tom. 34-35, 2001, 23-44. ANALYSIS OF AIR QUALITY PARAMETERS IN CSONGRÁD COUNTY L. MAKRA1, SZ. HORVÁTH1, A. ZEMPLÉNI2, V. CSISZÁR2, ZS. FODRÉ3, 3 4 1 BUCSINÉ I. KAPOCSI , G. MOTIKA and Z. SÜMEGHY 1Department of Climatology and Landscape Ecology, University of Szeged, H-6701 Szeged, P.O.B. 653, Hungary; E-mail: [email protected] 2Department of Probability Theory and Statistics, Eötvös Loránd University, H-1053 Budapest, Kecskemeti u. 10-12, Hungary 3State Health and Medical Service for Csongrád County; H-6726 Szeged, Derkovits fasor 7-11, Hungary 4Environmental Protection Inspectorate of Lower-Tisza Region, H-6701 Szeged, P.O.B.1048 Összefoglalás - A tanulmány célja a légszennyező paraméterek időbeli jellemzőinek és statisztikai kölcsönhatásainak vizsgálata Szegeden és Csongrád megyében. Néhány állomás NO2- és SO2-koncentráció idősoraira szélsőérték modelleket illesztünk, s e modellekre alapozva kiszámítjuk a visszatérési időket, azaz a vizsgált két paraméter adott együttes maximális koncentrációit meghaladó értékek jövőbeni legkorábbi együttes bekövetkezéséig terjedő időszakokat. A dolgozatban a vizsgált állomások havi átlagos NO2- és SO2- koncentrációinak, valamint az ülepedő por havi összegeinek idősorait elemezzük. Az adatok - az egyes légszennyező paraméterektől függően - 1985-től állnak rendelkezésre. Az egyes idősorok szerinti trendanalízis eredményei alapján nem tudunk egyértelmű térbeli rendszert kimutatni, mivel egyrészt a szignifikáns trendek periódusai eltérő előjelűek, másrészt az azonos előjelű szignifikáns trendek periódusai eltérők. Alkalmazzuk a kétmintás t-próba egy speciális esetét is, melyet Makra fejlesztett ki. Ez a próba lehetővé teszi annak eldöntését, hogy szignifikáns eltérés van-e két nem független, normális eloszlású minta középértékei között? E próba felhasználásával végzett ún. szakadásvizsgálat szerint az ülepedő por havi összegeinek idősora szignifikáns negatív előjelű szakadást mutat az idősor végén. A vizsgált paraméterek térbeli kapcsolatait faktoranalízis segítségével elemeztük. A célunk az volt, hogy az NO2- és SO2-koncentrációk, valamint az ülepedő por idősorai alapján objektív alrégiókat határolhassunk körül. A légszennyezők arányai a gépjárműforgalom lényeges szerepére utalnak. A forgalom változásai jelentős mértékben hozzájárulnak a levegőminőség napi változásához. Summary - The aim of the study is to determine partly spatial and temporal characteristics, partly statistical interrelationships concerning contaminating parameters at the town of Szeged and in Csongrád county. We also fit extreme-value models to the NO2 and SO2 concentrations observed at some stations and calculate return levels, which are about to be exceeded once in a given period, based on these models. Monthly averages for NO2 and SO2 concentrations and monthly totals for deposited particulates at given sites are analysed in this paper. Data have been available, depending on the pollutants, since at least 1985. Local trend analysis does not show a clear spatial structure among the sites since signs of significant periods are different and significant periods of the same sign are not similar among the sites. A special case of the two-sample t-test developed by Makra is also applied. This test makes it possible to determine whether or not averages of non-independent variables differ significantly. By using this test we made a so called tear analysis, according to which it was found that monthly totals of deposited dust tore considerably with negative signs at the end of the data sets. Spatial relations are analysed by factor analysis with the intention to determine objective subregions by applying data sets of NO2, SO2 and deposited dust. Ratios of pollutants refer definitely to the role of motor vehicle traffic. Variation of traffic contributes mostly to the change in daily air quality. Key words: air pollutants, RIE-network, monitoring station, trend analysis, a special case of the two-sample t-test, extreme value analysis, factor analysis 23 László Makra, Szilvia Horváth, András Zempléni, Villő Csiszár, Zsófia Fodré, Irén Bucsiné Kapocsi, Gábor Motika & Zoltán Sümeghy INTRODUCTION Air pollution is one of the greatest environmental problems facing mankind. In many urban areas large concentration of human activities induce considerable amounts of pollutants to be accumulated. As it is well known, the main pollution sources are motor vehicle traffic, which heavily affects air quality in densely urbanized regions, and emissions from building heating systems contribution of which is important in the winter months. Air pollution is harmful to the buildings, technical devices and may cause serious health damage, as well. The nature and importance of air quality problems depend on geographical (climate, local meteorological conditions at the moment, position, relief) and social (existing environmental regulations, urban planning choices) factors. Research of urban air has a wide literature. According to the subject of the papers the authors can make an analysis on characteristics of pollutants (e.g. Morawska et al., 1998), others deal with spatial and temporal variety of those (e.g. Hastie et al., 1996; Tripathi et al., 1996) or investigate statistical interrelationships among variability of pollutants (e.g. Spicer et al., 1996) or examine social policy on regulating emissions (e. g. Chin, 1996; Fang and Chen, 1999) or study connection of air pollution with meteorological components (e.g. + Kassomenos et al., 1995) or / evaluate urban air quality using + special methods (e.g. Angius et al., 1995) and special air quality + - - indicators (e.g. Kassomenos et al., + + * 1999). The aim of the present - study, considering the above a - z s i mentioned classification, is T complex: to determine partly spatial and temporal Fig. 1a Geographical position of Szeged, Hungary and built- up types of the city (Unger, 1997) characteristics, partly statistical (a : centre (2-4-storey buildings); b: housing estates with interrelationships concerning prefabricated concrete slabs (5-10-storey buildings); c: detached contaminating parameters and to houses (1-2-storey buildings); d: industrial areas; e: green areas; ∅ : analyze their connection with automatic environmental monitoring station; + : sites of meteorological elements. The measurements for SO , NO and deposited dust; * : site of 2 2 analysis is made on the data of a measurements for SO2 and NO2 only; - : sites of measurements for deposited dust only; +, *, - : RIE-network) middle-sized town, Szeged. The 24 Analysis of air quality parameters in Csongrád county analysis is made on the data sets of 9 settlements in Csongrád county (Fig. 1b), with special interest to the middle-sized town, Szeged, which is the largest city in the county. GEOGRAPHICAL POSITION, METEOROLOGY AND TOPOGRAPHY OF SZEGED AND CSONGRÁD COUNTY Szeged lies at approximately 20°06'E and 46°15'N near the confluence of the Tisza and Maros rivers. It is the largest town in the south-eastern part of Hungary. The city is flat and low (79 m above sea level), therefore its climate is free from orographical effects (Fig. 1a). Consequently its geographical conditions are favourable for the development of an undisturbed urban climate. The number of inhabitants of the city is up to 155,000 and the surface of its built-up area is about 46 km2. The total urban spread extends well beyond the city limits and includes north of the town the largest oil field in Hungary with several oil torches. This oil field is a significant source of NOx and sulfur dioxide. The power station, located in the western part of the town, and motor vehicle emissions have largely contributed to the nitrogen oxide levels in Szeged. Most territory of Hungary Körös za (including Csongrád county and is T Szeged agglomeration) are characterized in climatic classification of Köppen by Cf CSONGRÁD 0102030 kmclimate (temperate warm climate a z s i T with quite equal distribution of Lake Csaj KISTELEK precipitation amounts) or in that of HÓDMEZŐ- VÁSÁRHELY Trewartha by D.1 climate Lake Fehér (continental climate with a long Algyő warm season). Urban air quality Zákányszék Maroslele Maros SZEGED MAKÓ basically differs depending on the a Ásotthalom z is T meteorological elements. The averages for those in Szeged region are as follows. Mean annual Fig. 1b Geographical position of the measuring stations temperature is 11.2°C while mean in Csongrád county January and July temperatures are - 1.2°C and 22.4°C, respectively. As for yearly averages, the annual precipitation is 573 mm, the relative humidity is 71%, the windspeed is 3.2 m s-1, and the sunshine duration is 2102 hours. A detailed climatic classification for Hungary is based on the mean temperature of the growth season (tVS) and the aridity index (H) (where H = Q*/LvP and Q* is the annual mean net radiation and Lv is the latent heat of vaporization and P is the annual mean precipitation). According to these physical climatological characteristics climate of Szeged is warm-dry with tVS > 17.5°C and H > 1.15. The basis of the city structure is a boulvard-avenue street system crossed by the River Tisza (Fig. 1a). In this way the structure of the city is simple however, following to this system, motor vehicle traffic as well as air pollution are concentrated in the city. The industrial area is located mainly in the north-west part of the town. Thus the prevailing 25 László Makra, Szilvia Horváth, András Zempléni, Villő Csiszár, Zsófia Fodré, Irén