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1 This article was downloaded by: [Politechnika Gdanska] On: 26 May 2013, At: 23:03 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: Registered office: Mortimer House, Mortimer Street, London W1T 3JH, UK International Journal of Environmental Analytical Chemistry Publication details, including instructions for authors and subscription information: Application of passive sampling technique in monitoring research on quality of atmospheric air in the area of Tczew, Poland Mariusz Marć a, Bożena Zabiegała a & Jacek Namieśnik a a Department of Analytical Chemistry, Gdansk University of Technology, Narutowicza Str. 11/12, Gdansk, PL, , Poland Published online: 24 May To cite this article: Mariusz Marć, Bożena Zabiegała & Jacek Namieśnik (2013): Application of passive sampling technique in monitoring research on quality of atmospheric air in the area of Tczew, Poland, International Journal of Environmental Analytical Chemistry, DOI: / To link to this article: PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae, and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand, or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

2 Intern. J. Environ. Anal. Chem., Application of passive sampling technique in monitoring research on quality of atmospheric air in the area of Tczew, Poland Mariusz Marć, Bożena Zabiegała and Jacek Namieśnik Department of Analytical Chemistry, Gdansk University of Technology, Narutowicza Str. 11/12, PL , Gdansk, Poland (Received 28 December 2012; final version accepted 20 March 2013) This paper presents the results of atmospheric air quality research in Tczew (adjacent to the Vistula River) on the content of BTEX compounds. procedure applied during the sampling of the analytes from the air used the passive sampling technique (diffusive passive sampler, Radiello ). For determination of BTEX compounds in atmospheric air, two-stage thermal desorption technique combined with gas chromatography (TD-GC-FID) was applied. Research was conducted from March to December The annual average concentration of benzene, toluene, ethylbenzene and total xylenes determined in atmospheric air for the monitoring period were: 0.87 μg m 3, 2.9 μg m 3, 1.3 μg m 3 and 5.9 μg m 3, respectively. In order to pre-identify potential sources of emissions of BTEX compounds, statistical analysis was carried out. This determined interactions between specified concentration levels of BTEX compounds in atmospheric air for the monitored area. Keywords: urban air monitoring; atmospheric air quality; BTEX compounds; passive sampling technique; Radiello diffusive passive sampler 1. Introduction A review of literature published over the last decade suggest that the monitoring of atmospheric air quality in urbanised areas is a type of analytical research, with growing importance, therefore it is carried out by various research centres on a local, regional and global scale. One of the main objectives of these tests is to determine VOCs chemical compounds present in atmospheric air, with special regard to BTEX compounds (benzene, toluene, ethylbenzene and xylenes (o-, m-, p-xylene)) [1 6]. According to information contained in scientific literature BTEX compounds are considered to be indicators of the level of human exposure to chemicals from the VOCs group [7,8] and precursors of secondary air pollutants such as tropospheric ozone [9 11]. Main sources of emissions of BTEX compounds into atmospheric air in urbanised areas may be [12 15]: combustion of fossil fuels in municipal (local) coal fired boiler plants and old-style domestic ovens, motor vehicles equipped with gasoline and diesel engines (combustion of liquid fuels in motor vehicles engines), evaporation of liquid fuel directly into atmospheric air. Prolonged human body exposure to harmful organic compounds (including BTEX compounds) present in atmospheric air may lead to an increase in risk of serious diseases of the *Corresponding author. bozena.zabiegala@pg.gda.pl 2013 Taylor & Francis

3 2 M. Marć et al. cardiovascular, respiratory and nervous systems and may be a cause of cancer (e.g. leukemia) for those exposed. [16,17]. As a result of carcinogenic properties (identified as human carcinogens by experts from International Agency for Research on Cancer) [18], special attention is paid to the determination of benzene concentration in atmospheric air. This compound, being the only one from the BTEX compounds group, is subject to legal regulations defined in EU Directive (EU directive 2000/69/EC for 2010), in accordance with which the average annual benzene concentration in atmospheric air shall not exceed 5 μg m 3 [19]. Contrary to appearances, monitoring content of BTEX compounds in atmospheric air is not straightforward, owing to: very low levels of analyte content in the group of compounds, possible essential fluctuations in concentrations (time and space fluctuations) chances of interference, limited access to relevant reference materials necessary for the purpose of assuring an adequate level of QA/QC. One can distinguish three procedures in terms of analytics and monitoring of BTEX compounds in atmospheric air [20 29]: collection of air samples to applicable containers made of such materials as: Tedlar, Teflon, Nalofan or stainless steel and carrying out determination in suitably equipped laboratories, collection of analyte samples into applicable sorption media and determination of the amount of analytes retained on sorption medium or in a cryogenic trap (using thermal desorption technique) by means of introducing them with the use of a carrier gas stream into a gas chromatographic system, direct and continuous measurement of the concentration level for BTEX compounds as a result of applying relevant automatic monitors and analysers in the form of stationary devices (measuring sets installed on monitoring stations) and mobile appliances (portable and transportable). Use of the passive sampling technique at the stage of isolation and/or enrichment of analyte samples from gaseous mediums has recently proved popular in terms of monitoring concentration levels of BTEX compounds in atmospheric air. Application of the passive sampling technique allows for collection of integrated samples of analytes from atmospheric air in a few measuring points simultaneously (also including distant and hard to reach places), without the necessity of using an external source of power supply. In comparison to dynamic techniques of collecting analyte samples from atmospheric air, application of the passive sampling technique does not require the presence of qualified personnel and financial contributions related to purchase of special, often very expensive, measuring equipment essential for the purposes of carrying out insitu operations. Additionally, the selection of adequate sorption medium allows for selective determination of chemical compounds or group of compounds present in atmospheric air [30 33]. This article presents information related to the programme of monitoring research for determination of the levels of BTEX compounds in atmospheric air, as well as the results of measurements carried out with the use of the analytical procedure. At the stage of isolation and/ or enrichment of analyte samples from atmospheric air, the passive sampling technique was used (Radiello diffusive passive sampler). To liberate the analytes retained on the sorption bed, the two-stage thermal desorption technique was applied. Research was carried out from March to December 2011 in the medium-sized urbanised area ( inhabitants) of Tczew (adjacent

4 International Journal of Environmental Analytical Chemistry 3 to the Vistula River), located close to one of the main railway and road communication junctions in northern Poland (A1 highway and national road 91) and Tricity agglomeration (Gdansk, Gdynia and Sopot). The area of Tricity and its surroundings is one of the most industrialised regions in northern Poland. Its industry mostly comprises shipbuilding as well as many other big industrial enterprises, the activity of which fundamentally impacts atmospheric air quality (Gdansk Oil Refinery Grupa Lotos S. A, Phosphorus Fertilizer Manufacturing Plant Gdańskie Zakłady Nawozów Fosforowych Fosfory S. A, sulfur-processing plants Siarkopol Gdansk S.A, Heat and Power Generating Station Elektrociepłownia Wybrzeże S. A and loading harbours). In the neighbourhood of Tricity agglomeration, pharmaceutical plants of Polpharma S. A. (Starogard Gdański) and main communication junctions make the quality of atmospheric air in the area of Tczew affected not only by local emission sources, but also by pollution loads transported from the areas of Tricity agglomeration and main communication junctions. The results obtained have served as a basis for identification of potential sources of emission of the BTEX compounds group, emitted to atmospheric air in the area of Tczew. 2. Experimental 2.1. Characteristic of BTEX sampling site In order to determine the BTEX compounds in atmospheric air in the area of Tczew, the location of the stationary monitoring station (AM '09"N, 18 47'15"E) was used as the place for collection of analyte samples (Figure 1). The owner of the stationary monitoring station is Figure 1. Location of the air quality monitoring station (AM7) in Tczew, Poland.

5 4 M. Marć et al. Agency of Regional Air Quality Monitoring Foundation in the Gdansk Metropolitan Area (ARMAAG). In the neighbourhood of AM7 monitoring station infrastructure elements such as railway (the route joining the northern part of Poland with the southern one) and the main urban communication junction (Wojska Polskiego Street) are located. Additionally in the direct neighbourhood of AM7 monitoring station the company dealing with municipal and industrial wastes management is located. The period for samples collection of BTEX compounds from atmospheric air covered months from March to December Detailed information regarding meteorological conditions present in the period of samples collection in the areas surrounding AM7 monitoring station in Tczew were taken from the data bases of ARMAAG Foundation ( pl). Meteorological data are the supplement to the information obtained from monitoring research on the quality of atmospheric air. Knowledge about atmospheric air temperature, humidity, dominant wind direction and strength influences on the assessment of the passive sampler operation (atmospheric air temperature influences on diffusive speed of mass transfer) as well as on adequate interpretation of results obtained from research aimed at determination of content level for BTEX compounds in atmospheric air Characteristic of sampling technique At the stage of isolation and/or enrichment of BTEX compounds from the atmospheric air, a cylindrical diffusive passive sampler, Radiello (Fondazione Salvatore Maugeri, Padova, Italy) was applied. The sorption medium of Radiello diffusive passive sampler, is a synthetic adsorbent (Carbograph 4) placed inside the tube made of stainless steel net. The tube is placed in a cylindrical diffusive body made of microporous polyethylene (diffusion membrane). The structure of Radiello diffusive passive sampler used for isolation and/or enrichment of BTEX compounds from atmospheric air is presented in Figure 2. Detailed information about the given parameters related to the structure of Radiello diffusive passive sampler is included in Table 1. In order to protect Radiello diffusive passive sampler against adverse impact of atmospheric conditions (rainfall, intensive insolation, and strong wind), the samplers were placed in a Figure 2. Scheme of Radiello diffusive passive sampler: 1 diffusion membrane; 2 stainless steel net cylindrical cartridge filled with sorption medium.

6 International Journal of Environmental Analytical Chemistry 5 Table 1. Characteristics of Radiello diffusive passive sampler used in atmospheric air monitoring. Radiello diffusive passive sampler Parameter Diffusion membrane Length External diameter Thickness Porosity Diffusion zone length Parameter Material Sorption medium Sorption medium mass Length External diameter The technique of liberating the analytes retained on the sorption medium Diffusive membrane Microporous sintered polyethylene 60 mm 16 mm 5 mm 10 ± 2 μm 150 mm Cylindrical cartridge Stainless steel net Carbograph 4 (graphitised charcoal mesh) 300 ± 10 mg 60 mm 4.8 mm Two-stage thermal desorption cage made of stainless steel (Figure 3) at the height of ca. 3 m. Each time, inside the cage, two Radiello diffusive passive samplers were installed at the distance of 20 cm from each other, which allowed elimination of the competitiveness effects between the passive samplers (starvation effect). The exposure time for the passive samplers installed on AM7 monitoring station in Tczew amounted to 14 days. Transport of BTEX compounds from atmospheric air to the inside of the passive sampler takes place by means of free diffusion of analytes via diffusion membrane to the sorption medium (Carbograph 4), in which the analytes are retained. In order to determine the concentration of BTEX compounds in atmospheric air using the passive sampling technique, an equation based on Fick s first law of diffusion is applied [34 36]. Detailed description of the rule of the passive samplers of diffusion type operation (based on using the phenomenon of free Figure 3. A general view of the stainless steel cage with diffusive passive samplers installed at ARMAAG air quality monitoring station in Tczew (AM7).

7 6 M. Marć et al. analyte mass transport) and equations describing the rate of the analyte mass transfer towards sorption medium of the passive sampler can be found in many literature sources published in the last few years [37 42]. After the end of specified exposure time, the cylindrical tube with the sorption bed with the adsorbed analytes is removed from the diffusion element of Radiello diffusive passive sampler, closed in a glass container with tight polyethylene cap and transported to the analytical laboratory. The storage time for the cylindrical tube with the sorption bed in the glass container at a temperature of ca. 5 C before final determination stage did not exceed 72 hours. During the monitoring campaign from March to December 2011, days exposure were carried out. Each time, two Radiello diffusive passive samplers were exposed simultaneously at the sampling site for 14 days (ARMAAG Foundation monitoring station AM7 in Tczew). This gave a total of 40 samples during the monitoring campaign 2.3. Analytical procedure for the BTEX extraction and final determination The most important stage of the analytical procedure (after collection of analyte samples from the gaseous medium) is liberation of the analytes adsorbed on the sorption bed of Radiello diffusive passive sampler. The process of liberating the analytes adsorbed on the sorption bed took place by means of two-stage thermal desorption technique (extraction in increased temperature (280 C) in the stream of inert gas (Helium 45 ml min 1 ) thermal desorber designed and constructed by Omnisfera S.C., Gdansk, Poland) [43]. Detailed information related to the process of liberation of analytes from the sorption bed of Radiello diffusive passive sampler including GC conditions (qualitative and quantitative analysis) of liberated analytes are presented in Table Chemical standards Quantitative determination of organic compounds retained on the sorption bed of Radiello diffusive passive sampler was carried out with the use of external standard determination procedure (ESTD). External calibration was carried out with a mixture of volatile organic compounds ( EPA VOC Mix 2 ) containing 13 VOCs (including BTEX compounds) at 2000 μg/ml each component in methanol (Supelco, USA). Two five-point calibration curves were created for two ranges of masses of analytes introduced on the sorption medium: from 50 to 400 ng per sorption tube, from 400 to 2000 ng per sorption tube. Detailed information about preparing chemical standards of BTEX compounds can be found elsewhere [15,44,45] Calibration of TD-GC FID system A clean tube with the sorption bed of Radiello diffusive passive sampler was placed inside the stainless steel tube to be used for two-stage thermal desorption. Then 1 μl of standard solution ( EPA VOC Mix 2 ) (starting from the solution containing the smallest concentration of chemical compounds from VOCs group) was introduced on the clean sorption bed. In order to remove the solvent (methanol) from the sorption bed and to evenly distribute the components of standard mixture on the sorption bed, inert gas (helium) was let through the tube with sorption bed for the period of 10 minutes with the flow rate of 45 ml min 1 (Figure 4). Then,

8 International Journal of Environmental Analytical Chemistry 7 Table 2. Analytical procedure for determination of BTEX compounds presented in atmospheric air using the passive sampling technique at the stage of collection and/or enrichment of analytes from gaseous medium. Exposure of passive samplers Exposure time 2 weeks Transportation and storage of passive samplers Storage a cylindrical container with the sorption medium closed in a glass container with a tight polyethylene cap, storage time for the tube with the sorption medium in a glass container at the temperature of ca. 5 C before the stage of final determination did not exceed 72 hours. Liberate of analytes restrained on the sorption medium of the passive sampler Two-stage thermal desorption (a thermal desorber 1 st stage of thermal desorption: constructed by Omnisfera S.C., Gdansk, placing the cylindrical container inside the stainless Poland) steel tube (length: 89 mm, internal diameter: 6.4 mm), placing the stainless steel tube in the thermal desorber and heating it up to the temperature of 280 C for 20 minutes, transportation of analytes liberated from the sorption medium by inert gas stream (He, flow rate 45 ml/min) to the microtrap (37 mg Tenax TA and27mgcarbotrap). Cooled down to the temperature of 5 C 2 nd stage of thermal desorption: ballistic heating of the microtrap to the temperature of 280 C for 5 minutes, transportation of analytes liberated from the microtrap by carrier gas stream (He, flow rate 2.2 ml/min) to the front of the chromatographic column. Quantitative determination of analytes restrained on the sorption medium of the passive sampler Gas chromatograph Hewlett-Packard 5890 GC Series II Detector Flame Ionisation Detector Detector temperature 250 C Transfer line temperature 200 C Capillary column DB-1 (J&W) 30 m 0.32 mm 5 μm Carrier gas Temperature programme Data processing system Helium (2.2 ml/min) 40 C for 1 min; 5 C/min to 125 C; 10 C/min to 220 C; 220 C for 5 minutes CHEMSTATION the tube with the sorption bed was transferred to the thermal desorber, in which it was subject to two-stage thermal desorption in the conditions identical to the ones present in case of Radiello diffusive passive sampler installed on AM7 monitoring station in Tczew. The obtained equations of calibration curves are listed in Table Quality control/quality assurance of BTEX measurement Quality assurance and quality control procedures covered the analysis of field blanks and parallel duplicate samples. For field blanks, additional passive samplers were taken to the monitoring station and left unexposed during the exposure period (14 days). These field blanks were then analyzed under the same conditions applied during the analysis of samplers exposed

9 8 M. Marć et al. Figure 4. General view of the dedicated system for placing standard mixture on the tube with the sorption bed of Radiello diffusive passive sampler A carrier gas inlet (helium), B stainless steel tube where the tube with clean sorption bed of passive sampler is placed, C the place for introducing the sample of standard solution. to atmospheric air. Concentrations of BTEX compounds determined in atmospheric air were corrected with the value of blank test. The LOD, LOQ and uncertainty (the measurement uncertainty evaluated by the Radiello diffusive passive sampler manufacturer) values for the procedure of BTEX determination in atmospheric air with Radiello diffusive passive sampler at the sampling stage, are listed in Table Results and discussion Time-weighted average concentration (TWA) of BTEX compounds in atmospheric air in the area surrounding the monitoring station in Tczew (AM7) during the specific exposure time (14 days) of Radiello diffusive passive sampler was calculated based on the following Equation (1): Table 3. Organic compound Equations of calibration curves. C ¼ m Q T t 106 (1) Equations of the calibration curves for concentration range from 50 to 400 ng per sorption tube Benzene y = x R 2 = Toluene y = x R 2 = Ethylbenzene y = x R 2 = o-xylene y = x R 2 = p-xylene y = x R 2 = Organic compound Equations of the calibration curves for concentration range from 400 to 2000 ng per sorption tube Benzene y = x R 2 = Toluene y = x R 2 = Ethylbenzene y = x R 2 = o-xylene y = x R 2 = p-xylene y = x R 2 = Note: Where: y peak area; x amount of compound [ng].

10 International Journal of Environmental Analytical Chemistry 9 Table 4. LOD and LOQ values for the procedure of BTEX determination in atmospheric air with Radiello diffusive passive sampler at the sampling stage. Organic compound Limit of detection (LOD) 1 [μg m 3 ] Limit of quantification (LOQ) 1 [μg m 3 ] Uncertainty 2 [%] Benzene Toluene Ethylbenzene o-xylene p-xylene The values of LOD and LOQ for Radiello diffusive passive sampler are lower from the BTEX concentration ranges determined during this study. 2 The measurement uncertainty evaluated by the Radiello diffusive passive sampler manufacturer. where: Q T sampling rate at a current temperature [ml min 1 ], m mass of an analyte trapped by sorption medium determined by GC [μg], t exposure (sampling) time [min], C time weighted average concentration (TWA concentration) [μg m 3 ]. Because of the fact that monitoring research on the quality of atmospheric air in the area surrounding AM7 monitoring station was carried out under different atmospheric conditions (variable of atmospheric air temperature), Q T parameter had to be determined. Q T parameter serves for determination of the rate of analyte collection from gaseous medium with the use of a passive sampler for different temperature conditions. The values were specified using the relationship (2): 3 T 2 Q T ¼ Q 298 (2) 298 where: Q T sampling rate at the temperature T [K] [ml min 1 ], Q 298 the reference value at 298 K and 1013 hpa [ml min 1 ], T temperature [K] The values of Q 298 parameters were given by the manufacturer of Radiello diffusive passive sampler (Fondazione Salvatore Maugeri, Padova, Italy) and for BTEX are as follows: Benzene Q 298 = 26.8 [ml min 1 ], Toluene Q 298 = 30.0 [ml min 1 ], Ethylbenzene Q 298 = 25.7 [ml min 1 ], m, p-xylene Q 298 = 26.6 [ml min 1 ], o-xylene Q 298 = 24.6 [ml min 1 ]. Bearing in mind the fact that atmospheric air contamination may be transported over long distances as a result of atmospheric air mass transfer, it is important to determine, in relation to the area covered by monitoring, the dominant direction which the masses of atmospheric air are transported from. For the purposes of the above, a graphical image illustrating the distribution of wind directions (wind rose) around the areas of AM7 monitoring station in Tczew in 2011 was prepared (Figure 5). In case when the masses of atmospheric air are transferred from highly urbanised and industrialised areas to the area covered by monitoring research, the determined concentration levels of BTEX compounds in atmospheric air may be increased, whereas, in case when air masses transport takes place from less urbanised areas or areas deprived of

11 10 M. Marć et al. Figure 5. Annual wind rose for Tczew (AM7) monitoring station area. infrastructure elements, the phenomenon of dilution of analytes from BTEX group present in atmospheric air in the given area may take place, owing to which the concentrations of BTEX compounds in atmospheric air may reach lower level. When analysing data found in Figure 5, one can conclude that the dominant direction for air masses transport in the areas covered by atmospheric air quality monitoring (area surrounding AM7 monitoring station) in the period from March to December 2011 was south-west direction. Bearing in mind the above, one can state that organic compounds emitted from green areas, allotment gardens (often used all year round and in winter period heated with low efficiency heating appliances) and the main national communication junction covering national road 91 which is characterised by great intensity of truck traffic transporting goods from northern Poland to other areas of the country may be transported to the area surrounding AM7 monitoring station in Tczew Concentrations of benzene in the sampling area The monthly mean concentration of benzene determined in atmospheric air in the area surrounding AM7 monitoring station in Tczew in the period from March to December 2011 is presented in Figure 6. The error bars plotted in Figure 6 reflect the uncertainty evaluated by the Radiello diffusive passive sampler manufacturer (see Table 4). The highest monthly mean concentration

12 International Journal of Environmental Analytical Chemistry 11 Figure 6. Benzene concentration profiles in atmospheric air in the Tczew area obtained during the monitoring campaign carried out from March to December of benzene in atmospheric air in the area surrounding AM7 monitoring station was noted in October (1.8 μg m 3 ) and December (2.2 μg m 3 ), whereas the smallest monthly mean concentration of benzene in atmospheric air was noticed in May (0.25 μg m 3 ) and August (0.16 μg m 3 ). The annual average concentration of benzene in atmospheric air in the area surrounding AM7 monitoring station in Tczew for the measuring period from March to December amounted to 0.87 μg m 3. Referring to information listed in Figure 6, one can state that monthly mean concentration of benzene determined in atmospheric air in the areas surrounding AM7 monitoring station in Tczew depends on the temperature. Together with the atmospheric air temperature increase, benzene concentration in the atmospheric air decreases. When analysing data shown in Figure 6, one can note that in spring and summer months (May, June, July, August) benzene concentration in the atmospheric air is smaller than in autumn and winter months (October, December). The fact that average monthly benzene concentration in the atmospheric air depends on the temperature of atmospheric air may indicate that one of the main emission sources (apart from motorised vehicles driven by internal combustion engine) which influence on benzene content in atmospheric air in the monitored area may be the individual low efficiency heating systems of housing buildings and allotment buildings. With the decrease of atmospheric air temperature, the intensity of the heating appliances application (in housing premises and buildings on allotment sites) increases. Additionally, small concentration of benzene in atmospheric air in the period from May to August may be the result of increase of photochemical reactions intensity which take place under the influence of sun radiation the intensity of which in spring and summer months increase [46] Comparison of benzene levels in Tczew in years A listing of data related to annual average benzene concentration determined in atmospheric air in the area surrounding AM7 monitoring station in the years is presented in Figure 7.

13 12 M. Marć et al. Figure 7. The annual mean concentration of benzene un the atmospheric air at monitoring station in Tczew in the years [47] and in 2011 (*from March to December). The error bars placed in Figure 7 reflect the standard deviation of the obtained results. Detailed data on the annual average benzene concentration determined in atmospheric air in the years were taken from the paper published in 2012 by Król et al. Information presented in Figure 7 may be the basis for the conclusion that essential decrease of annual average benzene concentration in the atmospheric air is caused by higher, in comparison to previous years, annual average temperature of atmospheric air. In the period from March to December 2011 the lowest atmospheric air temperature amounted to 2.8 C. Adverse climate conditions (mostly low temperature maintained for the longer period of time) present in the area monitored in the years enforce prolongation of the heating period and so, the period for applying individual low efficiency heating systems, which may be the reason for higher values of benzene concentrations in the years (5.1 μgm 3 ;1.6μgm 3 ;3.0μgm 3 ;4.0μgm 3, respectively), than in the period from March to December 2011 (0.87 μg m 3 ) Concentration of toluene, ethylbenzene and total xylenes in the sampling area Information about the monthly mean concentration levels of toluene, ethylbenzene and xylenes determined in atmospheric air in the area surrounding AM7 monitoring station in Tczew is presented in Figure 8. The error bars plotted in Figure 8 reflect the uncertainty evaluated by the Radiello diffusive passive sampler manufacturer (see also Table 4). The annual average concentration of toluene, ethylbenzene and total xylenes determined in atmospheric air in the areas surrounding AM7 monitoring station in Tczew for the measuring period from March to December 2011 amounted to: 2.9 μg m 3, 1.3 μg m 3 and 5.9 μg m 3, respectively. Maximum monthly mean concentration of toluene in atmospheric air was noted in September (4.8 μg m 3 ) and October (4.7 μg m 3 ), whereas the highest monthly mean concentration of ethylbenzene and total xylenes determined in atmospheric air was noted in April (2.9 μg m 3 and 12.4 μg m 3, respectively) and September (2.0 μg m 3 and 10.6 μg m 3, respectively). The fact that the highest content levels of toluene, ethylbenzene and total xylenes

14 International Journal of Environmental Analytical Chemistry 13 Figure 8. Toluene, ethylbenzene and total xylenes concentration profiles in air of Tczew area obtained during the monitoring campaign carried out from March to December 2011.

15 14 M. Marć et al. are present in spring autumn months may lead to the conclusion that despite the traffic of motorised vehicles driven by combustion engines and individual heating systems of housing buildings, there is additional source of emission in the form of allotment gardens located in close vicinity of AM7 monitoring station which may have impact on the compounds content in atmospheric air. When analysing information listed in Figure 8, one can note that the lowest average monthly concentration of toluene, ethylbenzene and total xylenes in atmospheric air in the area surrounding AM7 monitoring station was noted in November and it amounted to: 1.3 μg m 3 ;0.42μg m 3 ; 1.9 μg m 3, respectively. The presence of toluene, ethylbenzene and xylenes at such low level in atmospheric air in autumn-winter months (November) may be caused by sudden change of atmospheric conditions in the monitored area. Figure 8 presents a detailed wind rose for autumn-winter months: October, November and December. The data listed in Figure 9 show that in November a sudden change of the dominant direction from which the inflow of air masses was observed, took place from southern direction in October and December (the inflow of air masses from the areas of Eaton Truck Componenets Sp. z.o.o industrial plant and housing areas) to south-west direction (the inflow of air masses from green areas, allotment gardens and main, national communication junction covering national road no. 91). Additionally, data rendered available by ARMAAG Foundation ( related to wind speed determined in the area surrounding AM7 monitoring station show that in the second half of November the intensity of air masses movement increased (average wind speed in the second half of November amounted to 2.6 m s 1 ) in comparison to wind speed noted in October (average wind speed 1.4 m s 1 ) and in December (average wind speed 2.2 m s 1 ). The increased intensity of wind in the monitored area may contribute to dilution of organic compounds (analytes from BTEX group) present in atmospheric air Relationship between averages of BTEX and meteorological variables for monitoring station AM7 in Tczew The analysis of correlations (The Pearson s correlation; Statistica 10 package (StatSoft, Poland)) allows to obtain information about potential sources of emission of organic compounds emitted to the atmospheric air in the monitored area and to specify the correlations between the characteristic organic compounds. The results of the statistical analysis carried out on the parameters determined in the atmospheric air (concentration levels of BTEX compounds) and meteorological parameters in the area surrounding AM7 monitoring station in Tczew are presented in Table 5. Figure 9. Wind rose of AM7 monitoring station area in October, November and December in 2011.

16 International Journal of Environmental Analytical Chemistry 15 Table 5. Pearson s correlation coefficient between averages of BTEX concentration and meteorological variables for AM7 monitoring station in Tczew from March to December 2011 (at a significance level of p < 0.05) AM7 Variable Benzene Toluene Ethylbenzene Total Xylene Temp Pressure Humidity Benzene 1.00 Toluene Ethylbenzene Total Xylene Temp Pressure Humidity Referring to information included in Table 5, one shall notice a very clear relationship (0.94) between determined concentration of xylenes and concentration of ethylbenzene in atmospheric air in the area surrounding AM7 monitoring station. It may indicate that the compounds (xylenes and ethylbenzene) may be emitted from the same sources of similar intensity level. Additionally, a moderate correlation was noted between concentration of xylenes and the concentration of toluene (0.64) and benzene (0.57). The information allows concluding that xylenes may be emitted from the same emission source as toluene and benzene. When assessing the results of statistical analysis carried out (Table 3), one can notice presence of strong inverse relationship ( 0.65) between atmospheric air temperature in the area surrounding AM7 monitoring station in Tczew and benzene concentration determined in atmospheric air. Such a correlation between atmospheric air temperature and benzene concentration may lead to a conclusion that emission source other than motorised vehicles driven by combustion engines may impact on benzene concentration in atmospheric air in the area surrounding AM7 monitoring station (e.g. individual low efficiency heating systems of housing buildings and allotment buildings). It is worth noticing that no clear relationship between the determined benzene concentration and toluene concentration (0.43) in atmospheric air in the area surrounding AM7 monitoring station in Tczew was observed. The information may lead to a conclusion that traffic is not the only, dominant source of benzene or toluene emission to atmospheric air in the monitored area. If the traffic of motorised vehicles is the only dominant source of benzene emission to the atmospheric air, the numerical value of the correlation coefficient is close to 1. Examples of values of determined correlation coefficients of benzene vs. toluene for selected medium- and large-sized cities are as follows: La Coruña 0.80 [48], Pamplona 0.96 [13], HoChiMinh 0.92 [49], Bari 0.93 [50], Cairo 0.93 [51], Antwerp 0.98 [52], Delhi [53] 4. Conclusions The results of atmospheric air quality research in terms of presence of BTEX compounds with the use of the passive sampling technique (Radiello diffusive passive sampler) at the stage of isolation and/or enrichment of analytes from gaseous medium show that in the period from March to December 2011 in the area of Tczew (adjacent to the Vistula River) no exceeding of allowable benzene concentration value (>5 μg m 3 ) was observed.

17 16 M. Marć et al. Owing to interpretation of research results, meteorological data and statistical analysis carried out which showed mutual correlations between the determined concentrations of BTEX compounds in the atmospheric air on the monitored area, it was possible to identify potential sources of emission of BTEX compounds emitted to atmospheric air. They may include: traffic of motorised vehicles driven by combustion engines, individual low efficiency heating systems of housing buildings and allotment gardens located in the vicinity of the monitoring station. The results of atmospheric air quality research directed at the determination of BTEX compounds in atmospheric air may supplement information for standard measurements (sulfur oxides concentration, nitrogen oxides concentration and meteorological parameters) made in stationary monitoring stations on the area of Tczew. Additionally, the research results presented in the paper showed, that the passive sampling technique may be successfully applied as the tool in atmospheric air quality monitoring in urbanised areas. Acknowledgements The authors are grateful to the Agency of Regional Air Quality Monitoring Foundation in the Gdansk Metropolitan Area (ARMAAG Foundation) for access to the monitoring stations, and to Michalina Bielawska for providing meteorological data during the monitoring operations. References [1] A.A. Ramadan, Environ. Monit. Assess. 160, 413 (2010). [2] H. Hellen, H. Hakola, T. Laurila, V. Hiltunen and T. Koskentalo, Sci. Total Environ. 298, 55 (2002). [3] S. Vardoulakis, N. Gonzalez-Flesca and B.E.A. Fisher, Atmos. Environ. 36, 1025 (2002). [4] G.A. Pilidis, S.P. Karakitsios and P.A. Kassomenos, Atmos. Environ. 39, 6051 (2005). [5] U. Wideqvist, V. Vesely, C. Johansson, A. Potter, E. Brorstrom-Lunden, K. Sjoberg and T. Jonsson, Atmos. Environ. 37, 1963 (2003). [6] H. Hellen, J. Kukkonen, M. Kauhaniemi, H. Hakola, T. Laurila and H. Pietarila, Atmos. Environ. 39, 4003 (2005). [7] S. Ly-Verdú, F.A. Esteve-Turrillas, A. Pastor and M. de la Guardia, Talanta. 80, 2041 (2010). [8] P. Schneider, I. Gebefugi, K. Richter, G. Wolke, J. Schnelle, H.- Erich Wichmann and J. Heinrich, Sci. Total Environ. 267, 41 (2001). [9] K.H. Chiu, U. Sree, S.H. Tseng, C.H. Wu and J.G. Lo, Atmos. Environ. 39, 941 (2005). [10] D. Alejo, M.C. Morales, V. Nuñez, L. Bencs, R. Van Grieken and P. Van Espen, Microchemical Journal. 99, 383 (2011). [11] V. Simon, M. Baer, L. Torres, S. Olivier, M. Meybeck and J.P. Della Massa, Sci. Total Environ. 334/ 335, 177 (2004). [12] K. Kume, T. Ohura, T. Amagai and M. Fusaya, Environ. Pollut. 153, 649 (2008). [13] M.A. Parra, D. Elustondo, R. Bermejo and J.M. Santamaría, Sci. Total Environ. 407, 999 (2009). [14] P. Iovino, S. Salvestrini and S. Capasso, Chemosphere. 73, 614 (2008). [15] B. Zabiegała, M. Urbanowicz, J. Namieśnik and T. Górecki, J. Environ. Qual. 906, 896 (2008). [16] R. Bono, R. Degan, M. Pazzi, V. Romanazzi and R. Rovere, Environ. Int. 36, 269 (2010). [17] M.R. Ras-Mallorqui, R.M. Marce-Recasens and F. Borrull-Ballarin, Talanta. 72, 941 (2007). [18] International Agency for Research on Cancer (IARC), Evaluations of Carcinogenicity Risk to Humans, IARC Monographs. 29, 93 (1982). [19] Directive 2000/69/EC of the European Parliament and of the Council. [20] H. Skov, A. Lindskog, F. Palmgren and C.S. Christensen, Atmos. Environ. 35, S141 (2001). [21] M. Michulec, W. Wardencki, M. Partyka and J. Namieśnik, Crit. Rev. Anal. Chem. 35, 117 (2005). [22] E. Gallego, F.J. Roca, J.F. Perales and X. Guardino, Talanta. 85, 662 (2011). [23] D.K.W. Wang and C.C. Austin, Anal. Bioanal. Chem. 386, 1089 (2006). [24] F.A. Esteve-Turrillas, S. Ly-Verdú, A. Pastor and M. de la Guardia, J. Chromatogr. A. 1216, 8549 (2009). [25] S. Cariou and J.M. Guillot, Anal. Bioanal. Chem. 384, 468 (2006). [26] S. Król, B. Zabiegała and J. Namieśnik, TrAC. 29, 1101 (2010).

18 International Journal of Environmental Analytical Chemistry 17 [27] S.V. Krupa and A.H. Legge, Environ. Pollut. 107, 31 (2000). [28] S. Beghi and J.M. Guillot, J. Chromatogr. A. 1183, 1 (2008). [29] M. Marć, B. Zabiegała and J. Namieśnik, Crit. Rev. Anal. Chem. 42, 2 (2012). [30] J. Begerow, E. Jermann, T. Keles, U. Ranft and L. Dunemann, Fresenius J. Anal. Chem. 351, 549 (1995). [31] J. Delcourt and J.P. Sandino, International archives of occupational and environmental health. 74, 49 (2001). [32] B. Zabiegała, T. Górecki, E. Przyk and J. Namieśnik, Atmos. Environ. 36, 2907 (2002). [33] J.E. Colman Lerner, E.Y. Sanchez, J.E. Sambeth and A.A. Porta, Atmos. Environ. 55, 440 (2012). [34] J. Roukos, N. Locoge, P. Sacco and H. Plaisance, Atmos. Environ. 45, 755 (2011). [35] A. Pennequin-Cardinal, H. Plaisance, N. Locoge, O. Ramalho, S. Kirchner and J.C. Galloo, Talanta. 65, 1233 (2005). [36] A. Pennequin-Cardinal, H. Plaisance, N. Locoge, O. Ramalho, S. Kirchner and J.C. Galloo, Atmos. Environ. 39, 2535 (2005). [37] B. Tolnai, A. Gelencser and J. Hlavay, Talanta. 54, 703 (2001). [38] T. Górecki and J. Namieśnik, TrAC. 21, 276 (2002). [39] A. Kot-Wasik, B. Zabiegała, M. Urbanowicz, E. Dominiak, A. Wasik and J. Namieśnik, Anal. Chim. Acta. 602, 141 (2007). [40] M. Partyka, B. Zabiegała and J. Namieśnik, Crit. Rev. Anal. Chem. 37, 51 (2007). [41] S. Seethapathy, T. Górecki and X. Li, J. Chromatogr. A. 1184, 234 (2008). [42] B. Zabiegała, A. Kot-Wasik, M. Urbanowicz and J. Namieśnik, Anal. Bioanal. Chem. 396, 273 (2010). [43] B. Zabiegała, M. Partyka, A. Gawrońska, A. Wasilewska and J. Namieśnik, Int. J. Environ. and Health. 1, 13 (2007). [44] B. Zabiegała, M. Urbanowicz, K. Szymanska and J. Namieśnik, J. Chromatogr. Sci. 48, 167 (2010). [45] B. Zabiegała, C. Sărbu, M. Urbanowicz, J. Namieśnik and J. Air, Waste Manager. Assos. 61, 260 (2011). [46] F. Geng, X. Tie, J. Xu, G. Zhou, L. Peng, W. Gao, X. Tang and C. Zhao, Atmos. Environ. 42, 6873 (2008). [47] S. Król, B. Zabiegała and J. Namieśnik, Anal. Bioanal. Chem. 403, 1067 (2012). [48] V. Fernandez-Villarrenaga, P. Lopez-Mahıa, S. Muniategui-Lorenzo, D. Prada-Rodrıguez, E. Fernandez-Fernandez and X. Tomas, Sci. Total Environ , 167 (2004). [49] T.T.N. Lan and P.A. Minh, J. Environ. Sci. 25, 348 (2013). [50] M. Amodio, G. de Gennaro, A. Marzocca, L. Trizio and M. Tutino, Procedia Environ. Sci. 4, 126 (2011). [51] M.I. Khoder, Atmos. Environ. 41, 554 (2007). [52] A.J. Buczynska, A. Krata, M. Stranger, A.F.L. Godoi, V. Kontozova-Deutsch, L. Bencs, I. Naveau, E. Roekens and R. Van Grieken, Atmos. Environ. 43, 311 (2009). [53] R.R. Hoque, P.S. Khillare, T. Agarwal, V. Shridhar and S. Balachandran, Sci. Total Environ. 392, 30 (2008).