FUNDAMENTAL SCIENCES AND APPLICATIONS

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1 ISSN JOURNAL FUNDAMENTAL SCIENCES AND APPLICATIONS VOL INTERNATIONAL SCIENTIFIC CONFERENCE Advanced Manufacturing Technologies THE SCIENTIFIC REPORTS

2 Journal of Fundamental Sciences and Applications, Vol. 15, 2009 International Conference on Advanced Manufacturing Technologies 81 Ultravolet Erythemal Radiation (UVER) measurements in Valencia, Spain (Second Series) Luis Javier Cañada, Aleksandar Georgiev, Rumen Popov Abstract. The ultraviolet radiation (UVA, UVB and UVC) can be very dangerous for the humans, mainly on the sea costs. Valencia, Spain is situated on the Mediterranean coast, where the tourist industry brings a lot of people to its beaches. The knowledge of the different UV radiation values is very important in this case. That was the reason to realize some measurements on 3 measurement places in Valencia under an acacia, lime and morus tree. Two types of measuring cycles are to be recognized. During the first cycle: the first sensor is under the tree (the measurements are done near the trunk of the three, in the central of the shadow and in the edge of the shadow) and the second one is in direct sun. During the second cycle: two stands are available (one for every sensor), every one of them with disc, which is used to define the diffuse component of the irradiance in sun and in shadow. The measurements were done with 2 sensors during the second cycle - the first one is under the tree, in the center of the shadow and the second one is in direct sun. Key words: Ultraviolet Erythemal Radiation, measurements, PMA2101 detector 1. Introduction The climate in Valencia, Spain is Mediterranean: the summer is warm and dry, the winter mild. The spring and the autumn are rainy seasons. There is a lot of sun whole the year. But sometimes the sun could be dangerous. The human overexposure to solar UV radiation may result in acute and chronic health effects on the skin, eyes and immune system [1]. Cloud increases the ratio of the UV in tree shade compared to the UV in full sun due to an increase in the diffuse component of the solar UV. This diffuse component is a major component of the solar ultraviolet radiation in tree shade [2]. Measurements in [3] showed that the horizontal plane received the highest erythemal ultraviolet levels from the solar zenith angle of 28 to 75, 42 to76, and 50 to 76 for the small, medium and large structures, respectively. There are some specific shade structures [4] that decrease UV exposures by the use of two types of side-on protection, namely, polycarbonate sheeting and ever green vegetation. The first step in valuation of influence UVER over human s health is to measure it. Journal of Fundamental Sciences and Applications, Vol. 15, 2009 Plovdiv, Bulgaria, ISSN

3 82 2. Measuring equipment The UVER is measured in the Polytechnic University of Valencia, Spain through the products of Solar Light Co., namely a Personal Measurement Assistant, model PMA 2100 and two Biologically-Weighted UVB Detectors. The Personal Measurement Assistant model PMA2100 (Fig.1.) is a sophisticated, multi-purpose measuring instrument combining the user-friendliness of simple meters with the capabilities of an advanced data logger. Two detectors of the type PMA2101 are used, too (Fig.2.). They give an accurate measurement of biologically weighted ultraviolet radiation from sunlight or artificial light sources, also called sunburning UV radiation (SUV). Fig. 1. PMA2100 model in action Fig. 2. PMA2101 detector in action 3. Measurements There were 3 measurement places under an acacia (Fig. 3), lime (Fig.4) and morus tree (Fig.5). Two types of cycles are to be recognized under the trees. Fig. 3. Acacia tree Fig. 4. Lime tree Fig. 5. Morus tree Description of the first cycle (two sensors are used, both sensors are in height about 1 m from the base, the base is short cut grass and the tree is high about 10m): the first one is under the tree, but the measurements are done near the trunk of the three, in the central of the shadow and in the edge of the shadow; the second one is in direct sun.

4 Description of the second cycle (the same two sensors are used, both sensors are in height about 1 m from the base, the base is short cut grass and the tree is high about 10m); two stands (one for every sensor), every one of them with disc, which is used to define the diffuse component of the irradiance in sun (Fig.6) and in shadow (Fig.7): the first one is under the tree, in the center of the shadow; the second one is in direct sun. 83 Fig. 6. PMA2101 detector in direct sun (2nd cycle) Fig. 7. PMA2101 detector in shadow (2nd cycle) Fig. 8. Readings under an acacia tree (near the trunk, in the shadow centre and edge) on The following measurements were done: first cycle (under an acacia, lime and morus tree); second cycle (under an acacia tree). Journal of Fundamental Sciences and Applications, Vol. 15, 2009 Plovdiv, Bulgaria, ISSN

5 84 Fig. 9. Measurements in direct sun on Fig. 10. Readings under a lime tree (near the trunk, in the shadow centre and edge) on The comparison between the measurements under the trees (acacia, lime and morus tree) are presented on the Figs (the readings are after the first cycle): under the acacia tree (Fig.8-9): the measurements started at 12:05 h and finished at 16:00 h on the 3 July 2006; temperature - 27 to 31 C; relative humidity - 61 to 74%; sunny; pressure: from 1011 to 1017 mbar; under the lime tree (Fig.10-11): the measurements started at 11:05 h and finished at 16:00 h on the 05 July 2006; temperature - 27 to 31 C; relative humidity - 65 to 73%; partly cloudy and sunny; pressure: from 1017 to 1018 mbar; under the morus tree (Fig.12-13): the measurements started at 10:00 h and finished at 13:55 h on the 20 July 2006; temperature - 27 to 34 C; relative humidity - 64 to 72%; partly cloudy; pressure: from 1022 to 1023 mbar.

6 85 Fig. 11. Measurements in direct sun on Fig. 12. Readings under a morus tree (near the trunk, in the shadow centre and edge) on Fig. 13. Measurements in direct sun on Journal of Fundamental Sciences and Applications, Vol. 15, 2009 Plovdiv, Bulgaria, ISSN

7 86 Fig. 14. Measurements under an acacia tree (diffuse and global irradiance) on The readings after the second cycle under an acacia tree are presented on the Figs : the tests started at 10:05 h and finished at 16:05 h on the 17 July 2006; temperature - 29 to 33 C; relative humidity - 61 to 72%; sunny; pressure: from 1022 to 1023 mbar. Fig. 15. Measurements in direct sun (global and diffuse irradiance) on Conclusions The UVER measurements, which were done in June and July 2006 in Valencia were not enough as number of planned tests. Nevertheless the following conclusions can be done on the base of the received data: the lowest values of the irradiance are near the trunk, followed by the values in the shadow centre and in the edge (first cycle);

8 87 the global and diffuse irradiance values are very closed under the acacia tree at the same time the difference between them is big enough in direct sun (second cycle); tests of the second cycle were done only under the acacia tree (they have to be done under the other trees, too). References 1. Dianne E. Godar. UV Doses Worldwide. J. of Photochemistry and photobiology, Vol. 81, 2005, A.V. Parisi, M.G. Kimlin, J.C.F. Wong, M. Wilson. Diffuse component of solar ultraviolet radiation in tree shade. J. of Photochemistry and Photobiology B: Biology, Vol. 54, 2000, D.J. Turnbull, A.V. Parisi. Annual variation of the angular distribution of the UV beneath public shade structures. J. of Photochemistry and Photobiology B: Biology, Vol. 76, 2004, D.J. Turnbull, A.V. Parisi. Increasing the ultraviolet protection provided by shade structures. J. of Photochemistry and Photobiology B: Biology, Vol. 78, 2005, Department of Mechanics Technical University Sofia, Branch Plovdiv 25 Tsanko Dustabanov St Plovdiv BULGARIA Journal of Fundamental Sciences and Applications, Vol. 15, 2009 Plovdiv, Bulgaria, ISSN