Search

Italy is one of the European nations characterized by the highest levels of ultraviolet radiation (UV) therefore it was important for both the resident population and the numerous tourists to know the risk level deriving from UV exposure. Based on these considerations starting from 2004 at the Institute of Biometorology of National Reasearch Council (IBIMET-CNR), in cooperation with the LaMMA Consortium, a continuous UV monitoring activity was started. The UV monitoring station was located in Sesto Fiorentino (43° 82' N, 11° 20' E, 40 m a.s.l.), a suburb of Florence, Tuscany (Central Italy). The radiometer used was the UVB-501 (Solar Light CO., Philadelphia, USA) with spectral response close to the erythemal action spectrum, periodically compared with a reference instruments (of the same type as the operational one) calibrated during international inter-comparison campaigns. Continuous measurements of erythemally effective UV radiation (also converted in UV Index) and averaged over 15-min intervals were performed starting from 2004 and stored in a database. On the basis of these 14 years of data an UV Index climatology was obtained. During the last few decades, weather circulation type classifications (CTCs) have been widely used to gain insight into processes at the synoptic scale, but also for studying the relationship between atmospheric circulation and surface climate variability. As at LaMMA, were evaluate the best performing CTCs based on COST733 software for the stratification of daily ground-level precipitation and surface air temperature across Italy, in this study we have done a very preliminary investigation on possible relationships between UV and such CTCs; especially in certain periods of the year a relationship between specific weather circulation and UV was present.

Solar radiation affects human beings in different ways with direct effects occurring when people are exposed outdoors during working or leisure/sport activities. Erythema is the most familiar short-term symptom of human skin associated with overexposure to unperceivable ultraviolet radiation (UV). In this study the newly developed Universal Thermal Climate Index (UTCI) will be used for the first time to investigate whether the perceived outdoor heat stress might represent a valuable proxy for the unperceivable effect of UV-induced risk of erythema in a Mediterranean city, Florence, Tuscany (Central Italy). The aim of this study is therefore to propose a real approach to link solar UV radiation and thermal factors by means of the application of two internationally recognized indices, in order to estimate their reciprocal interaction and the potential impact on human health. Meteorological data and UVB (280-320 nm) measurements were obtained for the 2004-2012 period by a weather station located in the municipality of Florence. The UTCI was assessed and continuous measurements of erythemally effective UV (UVEry) were performed by means of broadband temperature-corrected radiometers with the spectral response close to the erythemal action spectrum. Hourly UVEry doses were expressed as Standard Erythemal Doses (SEDs). Descriptive analyses of the hourly distribution per month of the frequencies of days with heat stress and UVEry exceeding 2.0, 3.0, 4.5 and 6.0 SEDs were carried out based on the general skin-type characteristics. The association between UVEry and UTCI was analyzed by a two-way contingency table approach. The probability of UVEry exceeding specific SED thresholds when heat stress occurs was often significantly higher than the same probability when no heat stress is perceived. However, during several months, too many days occur without any signs of heat discomfort, even when people may be exposed to relevant doses of harmful UVEry for the skin of various phototypes. These findings underlie the need for public health authorities to provide differentiated advice per month in relation to potential UV skin damage in the city of Florence. Such specific UV information is fundamental for educating the local population and tourists and making them aware of sun exposure.

Beside some positive effects of solar UV (280-400 nm) radiation (as the stimulation of previtamin D bio-synthesis ) it is well documented the risk associated to an overexposure to UV radiation, primarily for what concern skin damages whose first step is the onset of erythema. Based on this consideration measurements of the amount of UV radiation responsible for erythema (UVery) have been initiated in many countries. Broadband sensors with a spectral sensitivity mimicking the erythema action spectrum made possible the monitoring of this parameter in continuum day after day. On the other hand satellite-derived data of total O3 and cloud cover associated with radiative transfer model output allow an assessment of daily UVery dose as reported on the web pages of the Tropospheric Emission Monitoring Internet Service, TEMIS (www.temis.nl). The objective of this study was to compare ground-based and remotely sensed daily UVery data, to analyze the frequency distribution of the daily maximum UV-Index values and the UVery doses to which outdoor workers may be exposed to. Ground based data have been recorded in Florence up to now since 2000 with a time step of 15 minutes using a broadband sensor (Solar Light 501A) periodically calibrated during various intercomparison campaigns. Daily erythemal dose have been downloaded also from the TEMIS web pages. Results indicate that daily doses of UVery remotely sensed are in good agreement with ground-based ones both when considering all the days or only those with clear sky conditions. Nevertheless TEMIS derived data resulted always higher than ground based ones and average highest difference was reached in June (0.7 KJm2 , a 15% less than satellite-derived data). Daily UV-Index maximum (UV-Imax) values analyzed according to the WHO classification reported as "protection required", "moderate" and "high" showed an occurrence respectively of 54.7%, 71.3% and 26.8% . Days classifiable as "very high" accounted for 1.9%. Results are also illustrated in terms of daily UVery doses occurring during the working hours of different months indicating the high level of UVery to which outdoor workers are exposed to respect to 30 Jm2 , the limit still proposed by ICNIRP.

The objective of our study was to investigate the response of Sangiovese vines (one of the most diffused cultivar in Italy) to different solar UV regimes in open air and how plants grown without UVB and total UV react when exposed to full light conditions. Material and Method. Two years old grapevine plants were grown in 10 l pots under greenhouses covered with Teflon, transparent both to UV and visible wavelengths (Control), Mylar, transparent to wavelengths above 312 nm (-UVB) and LEE 226, transparent to wavelengths above 400 nm (-UVB/-UVA). Plant were fertilized and maintained in well watered conditions. Meteorological parameters, outside and inside greenhouses, were monitored and periodically spectral measurements in the range 290 to 800 nm were performed outside and inside each greenhouse to check spectral transparency of filters and PAR irradiance. Before bud break 20 plants were positioned both under Lee and Mylar filters while 10 plants were placed under Teflon. On July 9th 10 plants from Lee and 10 from Mylar were moved under Teflon in order to stimulate possible physiological reactions to the new environment. Leaf discs from the fully expanded 9th leaf from the bottom were taken and used for extraction of UV-B absorbing compounds in a mixture of HCl:methanol:water; absorption spectra were determined with a UV-visible spectrophotometer and absorbance was referred to both unit leaf area and unit of fresh and dry weight. Moreover epidermal flavonoids content, expressed in terms of FLAV-Index, was estimated using a non destructive approach by means of a Multiplex portable fluorimetric device. The photosynthetic properties were analyzed by the fluorescence of the chlorophyll a during the season: direct fluorescence parameters (JIP-test) were measured in different aged-leaves. Photosynthetic pigments were extracted from 5 leaf discs (1 cm2) per leaf with DMF and the absorbance of extracted solutions was read at 647, 664 and 480 nm with a DU spectrophotometer after 48 h of extraction at 4 °C. Results. Mean daily temperature differences measured under the three greenhouses were lower than 0.6°C.Temperature and humidity difference between outside and inside greenhouses not excided 2°C and 8% respectively. On July 9th, after 14 weeks of treatment, the 9th leaf of the control showed the UV-B absorbing compounds content statistically higher than both -UVB and -UVB/-UVA as confirmed also by FLAV-I data. The maximum quantum yield efficiency in the dark-adapted state (Fv/Fm) in plants -UVB was minor than in others light conditions. This difference was significant in younger leaves. On July 24th leaves of -UV-B moved under Teflon greenhouse increased their Fv/Fm reaching the control while -UVA/-UVB plants didn't show any significant change. UV-absorbing compounds measured on mature leaves both with destructive and non destructive method showed only a partial recover compared with control which remained anyway significantly higher. After 15 days mature leaves previously exposed to -UVB and -UVA/-UVB appeared unable to react to the new radiative regime increasing their content of UV-B absorbing compounds up to reach the level of leaves grown under full light; even several weeks later, on September 10th, these differences were still present. UV-B absorbing compounds estimated by means of the FLAV-I on younger leaves showed a different behaviour: on July 24th leaves of plants exposed to -UVB and -UVA/-UVB treatment was significantly lower than control but plants that were moved under Teflon greenhouse showed a partial recover relative to control whose level was reached finally on September 10th.

Measurements were performed under clear sky conditions in order to quantify ultraviolet (UV) and photosintetically active radiation (PAR) (global and diffuse component) on the wall of grapevine rows with different orientation. UV radiation seems to have a higher tendency to diffuse in comparison to PAR and then, the shaded portions of plants have a different "ultraviolet radiation"/"photosintetically active radiation" ratio respect to the ones in full sun with potential impacts on biochemical process.

An open-air experiment was performed in Pistoia (Italy) to investigate the possible protective role played by different contents of UV-B absorbing compounds to realistic UV-B supplementation and to study its effect on plant fruit production. A mutant line and its normal counterpart of Lycopersicon esculentum Mill, which differ in the content of UV-B absorbing compounds, were used. Additional UV-B radiation in the field was supplied to simulate a 20% stratospheric ozone depletion. Two groups of plants were grown: ‘control’, where plants received only natural solar UV-B radiation, and ‘UV-B’ treatment, where plants were grown under supplemental UV-B. The results of the experiment showed that the content of UV-B absorbing compounds of treated plants did not differ from that of the control in both lines. This indicates that natural sunlight, in Mediterranean areas, is saturating for synthesis of these compounds also in plants with normal content of UV-B absorbing compounds. Consequently, plants are not able to produce significant additional amounts of them, in response to a realistic UV-B supplementation, in order to protect the plant from additional UV-B radiation.

Plants show different levels of sensitivity to ultraviolet-B (UV-B) radiation and acclimation to high UV-B irradiances had been developed in many species. A field experiment was performed during 1995 to study the adaptive responses of oak plants (Quercus robur L.) to artificial UV-B supplementation. The most important effect of UV treatment was the increase in leaf thickness and the accumulation of phenolic compounds in the secondary wall of the adaxial epidermis of leaves in UV treated plants; the secondary wall of cells in the abaxial epidermis, while plant morphology was sensible to UV treatment

During the last few decades many experiments have been performed to evaluate the responses of plants to enhanced solar UV-B radiation (280–320 nm) that may occur because of stratospheric ozone depletion; most of them were performed in controlled environment conditions where plants were exposed to low photosynthetically active radiation (PAR) levels and high UV-B irradiance. Since environmental radiative regimes can play a role in the response of plants to UV-B enhancement, it appears doubtful whether it is valid to extrapolate the results from these experiments to plants grown in natural conditions. The objective of this work was to evaluate the effects on physiology and morphology of a bean (Phaseolus vulgaris L.) cultivar Nano Bobis, exposed to supplemental UV radiation in the open-air. UV-B radiation was supplied by fluorescent lamps to simulate a 20% stratospheric ozone reduction. Three groups of plants were grown: control (no supplemental UV), UV-A treatment (supplementation in the UV-A band) and UV-B treatment (supplemental UV-B and UV-A radiation). Each group was replicated three times.