Variations In Ultraviolet Radiation Research Articles

Triggering multiple sclerosis at conception and early gestation: The variation in ultraviolet radiation is as important as its intensity

Background and objectivesMedical science needs to further elucidate the role of ultraviolet radiation (UVR), geographic latitude, and the role of vitamin D in the autoimmune disease multiple sclerosis (MS). We separated several papers into categories out of the thousands published and used their conclusions to explore the relationship between UVR and MS. RelevanceMS is increasing in incidence, particularly in women where MS is two to three times that in men and particularly severe in African Americans. MethodsWe collected UVR data at our observatory in Central Maine and calculated the average coefficient of variation (CVUVR) for each month for 15 years (2007–2021, inclusive). ResultsThe month of conception (MOC) is more important than the month of birth (MOB) in explaining how UVR triggers the variable genetic predisposition to MS. We hypothesize that the rapidly increasing CVUVR is important in preventing an increase in the activity of the vitamin D receptor (VDR) from August to December, which then requires a higher intensity of UVR later in life to suppress the immune system, therefore predisposing to more MS. LimitationsOne observatory at about 44° latitude. ConclusionsWhile variation in UVR is important at the MOC if UVR exceeds a threshold (e.g., if the sunspot number equals or is greater than 90, usually at a solar cycle MAX, or at elevations above approximately 3,000 feet above sea level), the MS mitigating vitamin D-VDR mechanism is overwhelmed and the genotoxic effects of higher-intensity UVR promote MS in those with a genetic predisposition. What is new in this researchThis paper offers a new concept in MS research.

200-year ice core bromine reconstruction at Dome C (Antarctica): observational and modelling results

Abstract. Bromine enrichment (Brenr) has been proposed as an ice core proxy for past sea-ice reconstruction. Understanding the processes that influence bromine preservation in the ice is crucial to achieve a reliable interpretation of ice core signals and to potentially relate them to past sea-ice variability. Here, we present a 210 years bromine record that sheds light on the main processes controlling bromine preservation in the snow and ice at Dome C, East Antarctic plateau. Using observations alongside a modelling approach, we demonstrate that the bromine signal is preserved at Dome C and it is not affected by the strong variations in ultraviolet radiation reaching the Antarctic plateau due to the stratospheric ozone hole. Based on this, we investigate whether the Dome C Brenr record can be used as an effective tracer of past Antarctic sea ice. Due to the limited time window covered by satellite measurements and the low sea-ice variability observed during the last 30 years in East Antarctica, we cannot fully validate Brenr as an effective proxy for past sea-ice reconstructions at Dome C.

Measurement of variation of ultraviolet radiation due to different greenhouse gases using internet of things

Measurement of variation of ultraviolet radiation due to different greenhouse gases using internet of things

Two ultraviolet radiation datasets that cover China

Ultraviolet (UV) radiation has significant effects on ecosystems, environments, and human health, as well as atmospheric processes and climate change. Two ultraviolet radiation datasets are described in this paper. One contains hourly observations of UV radiation measured at 40 Chinese Ecosystem Research Network stations from 2005 to 2015. CUV3 broadband radiometers were used to observe the UV radiation, with an accuracy of 5%, which meets the World Meteorology Organization’s measurement standards. The extremum method was used to control the quality of the measured datasets. The other dataset contains daily cumulative UV radiation estimates that were calculated using an all-sky estimation model combined with a hybrid model. The reconstructed daily UV radiation data span from 1961 to 2014. The mean absolute bias error and root-mean-square error are smaller than 30% at most stations, and most of the mean bias error values are negative, which indicates underestimation of the UV radiation intensity. These datasets can improve our basic knowledge of the spatial and temporal variations in UV radiation. Additionally, these datasets can be used in studies of potential ozone formation and atmospheric oxidation, as well as simulations of ecological processes.

The attenuation effect on ultraviolet radiation caused by aerosol and cloud in Lhasa, Tibetan Plateau of China

Measurements of ultraviolet (UV) radiation and total radiation (G) in Lhasa, China during 2005–2013 are reported to explore the variations of UV radiation and the effects of aerosols and clouds on UV radiation under various cloud cover conditions. UV radiation increases from spring until summer and then decreases to lower values in winter; the annual average value is 0.91MJm−2d−1. The ratio of UV radiation to G (UV/G) exhibits an upward trend as cloud cover increases, especially for cloud cover higher than 5 octas conditions. The temporal variation displays an inverse relationship between the UV/G ratio and clearness index (Ks) under different cloud cover scenarios. Aerosols alone and aerosols combined with the cloud attenuation effect lead to distinct increasing trends in UV radiation from spring until the highest values in summer, after which the values gradually decrease until winter. The monthly average values of the UV cloud modification factor vary from approximately 73.9% in July to 93% in December; the annual average value is 82%.

Solar spectral irradiance and total solar irradiance at a solar minimum

Results are presented for a wavelet analysis of solar spectral irradiance (SSI) in the ultraviolet to infrared range and total solar irradiance (TSI). The study is based on data collected by the Solar Radiation and Climate Experiment (SORCE) satellite from March 10, 2007 to January 23, 2010. Cross-wavelet analysis finds relationships of varying degrees of tightness between SSI, TSI, and magnetic flux in a sunspot zone on the surface rotation timescales of solar activity complexes. Wavelet coherence shows how magnetic flux variations within a latitudinal sunspot zone are related with spectral irradiance variations. For example, variations in ultraviolet radiation at UV 200.5 nm are in phase with those of the magnetic flux associated with solar activity complexes. However, there is an unusual interval UV 310 to 380 nm, in which coherent structures disappear and UV radiation variations do not follow the changes in the magnetic flux.

Characteristics of UV radiation at Tazhong of the Tarim Basin, west China

Tazhong station, located at the hinterland of the Taklimakan Desert in northwest China, experiences frequent dusty weather events during spring and summer seasons (its dusty season) caused by unstable stratified atmosphere, abundant sand source and strong low-level wind. On average, it has 246.2 dusty days each year, of which 16.2 days are classified as sand and dust storm days. To better understand the characteristic of solar ultraviolet (UV) radiation and factors influencing its variations under such an extreme environment, UV radiation data were collected continuously from 2007 to 2011 at Tazhong station using UVS-AB-T radiometer by Kipp and Zonen. This study documents observational characteristics of the UV radiation variations observed during the five-year period. Monthly UV radiation in this region varied in the range of 14.1–37.8 MJ m−2 and the average annual amount was 320.7 MJ m−2. The highest value of UV radiation occurred in June (62.5 W m−2) while the lowest one in December (29.3 W m−2). It showed a notable diurnal cycle, with peak value at 12:00–13:00 LST. Furthermore, its seasonal variation exhibited some unique features, with averaged UV magnitude showing an order of summer > spring > autumn > winter. The seasonal values were 37.0, 29.1, 24.9 and 15.9 MJ m−2, respectively. In autumn and winter, its daily variations were relatively weak. However, significant daily variations were observed during spring and summer associated with frequent dust weather events occurring in the region. Further analysis showed that there was a significant correlation between the UV radiation and solar zenith angle under different weather conditions. Under the same solar zenith angle, UV radiation was higher during clear days while it was lower in sand and dust storm days. Our observations showed that there was a negative correlation between UV radiation and ozone, but such a relationship became absent in dusty days. The UV radiation was reduced by 6 % when cloud amount was 1–4 oktas, by 12 % when the cloud amount was 5–7 oktas, and by 24 % when the cloud amount was greater than 8 oktas. The relative reduction of UV radiation reached 26, 38, and 45 % in dust day, blowing sand day and sand and dust storm day, respectively. The results revealed that decrease in UV radiation can be attributed to cloud coverage and dust aerosols. Moreover, the reduction of UV radiation caused by dust aerosols was about 2–4 times greater than that caused by cloud coverage. These observational results are of value for improving our understanding of processes controlling UV radiation over sand desert and developing methods for its estimation and prediction.

Variation in ultraviolet radiation and diabetes: evidence of an epigenetic effect that modulates diabetics’ lifespan

BackgroundPublished research has shown that month-of-birth variations modulate the incidence of adult human diseases. This article explores diabetes type 2 as one of those diseases. This study uses the death records of approximately 829,000 diabetics (approximately 90% were type-2) born before the year 1945 (and dying between 1979 and 2005) to show that variations in adult lifespan vary with ultraviolet radiation (UVR) at solar cycle peaks (MAX, approximately a three-year period) with less at non-peaks (MIN, approximately an eight-year period). The MAX minus MIN (in years) was our measure of sensitivity (for example, responsiveness) to long-term variations in UVR.ResultsDiabetics were less sensitive than non-diabetics, and ethnic minorities were more sensitive than whites. Diabetic males gained 6.1 years, and females 2.3 years over non-diabetics, with diabetic males gaining an average of 3.8 years over diabetic females. Most variation in lifespan occurred in those conceived around the seasonal equinoxes, suggesting that the human epigenome at conception is especially influenced by rapid variation in UVR. With rapidly decreasing UVR at conception, lifespan decreased in the better-nourished, white, female diabetic population.ConclusionsRapidly changing UVR at the equinoxes modulates the expression of an epigenome involving the conservation of energy, a mechanism especially canalized in women. Decreasing UVR at conception and early gestation stimulates energy conservation in persons we consider ‘diabetic’ in today’s environment of caloric surfeit. In the late 19th and early 20th centuries ethnic minorities had poorer nutrition, laborious work, and leaner bodies, and in that environment a calorie-conserving epigenome was a survival advantage. Ethnic minorities with a similar epigenome lived long enough to express diabetes as we define it today and exceeded the lifespan of their non-diabetic contemporaries, while that epigenome in diabetics in the nutritional environment of today is detrimental to lifespan.

Short and long term variation in ultraviolet radiation and multiple sclerosis.

We examined the role of ultraviolet radiation (UVR) in persons diagnosed with multiple sclerosis (MS) in four different populations, Italians, Danish, White and African Americans. We tested whether variation in UVR as determined by seasons (short term variation) and solar cycles (long term variation) is related to MS birth month and to survival as measured by lifespan. Cases were selected from three Italian MS Case Registries (2,737); from the United States National Center for Health Statistics (56,020); and from the Danish Multiple Sclerosis registry (15,900). Chi-square tests were used to study the pattern of month of birth distribution in patients with MS comparing with general population data. T-tests were employed to study solar cycles association with lifespan. A surplus of births was observed in June for White Americans. A decrease of births in October and November, though not significant after multiple testing correction, was observed in the three populations. In White American with MS overall, males and females, we found that solar cycle is associated with lifespan. We found that season and solar cycles have some role in MS susceptibility and life duration. However, this is an exploratory analysis and further work is needed to discern the association.

Springtime feature of the seasonal behavior of near-ground ultraviolet radiation in certain regions of Russia

Based on satellite data of the near-ground ultraviolet radiation (UVR) taken by the TOMS instrument onboard the Earth Probe satellite, as well as the data of the aerosol optical depth and atmospheric moisture content obtained with the help of ground-based Aerosol Robotic Network (Aeronet) stations, we analyzed the springtime features of the variations of the near-ground UVR on some of the territory of Russia (near Yekaterinburg, Tomsk, Krasnoyarsk, Irkutsk, and Yakutsk) in terms of the UVR deviations from the well-defined seasonal behavior caused by the solar elevation. Data for the period of 1997–2003 have been analyzed. The possible mechanisms behind the observed specific feature in the UVR variations are discussed.

Diurnal Variations in Solar Ultraviolet Radiation at Typical Anatomical Sites

Solar ultraviolet (UV) radiation is an important environmental factor that affects human health. The understanding of diurnal variations of UV radiation at anatomical sites may be helpful in developing ways to protect humans from the harmful effects of UV radiation. In order to characterize the diurnal variations, the UV exposure values were measured at 30 min intervals by using Solar-UV Sensors and a rotating manikin in Shenyang city of China (41 degrees 51'N, 123 degrees 27'E). Measurement data for four representative days (in each of the four seasons respectively) were analyzed. The diurnal variations in solar UV radiation at the shoulder, the forehead and the chest were similar to those associated with a horizontal control measurement. However, the diurnal variations at the eye and the cheek exhibited bimodal distributions with two peaks in spring, summer and autumn, and a unimodal distribution in winter. The UV exposure peaks at the eye and the cheek were measured at solar elevation angles (SEA) of about 30 degrees and 40 degrees , respectively. The protection of some anatomical sites such as the eye from high UV exposure should not be focused solely on the periods before and after noon, especially in the places and seasons with high SEA.

Variation characteristics of ultraviolet radiation derived from measurement and reconstruction in Beijing, China

Four years measurements of broadband global solar radiation (RS) and total ultraviolet (UV) radiation (the sum of UV-A and UV-B) were conducted from 2005 to 2008 in Beijing. These data were used to determine the temporal variability of UV/RS and its dependence on water vapour content and clearness index. A simple, efficient and empirically derived all-weather model is proposed to estimate UV from RS. The estimated data were used to analyse the characteristics of long-term variations in UV radiation. Results revealed that annual mean UV was 0.37 ± 0.17 MJ m−2 d−1. The highest daily value of UV radiation was measured in May, while the lowest value occurred in December. The monthly mean value of UV/Rs gradually increased from 2.7% in November to 3.7% in August. The annual mean value of UV/Rs was 3.1%.The annual mean daily UV radiation during 1958–2005 was 0.46MJm−2 d−1. The interannual variations and long-term patterns of UV radiation derived from reconstructed daily UV values are compatible with changes in measured RS. Annual mean UV radiation levels decreased from the early 1960s to the late 1990s but began to increase in the late 1990s. Over the latter half of the 20th century, decrease in UV radiation was 0.018 MJ m−2 d−1 per decade. The decrease trends in long-term annual mean UV radiation of −0.026 MJ m−2 d−1 per year for 1958–1997 and −0.0024 MJ m−2 d−1 per year for 1958–2005. The decreasing trend in UV radiation was sharpest in spring and summer but more gradual in autumn and winter.

Incident Ultraviolet Radiation and Disappearance of the Aquatic Macrophyte Egeria densa in a Ramsar Wetlands Site

AbstractDuring mid 2004, abrupt environmental changes including a massive die off of the dominant macrophyte Egeria densa were observed within the wetlands of Río Cruces, a Ramsar site in southern Chile. One of the hypotheses presented to explain these changes was that increased ultraviolet radiation (UVR) may have been responsible. Since variation in UVR operates at regional scales, it is important to understand if the demise of E. densa also occurs at concurrent spatial and temporal scales. The current results demonstrate that monthly and annual variability of UVB was very stable during 1998 to 2006. Furthermore, in situ vertical profiles sampled across the wetlands and nearby rivers showed that UVR penetrates deeper into waters located outside the wetlands, where healthy stands of E. densa are commonly seen. The massive die off of E. densa within the Río Cruces wetlands cannot be explained by regional variability in UVR, and it is much more likely that the definitive reason is found locally within the wetlands rather than regionally.

Ultraviolet radiation spatio-temporal characteristics derived from the ground-based measurements taken in China

Ultraviolet (UV) radiation and broadband solar radiation ( R s) measured from January 2005 to June 2006 at 31 stations in Chinese Ecosystem Research Network (CERN) were used to investigate the spatio-temporal characteristics of UV radiation and UV fraction (the ratio of UV radiation to R s) in China. Results indicated that the seasonal variations of UV radiation and R s were consistent with the solar activities, which reached their lower values during winter period, and increased throughout the spring, peaking in June or July, in most sites. The Meiyu weather system and Southwest Monsoon produced different variation characteristics of UV radiation and R s in subtropical and tropical regions. The UV fraction values showed a similar seasonal trend as that of UV radiation, which was mainly determined by the seasonal change of the aerosol optical depth (AOD) and water vapor content in atmosphere. The seasonal variations of UV fraction were much smoother in southern China due to high water vapor content over the whole year. The UV radiation showed an increasing trend from east to west in China. In the western area, a simple increasing trend was observed from north to south, with the largest annual mean daily UV value 0.91 MJ m −2 appearing in the Qinghai-Tibet Plateau area. In east China there was a low center that appeared in the subtropical region due to high aerosol burden, with the lowest value 0.41 MJ m −2 observed in Yanting site. Two high centers were located in the tropics with higher solar altitudes and the north desert region with low atmospheric attenuation. The largest values of UV fraction appeared in the tropical and subtropical regions due to higher relative humidity (RH) in these areas. However, the smallest value did not appear in the north desert region where the RH was the lowest, they were found at the Luancheng site which featured relatively low humidity and abundant fine aerosols. The variations in the UV fraction were not such distinctive as those of the UV radiation in China due to the more complex influences of aerosol and water vapor.

Erythemal dose in Kathmandu, Nepal based on solar UV measurements from multichannel filter radiometer, its deviation from satellite and radiative transfer simulations

Biologically active solar Ultraviolet radiation is monitored in Kathmandu valley in Nepal (27.7°N, 85.5°E, 1350 m asl) using a multichannel broadband radiometer for the period of November 2004–March 2005. Result shows noontime one-hour average CIE weighted dose rate can reach up to 0.195 W m − 2 (UV index = 7.8 at solar zenith angle, SZA = 36.8°) for a cloud free sky. Radiative transfer calculations indicate that UV index around local noon can reach as high as 14 in a clear summer sky, but will strongly depend on the content of aerosol in the atmosphere. Comparison of ground-based measurement with TOMS satellite derived data reveals an overestimation of UV indices by TOMS, within the period of measurement, on average by 31 ± 4.5%. Modeled clear sky daily dose differed between 20 and 40% from ground-based measurement in February. Assuming constant aerosol level during the campaign, 5–25% of the variation in Ultraviolet radiation is caused by clouds alone.

Long-term (250,000 BP to 50,000 AP) variations in ultraviolet and visible radiation (0.175–0.690 μm)

Recent biological studies demonstrating sensitivity to ultraviolet (UV) radiation coupled with research on the radiative impact of stratospheric ozone depletion pose a challenge to climate modelers and reconstructionists to determine past variations in UV radiation. In this study, solar radiative waveband totals are computed applying a numerical model linking the parameterization of the amount of radiation as a function of orbital parameters with the atmospheric solar scattering. Variations are computed for three continuous solar wavebands (0.225–0.285, 0.3–0.325 and 0.325–0.690 μm) and one non-continuous shortwave band (0.175–0.225/0.285–300 μm). With the assumption of invariant latitudinal ozone concentrations over the past 250,000 years, radiation in all wavebands displays significant variations from present levels due to changes produced by Milankovitch orbital mechanisms (obliquity, eccentricity and precession). Specifically: (a) orbital changes produced the following percent ranges from present-day values in the 0.3–0.325 μm waveband over the last 250,000 years: −19% to 30% (June Solstice), −26% to +32% (December Solstice) and −3% to +3% (equinoxes); (b) precessional influences control variations in the total daily radiation; and (c) orbital changes produce a decrease in the amount of visible and UV radiation over the next 10 kyr in the Northern Hemisphere for the spring and summer while increasing visible and UV for the fall and winter. These initial results for long-period radiative variations (a) provide a first comparative range of values in future UV radiative change study related to ozone depletion; (b) generate baseline values for researchers interested in the potential environmental and biological effects of past UV radiative variations; and (c) aid in analyses of the influence of solar radiative changes based upon orbital mechanisms on climatic change.

Vitamin D3 from sunlight may improve the prognosis of breast-, colon- and prostate cancer (Norway).

To investigate whether prognosis of breast-, colon- and prostate cancer may be related to vitamin D(3), induced from solar ultra-violet (UV) radiation, through studies on geographical and seasonal variations in UV radiation. This study includes 115,096 cases of breast-, colon- or prostate cancer, diagnosed between 1964 and 1992. Among these, 45,667 deaths due to the cancer were registered. On the basis of a north-south gradient in solar UV radiation and geographical climatic differences, Norway was divided into eight residential regions. According to seasonal variations in UV radiation, four periods of diagnosis during the year were used. Case fatality according to residential region and to season of diagnosis was estimated using Cox regression. The effects of occupational sun exposure, childbearing pattern and educational level were also evaluated. No geographic variation in case fatality was observed for the three cancer types studied. A significant variation in prognosis by season of diagnosis was observed. Diagnoses during summer and fall, the seasons with the highest level of vitamin D(3), revealed the lowest risk of cancer death. The results suggest that a high level of vitamin D(3) at the time of diagnosis, and thus, during cancer treatment, may improve prognosis of the three cancer types studied.

Chaotic solar cycles modulate the incidence and severity of mental illness

This paper hypothesizes that the intensity of ultraviolet radiation (UVR) from the Sun predisposes humans to polygenic mutation fostering major mental illness (MMI) and other disorders of neurodevelopment. In addition, the variation in the intensity of this radiation acts to stress immune systems, possibly mediated by cytokines, resulting in variable clinical expressions of mental illness and autoimmune disorders. Organisms can adapt to chronic high-intensity UVR by producing melanin and by retaining various pigments. We found that 28% of 11-year solar cycles produce particularly severe solar flares during which UVR is 300% more intense and hence more damaging than normal. Out of a total of six severe cycles in the past 250 years, four have occurred in the past 55 years, possibly explaining the apparent increase in the incidence of MMI in recent decades. UVR is 10 times more mutagenic than ionizing radiation to nuclear DNA, and especially damaging to mitochondrial DNA. However, variable light as manifested by seasons stresses adaptability to UVR, possibly through an immune mechanism. We show that the region of the Earth having the most UVR, relative to the most variation in that light, is at 54±∼10° (N or S) latitude. Therefore, the most potential damage from sunlight occurs between the Equator and the Poles, not at the Equator itself. The human brain, our most important organ of adaptability, must be able to survive environmental variation, with successful matching to the environment resulting in adaptation. Unsuccessful adaptation to UVR (and possibly other types of radiation) results in mutation, which can produce neuro-chemical abnormalities manifested by MMI. We postulate that the combination of intensity and variation in UVR serves as a global modulator of MMI.

PAST SUN EXPOSURE, SKIN PHENOTYPE AND RISK OF MULTIPLE SCLEROSIS

The striking latitudinal gradient of multiple sclerosis (MS) prevalence may reflect variation in ultraviolet radiation (UVR). A Th1 cell mediated attack on myelin proteins appears to be important in the pathogenesis of MS and recent immunological work shows that UVR can suppress the Th1 cell mediated activity. We conducted a population based case-control study in Tasmania, Australia, to examine whether high past sun exposure was associated with a reduced risk of MS. Interviews were conducted with 136 cases with MS and 272 controls randomly drawn from the community and matched on sex and birth year. Measures included reported sun exposure, dermal actinic damage (a marker of cumulative lifetime sun exposure), and skin spectrophotometry. Higher (2.5 hours a day on average) sun exposure in summer on weekends and holidays over the age span of 6–15 years was associated with a decreased risk of MS (adjusted odds ratio, 0.31; 95 percent confidence interval, 0.16 to 0.59). High (grade 4–6) actinic damage was also independently associated with a decreased MS risk (adjusted odds ratio, 0.32; 95 percent confidence interval, 0.11 to 0.88). A dose response relationship was observed in both sun exposure over the age span of 6–15 years (p < 0.01) and actinic damage (p < 0.01). Higher sun exposure appears to be associated with a reduced risk of MS. These findings are consistent with insufficient UVR influencing the development of MS.

Determination of erythema-effective solar radiation in Japan and Germany with a spore monolayer film optimized for the detection of UVB and UVA--results of a field campaign.

The available physical and biological broad-band radiometers designed to determine erythema-effective radiation do not show any response or over/underestimate the biologically effective radiation to a high extent in the ultraviolet (UV)A spectral region. The data presented in this paper demonstrate that the biological system used in this study is the first one to make possible measurements of erythema-effective radiation in the sun in the UVA and UVB spectral region. These measurements were performed with a spore-film filter system as well as with spectroradiometers. It was demonstrated that this biotechnological method could be used to determine exact values expressed as minimal erythemal dose (MED). The spore-film system was tested in various field campaigns performed in Germany and in Japan. The seasonal daily variation of UV radiation in Germany determined in the period November 1995 to December 1996 using the spore-film filter system in sunny conditions tallied well with model calculations. The daily dose in Germany measured with the spore-film system close to the summer solstice, in sunny conditions (20.45 MED), was approximately 20 times higher than the lowest value measured close to the winter solstice (0.82 MED), a result which was in accordance with model calculations. The data determined with the spore-film filter system in Sapporo and Naha, Japan, fitted to the erythema-weighted data calculated from spectroradiometric measurements (Brewer), even at low solar radiation angles in a solar spectrum with less UVB but significant UVA. The spore-film dosimeter values were about 103 +/- 8% of the integrated dose of the Brewer instrument. The standard deviation of the spore-film measurements obtained in Japan was 12.8%. The responsivity of the spore-film system towards longer wavelengths within the UVA spectrum was tested with the Okasaki Large Spectrograph with monochromatic radiation. At a wavelength of 365 nm--in a spectral region which is dominant in many tanning lamps and with minor importance for solar radiation in summer conditions--the tested spore-film system gave results that were close (112% compared to the calibration dose) to the calibration dose which was used for irradiation.