The action spectrum for vitamin D3: initial skin reaction and prolonged exposure.

Vitamin D3 photosynthesis in the skin is formulated as a set of reaction equations, including side-reactions to lumisterol, tachysterol and toxisterols, and the accompanying reverse reactions, isomerisation of previtamin D3 to vitamin D3 and photodegradation of vitamin D3. The solution of this set is given for the stationary irradiance spectrum. The effective action spectrum for the instantaneous vitamin D3 production changes shape as a function of exposure, and therefore, no single action spectrum can be used.

Skin cancer risks avoided by the Montreal Protocol--worldwide modeling integrating coupled climate-chemistry models with a risk model for UV.

The assessment model for ultraviolet radiation and risk "AMOUR" is applied to output from two chemistry-climate models (CCMs). Results from the UK Chemistry and Aerosols CCM are used to quantify the worldwide skin cancer risk avoided by the Montreal Protocol and its amendments: by the year 2030, two million cases of skin cancer have been prevented yearly, which is 14% fewer skin cancer cases per year. In the "World Avoided," excess skin cancer incidence will continue to grow dramatically after 2030.

Know your standard: clarifying the CIE erythema action spectrum.

The standard erythema action spectrum provides an internationally accepted representation of the erythema-inducing effectiveness of wavelengths in the UV part of the spectrum. The action spectrum forms the basis of the UV index used for public health information, defines the standard erythema dose unit and the minimum erythema dose and is the default response spectrum aspired to by a range of UV radiometer manufacturers. However, there are several versions of this erythema action spectrum in use, and only one of them has been endorsed as a standard.

Calculations of the human vitamin D exposure from UV spectral measurements at three European stations.

The health benefits of solar UVB and vitamin D in reducing the risk of cancer and several other diseases have been well documented in recent years. In this study, quality-checked spectral UV irradiance measurements from three European stations (Jokioinen, Finland; Bilthoven, The Netherlands; and Thessaloniki, Greece) are used and the vitamin D effective dose (VDED) is calculated. The maximum average daily VDED is measured during the second half of June and it is up to 250 times higher than the corresponding winter minimum value.

Europe's darker atmosphere in the UV-B.

Irradiation in the ultraviolet wavelength range is found to be up to 50% lower in the European summer compared to sites with comparable latitudes in New Zealand. We have developed a method to quantitatively attribute the causes for such differences between sites by analysis of spectra. We conclude that these large differences are caused mainly by differences in total ozone, cloudiness, aerosol loading and Sun-Earth separation.

Variability of UV irradiance in Europe.

The diurnal and annual variability of solar UV radiation in Europe is described for different latitudes, seasons and different biologic weighting functions. For the description of this variability under cloudless skies the widely used one-dimensional version of the radiative transfer model UVSPEC is used. We reconfirm that the major factor influencing the diurnal and annual variability of UV irradiance is solar elevation.

Health effects from stratospheric ozone depletion and interactions with climate change.

The potential health effects of elevated levels of ambient UV-B radiation are diverse, and it is difficult to quantify the risks, especially as they are likely to be considerably modified by human behaviour. Nevertheless epidemiological and experimental studies have confirmed that UV radiation is a definite risk factor for certain types of cataract, with peak efficacy in the UV-B waveband. The causal link between squamous cell carcinoma and cumulative solar UV exposure has been well established.

Exposure to solar ultraviolet radiation in young Dutch children: assessment by means of a 6-week retrospective questionnaire.

We designed a 6-week retrospective questionnaire on sunlight exposure. Estimation of the short-term exposure to sunlight is important for observational human studies concerning the effects of ultraviolet radiation (UVR) on the human immune system and related resistance to infections. This questionnaire was given to the parents of 1672 1-year-old children in the Netherlands who participated in a birth cohort study.