Long term variations in erythema effective solar UV at Chilton, UK, from 1991 to 2015.

In this paper erythema effective UV radiant exposure data from the PHE solar network Chilton site for the 25 year period from 1991 to 2015 are presented. The year with the highest average daily erythema effective radiant exposure was 2003 at 1577 J m-2 and the year with the lowest average daily radiant exposure was 2010 at 1149 J m-2. Overall, the average daily radiant exposure per year ranged from 5655 J m-2 to 9.98 J m-2 with the average being 1306 J m-2. A preliminary analysis of the data set is carried out. A statistically significant (p = 0.01) increase in annual radiant exposure of 4.4% per year was observed from 1991-1995. Thereafter a small decrease in annual erythema effective radiant exposure of 0.8% (p = 0.002) per year was observed from 1995-2015 with a slightly faster rate of decrease from 2000-2015 of 1.0% (p = 0.007) per year. In terms of seasonal analyses, a statistically significant increase in erythema effective UV radiant exposure of 5.1% (p = 0.02) per year in the summer during 1991-1995 has been found along with small decreases in spring and summer during 1995-2015 (-1.0%; p = 0.01 and -0.7%; p = 0.01 respectively) and 2000-2015 (-1.1%; p = 0.03 and -1.2%; p = 0.003 respectively). The data suggest that the erythema effective UV dose available for impacting public health has been decreasing in recent years.

TEMPERATURE CORRECTION OF HISTORIC ERYTHEMA EFFECTIVE SOLAR UV DATA RESULTING IN A CONTINUOUS 25-YEAR DATA SET AT CHILTON, UK.

Public Health England has a solar network which has been established for over 25 years which measures erythema effective UV, UVA and photopic radiation. At the Chilton site there are erythema effective solar UV data available for 25 years from 1991 to 2015. Until October 2004, the data were gathered using a Solar Light R-B 500 radiometer (SL-500), which is not temperature regulated. From October 2004, the data are from a temperature regulated Solar Light R-B 501 radiometer (SL-501). A temperature correction model has been developed using overlapping SL-500 and SL-501 data from 2006 and verified using overlapping SL-500 and SL-501 data from 2005. This correction has been applied to the non-temperature regulated SL-500 Chilton data from 1991 to 2004 resulting in a 25-year dataset of SL-501 equivalent data for the analysis of long-term trends. The development and verification of this model is described.

Safety of light emitting diodes in toys.

Light emitting diodes (LEDs) are increasingly being used in toys. An assessment methodology is described for determining the accessible emission limits for the optical radiation from the toys, which takes account of expected use and reasonably foreseeable misuse of toys. Where data are available, it may be possible to assess the toy from the data sheet alone. If this information is not available, a simple measurement protocol is proposed.