Evaluation of solar ultraviolet radiation in Zanjan city using the ultraviolet index

Monitoring the amount of ultraviolet radiation from sunlight can provide a basis for assessing people's exposure, raise public awareness and warn people against this radiation. Measuring the sun's ultraviolet index over a working period is an accurate choice to achieve this goal.

In this study, the amount of solar UV index in one of the outdoor locations of Zanjan city was measured using Solarmeter model 5.6 UV index meter for one year period. Measurements were performed from 9 am to 5 pm every 30 minutes in direct sunlight in even days for one year period (2018-2019). Finally, the results were analyzed using Excel software.

The highest value of the maximum daily UV index was related to July, with an average value of 11.87 ± 0.649; while, the lowest value of the maximum daily UV index obtained in January, with an average value of 2.23 ± 0.944. In most months of the year, except for late November, December, January and cloudy days, the average value of the maximum daily UV index around noon exceeds the UV index alert threshold set by the World Health Organization (WHO). Even for the safe time period during spring and summer, the average UV index can exceed the UV index warning threshold.

Determining the intensity of the sun's hourly UV radiation is important and necessary to increase the peoples’ and workers’ awareness working in the open environment, as well as to plan for protective measures in any place, especially in Zanjan.