AIR POLLUTION IMPACT ON ULTRA VIOLET INDEX (UVI)

Introduction: UV index is a precaution index that shows level of exposure to sunlight UV. UV index can be calculated by the related formula according to solar spectral irradiance (Eλ). But this formula and others like this are mostly used when sky is clear. The aim of this investigation is determination of effect of PM2.5 and NO2 concentration on UV index. Material and methods: Two points with the same altitude were chosen and the PM2.5 and NO2 concentrations, and UV index were measured 4 h every day from 11am to 3 pm, in these points during one month from 15 October till 15 November 2016. Results: Simple and interaction regression models showed significant reverse relationship between contaminants concentration and UVI (Pvalue ≤ 0.05), although the effect of PM2.5 concentration was more significant than NO2 (Pvalue ≤ 0.001), in both point. Conclusions: There is a strong correlation between PM2.5 concentration and decrease in UV index. Also a significant correlation between NO2 concentration and UV index was found and any significant correlation between UV index and interaction effect of NO2 - PM2.5 was not appeared. Results of this study showed that air pollutants concentration can reduce UV index, thus it can change the risk of skin eczema and skin cancer.