As some regions of the world especially in the subtropics, e.g. the Middle East, experienc climate change impacts such as hotter temperature and dryer weather, near surface UV-radiation also increases that can have adverse effects on the humans and other living things. Hence, estimations of UV radiation dose on regular bases is important. Data of total ozone from ground station and also satellite can be used along with solar radiation intensities, to estimate UV radiation dose especially in the hot seasons, to be used for social use, in order to do preparation to protect themselves against the excessive UV radiation outdoors.
   This is particularly important in more populous areas as big cities such as Tehran. Total ozone data at the Geophysics station has been measured by Dobson spectrometer, now for nearly for the last decade. Using such data are used not only for calibration of satellite data, but here are used along with solar radiation in Geophysics Station, nearly at center of Tehran to calculate UV-radiation (as UV index), especially UV Erythema radiation.
   The aim of present study is to investigate monthly and seasonal variations of UV Erythema radiation using solar radiation along with total ozone over Tehran area for the period of 2013-2023 as UV radiation can affect human health. Daily solar radiation and total ozone data for a central station in Tehran (Institute of Geophysics) for period of 11 years (2013-2023) are used to find UV Erythema index which is calculated using solar zenith angle and total ozone acquired be a Dobson total ozone measuring system at the Geophysics Station.
   The results show that the UV Erythema index is large for the summer months especially for Julyof about 12.06 (extreme level, needing protective shield). The clear negative correlation between total ozone and UV-index shows a power relationship (αTo^-1.635) for warm months (May, June and July). Comparison between the UV indexes for  cities with different altitudes show that it increases with height by about 11 percent every kilometer. Also for the period of study, the trend of UV Erythema index in warm months has been on the increase, indicating that climate change may expose people in Tehran to more UV Erythema radiation. About 21.6 percent of days of the year, especially warm months in Tehran has extreme levels of UV Erythema index (>10, typically 11), requiring protective shields in the mid-days of these months, and it seems to have an increasing trend due to climate change.
    Such study can also be extended to other large cities, especially in southern part of Iran that are prone to large UV radiation in the warm months of the year, with adverse health effects for skin and eye.