UVC and most of UVB are absorbed by the ozone layer in the earth's stratosphere. Ultraviolet light causes sunburning and damages the skin's elastic protein, collagen. It is also a major factor in the development of the skin cancers rodent ulcer (BASAL CELL CARCINOMA), MALIGNANT MELANOMA and SQUAMOUS CELL CARCINOMA.
Lemon oil is extracted from the peel of the fruit. People with photosensitivity should not spend a great deal of time on a beach without protection. Lemon oil can be diluted and used to treat bad breath. Lemon oil may be helpful in treating burns. Lemon oil may be used in facial products to protect against blemishes.
The one I listed in the ingredient list is 100% pure lemon eucalyptus oil. Also note that Lemon Eucalyptus Essential Oil is different than the US designated Oil of Lemon Eucalyptus (OLE or Citriodiol) which is a refined version with increased concentration of PMD (explained in list of natural mosquito repellent oils).