Photo-oxidation. In the context of the Gulf oil spill, photo-oxidation occurs when sunlight facilitates a chemical reaction between the air and oil. As Overton explained, photo-oxidation basically takes a nonpolar molecule and makes it polar, which enhances the production of stable emulsions. Additionally, photo-oxidation can enhance phototoxicity. Although photo-oxidation has not been shown to have much of a direct effect on the human population, it does affect the ecology of our environment, which can indirectly impact human health.
Overton concluded by summarizing the types of issues that need to be considered when evaluating the complexity of exposure analysis. In addition to the effects that weathering has on the large number of existing chemicals and chemical structures within oil, the ongoing nature of the Gulf oil spill further complicates monitoring activities because not all the oil within the environment is at the same stage of the weathering process. Therefore, the exposure risks are constantly changing as the oil itself evolves within the environment.