Recent trends to improve fuel economy and reduce emissions have led to changes in engine design and operation. These changes include the introduction of gasoline direct injection, after treatment devices including exhaust gas recirculation and differences in combustion conditions. Overall this has led to a more severe environment for the lubricant, including an increase of nitrogen dioxide in the engine. The impact of increased nitrogen dioxide on the degradation of lubricant base oils has been investigated in this study. Squalane was used as a model base oil for the lubricant system and degraded in an environment of nitrogen dioxide. GC x GC separated the resultant product mixture for the degradation of the hydrocarbon, which, coupled with time of flight mass spectrometry, led to the identification of the major products; alcohols, ketones and alkane fragments. Nitrogen containing products were identified using a nitrogen chemiluminescence detector, with high concentrations of nitromethane being the dominant species. The total organic nitrogen content was quantified and compared to the input of nitrogen dioxide, showing a maximum of 17% of the intake incorporated into the liquid phase. The formation of alkyl nitrites have been found to be unstable due to the weak CO-NO bond which leads to the formation of alkoxy radicals. This experimental evidence has led to the elucidation of the mechanism for nitration which is presented in this study.