The polycyclic aromatic hydrocarbon (PAH) 1,4-naphthoquinone is produced through automobile exhaust and other such activities. 1,4-naphthoquinone can be transported for thousands of kilometers in the atmosphere and is consequently subjected to solar radiation. Due to its size and behavior in the atmosphere, 1,4-naphthoquinone has many negative consequences on the environment and human health. To simulate the chemistry of 1,4-naphtoquinone in cloud water, it was placed under a solar simulator with iron and highly purified water. Gas chromatography mass spectrometry was used to monitor the behavior of 1,4-naphoquinone over time when exposed to solar radiation in these conditions. This data will be used to propose a reaction pathway for 1,4-naphthoquinone in the atmosphere. Several key intermediates were identified including 1-napthol, 2-napthol, and juglone. These are important components in the formation of humic-like substances, which have been linked to lung damage and other health outcomes in humans.