Organic compounds released into the atmosphere from vegetation or industrial processes ultimately leads to the formation of harmful particulate matter. This is often initiated by the highly reactive species OH, which can add to double bonds. The radical which is formed is also highly reactive, which will combine with oxygen to form oxygenated organic matter. As it continues to be processed, it can begin to form particles in the atmosphere. Understanding the early steps of this mechanism is necessary for understanding how different chemicals lead to the formation of particulate matter. We have studied a series of molecules to investigate chemical trends in this process. We find that certain chemical structures can drastically reduce reactivity, changing how they are processed in the atmosphere. We discuss these trends, their origin, and implications.