The term that describes particles in the atmosphere that enhance condensation during haze formation is cloud condensation nuclei (CCN), which closely relates to the role of aerosols. Aerosols are tiny solid or liquid particles suspended in the atmosphere that can serve as surfaces on which water vapor can condense. This process is crucial in cloud formation and can lead to the development of haze when humidity levels are high enough.
While other choices include water vapor, which is essential for condensation but does not itself enhance the process, and fog droplets, which are the result of condensation rather than the particles that promote it, the presence of aerosols is vital for a range of atmospheric phenomena, including haze. They act as the catalysts for condensation, allowing moisture from the air to form droplets around them. Therefore, aerosols are key to the formation of haze, making them the most relevant answer to the question.