  Quasi-periodic propagating disturbances (PDs) are ubiquitous in polar coronal
holes on the Sun. It remains unclear as to what generates PDs. In this work, we
investigate how the PDs are generated in the solar atmosphere by analyzing a
fourhour dataset taken by the Atmospheric Imaging Assembly (AIA) on board the
Solar Dynamics Observatory (SDO). We find convincing evidence that spicular
activities in the solar transition region as seen in the AIA 304 {\AA} passband
are responsible for PDs in the corona as revealed in the AIA 171 {\AA} images.
We conclude that spicules are an important source that triggers coronal PDs.
