1 Introduction
2 Observations and data
2.1 $\mathsf{N H}_{3}$ and $\mathsf{H}_{2}\mathsf{O}$ Maser Observations
2.2 Archival Data / Catalogue
3 Results
3.1 Data overview
3.2 Ammonia line fitting
3.3 Physical parameters from $\mathsf{N H}_{3}$ lines
3.4 Physical parameters from CO lines
3.5 Deriving dust properties and spatial distributions
3.6 Identification of dense gas clumps with dendrogram
4 Discussion
4.1 Comparison of the $\mathsf{N H}_{3}$ and $\mathsf{C}^{18}\mathsf{O}$
4.2 Cause of weak $\mathsf{C}^{18}\mathsf{O}$ emission in dense clump
4.3 $\mathsf{C}^{18}\mathsf{O}$ depletion factor
4.4 The condition of weak CO depletion in the centre of PGCC G224.28–0.82
5 Conclusions