You are tasked with evaluating the performance of the HVAC system in a commercial office building. Employees have been experiencing uneven temperature distribution and stuffy air.

a$)$ Suggest an instrument to assess the HVAC system's effectiveness and comfort conditions

b$)$ Describe the specific measurements and readings you would prioritise. Review the data and compare it to established IAQ standards and guidelines to identify potential issues, prioritise corrective actions, and improve worker comfort and health.