| Problems | Reasons | Solutions | Principles | Targets |
| Strong sweat smell | Bacteria decompose sweat to produce smell plus poor ventilation | Negative ion generator, UV lamp and ozonizer | Negative ions can reduce dust, sterilize and disinfect air | Intelligent system to enrich oxygen, sterilize air, and improve air quality in underground gyms |
| Excessive bacteria and virus | Untimely disinfection | |||
| Excessive PM 2.5 | Isolated space with many body-builders but low utilization rate of fresh air system | |||
| Excessive CO and CO2 | O2 generator | More O2 | ||
| Low O2 | ||||
| Poor ventilation | Higher costs | HEPA filter | Ventilation | |
| Few ground space | Agglomeration effect of population in big cities | Develop and use underground space | More resilience for areas for “Dual Carbon” |