While current HP is above 50%, each stack of Song of Tang increases Critical Damage dealt by your Martial Art Skills by 2%. While current HP is below 50%, each stack of Song of Tang grants your Martial Art Skills 2% HP Drain with a maximum drain rate of 2.5% of your Max HP per second.
You have contracted a lung disease in a toxic area. Logging/Mining efficiency is reduced by 10%. After 20 gathering actions, your character will be forced into a coughing fit, interrupting your activities.