The fumes come from the engine, there's nothing the bleed system can do to mitigate that. All bleed components already don't use any lubricant, they don't add a

The fumes come from the engine, there's nothing the bleed system can do to mitigate that. All bleed components already don't use any lubricant, they don't add any fume. Also all bleed systems across the whole industry have an extremely similar architecture. So in the end the component that really matters for this is the engine. And both Airbus and Boeing use very similar engines from the same suppliers. And the engine manufacturer defines the maintenance tasks for it.