Ok, let's leave it at that whether Downdraft or not. The question was rather whether cooking odors are significantly stronger with a recirculating island solution than with an exhaust one?
However, I would not execute Downdraft as recirculation - then you have the humid air in the base cabinet, where it causes the furniture to swell. Or you have a very decorative pipe end sticking out 10 cm from the island. Pest or cholera.
Our downdraft has a lot of space in the cabinet, with an activated carbon filter. You don't smell anything in the room even when searing sharply. As mentioned, depending on the price range.... with well-known ones it's a catastrophe...
However, I would not implement downdraft as recirculation - then you have the humid air in the base cabinet, which causes the furniture to swell. Or you have a very decorative pipe end sticking out 10 cm from the island. Pest or cholera.
With which model is that supposed to be the case? These are closed systems with ventilation grilles in the base (what kind of pipe?!)