Tracer particles not following the mainstream floe

Hi

I am modeling CO2 as a tracer gas particles in air. I have been trying to simulate CO2 by Particle Tracing module, after I found the diameter size and density of CO2 particles.
I have noticed that the particles do not follow the flow, but they move almost in a straight line from where they are released and do not follow the mainstream flow. They are released from the inlet of the mainstream flow.
I have changed the type of Drag force laws, such as stokes, Haider, Schiller, but did not see significant differences.

I would appreciate it if you could guide me.

Thank you