Anti-cyclones entrap pollution particles! They have quite an impact on surface conditions because they take up a lot of air space as they move downwards over an area. Their descent encourages evaporation as well as pressure and temperature rises, but discourages cloud formation, rainfall and surface to lower atmospheric air movement. Pollution particles therefore become trapped between the earth's surface and the lower atmospheric limits of the anti-cyclone. At the earliest, if even that, they will not move until the anti-cyclone does.