Copernicus Access Hub is official source of earth observation data. CREODIAS as data and information access service platform is supplied from this data source. Our data repository is still supplemented by historical products type SY_AOD which you're looking for. Unfortunetly, this process is slow beacuse this data aren't accessable for our platform offhand, so we need to order each product and wait them to restore, there are also limits of ordering. That's the main difference in quantity of data. Please pay attention to fact, that all products from Sentinel-3 on our platform are online (full archive - https://creodias.eu/data-offer
) and can be downloaded immediately. A big part of products from Copernicus Access Hub are in offline status, so if you want to download them, you need to first make order and wait for processing.