Awwal 09, 1432 / April 13, 2011, SPA -- The dusty weather conditions over the city of Riyadh today has not affected the taking off and landing air traffic at King Khalid International Airport, Civil Aviation Authority said in a statement. The air control department has received warnings since early today that horizontal vision levels will be low due to a wave of dust, the statement said, adding that the warning went into effect until 6:00 hrs this evening.