RIYADH: Ministry of Health has advised all citizens and residents, especially patients with asthma or chest infections to guard against exposure to the sweeping dust wave in some areas of the Kingdom. It asked all to exercise caution and venture out of homes only when it is absolutely necessary. The ministry also stressed on the use of face masks, noting that dust particles affect the respiratory tract, causing allergic rhinitis. Minister of Health Dr. Abdullah Al-Rabeah has issued instructions to all managers of health affairs departments to take necessary measures to face the dust wave.