If you live in any dry, flat or arid states in the U.S., these states experience a regular sandstorm event. The problem with these sandstorms is that they often blow in high, blow in strong, and leave behind enough dust and/or sand to choke every living thing within miles. You may also have to have an HVAC contractor come out to perform duct cleaning in your home or office building after a sandstorm dies down. Duct cleaning in a sandstorm has some unique and key things to remember, and things which you should clearly know if you have just moved into a sandstorm-prone state.
DO NOT Operate Your Central A/C During a Sandstorm
The particles in a sandstorm go right through an air conditioner's condenser box. As it settles, the sand/dust may get sucked inside and blow through your ventilation system. Whenever possible, do not operate your central A/C during a sandstorm. If you see a sandstorm coming, shut down the A/C and your entire furnace/forced air system. This prevents a lot of the sand/dust from getting inside, and will also prevent a more expensive duct cleaning bill.
Wait for the HVAC Contractor to Clear Your Ventilation System
A lot of the particles that a sandstorm picks up can be very harmful to your lungs. You want to be absolutely certain that you do not encourage these particles to become airborne inside your home or office. That said, your entire heating and cooling system needs to be cleared by an HVAC contractor before you can turn on any heat or A/C, and the furnace fan should be off as well. Once the contractor has completely cleared the ventilation system and cleaned out the condenser box outside, you can turn on whatever heating and cooling feature you need. If it is going to be especially uncomfortable weather-wise while you wait for the contractor, you may want to stay at a hotel until then.
Wear a Mask or Evacuate the Structure During Cleaning
When the contractor does arrive to clean out your ventilation system, it is a good idea to get all of the inhabitants out of the house (including pets). If you and your family members or roommates cannot leave and go somewhere else, you will all need to wear some type of respirator over your mouth and nose until the duct cleaning is complete. As for any pets, see if they can stay with a neighbor or kennel/board them for a few hours until the contractor has finished the job.