At home we have an IQAir HealthPro Plus. At my wife’s office where she is at greater risk of encountering chemicals, she has a IQAir Multigas Air Purifier. These are an invaluable part of making the environment safe. Since their capacity is capable of handling much larger spaces than the size of our home, we can rest easier knowing that the air we’re breathing is far less contaminated than the air outside.
As for why we recommend the IQAir line of products vs the standard HEPA air purifier that you can get most anywhere, it’s about the capacity, efficiency, and capabilities of the unit. The IQAir line consistently rates the highest out of most any air purifiers though there are other high end units available. If they rate well and work, get them. You’re looking for something that can remove chemicals, gasses, VOC’s, preferably medical grade, and something that can handle the space you’re putting it in (large capacity).
There are also air purifiers available for vehicles. These plug into the cigarette lighter and help remove the toxins that enter the car while driving. One major complaint of people with chemical sensitivities are the exhaust fumes from other cars on the road. Even if you drive with your windows up and the air in your car off or re-circulated, it’s still bringing in outside air.