Hi leeman,
While it may be more than you are looking for … there is also a lot more information in post #2 here and the more detailed posts and information it links to about safe, natural, organic, “chemical free”, and “green” mattresses and mattress materials that can help you sort through some of the marketing information and terminology that you will encounter in the industry and can help you differentiate between them and answer “how safe is safe enough for me” and that can help you decide on the type of materials and components you are most comfortable having in your mattress or on the certifications that may be important to you. These types of issues are complex and are generally specific to each person and their individual sensitivities, circumstances, criteria, beliefs, and lifestyle choices.
The only reliable way to to assess the “safety” of different materials in more general terms is based on lab tests and the certifications they have for harmful substances and VOCs so that you have some assurance than the VOCs are below the testing limits for the certification. If the materials in a mattress or the mattress itself has a reliable “safety” certification then for most people they would certainly be “safe enough” … regardless of the type of material or the name of the manufacturer on the label although it’s still possible that a small minority of people that have some medical conditions (such as MCS or multiple chemical sensitivities) or for other reasons are more sensitive may still be sensitive to some types of memory foam that would be fine for the large majority of people. The most common certification for memory foam would be CertiPUR.
A mattress will tend to soften and break down from the top down and since so many of the innerspring mattresses sold in the mainstream industry are made by major manufacturers that all tend to use lower quality and less durable materials in their comfort layers … innerspring mattresses have developed a reputation for being less durable and when in fact it’s the softening and breakdown of the comfort layers (usually some type or combination of foam) on top of the innersprings that are by far the biggest cause of the sagging issues that have become so common in the industry and not the innerspring itself. A well constructed innerspring mattress that uses high quality and durable materials in the comfort layers won’t have the same sagging issues that you tend to see in so many of the mainstream innerspring mattresses although marketing “against” innerspring mattresses has led many consumers to believe the “story” that “innersprings are bad” or “less durable” but this would only apply to mattresses that use lower quality and less durable comfort layers above the springs.
All the major brands (such as Sealy/Stearns & Foster, Simmons, and Serta) tend to use lower quality materials in their mattresses than most of their smaller competitors that will tend to soften or break down prematurely relative to the price you pay which is why I would generally suggest avoiding all of them completely (and the major retailers that focus on them as well) along with any mattress where you aren’t able to find out the type and quality/durability of the materials inside it (see the guidelines here along with post #3 here and post #12 here and post #404 here).
Assuming that the materials in a mattress you are considering are durable enough for your body type and meet the quality/durability guidelines here relative to your weight range … the choice between different types and combinations of materials and components or different types of mattresses are more of a preference and a budget choice than a “better/worse” choice (see this article).
I’m looking forward to your comments and feedback after your visit. Just in case you haven’t seen it yet … the better options or possibilities I’m aware of in and around the Las Vegas area (subject to making sure that any mattress you are considering meets the quality/value guidelines here) are listed in post #2 here.
Phoenix