We absolutely try to identify that if we see that there's circumstances, and we often learn why we're there is because that there's a suspected mold problem, whether it be a leak in the wall or whether there has been a leak in the wall. So under those circumstances, if we're looking to see whether that has an effect, we can take air samples inside the wall cavity, we can take samples on surfaces, we take air samples and other samples that might be related to that, we could take bulk samples back to the lab and have them analyzed. So we absolutely can do that and try to help that. But, even beyond that we can tell them the nature of the kinds of leaks and the kinds of problems that are associated with that. For instance, if it's a toilet backup, they could have a sewage type backup. There's guidelines that are published by the EPA or the CDC. If that happens on a carpet, that carpet should be replaced. Anything that's a porous material, if you can replace it, it should be replaced. If it's a material like the plywood on the floor or underneath the carpet or something like that that you can't necessarily replace, then it should be treated properly and sealed and encapsulated and that kind of thing before you put it back together. So we can provide some of that information – about how to properly prepare it as part of our investigation and part of our report.
One of the other things that we're finding when we find damage like that and especially if they've gone in and they've done some sheet rock work or done some other kinds of work. A lot of times we hear stories that, "Well, they've come in and they've done this and I'm still having these health symptoms." The background particulate in the air is a really important part of indoor air quality health and it's a really overlooked part. I don't understand exactly why because there's literally hundreds, if not thousands, of studies globally about the problem that background particulate provide causes for breathing difficulties and other things in the indoor environment. But when you're doing drywall work and all that kind of stuff, the particles, the dust and stuff that's in the air is going to spike. And those can cause serious health issues also especially with breathing difficulties. And the way that you get that out of the air is with filtration. Again, it goes back to what we've found on these HVAC systems, which is your primary source of filtration for the indoor environment. The filters that they have in those are statistically equivalent to no filter at all when it comes to particles as such small as respirable particulate. And that's the one that causes the big damage.
So people can be exposed to this background particulate, either from work that's being done or from deterioration in the indoor environment due to some of the damage that has been done that doesn't show up in most reports – some of the reports will show that it's 1, 2, 3, 4, or 5 on some kind of a scale like that. And some of them refer to it that, whether or not this is likely to cause enough debris on the slide to prevent an accurate count of the particulate. But they're not looking at the particulate itself as a health cause to the individual.
We actually do a statistical count in at least three cells to give an idea of what the background particulate is in the indoor environment. We find that the background particulate indoors is most often much higher than outdoors. And in some cases, much much higher. To give you an equivalent, see, we took air samples from 56 locations that were taken during the code yellow and code red we have because of the fires up north. And in those air samples, about 24% of the samples had particulate levels above 200,000.
What we're finding in the homes, and we're biased towards those that have some problems, is about 25% of the indoor air particulate is higher than 200,000. So in many cases in these damaged homes we go into, the background particulate is high enough that if it were in the outdoor area that they'd have code yellow or code red declared, you know, and nothing has being done about it, and these filters that we have in there, are incapable.