DIAGNOSING AN UNHEALTHY BUILDING WITH AIRBORNE PARTICLE COUNTS
Airborne particles are an often-overlooked aspect of indoor air quality (IAQ). Even among my own peers, particles are rarely a top priority. In this area, I’m an outlier.
When I do indoor air quality surveys, not only do I look at the standard environmental indicators like carbon dioxide, carbon monoxide, temperature, and relative humidity, but I also collect airborne particle counts at that time. I’m finding more and more that the presence of particles in the air is causing upper respiratory irritation. Many times, the complaints being expressed by building occupants are related to elevated particles. In fact, a few recent cases I’ve worked on were solved because I collected airborne particle counts during my survey.
The first case was in a commercial high-rise building where people were suffering from coughing, sneezing, and itchy eyes. When we talked to the occupants, they mentioned seeing a lot of dust on their desks and cubicle workstations. I took a look and noticed that the dust we found was the same light blue color as the carpets we were walking on. That gave us a good indicator of where the dust was coming from.
Our first suspicion was that the custodians were kicking the dust up and not vacuuming it properly. The problem was that in this particular building, the contracted custodians used purple backpack vacuums with a HEPA air filter. That usually means the vacuums will be capturing particles down to .3 microns in diameter. We went to the custodial closet, took the vacuum canister apart, and took a look at the three-stage filter.
Stage one was dirty; stage two was loaded with dust and dirt; and stage three, the HEPA filter, was also dirty! Basically, the vacuum cleaner was actually releasing more particles in the air that then settled as dust on the surfaces.
The Fix: We directed the building management to inform the custodians that they needed to clean their vacuum filters and get on a program to change their filters on a regular basis.
The Result: The complaints went away.
It’s in the Walls
I was called to a federal building that has been struggling with a reoccurring leak for many years. The building would leak in one gentleman’s office, the building owner would repair the leak, and for six months, everything would be fine until it leaked again. The building owner would find the new leak, repair that, and the cycle would continue.
When we arrived, the three acoustical ceiling tiles along the wall near the window were missing. The tiles had been removed 10 days before, and during that time, that gentleman started reporting upper respiratory problems. We ran particle counts in this man’s office and found the airborne levels of PM10, which are larger-sized particles, were twice the allowed average set by the U.S. Environmental Protection Agency (EPA). Meanwhile, the smaller particles, PM2.5, were right at the limit allowed by the EPA. To make matters worse for this gentleman, the next day he was scheduled for a doctor’s appointment to have sinus work done.
The Fix: We recommended putting the man in another office in an unaffected area, fix the leak, replace the ceiling tiles, and do a hyper-clean of all ceilings, walls, and carpeting in the space to remove particles from the air until everything was fixed and clean.
The Result: Potential health problems will be avoided.
Our last story involved a federal courthouse. We hadn’t received any specific complaints from people, so we ran the same series of tests across the second floor. As we did, we found one specific set of four offices had high levels of airborne particles. We always go above the ceiling to see what was going on up there, and when we looked above the ceilings in these offices, we found a lot of insulation from the deck above had fallen onto the ceiling tiles.
The building engineer mentioned that the building had been reroofed two months prior. All of that insulation failed and fell onto the ceiling tiles as a result of the roofing project. Unfortunately, since the area above the ceiling is used as an air return, the particles, fibers, and dust from the insulation worked their way down into the tenant spaces.
The Fix: The large chunks of insulation needed to be removed, the ceiling tiles needed to be vacuumed, and the damage that was done to the underside of the deck above needed to be repaired.
The Result: The airborne particle count of these four offices went back to normal.
If we didn’t check airborne particles during our surveys, we would not have had the data to solve the problems in any of these buildings and insist on the repairs that needed to be done.
I’m beginning to encourage others in my field to make particle counts part of their initial survey and learn how to read that data so they can give their clients valid information. We have lots of data using particle counters that show us what is healthy and what isn’t healthy inside all kinds of commercial buildings. Airborne particles can give a lot of insight into what’s going on in your building too.