Follow the Fresh Air
Industrial hygienists rely on instruments to measure all kinds of exposures. We are the samplers, and instruments are part of the process of risk assessment. But over-reliance on instrumentation when performing indoor air quality investigations can be a detriment.

Don’t get me wrong. There is definitely a place for instruments.  PERCEPTION AND CAUSATION I was taught that an IAQ investigation involved three major aspects: measurements, interviews of concerned or affected persons, and a walk-through evaluation. Measurements are my expertise. I have invested many hours in understanding the instruments I use to make risk assessments. I use IAQ meters, 4-gas meters, particulate meters, photoionization detectors (PIDs), and others. This is what IHs are trained to do: we learn how to use our instruments and how to get the most valuable information from them. They provide numbers we can use to relate to exposure limits or IAQ parameters, so it’s easy to see how we can fail to give sufficient effort to the other two parts of the investigation. When people get sick from unidentified agents, they present challenges to the IAQ investigator. Interviews with these individuals, although necessary, revolve around their perceptions of the problem, which are often misleading. I’ve noticed that safety and health professionals withdraw emotionally from people who claim that “the building is making me sick.”  Early in my career, I spent over a year investigating one such complaint. A person reported allergic-type symptoms and understandably wanted to know what caused the problem. But the tools available to us for determining causation are not that specific. I measured IAQ parameters, looked in the supply air ducts, and sampled for a few substances, such as fiberglass. Building occupants often fixate on mold, but my search yielded no finding of mold or any other agent of concern. The occupational health practitioner, seeing my report, bluntly told the sufferer that the problem was “all in her head.” As you can imagine, she was outraged. A few weeks later, a colleague of hers who worked in the same area of the building reported what I believe was the acquisition of yet another allergy. What was causing these allergies? Complicating matters, my efforts to coordinate and work with local management yielded little help. They did not want to discuss the problem openly. There were, in fact, many complaints about this building over years. An open conversation would likely reveal years of resentment and mistrust. When I looked at the data, I estimated that one or two allergic cases were developing each year, yet I found only a slightly higher than normal perception of household dust.  Although I left the company shortly thereafter, I continued to wonder about the cause of these illnesses. I wrote a research paper in graduate school on the psychosocial factors of IAQ. I learned that slight temperature changes affect perceptions of IAQ problems and that people often report illness when a known pollutant source (such as old carpet) is in the building where they work. One study discussed how management’s suppression of complaints contributed to workplace stress, lower productivity, and reduced sense of cohesiveness. While this research was interesting, the only prescription I found was to have an open mind and keep looking for the cause. A GOOD WALK-THROUGH I am convinced that most safety and health professionals are ill-prepared to deal with IAQ matters. The conscientious ones dutifully work through the guidance, not expecting to find anything of note. This can lead to resignation and apathy. “People get sick,” they think, “and there isn’t a lot I can do about it.”  In my opinion, the first step in getting to the bottom of troublesome IAQ problems is to recognize that IAQ measurements aren’t nearly as valuable as a good walk-through. The problem we face is understanding what to look for. We rely on published checklists, but since we haven’t created them ourselves, we don’t always know what relevance they have. For example, one checklist had me looking for chemicals under kitchen sinks, which may be helpful on occasion but is usually noise in a sea of possible causes. So what should we be looking for?
 The first step in getting to the bottom of troublesome IAQ problems is to recognize that IAQ measurements aren’t nearly as valuable as a good walk-through.
JOHN L. PARKER, MSPH, CIH, CSP, is a principal industrial hygienist with Northrop Grumman Corporation with 17 years of experience. He lives in Baltimore, Md.   Send feedback to The Synergist.

Just as the mantra for accountants is to “follow the money,” I suggest IAQ investigators follow the fresh air. In most cases this means investigating the design and operation of the building’s heating, ventilation, and air conditioning (HVAC) systems. To do this you need to enlist the help of some maintenance personnel, and you need to ask them to show you the movement of the fresh air through the building, from the supply through the return. I think the reason I’ve neglected to use the expertise of maintenance technicians to their fullest is that I didn’t want to step on their toes. They are our most valuable asset in solving IAQ problems, but they’re human and make mistakes. They frequently wear many hats and can get complacent like the rest of us. They too rely on instruments to tell them how the system is operating. That’s why you need them to give you a guided tour of the HVAC system. Most likely, they will be the ones to show you the problems they have failed to catch on their own. Relying on HVAC technicians has improved my IAQ investigations on several occasions. In one case, I had about a dozen people telling me they were experiencing symptoms directly related to the building’s environment. Measurements of temperature, relative humidity, carbon dioxide, and volatile organic compounds were normal. Yet the building had an odd odor that dated back some 10 years when the roof was repaired. I arranged to have maintenance show me the air handler. As we walked the system, I noticed the fresh air intake was open a mere sliver and was clearly not at 10 percent. We adjusted it, and I returned a few days later to follow up with occupants. The change was dramatic. People who had been suffering from allergies for years reported significant improvement. In another case, a colleague was investigating a similar case of illnesses reported in a section of the building. We walked through the area together with maintenance. The building had a computerized control system that said the fresh air was 10 percent. After about 40 minutes of following the fresh air through the HVAC system, we found a fresh air actuator had broken off from the damper it was supposed to control. Needless to say, we had it repaired. GOOD INVESTIGATIONS I’m not certain we appreciate the effect fresh air has on people’s health. Medical practitioners have been prescribing fresh air and sunshine for centuries. It may be that fresh air has ions that reduce the bacterial count in the air. We don’t measure these things, but they affect human health. Whatever the case, I’ve found following the fresh air to be invaluable to performing good IAQ investigations. I hope it will help you, too. 

AIHA: The IAQ Investigator’s Guide, third edition (2016).