Skip to main content


The Human Body: A Forgotten Air Monitor

When working in any type of environment, employees may have concerns about the quality of the air they’re breathing. Air monitoring equipment can be used as a screening tool to help identify chemicals that are present, as well as their concentrations. There are a number of air monitoring technologies available today, from direct-read monitors that provide real-time measurements, such as a Jerome mercury analyzer, to equipment that is used to collect air samples that are then analyzed in a laboratory.

But while these technologies can help keep a work site safe, employees sometimes forget about another important piece of monitoring equipment available to them: their bodies. The human body is remarkable, with different senses that can be used to alert us when something in our environment may be unsafe or otherwise unacceptable. Our bodies use these senses to interpret and organize information, and then, hopefully, we use that information to make wise decisions. These senses are the same ones our ancestors used to help them survive.

During a job interview earlier in my career, the interviewer – an experienced industrial hygienist – asked me, “What do you put more emphasis on during an industrial hygiene study, the air sampling results or what you visually see or sense?” At that point in my professional life, I wasn’t completely sure how to answer the question, but I nervously replied, “What you see or sense.” The interviewer told me I was correct. In the years since that interview, experience has taught me that, in order to get a clear picture of an environment and its potential airborne agents, you should use both the results provided by your air monitoring equipment and what your senses are telling you.

Prior to finding employment in the energy industry, I worked for a private consulting firm. Among other things, my duties included collecting air samples of different chemicals in a wide range of environments to determine either employee exposure levels to chemical agents or the airborne concentration of a specific chemical that was causing concern. On some of these projects, the air sampling results indicated that no regulatory levels, nor any other occupational exposure guidelines, had been exceeded or violated. But other employees and I experienced adverse health effects on the sites, such as eye irritation, coughing and even headaches in some cases. It turns out that formaldehyde, sodium hydroxide and peracetic acid were some of the chemicals responsible for causing those effects. These and other experiences have taught me that it is a mistake to rely solely on air sampling data.

In my current role as an industrial hygienist for an investor-owned utility company, I once found myself in a situation similar to the ones I experienced while working for the consulting firm. I was investigating an odor complaint that had been reported while work was being performed inside an underground electrical space. The crew had performed the required testing for oxygen, hydrogen sulfide, carbon monoxide and combustible gas using a calibrated and bump-tested four-gas meter. After the test was complete and results indicated the space was safe for work, the crew entered the space to being performing their tasks. However, they soon became concerned about an odor they smelled, which later was determined to be hydrogen sulfide. The odor caused the crew to experience a burning sensation in their eyes and respiratory tracts.

Hydrogen sulfide is classified as a chemical asphyxiant, but exposure to low concentrations can cause irritation of the eyes, nose and throat. Had crew members relied only on the results provided by the four-gas meter – and ignored what they were smelling and feeling – they would have continued to experience adverse health effects throughout the duration of the work in the underground space.

As I noted at the beginning of this article, there is a variety of air sampling equipment available for use today. Some of that equipment has limitations, whether due to the impact of humidity, temperature or other interferences, such as chemical reactions and even the air sampling method itself. The situations I described above demonstrate that the ideal evaluation approach is to use a combination of data derived from air sampling and feedback derived from using our human senses.

About the Author: Dion Creggett, MPH, CIH, CSP, is a senior industrial hygiene administrator for ComEd, an Exelon company. He earned a bachelor’s degree in environmental health and a master’s degree in public health with a concentration in industrial hygiene. He can be reached at

Tailgate Topics