Creating a Healthy Oasis: How to Tackle Sick Building Syndrome
Sometimes a building just doesn’t feel good to be in. People get headaches, itchy eyes, a scratchy throat, or feel unusually tired at work—then feel better after they leave. That cluster of complaints is often called “sick building syndrome” (SBS). It isn’t one single disease. It’s usually a mix of everyday issues: not enough fresh air, stale or uneven airflow, the building pulling in dust or fumes, humidity that’s too high or too low, and hot–cold spots that make comfort hard to maintain.
If you're noticing these symptoms, it's important to take action to improve the indoor air quality in your building. The fix doesn’t have to be complicated. Start with the basics that make any space feel better: bring in clean outside air, keep the building slightly positive so contaminants stay out, control humidity, and remove or capture problem sources where they start. Then verify it’s working with a few simple checks—CO₂, temperature, and humidity.
In this guide, we’ll show facility leaders how to spot the signs, run a quick investigation, and choose practical upgrades that fit real-world operations. You’ll also see how Cambridge Air Solutions’ outside-air-focused systems, including make-up air, high-efficiency heating with destratification, and fresh-air cooling, can help you create a healthier, more comfortable building without sacrificing efficiency.
What is Sick Building Syndrome?
SBS is a term used to describe a range of symptoms that can occur in buildings where the indoor environment is perceived as unhealthy or uncomfortable. The causes of SBS can vary and often involve a combination of factors. Poor indoor air quality, inadequate ventilation, high humidity, and temperature fluctuations can all contribute to SBS. In addition, the presence of chemical and biological contaminants within the building can also cause SBS.
This is different from building-related illness, which is when a specific, diagnosable illness is linked to an identified agent in the building. In this instance, medical evaluation and targeted treatment are required, including addressing the cause within the building, whether it is carbon monoxide, mold, or something else.
How to Diagnose Sick Building Syndrome
To properly handle sick building syndrome and ensure employees are working in a safe and comfortable environment, you must first diagnose the issue. Here are the five essential steps you can follow.
1. Map the Symptoms and the Space
Start with people and patterns. Ask occupants where and when they feel unwell and what improves their symptoms (going outside, moving to another area, certain times of day, etc.). Plot these notes on a floor plan so clusters pop out, identifying by department, shift, or process area. Note nearby doors, docks, exhaust fans, printers, chemical storage, forklifts, and high-heat zones. A simple one-page survey and a marked-up map will quickly show whether you’re dealing with a building-wide issue or a few problem zones.
2. Check Ventilation and Pressure First
Fresh air and building pressure are the fastest levers to pull. Verify that outside-air intakes are open, clean, and unobstructed, confirming that fans and dampers are actually delivering air to the zones where people work, not just the ceiling. Take quick doorway pressure readings or use a smoke tube at main entrances and dock doors. You want the building slightly positive to keep dust, vehicle fumes, and humid air from being sucked inside. If you run large exhaust (paint booths, process fans), make sure make-up air units are sized and sequenced to offset them.
3. Run Simple IAQ Spot Checks
Use quick measurements to pinpoint problem periods. Log CO₂, temperature, and relative humidity at occupant height in the complaint zones during busy hours. CO₂ trends help you understand whether outside air is keeping up with occupancy; humidity trends reveal comfort and moisture risks (too low feels dry and irritating, too high can feel musty and promote growth). If odors or chemical use are involved, add short-term VOC readings or formaldehyde badges as needed. You don’t need a month-long study, just 48–72 hours of good data during typical operations to guide action.
4. Inventory and Isolate Success
List anything that could be adding contaminants or strong odors like cleaning chemicals, paints/solvents, combustion equipment, idling trucks, battery charging, hot work, or dusty processes. Check whether these sources are enclosed, locally exhausted, or simply venting into the space. Look for obvious fixes: relocate chemical storage, add or repair local capture hoods, seal dock doors, create physical separation for high-emission tasks, and verify forklift charging areas are ventilated. Small source-control tweaks often deliver quick comfort wins.
5. Compare to Targets and Build a Punch List
Bring the observations together and translate them into actions. If CO₂ routinely spikes during peak occupancy, plan to increase outside air and improve distribution to the affected zones. If smoke tests show negative pressure at doors, increase make-up air and rebalance exhaust to push the building slightly positive. If humidity sits out of range, adjust sequences or add capacity to keep it stable. Prioritize “fast wins” (damper positions, schedule tweaks, filter changes, dock sealing) first, then larger items (adding make-up air, upgrading heating/ventilation, local capture). Document the baseline (your map, spot-check data, and notes) so you can measure improvement after changes—and keep what works.
How to Track Sick Building Syndrome
As a building owner, you have a responsibility to provide a healthy and comfortable indoor environment for your tenants or employees. Fortunately, there are solutions available that can help you combat SBS and improve indoor air quality in your facility.
Fixing SBS usually comes down to doing the basics really well. Bring in enough clean outside air, keep the building slightly positive so bad air stays out, manage humidity, control sources at the point of creation, even out temperatures/airflow, and keep an eye on the numbers with simple monitoring. Cambridge’s outside-air-first equipment is built to deliver those fundamentals in real-world facilities.
M-Series Make-Up Air Units
M-Series MAUs introduce tempered 100% outside air to dilute indoor pollutants and offset process exhaust, helping you maintain a gentle positive pressure throughout the building. In practice, that means fewer “stuffy” zones, fewer drafts from open doors, and fewer episodes where the building pulls in dust or vehicle fumes. For SBS projects, the win is twofold: you boost fresh air to the occupied zones and you stabilize the pressure so contaminants stop migrating from docks and process areas.
S-Series HTHV Heaters
S-Series high-temperature heating & ventilation (HTHV) units deliver efficient heating while actively mixing air top-to-bottom to reduce hot/cold spots that often get blamed for “not feeling right.” They can be configured to bring in outside air, so you heat while you ventilate and destratify. For SBS complaints, that combination is powerful: occupants feel more uniform temperatures, and outside air is better distributed across the working level, improving both comfort and perceived air quality.
E-Series Direct Evaporative Cooling
When summer load and occupancy push indoor air stale, E-Series provides high volumes of cooled, fresh outside air. This supports dilution and pressurization at the same time, which is exactly what most SBS spaces need in warm seasons. In suitable climates, direct evaporative cooling is an energy-savvy way to keep fresh air rates high without relying on heavy mechanical cooling, while still pushing contaminants out through controlled exfiltration.
ESC-Series Indirect/Two-Stage Evaporative
For locations where humidity control is a concern, ESC-Series systems use an indirect stage (and optional two-stage approaches) to lower supply air temperature without adding as much moisture. The result is plenty of outside air for dilution and pressure control, with more flexibility to keep RH in a comfortable range. This is a strong fit for mixed climates or facilities that swing between humid and dry seasons but still want high ventilation rates for SBS reduction.
Connect with Cambridge Air Solutions to Mitigate Sick Building Syndrome
By collaborating with us, you can effectively combat SBS and promote a healthier indoor environment for those that rely on you. Our solutions tackle the underlying causes of SBS by delivering fresh, pure air and maintaining optimal temperature and humidity levels.
Acting promptly is crucial if you suspect SBS in your building. SBS not only impacts the health of your hard-working people, but it also hinders productivity and increases absenteeism. Partnering with us allows you to proactively prevent SBS, fostering a healthier and more comfortable indoor environment for your team.
Contact your local Cambridge Air Solutions representative today to learn more about how we can help you combat SBS and improve indoor air quality in your building and together, we can create a healthier and more productive environment.