Mold Air Sampling and Analysis
Some people are very sensitive to molds. For these individuals, exposure can cause symptoms such as nasal congestion, eye irritation, wheezing, or skin irritation. Those with mold allergies may experience symptoms within minutes of exposure. While over 1,000 species of mold exist, not all are harmful. Mold requires moisture, oxygen, and a food source to grow—and can be found almost anywhere.
Spore traps are the most common method of collecting air samples to assess potential indoor mold amplification. These samples must be collected using strict protocols, with proper training and calibrated equipment to ensure accuracy. After collection, a chain of custody form is completed by the field technician. Samples are then shipped to a certified laboratory for analysis. It's important to understand that air sampling provides a “snapshot in time,” with environmental conditions such as temperature, humidity, and air movement affecting results.
There are currently no federal standards for acceptable mold levels in buildings. However, two primary insights can be gained from this type of testing:
- The lab will identify and classify mold spore types. Certain species should not be found indoors and may require further investigation.
- The spore count helps assess whether mold levels inside the building are elevated compared to an outdoor or control sample.
At least two samples are recommended: one from a control area (like outside or a clean entryway), and one from the area of concern (such as a basement or water-damaged room). More samples provide a more complete picture of indoor air quality.
Typical Indoor Mold Spore Concentration Ranges
| Description | Spores (cts/m³) | Predominant Types |
|---|---|---|
| Clean, non-HVAC buildings | < 2,000 | Total for all spore types |
| Clean, HVAC buildings | < 1,000 | Total for all spore types |
| Clean residential | < 700 | Penicillium, Aspergillus |
| Possible indoor amplification | 1,000 – 5,000 | Penicillium, Aspergillus, Cladosporium |
| Indoor amplification likely | 5,000 – 10,000 | Penicillium, Aspergillus, Cladosporium |
| Chronic indoor amplification | 10,000 – 500,000 | Penicillium, Aspergillus, Cladosporium |
| Inadequate cleanup or demolition | 50,000 – 10,000,000 | Stachybotrys, Chaetomium, Cladosporium, Ulocladium, etc. |
Certain molds, like Chaetomium and Stachybotrys chartarum, are considered highly hazardous. While important in nature for decomposing organic material, they should not be present indoors and are often associated with flood damage.
Controlling Moisture and Mold Prevention
Keep indoor relative humidity between 20% and 65%. Use dehumidifiers in summer and adjust whole-house humidifiers in winter. Ensure bathroom and kitchen fans exhaust outdoors, not into attics. Keep gutters clean and direct downspouts at least 5–10 feet away from the home. Avoid using dryer vent bypass kits that return air indoors. If you see condensation or ice on your windows, you likely have excess humidity. Proactive maintenance is key to avoiding mold issues.
Note: Medical concerns related to mold should be addressed by qualified healthcare professionals.