Does Your Phone Cause Black Mold to Grow?

About This Episode

Author / Host: Daniel Stih is an aerospace engineer, senior iOS software engineer, first-ascent mountaineer, and author of 12 books. For more than 20 years, he has investigated complex problems spanning environmental health, engineering, technology, and human decision-making. Learn more about his approach: Why I Think This Way.

Central Question: Do electric fields, magnetic fields, Wi-Fi, or cell phones influence the growth of black mold?

People have claimed for years that electromagnetic fields (EMFs) may contribute to mold growth, while others dismiss the idea entirely. Rather than relying on opinions or internet speculation, I designed a simple exploratory experiment to observe whether mold exposed to different electromagnetic environments grew differently than mold grown under similar conditions without those exposures.

Using identical agar plates prepared from outdoor air samples, I compared mold growth after exposure to electric fields, magnetic fields, Wi-Fi, grounded conditions, and an outdoor control. While the experiment was not designed to provide definitive scientific proof, it offers observations that help distinguish reasonable questions from unsupported claims

 


 

Questions Answered in This Episode

  • Does your cell phone cause black mold to grow?
  • Can electric fields affect mold growth?
  • Does Wi-Fi increase mold growth?
  • How was the experiment designed?
  • What were the limitations of the experiment?
  • What conclusions can—and cannot—be drawn from the results?

Editorial Summary
 

Why I Performed This Experiment

Claims about EMFs and mold growth are common, but there is relatively little publicly available experimental evidence that directly examines the question. Rather than accepting or dismissing these claims outright, I designed a controlled exploratory experiment to observe whether different electromagnetic environments produced measurable differences in mold growth.
 

How the Experiment Was Conducted

Ten agar plates were prepared from outdoor air samples and randomly assigned to five environmental conditions: elevated electric fields, elevated magnetic fields, elevated RF from a Wi-Fi router, grounded conditions with reduced electric fields, and an outdoor control located away from nearby electrical infrastructure. Colony growth was then compared after seven days.
 

What the Results Suggest

The observations showed differences in total colony growth among the exposure groups. Plates exposed to elevated electric fields consistently produced the highest colony counts, while plates located near the Wi-Fi router showed the lowest average growth. However, variability between samples and multiple uncontrolled environmental factors prevent these observations from being interpreted as proof of cause and effect.

Electric Fields grew the most consistently… RF WiFi grew the least overall.”
 

The Practical Conclusion

Perhaps the most important conclusion is what the experiment didn't show. It did not demonstrate that cell phones cause black mold to grow. Instead, it reinforces a much simpler and better-established principle: mold growth depends primarily on moisture. If you're concerned about mold in your home, keeping building materials dry remains far more important than reducing EMF exposure.

No. Your phone does not help black mold grow.


Experimental Design & Procedure

 

Sample Preparation Equipment & Supplies

MEA agar plates from the laboratory, Anderson sampler, Bio Primary Standard calibrator, vane high flow vacuum pump, alcohol swabs to clean the equipment prior to sampling, stop watch.

Sample Preparation procedure

The plates were prepared by impacting 113 liters of air of outdoor air onto each of them using an Anderson sampler calibrated with a digital Bio primary standard calibration tool. Air sampling is used as it’s practical and allows one to observe growth rates over time vs other sampling methods.

Sample Randomization

After being collected outdoors, the 10 samples were randomized using a random number generator into 5 groups or two, to minimize variability inherit with air sampling.

EMF Measurement Equipment

  • A W.F. Bell 4010 was used to measure A/C magnetic fields.
  • Electric fields were measured using the Body Voltage method with a multimeter, one end connected to ground as reference.
  • The WiFi signal was not characterized for field strength or frequencies. The unit was operating and transmitting at typical low and high bands for Wifi in residential buildings.

Sample Conditions

Two (2) samples were placed in each of the following conditions and locations:

Exposed to A/C Electric fields by placing the plates on a table in the living room next to an electrical cord plugged in. The cord was placed on the table next to the plates. The magnetic field in this location is ambient -  what’s normal for the building.

  • 2.7 Volts (2,700 mV)
  • 1.0 mG ambient
  • RF ambient

Exposed to A/C Magnetic fields by taping the plates to the cover of the fuse box.

Note: it was interesting to note that while the A/C magnetic field was high at the fuse box, the body voltage was lower than what’s typically found near electric cords plugged into a wall. This is likely as the metal cover for the fuse box and the box is grounded, providing shielding from electric wires inside the box. An interesting natural phenomenon about EMFs - while grounded metal can be used to shield/reduce electric fields, it’s not as easy to shield or reduce magnetic fields. Magnetic fields are not affected by grounding. The 600 mV observed is therefore not due to sources inside the fuse box, rather to wires in walls outside of it - there is a light switch on the wall two feet to one side of the fuse box for lights in the hallway in that location.

  • 0.6 Volts (600 mV)
  • 15- 60 mG. (Normally 15 mG. Varied depending of use of power. 60 mG+ when air-conditioner/ heater blower running, otherwise approximately 15 mG.)
  • RF ambient
     

Exposed to RF (high frequency radiation) by placing the plates on top of the WiFi router.

Note: In hindsight this will have exposed the plates to some elevated level of magnetic field and electric fields due to proximity to the power transformer and electric cord for the WiFi equipment. The experiment tool place in the middle unit of a 6-unit condominium duplex.

Note: These plates were exposed to both a high level of RF as well as elevated levels of electric fields. In regard to magnetic fields, while not as high as what the plates at the fuse box were exposed, elevated levels of magnetic fields due to the power transformer in the WiFi equipment.

  • 3.2 Volts (3,200 mV)
  • 1.5 - 3.5 mG. (1.5 mG with interment pulses to 3.5 mG from the WiFi unit. An average of 2.5 mG is used in the data table that follows.)
  • Elevated RF. Assumed, not quantified.
     

Shielded from Electric fields by placing the plates on a sheet of conductive Velostat material connected to a cord plugged in to the electrical ground. The magnetic field in this location is ambient, what’s normal for the building.

  • 1.0 mG ambient
  • 0 Volts
  • RF ambient

Outside, in Nature, 30 minutes from town

  • 0.0 mG (as measured with the meter)
  • Volts (Not measured. Assumed to be 0. No visible power lines)
  • RF (Not measured. No Wifi present. limited cellular coverage)
Sample Location & Conditions Electric Field (mVolts) Magnetic Field (mG) RF
Plates on a table in living room next to an electrical cord. 2,700 1.0 Ambient
Plates at cover of the fuse box 600 15 - 60 Ambient
Plates placed on the top of the WiFi router. 3,200 2.5 Extreme
Plates on a sheet of conductive Velostat connected to a cord plugged into ground (shielding from electric fields)      
Outside in nature, 30 minutes from town, no power lines Assumed 0 0.0 No WiFi. Limited cellular coverage

The plates were allowed to sit in under the measured conditions for 7 days.


Observations & Conclusions

Table 1: Mold Colony Counts After 1 Week of Exposure

  Plate Counts  
Sample # # White Colonies #Yellow Colonies # Green Colonies # Black Colnies Comments and types of mold present based on sampling a few of the colonies
Electric Fields 1 2 1 3 1 Black is Stachybotrys. Yellow is Aspergillus sp.
Electric Fields 2 1   4 2 Green are Asp/Pen-like
Magnetic Fields 1 3   7    
Magnetic Fields 2     2    
RF WiFi 1 1   3    
RF WiFi 2 2   1 1 Black is Cladosporium
NO Electric (Grounded) 1 1   7    
NO Electric (Grounded) 2 2   2    
Outside in nature 1 3   1 1 Black Alternaria

Outside in nature 2

 

1   2 1 Black Torrula.


Table 2: Total Colony Counts by Sample Type

Sample Type Sample 1 Sample 2 Average Total Colonies
Electric Fields 7 7 7.0
Magnetic Fields 10 2 6.0
RF WiFi 5 6 5.5
No Electric (Grounded) 9 4 6.5
Outside in Nature 8 5 6.5

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END OF DAY 6, OUTSIDE NOT YET INCLUDED

Q. Is there a difference based on only considering total CUFs?

A. Yes.

  • Some exposures (Electric Fields) appear to correlate with increased growth; others less.
  • RF / WiFi had the lowest growth.
  • Comments: The Rf/Wifi plates had condensation on the lids (as did the outdoor samples). It’s not known whether that and/or lack of light or something else were factors. Consider the samples were exposed to high electric and slightly increased magnetic fields, in addition to the RF, from the power source to the WiFi. If the previous is true (electric fields correlate with increased growth) there should have caused an increase in growth regardless of condensation and/or light factors. Consider that mold hidden in walls in a house will be in the dark and might have condensation under wet conditions or another a similar, related variable, in which case it’s a moot point - that would meant that even if EMFs effect growth rate, unless mold is out in the open, those factors will not affect growth.
  • Grounding (no electric exposure) appears to result in healthier microbial profiles (more green colonies, fewer black colonies). Being grounded is HEALTHIER FOR MOLD as well as humans.

*******************************************************

END OF DAY 7, ALL SAMPLES (OUTSIDE INCLUDED)

Q: Based on the total counts, not colors, is there a difference - did one set of plates (sample type) grow more than the other?

A: Yes — based on total colony counts only (ignoring colors), there are differences between the sample types (conditions) as follows:

  • Electric Fields had the highest consistent total growth.
  • Magnetic Fields were the most variable.
  • Grounded and Nature samples had a moderate average, with variation between replicates.
  • RF WiFi had the lowest average total colony count.

Yes — some sets of plates did grow more or less than others, when looking only at total counts:

  • Electric Fields grew the most consistently.
  • Magnetic and Grounded showed variable results.
  • RF WiFi grew the least overall.

**********************************************************

TO SUMMARIZE:

I was unable to draw definitive conclusions. To perform such as experiment effectively requires a significant amount of money, resources in lab personal, and strict control of environmental conditions, adding to complexity and cost.  This is not something you can do yourself at home.

Observations and Conclusions:

1. No, your cell phone does not help black mold grow.

2. Electric cords may help mold grow. Do the sensible thing and unplug them. The only sample Stachybotrys was detected was in one of those. The only sample Aspergillus was a clearly isolated and identified was one of those samples. Chance? Coincide? Watch the video and see for yourself.

3. While this study showed there might be some connection between EMFs and mold growth, specifically molds exposed to electric fields, more research needs to be done.

4.  Grounding yourself (to reduce electric fields) may be good for your health - it’s also good for the health of mold. The best way to prevent mold is to keep things dry - when there’s a leak in your home dry things out as fast as possible.It does not matter how low of EMF you make your home - water it and mold will grow

5 .For cases where mold growth was enhanced by EMFs, could it be the “healthier“ growth is due to how competing organisms such as bacteria are affected. If certain fields support or inhibit bacteria growth, mold will have more or less competing organisms. Factors such as bacteria and other competing organisms and their interactions with mold and EMFs has not been studied.

6. Under conditions shielded from electric fields (grounded), there appears to be less mold growth; the kinds of mold that grow are mostly outdoor types, and the mold that grows appears healthy and comfortable, perhaps as it does not need to compete with other organisms as much. Could it be that bacteria also thrive in electric fields, molds capable of making mycotoxins that inhibit that bacteria have an advantage?

7. This is a complex topic. I don’t think it’s worth studying further, as we have better things to study for the purpose of obtaining and maintaining optimal health. In regard to mold, it’s as simple as keep things dry, and if they get wet dry them out as fast as possible. Notice in the video mold growth was visible in 48 hours.

Conclusion regarding the initial question:

No. Your cell phone does not help black mold grow.

If you are concerned about EMFs, or proactively would like to do something that supports your health and well being, consider unplugging any and all electrical cords next to or near your bed.

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