The presence of airborne mold particles in living areas can be dangerous to both humans and household pets. Some people even have immediate reactions such as coughing or uncontrolled sneezing if they enter a room with airborne mold particles.

Mold air testing involves collecting and analyzing air samples to test for the presence and concentration of mold spores in the air. The test can help you tell if you have mold in your house that needs to be removed. In most cases, the presence of mold in the air is a sign that you have a significant mold problem.

testing air for mold

There are several ways to test for mold spores in the air, most involving the use of an air sampler or mold testing devices. You can purchase mold testing devices and air samplers and do the tests on your own. However, it’s always advisable to have a trained mold inspector do the testing for more accurate results.

Here is how to test for mold spores before you order for a comprehensive mold inspection and remediation.


  • Mold testing kit- Look for a mold testing kit in your local home improvement store or online that includes an air sampler. You can purchase a simple mold testing kit for as little as $20 although you need to be sure that the device is working as advertised and has good reviews.
  • Protective gloves and face-coverings- You need these if you will be going into a disused house, basement, or attic where you are certain that there is significant mold in the air.

Mold air testing should be done over a number of days and in different rooms for more conclusive results. If possible, send the kit to a certified mold expert for further analysis to check for the type of mold or for the presence of microscopic mold.

Step 1- Preparing your room

You will have more accurate and faster results if you can seal off the room where you suspect that there is mold in the air. Small spaces such as bathrooms, attics, or basements should be sealed before the air test. You can also do the same for larger spaces such as living rooms if possible.

Close all the windows and doors in the area where the test will be done at least twenty-four hours in advance to prevent mold particles from escaping. Also ensure that any air purifiers, fans, and AC systems that may disturb the air are turned off during the sampling/collection phase. This will allow for any floating mold particles to remain in the air.

preparing a room for mold air testing

Step 2- Prepare your Testing kit

There are different types of mold testing kits available in the market. Each of them comes with specific instructions on how they should be used. However, standard air testing kits have what looks like a petri dish with an airtight lid. The petri contains laboratory-prepared mold food (microbial culture) that is important for mold growth.

To prepare your test kit, unpack it as per the instruction manual accompanying it and open the petri dish ensuring that you do not touch or disturb its contents. Use a pair of gloves when handling the testing kit if possible, to prevent contamination.

Step 3- Positioning your air sampler

The open petri dish with “mold food” will be used to collect any floating mold particles or spores in your living areas. Find a place where there is the least disturbance and place the petri dish there to begin collecting the samples. Be sure to wear your protective face covering if you are placing the sampling dish in an area where there is significant mold presence.

Step 4- Collection phase

Most mold air sampling kits are designed to collect samples over a forty-eight-hour period so leave the petri dish intact for as long as required. During this period, some of the mold spores floating in the air will settle into the open petri dish and start feeding on the microbial cultures for growth. Ensure that the conditions in the room remain the same throughout this phase by keeping windows and doors closed.

Step 5- The Growth Phase

After the forty-eight-hour sampling period has lapsed, carefully remove the open petri dish from its position and replace the lid. Depending on the model and type of lid on your testing kit, you may need to seal it further using removable tape. This will ensure that there is no air going into the petri dish in the growth phase.

Now transfer the sealed petri dish into a dark space such as inside a drawer or sealed box. By keeping the petri dish in a dark space, any mold spores that had settled into the Petri will start feeding on the microbial cultures and grow. Keep the Petri there for at least two days before you check if there is any growth. If there is no mold after two days, put it back and check again after every two days.

Step 6- Testing Results

You will know there is mold in the air if there is mold growth in the petri dish after the growth period.

Here is how to determine the concentration of mold in the air from this DIY test:

  • After two days- Significant mold presence in the dish means you have a high concentration of mold in your house. Find a mold remediation service immediately.
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