Do I need air tests during my mold inspection? The answer on the first time inspection is typically no! Air tests are valuable tools that an industrial hygienist (mold inspector) can use. If you don’t take air samples how do you know? The answer is simple as well as complex. But in essence, if you FIND a problem during your inspection, there isn’t much reason to spend money to find out what you already know. Further if there are design or construction defects in your home, poor ventilation, maybe even something as simple as a front load washing machine having mold in the door gasket, these things will ALL through off air sample results. Even something as benign as cutting the grass before you take the outdoor sample will cause the outdoor sample to have very high readings which will skew the analysis when comparing to the indoor air sample counts. Some issues with air samples can be:
- Results and conclusions are subjective- most people (even laboratories) don’t understand how to accurately compare indoor and outdoor spore counts and read the results-
- Conditions impact results- Typically and indoor sample is compared to an outdoor sample and the comparison determines the “issue” or lack thereof inside the room. If it is windy, or there is old wood, lots of foliage or other atmospheric conditions that may exist these can all cause the “control” (outdoor sample to be in accurate). This outdoor sample is what you use to contrast with the indoor sample to make a determination.
- Data is interpreted and NOT pass fail- non-viable Air samples (which represent 98% of all air samples collected) are interpreted. They are not empirical. So there is some individual who is making a subjective judgement on many things that impact the labs ability to actually read the slide from the sample.
- Collection methods can impact results- Depending upon where the control sample (outdoor sample) is taken could dramatically impact its result and thereby making the interior sample comparison inaccurate. This is a huge problem
- False positives/False negatives- Design and construction defect such as openings that allow air from under the home to enter the home can dramatically impact the spore counts inside of the home. See our article on how a crawlspace impacts your home for more information on this.
- Cost a lot of money and only tell you what you should already know
Do I need air tests during my mold inspection?
Do I need air tests during my mold inspection?
Taking air samples is the default for companies who do inspections and don’t know how to do a comprehensive site investigation. It is the “easy way out” The logic is that if it isn’t in the air, it isn’t there is foolish! The answer is to perform a complete physical examination and moisture analysis. IF there is mold found, remove it plain and simple! Don’t be fooled into thinking that you have a GREAT deal because you get air samples. Worse yet, what happens if you take air samples and they are positive? What do you fix? THIS IS NOT what a competent mold investigation should tell you.[/one-half]
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Do I need air tests during my mold inspection? Some of the issues with air samples can be:
- Results and conclusions are subjective- With air samples an indoor sample is compared to an outdoor sample. Concentrations of various types of spores are compared as are total counts. However, conditions greatly skew these results. Circumstances like wind, debris on the slide and personal bias impact how results are gathered and interpreted. While air samples can be useful, they should NOT be relied upon to make a decision either way.
- Conditions change from moment to moment- We have participated in over 40,000 inspections many of them with air samples. One common theme of all of the samples we have collected is that results vary widely from moment to moment. We have seen rooms that have mold literally coated on the walls from floor to ceiling as thick as Christmas Tree flocking and have had the air tests come up NEGATIVE. We have seen other circumstances where air tests are positive and there is nothing wrong at all. Air tests are tools but they should not substitute for a good, comprehensive physical inspection by someone who specializes in mold investigation.
Air tests should not be taken in a home that has a raised foundation or crawlspace!
Homes that have an understructure or crawlspace have openings which afford air exchange between the crawlspace and the interior rooms/floor above. In a Duke University study, they concluded that in a typical home with a crawlspace, as much as 70-80% of the air inside the home has passed through the crawlspace!. ALL crawlspaces are not good. There is bacteria, mold and all sorts of stuff present in almost every crawlspace. Why would you want to breath air from your crawlspace? you shouldn’t. But this is why if you have a crawlspace, taking air samples inside of a home, will likely only tell you that mold spores (present in EVERY crawlspace) are coming into the home via pathways from electrical, plumbing conduits and other openings into the interior that are not sealed.