Hello Mr. Shepard:
The point in question is not if spore concentrations do or do not decrease after rain. The point in question is whether the person collecting the samples is sufficiently proficient in aerobiology and sampling theory to know that if their data quality objectives are properly designed, IT WON’T MATTER if there is or is not a decrease in spores after a rainfall, and therefore, they won’t have to sit around and, literally worry about the weather in deciding whether or not (or when) to sample.
We know that spore counts vary with season.
We know that spore counts vary with temperature.
We know that spore counts vary with wind speed.
We know that spore counts vary with light variations.
We know that spore counts vary with sampling velocity.
We know that spore counts vary with altitude.
We know that spore counts vary with elevation in a room.
We know that spore counts vary with time.
We know that spore counts vary with relative humidity.
So, do we, then, explain to the client, “Well, Gosh, I’d like to sample for airborne moulds, but we will have to wait until noon on June 3rd, provided the outdoor temperature is at least 75F, and there is no wind, and it will have to be a bright day with no rain in the last two hours, and by the way, you will have to move your house from Boulder, Colorado to sea level.”
No – what we do if we are profficient in sampling for spores in the air is establish data quality objectives, such that we will be able to interpret our data
Regardless of the season.
Regardless of the temperature.
Regardless of the wind speed.
Regardless of the light variations.
Regardless of the sampling velocity.
Regardless of the altitude.
Regardless of the elevation in a room.
Regardless of the time.
Regardless of the relative humidity.
and be ready to stand up in court, and explain exactly WHY those variations were already taken into account in the interpretation of the data.
Having said that – it is important to know that following a rain storm, only some spores may decrease, whereas others may increase. (Since you used a quote, I too get to use one too…)
“After rain, near ground level there is often a “damp-air spora” dominated by various kinds of ascospore whose active release depends on the turgor of the asci in which they form. This damp-air spora replaces the “dry-air spora” consisting of spores of Clasporium, Alternaria*, smuts and rusts that is largely washed out of the air by the same rainfall giving rise to the damp-air spora*.” (Madelin TM, Madelin MF, Biological Analysis of Fungi and Associated Molds, BIOAEROSOLS HANDBOOK, 1995
Now, in my mind, if a person collecting air samples for moulds, did not already know that, they should not be collecting air samples in the first place, since they can’t interpret the data, and therefore, they are pretending to be proficient in the service they are providing, when in fact, they are not proficient and they providing nonsensical “data” they can’t interpret, and therefore, they are ripping off their client (but making bu$ine$$ for me!)
Therefore, it needs repeating: “…The point in question is whether the person collecting the samples is sufficiently proficient in aerobiology and sampling theory to know that if their data quality objectives are properly designed, IT WON’T MATTER if there is or is not a decrease in spores after a rainfall…”
Caoimhín P. Connell
Forensic Industrial Hygienist
Forensic Applications, Inc.
The opinions expressed here are exclusively my personal opinions and do not necessarily reflect my professional opinion, opinion of my employer, agency, peers, or professional affiliates. The above post is for information only and does not reflect professional advice and is not intended to supercede the professional advice of others.