25 mm cassette with a 0.8 μ MCE filter (only accepted filter type!)
Sampling volume of 300L obtained by using a flowrate of 20 LPM
Sampling height at 1,45 m (4.76 feet)
SAMPLING WITH MYCOMETER-AIR
Reproducibility of air sampling results can be affected by both; the sample collection process and the analysis. The Mycometer-air analysis methodology is very reproducible (as documented by USEPA in 2011) so the main source of variability in results is sampling. Experiments have shown that the main reason for variability in air sampling is human or other activity in the room prior to or during sampling. Activity in a space aerosolizes settled mould and other particles. In experiments where passive sampling was applied it was found that, in rooms where there had been no activity for about 12 hours, the level of mould in the air was only around 9 %, sometimes as low as 1% of that found in the same room after the rooms had been occupied for some hours. However, when an aggressive sampling protocol (where a blower was used to uniformly agitate settled particles on surfaces) was used, the level of mould in the air was found to be independent of the level of activity in the room prior to sampling. For most purposes therefore, Mycometer strongly recommends the use of the aggressive sampling protocol developed by Mycometer. In addition to being more representative of the actual presence of fungal particles in the space, the use of the aggressive sampling protocol will significantly decrease the possibility of false negative results.
Blowing on surfaces with the handheld Makita blower (see picture) aerosolizes mould particles as well as other particles. Therefore, the use of airway protection is mandatory for all persons in the room, even when there is no signs of a mould source. In a room with no ventilation or open windows, the level of particles are back to "before blowing" levels after approximately 2 hours. If a ventilation system is running or if windows are open, the “before blowing” levels are likely obtained much sooner.
For aggressive sampling with the Mycometer-air method, a MakitaLXT BUB182Z cordless leaf blower is used. It creates a maximum airflow of 43 liters per second. (1.53 ft3/s ), which is close to the range of most household vacuum cleaners. The air speed at 2 meters distance is 3,3 m/sek. It must be used without attachments such as the directional rubber tube or cone.
Sampling in practice
Before taking samples, start by performing a visual examination in accordance with ASTM 7338-10 Standard Guide for Assessment of Fungal Growth in Buildings or other notable guidance documents.
Choose whether a passive or aggressive (agitated) sampling protocol fits your purpose.
Examples of questions a reproducible air sampling method can answer:
- Are there elevated levels of mould in the air compared to those found in normal non problem buildings or non-complain areas?
- Are there major differences in the level of air borne mould in different rooms in the building, indicating a mould source? (note that this approach may also help localizing a possible source)
- Is the final cleaning (removing settled mould particles left from the remediation) successful?
- Initial diagnostic assessment
- Rapid remediation clearance testing
- Pre/Post HVAC cleaning documentation
- Healthy Building Assessments
- Expedite disaster response damage assessment
- Healthcare ICRA documentation
- Routine maintenance cleaning confirmation