664: Joe Spurgeon, PhD - Surface Dust Samples, ERMI Scores and Assessing Mold Exposures

[Music] this is iaq radio indoor air quality radio the voice of the indoor air quality industry with your hosts radio joe hughes and the z-man cliff zlotnik and now radio joe hughes good day and welcome to iaq radio plus this week we welcome dr joe spurgeon for a discussion on surface dust samples army scores and assessing mold exposure before we get started let's thank our sponsors they're the reason we can continue doing the show and don't forget after the show you can continue the discussion at afterthoughts.iaqradio.com sponsored by first on site our marquee sponsor is first on site at firstonsight.com our association sponsors are the american conference of governmental industrial hygienists acgih.org the american industrial hygiene association aiha.org the cleaning industry research institute ciri science.org the indoor air quality association iaqa.org the institute for inspection cleaning and restoration certification iicrc.org industry sponsors are aeml laboratories aemlinc.com particles plus particlesplus.com tsi inc tsi.com sunbelt rentals sunbeltrentals.com april air april air dot com healthy indoors magazine healthy indoors.com and now you can win a cool prize it's time for the iaq radio trivia question be the first to correctly answer simply email your answer to c zlotnik at c s dot com or if listening live just text your answer from your computer and now here's the z-man hello everyone i'm sorry to report that no one identified the fence on the campus of carnegie mellon university as the 1993 guinness book of world records holders for most painted object in the world the iq radio trivia question for today may 6 2022 has been sponsored by tsi inc an industry leader in precision instrumentation for the monitoring of indoor air learn how to expand your ieq investigations at tsi.com here's today's ieq radio trivia question name the epa's technical contact for environmental measurement and monitoring back to you joe okay so today we've got dr joe spurgeon he has a multi-disciplinary doctorate degree in analytical chemistry and environmental health from the university of pittsburgh and he was a certified industrial hygienist from 1993 to 2013. his career has included working as a research chemist on the nbs lead paint poisoning program he directed the faa's combustion toxicology laboratory he performed health assessments for the cdc's atsdr program implementing the us epa's laboratory exposure assessment project and has worked as a consultant specializing in microbial indoor air quality for the u.s public health service he has also performed over 4 000 residential and commercial investigations involving water intrusion microbial contaminants and has served as an expert witness in numerous mold cases welcome back joe thank you always great to have you let's jump right into it um we've got the presentation here we're going we're calling this now surface dust samples army scores and assessing mold exposure i guess before we get started what led to your interest in this this topic and and you know going into such detail and and putting together a nice presentation like this well a couple of things number one uh reviewing a lot of reports uh from a number of consultants and working at an expert witness allowed me to uh review those reports and it seems to me as as an industry we've kind of overstepped the use of dust sampling and the use of things like hermes scores and secondly i'm a little bit concerned about the the way we use sampling methodologies and we don't really consider the implications of the methods themselves how we analyze our and the the implications of how we analyze them and the impact on our ability to interpret so i'd like to kind of get a discussion going uh always if possible within the industry on those topics all right well let's let's jump right into it joe john if you could put that up you may have to speak up a little bit jack i have a little trouble hearing you but oh okay yeah there we go get a little closer if you will all right so this is our title i think we can jump to the next one all right all right uh again some of the topics that we've been talking about are sampling objectives collecting surface dust samples how they're analyzed by the laboratory and how the reports are how the results are reported i think that's a very important topic the early method and how it's used to assess occupational uh occupant exposure potentials and just maybe one slide on the hearsay method just to make a point all right next next yes sampling objectives talk a little bit about uh occupant exposure potential versus occupant risk next so sampling objectives uh how will the sample results be used and within the ieq community there's probably three primary objectives assessing building related contamination or brc and that's whether or not the structures the systems contents are contaminated that's very typical a common objective they can be used to assess occupant exposure potential that is are there contaminants of concern for example mold bacteria allergens etc that are capable of causing adverse effects and if there are are they present at concentrations capable of causing those effects next and there's our third one okay yeah so the third primary objective is to assess occupant risk and for example our occupants experience adverse health effects due to the contaminants that were detected and for example should occupants vacate homes or offices and in my opinion that's the job of the treating physician not the job of the mold investigator or independent environmental professional in my opinion we should expedite our report if we find a bad situation we should inform the client and inform the client that they should get our report to the physician as soon as possible and offer to explain our report to the physician if it's requested but i run into a lot of situations where the iep has recommended to the client that they should vacate their home or office and i think that's maybe going a little bit too far we don't really have that expertise or that function and even though you've got quite a background in that area you're still telling people and you yourself don't recommend people leave home well i qualified for a doctorate in public health with a concentration in environmental health i've had graduate work in toxicology and inhalation toxicology and i managed the faa's combustion toxicology laboratory for the better part of 10 years so i think i'm probably better educated in this area than most of the ieps doing this and and i certainly don't feel qualified to make those decisions and i never have so yeah i think that we need to have some caution in that area all right good good uh good little warning for our audience here let's go to this next one here critical step yeah the next topic i'd like to talk about are collecting surface dust samples and i believe that is a critical step i think we're all familiar with the old adage of garbage in garbage out and anyone who's ever collected a field sample knows that it's not that simple to get a good sample easy to get a sample but not easy to get a good sample next let's go over why all right let's do that uh the sample describes the environment and according to coppin and i've given the reference here one of the primary challenges of assessing exposures to environmental complaints i'm sorry contaminants is the collection of a representative sample with the sampling step typically contributing the largest variability in the assessment of the results and i think we're all familiar with this uh issue so a sample that's not representative of the fungal loading in the indoor space that was sampled is not going to be representative of the occupant exposure potential in that space and i hope uh we're all represent all recognizing that this is an issue when we collect the next sample if i take a sample of uh you know let's take a swab directly on an area where i got a little two by two square inch section of mold and take a sample right on that may not be representative of the exposure for the people in that room yeah especially if it was the only spot of visible mold in the entire property yeah okay so yeah we have a goal of collecting a sample that's representative of the indoor environment but we also want to be aware that we also want to be able to interpret that sample so let's take an example where we're taking a dust sample with a swiffer cloth for example and the individual collects that one sample from the basement the first floor and the second floor from multiple surfaces of different types and they're analyzing that sample with qpcr that individual might argue that that is a representative sample of the indoor environment well that's all well and good but then i might argue that it's impossible to interpret the sample result for that sample that individual may interpret it but i would argue that it cannot be interpreted so i think we want to recognize that we not only want a representative sample we want a sample that can be interpreted you know joe you you do a lot of expert witness work um i'm i'm guessing this is one area you spend a lot of time educating attorneys and and discussing when it comes to reviewing other people's reports uh yeah this is a this is an important point that i tend to hammer on okay and then i've got a quick uh text from the audience going back to your recommending a physician should that physician be qualified as an immunologist allergist general practitioner do you get to that point no i don't get to that point um i think we all are aware that it's very difficult if you if you do the best job you can and wait and write a wonderful moan report that's very good i can write the best mold report that i possibly can and turn that over to a family physician and they don't know what to do with it and i think we're all aware of that problem i don't know who to recommend as far as the physician goes on a local basis so it's kind of a catch-22 to say yes it is i understand that but i don't recognize that i'm not a doctor so i think it was a good a good clarification this is a problem with with the entire industry absolutely all right let's go to the next one john okay so planning to collect a good sample uh if the result is to be meaningful i think we need to understand the sampling rationale the reasoning behind the collection of the sample so the sampling rationale includes you know why am i collecting this sample in this location using this sample what do i expect to learn from the sample why am i requesting this method of analysis to be used on this sample are there assessment guidelines or decision criteria that we're going to be able to use to interpret the sample results and why am i going to use this particular method of data interpretation with this sample to achieve the objectives that i have for this project let me let me clarify on this one joe are you saying this should be in the report or you should just be thinking about these things before you develop your sampling rationale no this is what uh when i'm called by a client i normally take uh a telephone interview when i when i when the client calls me and i'm thinking about this during the telephone interview with the client when i'm coming up with my project plan and my sampling plan so i want to know what i'm going to do when i get on site once i get on site this is going to change it's like coming up with a plan during a battle i mean the plan is nothing once you get on site but at least you have an idea of what you're going to do when you get there so selecting a method a sampling method for example very few standardized method or validated methods for mold sampling and collecting a sample that's both representative and that can be interpreted as not a simple task uh very few recommendations sampling methods are not a six each topic in academia and they're not well funded you can't get money to to research them so finding reliable guidance on method selection is is very difficult next uh these are the criteria i use for evaluating methods and for selecting methods and putting them in my toolbox for example and i call them the sox criteria it's just basic guidance but does the method have significance for the sample result that is are there numerical guidelines for interpreting the lab report and i know numerical guidelines is a hot button but there can be explicit guidelines that are written down consensus guidelines from a consensus body or implicit guidelines that we call professional judgment and i will suggest to you that it's impossible to interpret a numerical laboratory report spores per cubic meter for example without using numerical guidelines it's impossible what we normally do is use implicit guidelines that is professional judgment to interpret that report but in the back of our mind we have to have some numerical guideline to interpret a numerical laboratory report objective decision criteria for interpreting the sample result can we determine whether or not that sample result is low average or high if we can't if i collect the samples yeah are there consistent assessments of condition across project and between inspectors independent of experience or bias if we get the same result in two or three different projects are we going to make the same decision are we consistent and is there's a stable basis for assessment that does not vary with local conditions for example if you're taking an air sample and using indoor outdoor comparisons are outdoor sport counts stable do you make the same decision from property to property okay next okay uh people might be curious why i uh took these four sampling methods on the front of my book for for carpets but in my opinion only one of these four sampling methods meet the sox criteria and describe the exposure potential of a carpet dust sample so what i'm trying to illustrate or the concept that was in my mind that there are problems that exist with very common sampling methods and as a matter of fact the least used sampling method is the only one that meets these criteria the most commonly used sampling method doesn't meet these criteria for example so the next section uh i'm going to discuss one of these problems before you do joe could you go back john let's just go over these four methods real quick for those that aren't as familiar with your work um the top one you got a little template there and you're using a uh a cassette to suck up dust go ahead well it's a closed face cassette with a beveled tip tubing on it and it's using an area template yeah it's attached to a pump with sampling pump that draws air through there right then we have the open faced uh fixed area cassette and then we have just an open face cassette that's just brushed across an unmeasured area of carpet and then we have basically uh a area template with a not not a micro vacuum but a vacuum to vacuum up carpet dust and are we going to tell people which one you think is the one that is uh that meets the sox criteria well i have a whole chapter on comparing these uh methods and it's the one on the left in the middle with the open face fixed area micro back cassette it has the least uh relative standard deviation and the most sensitivity and you can develop decision criteria based on that methodology and that just for um a quick so for those that aren't familiar the the one underneath the title there with the little uh wooden box that's typical of what people use for an army sample yeah that yes or it should be and for other methods but yes that was used for the army sample yes okay let's go to the next one john okay let's talk about uh analyzing dust samples and reporting the results and and a couple of comments first of all when you submit your sample to a laboratory you have options uh and you should be an informed consumer of laboratory services and i want to make a comment that in my opinion this is a very important section to understand so if you have any questions on this presentation they really should be about this section this this is a critical section to understand okay so next all right this is an example about uh selecting the reporting basis uh for your sample this was a story that john tiffany told on himself uh and it was about a failed clearance because of choosing the wrong reporting basis for a sample and the first thing to understand that mold is in the carpet dust not in the carpet fibers so this was a project that he had back in the 90s uh and it was in a corporate fortune 50 uh corporate headquarters and the ceo had caught a cold and he didn't think he should have a cold so john got a very nice contract to do an investigation in the corporate headquarters because the ceo had caught a cold so part of the car carpet sampling was that they set the clearance criteria in colony forming units per milligram which was correct and they cleaned the carpet and they uh failed to meet the clearance criteria so they cleaned it again and it failed to meet the clearance criteria they actually did it a third time and it failed and john had to finally go to the corporate ceo and admit that the clearance criteria were incorrect they were sampling a larger and larger and larger area of carpet to collect the same weight of dust but that dust contained the same cfus of mold so they could not clear the carpet so he had to convince the ceo to change the clearance criteria from ce cfus per milligram of dust to cfus per square foot of dust and once they did that then the carpet cleared so this just points out the importance of how you report your sample results and the idea of thinking about what you're doing before you do it and not only how you report your sample results but how you instruct the lab to give you your sample results yes yes but if you don't think to measure the area that you sample before you do it you don't have that data you can't report it on an area basis so you have to know the sampling rationale the sampling parameters before you start or you haven't got the information available to you excellent let's go to the next one okay so analyzing surface dust samples so how the samples analyzed and reported by the laboratory does affect the ability to assess both building related contamination and occupant exposure potential and the options for reporting dust samples basically there's three options so the standard method that the laboratory is going to use i call the weight analyzed basis and the result is four equivalents per milligram this is what you're all familiar with so it's reported as four equivalents per milligram of dust analyzed and that last word is critical of dust analyzed the second option is total weight basis and here you have to request a laboratory to weigh the sample and the laboratory analyzes four equivalents per milligram then they multiply that by the total weight of the sample and they will report to you score equivalents per sample the third option is the area basis where you measure the area that was sampled you request the sample to be weighed they report to you spore equivalents per sample you divide that by the area that was sampled and in your report you report spore equivalents per square inch per square centimeter per square foot whatever you want but you report it on an area basis and that what that's what i will suggest to you is the preferred methodology okay next joe before we go i've got a question this spore equivalence what type of analysis is that qpcr okay i think that's important to clarify so this is if you're using qpcr all right what i was talking about you knew i knew too but i wanted to make sure everybody knows can you real quick go to the next slide just let me see what it says okay go back now okay yeah all right so this is a little bit of a typo but uh this is a carpet dust example uh let's just assume this in this example that similar dust samples were collected in i'm going to say on two floors of a house rather than in two houses using a micro back cassette and that you submit the two samples to a laboratory for analysis without any other directions just using a typical chain of custom okay next so if you do that they're going to use by default the weight analyze basis to analyze your samples so they're not going away your sample and they're just going to take a five milligram portion of each sample and analyze so let's assume that the dust collected was 100 milligrams of dust on the first floor in 10 milligrams on the second floor and they're going to take five milligrams from each sample and they're going to analyze and let's assume that we had 1 000 spore equivalents detected in both five milligram portions of samples so that they found 200 spore equivalents per milligrams reported for both floors so as far as the inspector is going to learn from the laboratory there was the same exposure potential reported for both floors 200 spore equivalents per milligram that's what's going to be reported in the laboratory report but the total fungal loading is actually twenty thousand spore equivalents on the first floor and two thousand spore equivalents on the second floor so the cleanliness of the carpets different by a factor of ten although the inspector is never going to learn this not based on the laboratory report and this was because they just went with the weight of the weight analyze basis right this is the default standard operating procedure for most laboratories okay and if you don't tell them different that's what they're going to use all right next all right so instead let's assume that the mold inspector requested a or wanted to use an area basis to report their results so in this example the inspector measures the area that was sampled requests the analysis on a total weight basis as for equivalence per sample and that's what's reported to them so the reports spore equivalence per sample and then the results are standardized by area either by square inch per square centimeter per square foot whatever you want to choose doesn't make any difference using this method the sample results are standardized and since they're standardized just like spores per cubic meter they can be compared and this method accounts for variations in both dust weight and area sample and this is just an example of calculations but the point is using the area basic basis method the inspector receives a report from the laboratory that shows the difference in the cleanliness of the two carpets 200 spore equivalents per square centimeter 20 spore equivalents per square square centimeter on the first and second floors so now the inspector is aware of the difference in cleanliness between the two carpets that were sampled a big difference big difference okay not only that if you use the area basis they now can take those data and complete compare those results between projects on an area analyzed basis you cannot compare the results between projects secondly looking at an area basis i've given you two references here but the health effects were better associated with results reported on an area basis rather than a weight basis results reported on an area basis are standardized by area and allow conditions and occupant exposure potentials to be compared between projects you cannot do this if your results are reported on a weight analyzed basis all right you cannot compare airborne samples of spores using raw counts you can compare them using spores per cubic meter because spores per cubic meter are standardized based on air volume you have to standardize your results before you can compare the results with other results excellent this i think this is a good time for us to break for halftime joe and we'll come back with the second half of our interview with dr joe spurgeon we're talking dust sampling surface dust samples army spores we'll get into that in a moment and assessing mold exposures our 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reliability and ease for all your iaq and restoration needs at sunbeltrentals.com april air healthy air healthy home aprilaire.com and healthy indoors magazine a free online magazine for industry professionals and consumers healthyindoors.com okay we're back for the second half of our interview let's jump right back into it john we're going to get into the army section now i believe all right um yeah a little bit about the army method now changing gears going to be talking about building related contamination very briefly and occupant exposure potential with most of the emphasis on occupant exposure potential next all right some issues with perme scores so unless the collection method looked like this photo and it was collected from a carpet and it was reported on a weight analyzed basis uh then it was not an army sample and we should be very careful uh [Music] using army scores to assess the result because it was really not a goody sample okay you know i see this all the time i mean people swiffering you know on the top of their refrigerator or mailboxes and comparing them and so forth so what you're saying is it's it if ermey was developed to be used this way and there's really no support for those other types of other methods for using the army i don't want to say that what i'm saying is the they should be using an army score associated or correlated with that type of sampling and from that type of service and that doesn't exist does it the standard ermey score based on carpet sampling using this methodology from the initial 1000 and some odd houses should not be used and i don't think you have a problem with ermey in general it's just the misuse of it yeah i'm not going to argue about the initial use of ernie i i think it's been overextended by the iaq community gotcha okay john there we go all right now that i've said that uh the data that i'm going to present uh were collected with filter cassettes and surface swabs they were reported on an area basis rather than a weight analyzed basis so they're not kermi samples so neither are swiffer samples from these samples however what i'm going to present we can consider the implications of the concepts i'm going to present not necessarily the numbers so look at the concepts don't look at the numbers necessarily but look at the types of information and consider those i think they're valid so again concentrate on the concepts i think they're valid next right all right so the initial army method uh as joe was saying was developed to assess building-related contamination using carpet dust and if you look at the right-hand y-axis percent of homes in the u.s plotted versus uh army scores and that was the initial use and i have no argument with that next please however i i think the ieq community uses army scores as a measure of occupant exposure potential and now we're talking about the right-hand y-axis and now we switch to looking at correlating hermes scores with mold level and that is a total fungal loading and i think that's incorrect burmese scores are a function of the difference between group one and group two fungi not the total fungal loading so i think right off the bat we have a difference army scores are not associated with mold level they're associated with the difference between group 1 and group 2 mold levels so that's a problem to begin with next so let's look at what happens when we do associate hermes scores with mold level so here we have a plot of herme scores from minus six to plus five and it's plotted against group one contaminant fungi the concentration of those fungi and what we get is a bell-shaped curve okay just a standard bell-shaped curve this is what you would actually expect because early scores are calculated using the logs we don't want to get into that but this is really what you would expect okay so what we have is the highest occupant exposures are not at an early score of plus 20 the highest fungal loadings and occupant exposure potentials are at an early score of between 0 and 2. okay right in here and that's because we're just looking at the group one fungi now we're not subtracting out the group two no no you you can do this for group one group two total fungus this is just an example but you've got the same same shape you get a bell-shaped curve all right it's a it's a function of using the logs to calculate the army graph that's that's why all right so no matter what you use group one group two total doesn't make any difference but what if you subtract subtract group two from group one well you subtract group two from group one you get the army curve right but this is not subtracted out is can you use or should you use ermey scores to associate with occupant exposure potential and what i'm saying is you should not all right and this is why maximum concentrations occur at early scores between 0 and 2. okay next all right here's some carpet dust samples 39 carpet dust samples again this is total fungi now not just group one this is total fungi total loading versus early score we have three groups of samples so the first group down here in this green box is from mine memory scores of minus six to plus 15 and they're all very low concentrations of fungi so basically no exposure potential at all very low exposure potential over a very wide range of army scores minus six to plus 15. so again no association with exposure potential with army scorers we also have a group at minus six so at minus six we have a 49-fold variation in total fungi and from minus 2.5 to plus 2.5 we have a 100 fold variation in total fungal concentration from 700 to 70 000 it's more equivalent so again i can't find any association with total fungal loading and occupant exposure potential with hermes scores okay next section right if we look at individual houses we have houses one two and three all with an army score of plus 0.7 total fungi from 13 to 69 000 with a variation of with a five-fold variation in total fungi we have houses four through six with an army score of minus six total fungi varying from five hundred to thirty four thousand with a sixty eight fold variation in total fungi and we look at houses two and six we have total fungi of 39 000 with plus 0.7 score a house six with 34 000 fungi with a minus six score again no no association between fermi scores and total fungi john could you go back to the first army slide that shows the keep going keep going i just want people to be there we go hey that one right there so i just want people to be able to kind of relate back to this slide on the one and and that will help with what we just saw on the other slide go ahead back john so minus 10 to -4 is in the green area okay next all right we can also set up this is just an example i set up but we can also have a situation where total fungi at 110 000 has an early score of plus one and total fungi at 150 000 has a total army score of plus 0.3 so the higher the fungal loading the lower the army score so again there's no logic here as far as associating hermes scores with total fungi total fungal loading and octane exposure potential okay excellent we have some issues with that understood all right so this is going on to another topic this is a different topic uh this has to do with just surface sampling itself not with hermes so we're moving to a different topic now okay so this is uh sampling surfaces other than carbons and the interpretation of sample results for different surfaces so what i see often is multiple surfaces often sampled using swiffer cloths for example or any sample medium and these are plots of total fungi and let's just assume you get a laboratory report that says the sample contained 10 000 spore equivalents of of total mold for example so how do we interpret that is that high low average what is it well the point is that if that sample had been collected from an air return that would have been the 10th percentile concentration very low no problem at all if it had been collected from a carpet it would have been the 50th percentile concentration so an average typical concentration if it had been collected from an article of clothing it would have been the 97th percentile concentration so very high very elevated and it would have been a concern so understanding where the sample was collected is important to the interpretation of that sample result next okay and putting it in terms of army scores this is what the relative results would have been like all the way from a minus eight to a plus uh 16 or 18 depending on what surface was sampled so the conclusion is that the surface sample should be considered when assessing the sample result and i don't think we do that very well i don't even think this is understood very well no it's it's not i think uh it goes back to your your slide that said army was developed for a certain thing you know carpet well it was developed for carpet and if you want to develop an army score for air returns that's fine or air grills that's fine but don't use the carpet score for a return or a swiffer that's collected from the basement the first floor and the second floor even worse okay next all right so some of the characteristics of army scores so hermes scores only apply to carpet dust samples that were collected using a specific sampling method not to mix surfaces sampled using a swiffer for example results are reported on a weight analyzed basis rather than an area basis so sample results are not standardized and really can't be compared uh scores are calculated based on the difference between group one and group two fungi so scores do not reflect total fungal loading or occupant exposure potential and an army score does not represent a unique fungal loading for assessing occupant exposure potential next all right so assessing occupant exposure potential uh i'm going to be talking about an alternative method using total fungal loading so let's see what we can do with that i've been kind of raining on our everyone's parade so far uh there is an alternative approach that i use and i can only describe what i use there's probably many approaches but it can be used to assess building related contamination and occupant exposure potential if you wish to use it the method may look complex but it's actually fairly simple to learn and to use and you can put it in operation in a weekend i've taught several people how to use it it takes about a weekend to put it into operation uh once you do that it is operational and you can uh kind of forget about it and use it next so this is just an example let's assume these are 18 uh samples that you've collected from soft surfaces and these are the data for orobacidium for example so you would list the samples from lowest to highest concentration uh and for example the ninth sample out of 18 would be the 50th percentile sample and this has a concentration of around 2 thousand sport equivalents so going to the next one what you would do is create a table like the fiftieth percentile was two thousands four equivalents for obsidian you would create a table like this from the 16th 50th 75th 95th percentile concentrations uh and once you create this table for orobasidium you could create it for penicillium brother compactant total fungi for stachybotrys for platysma whatever you want uh you can do it for soft surfaces air returns air supplies hard surfaces whatever you want once you create these tables you're done you can stop that's all you need what i'm going to be doing is using graphs in the following presentation just to illustrate the concept you don't need the graphs all you need is a table like this and it doesn't take you very long to create one joe how is this sampled is this um an open-faced cassette sample or is this what kind of sample are we looking at this is a micro uh this from a soft surface micro back anyone however you sample this is an open face cassette that i use okay uh yes but however you sample you use your methodology because you want it to reflect your methodology and i got a question from the audience is this method in your book it is and i also i i've taught several people how to use it uh contact me i'd be glad to help you if you're interested all right okay so again uh this is soft surface micro back cassette these are the plots and also it can be just a simple table i'm just using plots to make it visual for you but these are uh total fungi these are total aspergillus total herme 36 herme fungi aspergillus total penicillium so we can see that total fungi the 50th percentile is 3 000 spore equivalents so how could this help us let's go to the next one so these are air supply grills uh collected using swab samples so if the samples are collected from air supply grills using a swab sample analyzed by qpcr the point is you can use this graph or the table as i indicated to you to interpret the next 10 50 or 100 samples that you collect using this methodology from air supply grills and that's very powerful so for a couple of hours work done on a saturday morning you can interpret the next 100 samples you collect and air supply grills are an interesting choice of location and i know you can do this in any number of locations but maybe you could just spend a minute on why air supply grills can be so informative yeah because the air delivery system can be a source of occupant exposure if i have the resources available to me during an inspection i like to sample the air return the air supply and horizontal surfaces and i like to correlate the results for those three locations i consider what's on the air supply grill or the boot of the grill uh a potential occupant exposure source there can be a lot of stuff in a wet hvac system i want to know what's coming out of the system not what's in the system what's coming out of the system what's on the air supply grill is probably what's being exposed into the breathing zone of the occupants and if i can correlate what's on the grill and what's on horizontal surfaces i'm even more certain of what's been circulated in the indoor hair excellent next john all right so how can we interpret those samples then uh this may look complex it's not what we're interested in is the 50th percentile concentration which is the median concentration and the average concentration which is the 73rd percentile but we're close to 75 time and also if we were doing clearance sampling the 16th percentile concentration which is one standard deviation below the median and the 84th percentile which is one standard deviation above the median don't worry about this in this situation but the median concentration on the average concentration next okay why so if i'm assessing building related contamination i want to use the 50th percentile concentration to assess building related contamination if i'm assessing occupant exposure potential i want to use the 75th percentile concentration because the dose is equal to the average concentration times the exposure time so those are the two concentrations i'm interested in all right next all right here's the how i determine whether or not concentrations are typical or elevated so here's the cumulative percentile distributions from the 10th percentile to the 95th percentile for the army group 1 and group 2 fungi and if we look at the percentiles some of them are in blue and some of them are in red so these are the ratios of the group one contaminant fungi to the group two common environmental fungi and those that are in blue are those where the common environmental fungi dominate those that are in red are where the contaminant fungi die so we're switching from typical environments to contaminated environments and that switchover is at the 70th percentile concentration okay so that's my breakpoint so how i analyze it is this way first i use the distribution of total fungi for the 36 army fungi rather than a score to assess condition that is i assess i use that to assess building related contamination or the clean versus discard decision for soft surface items for example second i then use the distribution of the individual fungi to identify contaminants of concern that is to assess occupant exposure potentials interesting next so here's the distributions for all 36 army fungi group 1 fungi group 2 fungi and total fungi so i used the distributions for the group 1 and group 2 and total fungi to assess building-related contamination and i used the distributions for the 36 fungi to assess occupant exposure potential okay now go to the next lecture all right so here's an example of a carpet dust report it's it's a real report and it's from one of the individuals i taught how to use this methodology so it's a real system the first thing i'll point out is orobasilium and the reason i point that out is that it's the largest number in the middle column so everybody's eye just immediately goes towards four obsidians two thousand but we don't know whether it's important or not but if you look at the last column then we can see yeah it's important it's 85th percentile concentration so it's elevated all right so we know it's elevated if we look at plutonium plutonium is 29 spore equivalents but if we look at hespergillistocracious it's 28 spore equivalents for the same concentration so is one important and one not important are they both important both not important well plutomium is at the 40th percentile concentration eucracis is at the 90th percentile concentration so cotonium is kind of typical concentration nothing to worry about locations 90th percentile it's elevated if we look at total spores detected i didn't indicate the group 2 fungi but we're given the total fungal loading so i can evaluate the condition of the space that was sampled and i can evaluate total fungal loading and occupant exposure potential in general and building related contamination to see what the condition of space was and fourth i can tell the client but i can tell any physician that's involved that we had six contaminants of concern detected in the last column the red dots indicate those specific fungi that were detected at elevated concentrations so we're going to use more information from this approach than simply an early score this is all from a carpet dust sample yeah and just one well take as many as you want as many as the client can afford i i not a proponent of just taking one sample but sometimes you have resources to work with sure you're going to take one one sample i would rather have a report like this than simply an early score yep i agree next uh this is a hurts me method i'm not going to go over this if anyone's interested it's on the report with the next please next all right this is what i want to get to is about or hurts me uh this is the prevalence of the uh five hershey fungi by surface type that we have carpet soft surface clothing hard surface fair returns and supplies and the point is that if you're going to use whether it's an army score or hurts me score or whatever that all of these fungi are not always detected on every type of surface [Music] these you know here's we have 93 samples and this is the prevalence on 93 different surface samples the prevalence of detection so if you're going to use something like hurts me [Music] hurts me scores were based on less than three percent of the fungal loading typically less than one percent of the fungal loading and on many of these surfaces these fungi weren't even detected so the sampling locations are an obvious influence on the interpretation of the results and that's the only point i want to make okay next so in certainly hermes scores have several limitations as currently applied in ieq investigations i think they only should be applied to carpet dust samples they're based on a specific sampling method reported using the weight analyzed basis and they do not reflect total fungal loading next and with that i will close out my presentation joe with that i want to go to the roundup john and i will get to ralph i'll get to your question in the roundup [Music] the roundup is brought to you by april air providing healthy humidity ventilation and air purity solutions for new and existing homes april air healthy air healthy home at aprilaire.com okay john let's go back to that presentation about the third from the last powerpoint i've got a question isn't walla me a semi see me present above your outpoint of 70 uh this one here yeah um one of the one audience said isn't wala mia present above your out point of 70 yeah it's at 75 yeah we just you just didn't put a a red dot there i guess yeah you could i mean it would be a that's that's your professional judgment as to what percentage you hit it yeah okay excellent 70 uh 75s on the borderline i just hit the ones above 80 percent and above that's what i hit gotcha cliff final questions carl yeah yeah just just one question joe um you know one of the things i've learned from looking at thousands of hvac systems in in homes particularly homes that have fire damage a lot of times the residue found on the supply grill or on the supply register is inconsistent with the residue inside the duct work because what happens is an air stream is coming out of that register and when you have a lot of sort of residue in the air in that room it impinges onto that register didn't come through this was this didn't come through the register to get in the room this is impingement of dust uh that's already in the room so i just wondered if you've ever encountered the same thing or if you could comment or i can't really comment it's a matter of uh you have to use your procedures and standardize on it get a database and compare your results within your database my point is establish a database for how you sample and how you investigate and compare the next results you get against your database that's my recommendation i don't think enough of us do that oh very few actually joe i just want to kind of summarize real quick you did a good summary but i'm i'm getting the impression that um army maybe not earn me so much as qpcr has some real potential if used properly oh yeah i personally i believe qpcr is a very good methodology i don't even know i haven't well i mean i've been retired for a while but but my gosh yes it's very good i still think there's places to use cultural samples i use cultural samples and qpcr depending on the objective of my sampling and the project objectives i also really like the way you differentiate between building related contamination and occupant exposure potential i think is is the terminology you use i get the impression that most people get them mixed up and what they're really trying to do is figure out if there's building related contamination and they automatically assume that's also an occupant exposure potential comet yeah they're two different things if i were going to take an air sample in a house for example and i were interested in assessing building related contamination okay i i might take five-minute slit impaction cassette samples fine if i'm going to assess occupant exposure potential i'm going to take 60 to 90 minute filter cassette samples so i have to understand my objective and i differentiate between those two objectives and i'm going to use different sampling methods if i'm taking surface dust samples building related contamination okay take a tape lift sample if you're looking at brc if i'm looking at occupant exposure potential i'm going to be using qpcr or culturable samples so to me there is a difference absolutely and i i just i've always felt like a lot of ieps should stick more to determining if there's building related contamination and stay away from the occupant exposure potential they just don't have the they don't have the uh go ahead i yeah i kind of disagree with that well then don't take people's money okay give them the impression that they're doing a complete inspection but isn't building related contamination important it's yes it's very important but if there's an occupant exposure don't give the people the impression that you're doing a complete inspection gotcha gotcha joe anything you'd like to add before we go it's always a pleasure talking with you always enlightening and um we love having you on no i've been hitting this this idea of sampling methodology and lack of uh validation uh for many many years i haven't made much progress i think you're making a little more progress than you may realize here i don't know i i i know there's a group of people that you and i email with quite regularly that are at least trying to figure this out and uh that's a start great all right well i want to thank dr joe spurgeon for joining us today this was always sometimes i get a little uh uh over my head at times but that's okay you know i'll go back and listen again and check it out but for those of you that have any questions please send questions to me at joe.hughes at iaptraining.com i know joe's always interested in getting comments and feedback on his presentations he doesn't think he has all the answers he wants our input as well and and especially those of you that you know have some good background in in this type of thing uh also if you get a chance join us on afterthoughts.iaqradio.com uh sponsored by first on site this is radio joe hughes saying thanks to dr joe spurgeon my co-host the z-man cliff zlotnik john you got to have faith that the controls most importantly our audience and sponsors we will be back in two weeks live but next week we've got a great flashback show for you let's see david jacobs will be with us in two weeks live from the national center for healthy housing so come back and join us for the next episode of iaq radio plus for iaq radio i'm spike reel saying thanks for listening [Music] oh [Music]

Channel: IAQ Radio

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Id: XEx_cweGa9I

Length: 68min 56sec (4136 seconds)

Published: Fri May 06 2022