Ask The Experts
I was speaking with Jack, a gentleman from Florida, who was asking me about how to convert particle counts to particle mass (ug/m3). He had also asked if there were guidlines for particle limits in residential settings. He has posted his question in the comments section of this blog. Jim Akey from Lighthouse Worldwide Solutions jumped in to answer the questions and offered Jack some great resources on the topic.
Click on the “comments†link below to read the question and response from Jim Akey and/or join in the discussion.
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Jack Said,
March 25, 2006 @ 5:56 pm
Greetings, and thanks for providing this great concept
Is there a way to convert particle counts (at 2.5, or 5, or 10, for example) to even a rough equivalent in ug/m3?
( a reason for asking is that it seems that most guidelines for indoor air settings, – I’m particularly interested at this time in residential- that I have seen, are given in the mass concentration rather than a “countâ€)
another related question- could you please direct me to any sources that do discuss what particle counts (2.5, for example) one would “typically†find in a “normal†residential setting? I realize there are a lot of variables there- but maybe some sources would provide a range???
thanks very much
Jim Akey Said,
March 25, 2006 @ 5:58 pm
Hello Jack:
You are correct in your assumption that most “standards†for indoor air quality require the measurment(s) be reported in ug / m3 (mass concentration or density). These standards were written and published by the US EPA. The EPA website (www.epa.gov) has a number of good articles and papers written on Particulate Matter (PM) 10; 5.0; and 2.5. One link to start with is:
http://www.epa.gov/air/particlepollution/standards.html
Both particle counts and mass concentration readings are important in determining the overall quality of air in residential settings. There is a formula that we provide our customers that will roughly equate particle counts to mass concentration. This formula should only be used as a guide, as we take a couple of liberties in determining mass concentration from particle counts. First, we group particle sizes in bins – say your particle counter’s first 2 channels are 0.3 microns and 0.5 microns – in our formula, we consider all these particles to be the mean of this range, or 0.4 microns. Particle counters do not analyze the composition of the particles (and different elements have varying weights), so we use the weight and absorption coeffecient of carbon. These 2 variables can be changed, but we have found that the formula is pretty accuracte in most cases.
Customers frequently ask me what are “typical†readings (particle counts) for the different particle sizes. I have not found any published ranges, and for good reason. There are literally hundreds of variables that will effect the particulate counts. Some of these include Weather (there are less particles present on a rainy day – many more on a windy day), Geographical location (in a city, out in the country, etc.), Activities occurring in the sampling location (are people moving around on the carpet, is the HVAC system runnning, are the windows open, pets present, mold growing, etc.). I have found that after using a particle counter in many similar settings, the user gathers a large amount of data (a baseline) that will reflect a “typical†particle count in their region.
One can also compare particle counts to some of the clean room standards being used by the electronics, pharmaceutical, medical, etc. industries. For instance, sitting at my desk, I generally fall within a Class 100,000 clean room (Fed 209e standard – Class 100,00 is the least clean of these classifications). A Class 100,000 cleanroom classification states that there can be no more than 100,000 particles at 0.5 and greater per cubic foot of air.
Jack, ther are a LOT of excellent resources available to learn more about Indoor Air Quality in general, and particulate sources, etc. I would suggest you start with a few as listed below:
http://www.iaqa.org
http://www.nadca.com
http://www.iest.org
http://www.aerotechlabs.com
http://www.safety-epa.com
If you have further questions, please feel free to contact me.
Jim Akey
Inside Sales
Lighthouse Worldwide Solutions
110 Pacific Avenue
Tillamook, OR 97141
Phone: (503) 842-0700
Fax: (503) 842-0701
Cellular: (541) 261-5174
jakey@golighthouse.com
http://www.golighthouse.com
Jack Said,
March 25, 2006 @ 5:59 pm
Rod and Jim,
Thanks very much for your help and information!
Jp Leblanc Said,
September 16, 2006 @ 1:00 pm
Hi. I am a Quality Auditor at a truck manufacturing plant in Ontario, Canada. I am currently taking particle readings in the paint system, and in the booths themselves. There is a Prime line system, the topcoat system,and the plastic line. I am having trouble finding out what the limit levels would be in a clean air system. I know that readings inside the tack, spray, and flash booths should be “0″, but what limits are there within the clean room> I am currently taking readings at 5 microns. Any help would be appreciated.
Muna Kamel Said,
March 1, 2007 @ 8:56 am
What would be the best particle counters for clean room class A and C rooms which would meet the GMP requirements.
Rod Said,
March 1, 2007 @ 8:59 am
Muna,
A Class A Clean room is equal to an ISO 5 or Class 100 (Fed. Std. 209e) clean room here in the US.
A Solair 3100 / 3100+ would be the best fit, but if funding is not available, you can get by with a 3016 for verification purposes – The GMP standard requires that 1.0 CFM of air be sampled.
The Solair 3100 or 3100+ is a 1.0 CFM (28.3 LPM) portable particle counter:
The 3016 is a 0.1 CFM (2.83 LPM) handheld particle counter:
Lutfi Asyairi Said,
September 19, 2007 @ 1:36 am
Hi, i work in Pharmaceutical clean room.
i want to ask some question:
On ISO standard room classification was based on standard eror which calculate from discrate particle counter, how we classified the clean room if we used continous particle counter ?? do we need to calculate sampling location and the standard error??
Thanks in advance