Applications of the Opticle Particle Counter in an IAQ

Assessment

Columbia SC Chapter IAQA Workshop June 26, 2008

Presented by:

Craig Whittaker, CIE, Ph.D. Environmental Solutions Group

Brief History of the Particle Counter

Parallels the development of the personal computer

First developed in the 50s to monitor dust in manufacturing

Evolved into a tool for assessing clean rooms

Greatest design advances made in last few years

The IAQ professional now

has several options for small,

powerful and intuitive devices that offer real-

time data logging & other features

Most airborne particles are either biological contaminants, gases or dust

Handheld particle counters today are well-equipped for measuring airborne biological contamination

Current Technology

Biological contaminants include: Mold Dust mites Viruses Animal dander Bacteria Pollen Skin fragments Insect parts

Recent Studies on the Health Effects of Fine Airborne Particles

European study found that fine particles that are inhaled can affect the blood vessels, leading to an increased risk of heart disease - American Journal of Respiratory and Critical Care Medicine

Children with asthma had significantly decreased lung function following exposure to indoor air pollution that included fine airborne particles - National Institute of Allergy and Infectious Diseases

How Does the Particle Counter Work?

Counts particles

that block a beam of light reflecting

onto a screen QuickTime™ and aGIF decompressor

are needed to see this picture.

The three components of a particle counter:

1) airflow system

2) optical system

3) electronics

The Airflow System

Includes an isokinetic probe, air chamber and pump

Its job is to capture a sample of moving air at the same velocity it is moving, allowing a normalized count

The Optical System

Includes a high-grade laser, optical measuring components and a

detection surface (screen)

Its job is to measure the scattered light against the screen

The Electronics

Includes computerized amplification and counting circuitry

Its job is to amplify the low level signals from the detector surface and convert each scattered light pulse to a number

representing its corresponding size

Tabletop vs. Portable Unit

Tabletop unit has a larger pump and can attach to multiple sensors throughout an area for continuous monitoring of clean rooms

Portable unit is designed for point-of-use measurements in critical locations to include clean rooms, medical facilities and HVAC systems analysis in commercial & residential buildings

One of the most useful aspects of the portable unit is the ability to track

contamination - everything from

fine dust to biologicals - to the

source

One of the most common applications of the portable unit is for

measuring the efficiency of

filtration systems

Limitations of the Laser Particle Counter

Refracted light varies due to differences in particle shape & shininess

Particles are not always evenly distributed throughout a room

The electronics employ a bell-curve (Gaussian) distribution method of categorizing particle sizes

Guidelines for Use

Store unit at room temperature in a vibration-free environment

Keep unit clean per manufacturer’s instructions

Stay clear of electrical equipment while collecting readings

Consider keeping a log of preventive maintenance, recalibrations and any unusual performance

Application: Trend Analysis

Noting gradual or sudden changes in airborne contamination when an HVAC system is powered

on/off1

Establish baseline readings prior to a process that may change the indoor air environment

Monitoring filter efficiency by sampling air immediately before entering & after entering the filter

1NADCA’s ACR 2006 contains particle profiling procedures for HVAC systems

The single most important advantage of the handheld particle counter is the

ability to conveniently collect multiple readings in an area to generate a

statistically valid sample based on the average particle counts for the area.

Case Study #1: Outpatient Surgical Center

Two operating rooms and sterilization and surgical preparatory rooms flooded with clean water over

a weekend. Water soaked floors and drywall.

Our firm arrived immediately after standing water was extracted to collect baseline (first-response) airborne particle readings prior to installation of

HEPA air scrubbers.

Safety was of primary importance to the client but speed of remediation

was also crucial. The remediation and

reconstruction had to be complete and post-

remediation verification obtained in only 48 hours

Handheld particle counters were used extensively to monitor the effectiveness

of air scrubbers

Particle counts were recorded at entering and exiting points of twelve air scrubbers

Scrubber positions were adjusted frequently to

address ‘hot spots’ where counts had

spiked

Every phase of the project was guided in part by the particle

readings

The remediation was completed ahead of

schedule and particle counts were excellent.

All that remained to be installed was the

new flooring.

The ‘sterile’ vinyl arrived in the back of

a filthy truck

Particle counts jumped nearly 7000% in the

operating rooms upon bringing the vinyl into

the rooms

The floors were finished at midnight with the rooms scheduled to

open at 7:00 am.

We logged airborne particle counts until

5:30 am; counts were low enough to indicate a successful clearance

Spore counts were collected for lab analysis in one hand while re-

checking particle counts in the other

hand

Rush analysis by a local lab confirmed that no fungal spores were present

in the operating suite.

Surgeries were performed on schedule and the client was relieved

Case Study #2: Physician’s Residence

A medical doctor who recently purchased a 100-year-old home on the NC coast had experienced flu-like symptoms since moving in two months

ago

His wife and child have no symptoms, but they sometimes noticed a musty odor on the main

level

A visual assessment yielded no moist building materials or fungal growth inside the home

Airborne particle counts were abnormally high in the 2.5-µm classification

in the kitchen. After ruling out food items as the source, we collected a particle reading in a

base cabinet and found the 2.5 -µm count to be 700% higher than the average count for that size particle elsewhere

in the house

0500

1000150020002500

Avg. PC's in2.5-micronsize zone

Out ofkitchenInkitchenIncabinets

The culprit appeared to be gold-colored

material on an exterior plaster wall in a base

cabinet where cooking items were stored. We removed several items to expose the material

for sampling & for taking this picture.

Lab analysis indicated an elevated count of 2320 aspergillus/penicillium spores/m3 in the total spore

count. An air culture indicated a count of 320 cfu/m3 of aspergillus.

The physician/homeowner was subsequently tested and found to have a fungal infection in his digestive tract. Remediation and antibiotics have resolved his

medical issue.

Case Study #3: Office Building

An employee at a call center that had experienced a water leak from the HVAC system one year ago

was taken to the hospital after cleaning under her desk. She developed a severe rash on her

arms & was having trouble breathing.

The employee told us that the carpet under her desk remained wet for a few days following the

leak incident of a year ago

Particle counts were collected in thirty locations throughout the 10,000 SF building. Ambient readings and readings at air supplies were

collected.

Particle counts were normal for the building in all areas except near the affected employee’s desk,

averaging 1167 count in the 1.0 to 10.0-µm classifications. Readings near the desk averaged

1483.

After slightly agitating the

carpet under the employee’s desk, particle readings

jumped over 300% from 1483 to 4619 in the 1.0 - 10.0 µm

classifications.

010002000300040005000

Avg. PC's in1.0 - 10.0microns

Office-wideAt desk

Agitated

Lab analysis indicated an elevated presence of aspergillus/penicillium in a sample of the carpet

and an elevated count of 1320 aspergillus/penicillium spores/m3 in the total

spore count collection from under the desk. An air culture indicated a count of 271 cfu/m3 of

penicillium. The employee is allergic to penicillin and her doctor believes that her immune system had a reaction to the spores released from the carpet

during vacuuming. The carpet was replaced and the area cleaned and

the employee has had no further issues.

Case Study #4: Three Crawl Spaces

Examines the relationship between room particulate counts in residences with crawl spaces with some areas of visible fungal

contamination.

Question: is there a correlation between elevated airborne particle counts in an area with no visible contamination and an adjacent but hidden area

with visible contamination such as in a crawl space?

Conclusion

Based on somewhat limited data, the opticle particle counter appears to provide the IAQ

investigator who is assessing an apparently clean area with information

that relates to fungal contamination in an adjacent but hidden contaminated area.

Data Set from 21 Locations

A collection of pre- and post-remedial readings from residential, office and

medical buildings

Criteria for inclusion:Our firm performed the assessments

The identical calibrated equipment was used for data collection

Lab analysis was performed by the same labData is less than one year old

Total Countsn = 21

0

10000

20000

30000

40000

50000

60000

70000

80000

90000

Total Counts

Raw Counts

PC Initial SpT Initial Cult Initial PC PRV SpT PRV Cult PRV

Averaged Countsn = 21

0

500

1000

1500

2000

2500

3000

3500

4000

4500

Averaged Counts

PC Initial SpT Initial Cult Initial PC PRV SpT PRV Cult PRV

Conclusion

The opticle particle counter provides the IAQ investigator with a convenient means to

gather a substantial amount of reliable, real-time data relating to air quality. It is a valuable

addition to the IAQ investigator’s toolkit.

More research is needed, however, to determine how the data is to be

interpreted.

Additional Research Areas

What role does the environmental condition play?

DampnessBarometric Pressure

Building PressurizationTemperature

Selection of a Particle Counter

• Define the intended use of the device - will you be assessing cleanrooms or ‘dirty’ areas (or both?)

• Decide on the features you require - will you be storing large amounts of data, assessing for certain particle sizes, printing readings on site, or downloading data into a computer?

• How easy is the unit to use? Can it survive a fall or extreme conditions? Does it have a touch-screen interface? Can it record temperature & humidity readings in addition to particle sizes and mass concentration?

• You may want to try renting a unit prior to making a purchase so you don’t make a mistake (these devices start around $2000)

ISO 14664-1 Cleanroom Standards

0.1 µm 0.2 µm 0.3 µm 0.5 µm 1 µm 5 µm

ISO 1 10 2

ISO 2 100 24 10 4

ISO 3 1,000 237 102 35 8

ISO 4 10,000 2,370 1,020 352 83

ISO 5 100,000 23,700 10,020 3.520 832 29

ISO 6 1,000,000 237,000 102,000 35,200 8,320 293

ISO 7 352,000 83,200 2,930

ISO 8 3,520,000 832,000 29,300

ISO 9 35,200,000 8,320,000 293,000

Selected Resources

American Industrial Hygiene Association, Assessment, Remediation, and Post-Remediation Verification of Mold in Buildings (2004)

National Air Duct Cleaners Association, Assessment, Cleaning and Restoration of HVAC Systems (ACR 2006)

Hollace S. Bailey, Fungal Contamination: A Manual for Investigation, Remediation and Control (2005)

Particle Measuring Systems, Counting Efficiency and Resolution in Optical Particle Counters (2007)

Authors

Craig Whittaker, Ph.D., CIE Environmental Solutions Group

Steven Armstrong, M.S., P.G. Environmental Solutions Group

Thank you for attending!Are there any questions?