1. Indoor Environmental Quality: Investigating the Problem
John W. Martyny, Ph.D., CIH

3. Causes of IAQ problems. Outdoor pollution Indoor pollution
Building material off-gassing
Inadequate ventilation

5. How are IAQ Investigations Conducted?

6. IAQ Investigations Building Characterization Symptom Survey
Ventilation System Evaluation
Source Identification
Sampling
Remediation

7. Building Characterization
Type and age of building
Construction materials
Primary uses
Cleaning practices

8. Type and Age of Building
Previous ventilation systems.
What remodeling has taken place?
What were the prior uses?
Is asbestos a concern?
Is mold a concern?

9. Construction Materials
Wood Construction vrs Metal
Fire proofing material
Crawl spaces
Carpeting and wall coverings

10. Primary Uses Is a manufacturing area included?
What is the occupant density?
Computer usage.
Has the primary usage changed?

11. Cleaning Practices Who cleans the building?
When is the building cleaned?
Cleaning product storage.
Cleaning product MSDS information?

12. Symptom Surveys Questionnaires vrs. Interviews The survey must:
Cover a majority of the staff.
Be pre-tested.
Eliminate bias.
Not suggest answers.
Not be a group effort.

13. Questionnaire Topics Demographic Questions Comfort Questions
Medication Questions
Diagnosed Illness Questions
Symptom Questions
Air Quality Control Questions
Job Satisfaction Questions

14. Ventilation System Evaluation
Visual inspection of System.
Carbon dioxide (tracer gas) measurements.
Look for the following:
Water infiltration
Maintenance history
General condition
Use of local exhaust
Placement of exhausts and intakes

22. Ventilation System Characterization
System Type
Constant Volume
Variable Air Volume
Unit Ventilators
Zones
Single Zone
Multi-Zone
Reheat or No Reheat
Ducts - Lined or Unlined

30. Unit Ventilators Not actually an air handling system.
Mount on outside wall.
Provide some filtration, conditioning, and movement.

32. Constant Volume Systems
Provides a constant supply airflow rate to zones with similar thermal loads.
Air temperature is controlled at the air handler or with reheat coils.
Outside air is determined by:
Outside air temp.
Damper settings
Temperature demand

33. Variable Air Volume Systems
Provides a constant temperature air to the duct system.
Air from the duct system is supplied to the zone to manage thermal load by the use of VAV boxes.
Outside air is determined by:
Thermal demand of zone.
Outside air temperature.
VAV box and damper minimum settings.

34. Results of CO2 and ACH SamplingCV
VAV UV
GM of CO 2
715
ppm
666
573 CO
Range (
ppm)
318 – 1,763
295 – 1,450
% of Time > 1000 0%
11% 9%
Mean ACH
4.6
2.8
2.7
Range ACH
1.9 – 7.5
0.8 – 4.6
0.4 – 4.6

35. Particle Ratio ResultsCV
VAV UV
GM Ratio < 1 m
0.68
0.57
0.38
GM Ratio 1 – 3
1.39
3.08
5.47
GM Ratio > 3
3.20
4.80
14.76

36. Complaints by System Type
Type of Complaint
More than
Expected
Less than
Too cold
VAV CV
Individuals w/ complaints
Eye Symptoms
Headache Symptoms UV
Nasal Symptoms
VAV, CV
Throat Symptoms
Dustiness Complaints

37. Source Identification
Look for the following:
Manufacturing areas
Print shops
Construction
Cleaning agents

38. Sampling
Initial Site Assessment
Secondary Sampling

39. Initial Site Assessment
HVAC system measurements:
Carbon dioxide, air flow.
Ambient air measurements
Carbon monoxide, carbon dioxide, temperature, relative humidity.

42. Secondary Sampling Should only be conducted when: HVAC measurements
Specific information is to be collected
Knowledgeable personnel are present
HVAC measurements
Tracer gas, duct velocities
Ambient Air
Chemicals - VOC’s, aldehydes, MVOC’s, odors, particulates, etc.
Bioaerosol Sampling
Medical monitoring

43. Why conduct tracer gas testing?
To determine air exchange rate for a building or area of a building.
To determine fresh air distribution for a building or area of a building.
To determine ventilation infiltration.
To determine exhaust system effectiveness.

44. Tracer Gas Testing Methods
Tracer gas characteristics.
Tracer gas introduction methods:
Injection
Constant Flow
Duct injection
Hood Testing
Concentration measurement methods GC
Infrared

45. Tracer Gas Testing Methods (Cont)
Tracer gas introduction:
Air Change Studies
Contamination Studies
Hood Studies

46. Results What do results indicate? Limitations!
Comparisons with carbon dioxide methods for ventilation.

48. Why conduct bioaerosol Sampling?
Should only be done by experienced personnel and under limited conditions.
To attempt to document the presence of a bioaerosol.
To attempt to determine the type or species of a bioaerosol.
To attempt to determine the cause of specific diagnosed diseases.
To attempt to determine the effectiveness of a mitigation program.

49. Why not to conduct bioaerosol sampling.
To determine the presence or absence of a bioaerosol.
To determine if an area is safe.
To determine the cause of frequent colds, flu, rashes, etc..
To show that mold from the carpet, etc. is entering the air.

50. Where to conduct bioaerosol sampling.
Choosing sampling areas.
Choosing control areas.
Choosing outside control areas.
How many samples to collect?

51. Types of bioaerosol sampling.
Bulk Sampling
Viable Sampling
Non-viable sampling
Dust sampling
By-product sampling

55. Particulate Sampling Methodology Results - What do they mean????
Mass collection
Particle counters
Condensation nuclei counters
Results - What do they mean????
Mass
Mass/particle size
Particle numbers
Ratios

59. Sampling complications
Interpretation of results is difficult.
Generally low probability of identifying a problem.
High cost
Grab samples may give non-typical results.
Source identification may not be possible
Source reduction will still need to be done.

60. Remediation Increase outside air Decrease outside air Control sources
Local exhaust ventilation
Elimination
Control devices
Contain construction or remodeling
Isolate manufacturing areas

63. Factors confounding IAQ investigations
Ergonomic problems
Smoking policies
Comfort Complaints

64. Comfort Factors Complaint Low School High School Cold 32% 73% Hot 21%
50%
Stuffy 7%
52%
Moldy
14%
10%
Dusty
11%
23%
Noisy 0%
19%
Dry
11%
25%
Crowded 0%
17%