In this section, the statistical perspective of monitoring location and time discussed in the previous sections is applied to translate the monitoring objectives, stated in the second section, into the following three monitoring requirement:
1) To meet the first monitoring objective, the monitoring location should be representative of the symptomatic and asymptomatic areas and control locations. These areas are contained in the third through sixth sub-populations of monitoring locations. Each sub-population may contain several areas. The first and second sub-populations may be included in the monitoring as control areas. Other monitoring location for control includes the outdoor, at roof and street levels, and the heating, ventilating, and air-conditioning systems at downstream and upstream of the intake fan and at the return fan. At each of the monitoring
locations the monitoring should be representative of each of the thirteen sub populations of monitoring time.
2) To meet the second monitoring objective, the monitoring locations should be representative of all of the six sub- populations of monitoring locations. In this case, the monitoring locations for control are the outdoor, at roof and street levels, and the heating, ventilating, and air- conditioning systems at downstream and upstream of the intake fan and at the return fan.
3) To meet the third and fourth monitoring objectives, the monitoring should be reliable, valid, and practical. This requirement will be discussed in detail in Chapter 6.
5.9 CONCLUSION
The generic theory of monitoring approach, location, and time are identified in this chapter. The monitoring of airborne pollutants may be conducted either once or continuous, using either sequential mobile or stationary monitoring location, by either direct reading or integrative monitor. In theory, the monitoring should be carried out in representative areas and time. Representative requires two conditions which provide the answers to the two research questions addressed in this chapter. Firstly, the monitoring location should be randomly selected from the six sub- populations of monitoring location and secondly, the monitoring time should be randomly selected from the thirteen sub-populations of monitoring time.
5.10 REFERENCES
1. Armstrong, 0. W. et al (1989). 'Sick Building Syndrome. Traced to Excessive Total Suspended Particles', in ASHRAE. The Human Equation: Health and C om fort.
Proceedings of the ASHRAE/SOEH Conference. lAQ '89, Apr. 17-20, 1989, San Diego, California
2. ASHRAE Standard 62-1989. Ventilation for Acceptable Indoor Air Quality. Atlanta, Georgia: American Society of Heating, Refrigerating and AirConditioning Engineers, Inc.
3. Goyer, N. (1990). Chemical contaminants in office buildings'. American Industrial Hygiene Association Journal. Vol. 51, No. 12, pp615-619
4. Grot, R. A. et al (1991). Indoor Air Quality Evaluation of A New Office Building'. ASHRAE Journal. Sep. 1991, pp16- 25
5. Kagawa, J. (1993). Indoor Air Quality Standards and Regulations in Japan', Indoor Environment. 1993, Vol. 2, pp223-231
6. Otson, R. and Fellin, P. (1992). Volatile Organics in the Indoor Environment: Sources and Occurence', in Nriagu (ed ). Gaseous Pollutants: Characterization and Cycling. Chichester: John Wiley & Sons, Inc., pp335-421.
7. Purnell, C. J. and 1RS Staff (1987). Occupational Health Review. Number 9, pp17-19
8. Quinlan, P. et al (1989). Protocol for the comprehensive evaluation of building- associated illness', in Cone, J. E. and Hodgson, M. J. feds.1. Problem Buildings: Building Associated Illness and the Sick Building Svndrome. Occupational Medicine: State of the Art Reviews, Oct-Dec 1989, Vol. 4, No. 4, pp771-797
9. Roach, S. A. (1966). A More Rational Basis for Air Sampling Programs', American Industrial Hvgiene Association Journal. Vol. 27, p i-12, in Warner, P. O. (1976). Analysis of Air Pollutants. London: John Wiley & Sons, p200.
10. Rohbock, E. et al (1988). Indoor air composition in office rooms with central air supply', in Perry, R. and Kirk, P. W. (eds.). Indoor and Ambient Air Quality. London: Selper Ltd., pp503-511.
11. Saltzman, B. E. (1988). Basic Factors in Gas and Vapour Sampling and Analysis', in
American Conference of Governmental Industrial Hygienists. Advances in A ll Sampling. Michigan, USA: Lewis Publishers
12. Shaw, 0. Y. et al (1991 ). 'Indoor Air Quality Assessment in An Office-Library Building. Part I: Test Methods', in ASHRAE Transaction 1991. Part 2, Vol. 97, pp129-135.
13. Skov et al (1990). Influence of indoor climate on sick building syndrome in an office environment'. Scan J Work Environ Health. 1990, Vol. 16, No. 5, pp363-371.
14. Smith, F. et al (1988). ' Evaluating and Presenting Quality Assurance Sampling Data' in Keith, L. H. fed.) Principles of Environmental Sampling. ACS, pp157-168
15. Weschler, C. J. et al (1990). Concentrations of volatile organic compounds at a building with health and comfort complaints'. American Industrial Hvgiene Association Journal. Vol. 51, No. 5, May 1990, pp261 -268
16. Yocom, J. E. and McCarthy, S. M. (1991). Guide. New York: John Wiley & Sons
Chapter 6
RELIABILITY, VALIDITY, AND PRACTICALITY
(METHODOLOGY 2)
6.1 RESEARCH QUESTIONS
This chapter seeks to address two research questions:
1) how reliable and valid is the proposed monitoring methodology: 2) how much is the estimable error.
6.2 SUMMARY
The reliability and validity of the methodology of monitoring airborne pollutants are subjected to uncertainties which cause errors. As some of the errors are estimable, an attempt was made to approximate the estimable errors. Furthermore, the monitoring of gaseous airborne pollutants was conducted at four calibration settings. To be valid, the data at the four settings should be first converted to a common calibration setting before a comparison could be made. In this chapter, a conversion formula for that purpose is derived.
6.3 INTRODUCTION
As stated in Chapter 5, reliability, validity, and practicality are the third monitoring requirement. The purpose of this requirement is to ensure a well-grounded research. 'Reliability', in this context, means the monitoring gives consistent resul^'Validity' means the monitoring monitors what it is supposed to monitor. In this c a ^ , the monitoring should use valid particulate and gas monitors. To be valid, the monitors should be calibrated. 'Practicality',in this context, means the monitoring is economical and convenient. A trade-off is normally required between reliability, validity, and practicality.
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This chapter is divided into four sections. The first section, Section 6.4, discusses the calibration of the gas monitor, calibration history and parameters, and the derivation of the conversion formula. The second section. Section 6.5, discusses reliability in four sub-sections: the reliability in monitoring time, of standard gas, of the concentration measured, and of the population measured. The third section , Section 6.6, discusses the validity of monitoring location, time and instrument. The fourth section. Section 6.7 , is the conclusion.