B033 IAQ sampling point

Sampling point densities in indoor air quality assessment

Brief:

Maintaining acceptable indoor air quality (IAQ) has become a public issue, policymakers have had developed strategies to address the performance of it. Pollutant concentration measured during the occupied period of a space is a key parameter to determine IAQ. In Hong Kong, the Environmental Protection Department (HKEPD) has launched an IAQ certification scheme to promote an acceptable IAQ in workplaces. However, the associated uncertainties and measurement efforts have not been detailed for practical measurement in indoor spaces.

In this study, indoor carbon dioxide (CO₂) concentration was selected as an IAQ indicator to investigate the probable errors and measurement efforts in different sampling schemes regarding the sampling point density. The results showed that there was a strong correlation between the sampling point density and the probability of obtaining the measured quantity at certain confidence levels. Moreover, the confidence level in determining the IAQ in the occupied period for a ventilated space was reduced 10% at a 5% error set limit when the number of sampling points was reduced 50% to the one recommended in the HKEPD certification scheme.

Further information:

Mui KW, Wong LT, Hui PS, 2006. Sampling point densities in indoor air quality assessment, Sichuan-Hong Kong Joint Symposium 2006 – Trends and Challenges in Green, Healthy and Safe Buildings, HKIE/ASHRAE/CIBSE, 30 Jun-1 Jul, Chengdu, China, pp. 1-7.