Microbiology Experiment 3 Final Report Luo Jinjing Lian Juan and Ng Wenfa.pdf (1013.31 kB)
Experiment series in environmental engineering: Experiment 9 (NUS ChBE, AY 2004/2005, Semester 1)
Concern about indoor air quality (IAQ) has increased over
recent years due to the relative decrease in the severity of outdoor air
quality problems and the increasing amount of time that people spend indoors.
The phenomenon of “sick building syndrome” has gained widespread notice and is
a subject of intense research now. The main determinants of IAQ are physical,
chemical and microbiological factors. Physical factors would include
temperature, relative humidity and ventilation rate. Major chemical factors
would include carbon dioxide, carbon monoxide, ozone and formaldehyde. Fungi
and bacteria caused most of the IAQ problems from the microbiological
standpoint. The objective of this experiment is to determine the number and
particle size distribution of airborne microbiological contaminant in indoor
and outdoor air. The Anderson Six Stage Sampler would be used in the air
sampling as it is able to differentiate the various bacteria and fungi in the
air into different particle size range. The results show that indoor air has a
higher concentration of bacteria and fungi than outdoor air. This indicates
that indoor air may be more contaminated due to restricted ventilation. The
indoor air bacteria CFUs per m3 of air sample is 750 which is higher
than the standard of 500 CFUs per m3 of air sample. There are no
fungi detected in the indoor air. For the outdoor air, the bacteria CFUs per m3
of air sample is 350 and that of fungi is 64 which are both smaller than the
standard. In addition, very few bacteria CFUs and no fungi CFUs are in the size
range of 0.65 to 1.1 microns which can penetrate deep into the alveoli region
of the lungs. Done by: Luo Jinjing, Lian Juan, and Ng Wenfa