The mean total bacterial counts on the university campus
found by screening ranged from 89.9 to –279 cfu m3
,
which met the ‘‘excellent class level’’ requirement set by
HKEPD. The predominant bacterial genera found on the
campus included Micrococcus and Staphylococcus. Overall
the results showed that there was a logarithmic relation
between total bacterial counts and the number of genera
that were predominant.
Total bacterial counts and each predominant genus
correlated with temperature, relative humidity, CO2, and
population density. It was found that the concentration
of CO2 had the greatest influence on the bacterial counts
in the campus, which indicated that ventilation played the
most important role in reducing the level of airborne
bacteria on the campus.
The limitation of this study was that the correlation
models were not general and only reflected the situation on
this one campus. Further studies need to be performed to
determine whether the models can be applied to other
indoor areas in Hong Kong.