CFM per person at high occupancy (assembly) and air changes at
lower occupancy levels is probably the most logical choice because
many indoor air pollutants can accumulate with little or no effect
on CO2 levels. RH can be probably be controlled by other means
more efficiently. What is really needed is a "smart" ventilation
system which monitors occupancy (but not by measuring CO2 because
of the time lag) and maintains higher levels of ventilation during
those times. A VOC monitor might provide a baseline for minimum
air exchange rates during unoccupied times. Since there are many
different sources and many different pollutants, a minimum should
err on the conservative side (higher rate of exchange). "This is
just "Pie in the Sky" thinking but (AI) technology really can
provide the best solution to balancing energy efficiency and
indoor air quality in my mind.
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