where C i, Hood OFF is the average particle number concentration for the
size category i during a test with no range hood operating; and ei, Hood
ON is the whole-house particle reduction effectiveness for the size category
i that was observed with range hood operating (the value varies
with range hood flow rates). This number-weighted particle
reduction effectiveness (E), which is specific for each range hood
flow rate, represents the integrated UFP reduction for the whole
house due to the range hood. Eq. (2) was evaluated for the different
flow rates and burner positions. This metric provides general insight
into the effectiveness in removing ultrafine particles released from
cooking appliances when using kitchen range hood.