Table 4.

Number of Legionnaires’ disease cases in Genesee County in 2014 and 2015 that was potentially affected by each of the five highest impact aerosol sources using three different aerosol concentration levels ($>0.001$, $>0.0001$ and $>0.00001$ ${\mathrm{g}/\mathrm{m}}^2$).

Aerosol source ID	Number of cases potentially affected at aerosol concentration
	$>0.001$ ${\mathrm{g}/\mathrm{m}}^2$	$>0.0001$ ${\mathrm{g}/\mathrm{m}}^2$	$>0.00001$ ${\mathrm{g}/\mathrm{m}}^2$
AS01	0	9	13
AS02	1	8	11
AS05	1	8	13
AS100	0	7	13
AS102	2	6	12

^Note: The concentration of aerosols downwind of each aerosol source was calculated for the exposure windows of each of the Legionnaires’ disease cases, using a Gaussian plume model (Korsakissok and Mallet 2009) and the wind speed and direction. We maximized transport of Legionella in aerosols to 2 miles. Because no data were available on emission rates, we assumed a constant emission rate of $300\mathrm{g}/\mathrm{s}$ (based on Nygård et al. 2008) for each source. The modeled aerosol concentrations at case residences is therefore relative rather than absolute. Aerosol concentrations are relative, assuming each source emitted aerosols at the same rate. Hospital inpatient stays and visits were excluded.