Table 1 Eight sources of airborne microorganisms in the built environment and data about source strength. For most sources, no information is presently available about source strength

Humans

3.7 × 10⁷ bacterial genome copies per person-hour^a

[33]

7.3 × 10⁶ fungal genome copies per person-hour^a

31 mg total per person-hour^a

2.2 × 10² (median) and 2.6 × 10⁵ (max) influenza genome copies (<5 μm) per person-hour^a

[41]

Pets

TBD

N/A

Plants

TBD

N/A

Plumbing systems

TBD

N/A

Heating, ventilation, and air-conditioning (HVAC) systems

TBD

N/A

Mold

TBD

N/A

Resuspension of settled dust

TBD from walking

N/A

4 × 10⁴ (median) and 7.4 × 10⁵ (max) bacterial genome copies per min from vacuum cleaners

[99]

Outdoor air

Depends on concentration in outdoor air, ventilation rate, and penetration efficiency

N/A