Outdoors is safest: aerosols disperse into a near‑infinite volume.
Indoors, viral quanta build up as people exhale into limited airspace.
Risk rises with emission rate, poor mixing, low ventilation and time.
Dilution lowers dose — and dose drives infection.
See this info:
www.gov.uk/guidance/ven...
Guidance on the ventilation of indoor spaces to reduce the spread of respiratory infections, including coronavirus (COVID-19).
