Fig 1.

Air sample timeline. Photographs of different air sample plates over 9 d. Penicillium isolates, green colonies, are clearly visible at 9 d when PCR direct from conidia was performed along with fungal genera counts. Also visible at 9 d are the dark coloured colonies of the Cladosporium genus. Black particulate matter from underground station sample locations is clearly visible on the agar plates of 1, 3, 4 and 9 d. The 6 d plate was collected from an underground station with fewer particulates circulating in the air.