How it is studied
Shape, size, colour and internal partitions help distinguish spore groups under a microscope. The result depends on visible features; a morphological count does not necessarily identify every species or prove that spores are alive.
An example to interpret it
Comparison example: a series rises from 40 to 80 spores/m³. Before describing a doubling, check that both samples use the same group, duration and method. Do not add a daily concentration to an hourly concentration as if they were equivalent counts.
What to check
Culture, molecular analysis and microscopy measure different properties. Their results can complement each other, but comparison requires explicit units and methods.