"Environmental Light Microscopy", as addressed here, involves the analysis of particles from an environment in order to identify the presence of a hazard to equipement, a product, or to a life form, including humans; to identify the sources of particles at a particular location; or to address other concerns regarding particles at a specific location. The sample to be analzed may be a colection of free particles or a tapelift of particles in a fixed adhesive. Tapelifts that use an adhesive that is easily disolved is treated as a sample of free particles.

The microscope described here is one possible configuration. This example uses a Nikon Labophot Pol scope as the base unit with an Abbe Phase Contrast turret condenser and a ring-light epi-illuminator (image 1). The illumination light path through the particle will be shown with a frosted slide in the position of the particle (image 2).

Axial illumination using the phase contrast condenser in the "0" position with the substage iris clossed down.

Transmitted Brightfield Illumination using the phase contrast condenser in the "0" position with the substage iris open 2/3rds.

Transmitted Oblique Illumination using the phase contrast condenser in the "Off 0" position with the substage iris wide open.

Transmitted Darkfield Illumination using the phase contrast condenser in the "PH4" position with the 20X objective.

Reflected Darkfield Illumination with a ring-light accessory.

Polarized Light

Transmitted Polarized Light with Reflected Darkfield