Protective air filtration for evidence storage facilities and the people who manage them

Police departments are tasked with the storage of evidence from the time it is collected until it is no longer needed by the justice system. Laws governing this task vary from state to state.

In the past few years, steps have been taken to identify the best practices for management of evidence in the many forms it can take. For example, The Biological Evidence Preservation Handbook (see link below) identifies 15 common sources of DNA, a range that includes a weapon, eyeglasses, and a cigarette butt. Some forms of evidence may require refrigeration; some simply need low humidity to remain stable. Each has to be properly inventoried for short-term or long-term storage.

In the course of a single day, evidence handlers may manage packaged evidence that includes human and animal tissue, powdered narcotics, chemicals, swabs containing biological material, bones, hair, unidentified substances, and items wet with biological material.

Respiratory concerns and two ideas that address them

People who work in evidence rooms have legitimate concerns about what they may be inhaling. One customer said:

We house drugs, biohazards, and numerous other items that have the potential to cause health related issues.

We ask evidence facility managers to consider two types of potential solutions:
Ductless Fume hoods for intake, when evidence is labeled and entered into the inventory system;
Ambient air cleaners that trap particles and odors for day-to-day operations.

Ductless containment hoods

Fume Hoods create an enclosed, operator-friendly environment because they pull particles away from users into filters that trap them before they can spread. They are widely used in factories, pharmacies, dental offices – anywhere potentially hazardous substances and/or unpleasant odors are encountered.

Ductless Fume Hoods, like the one to the left, increase respiratory protection without adding a line item to the capital budget because expensive remodeling of the building ventilation system is not required. And, because the hood is not attached to ductwork, it can be located exactly where you need it and re-located repeatedly if necessary.

Sentry Air’s 30-inch wide ductless fume hood can be configured with both HEPA filtration to trap particles and activated carbon filtration to trap odors and chemicals. The transparent top makes the room’s light available inside the hood. If desired, a fluorescent lamp can be optioned. Electrical cords for instruments used inside the hood, such as a laptop, can be pulled through access holes on each side of the hood.

Hazardous chemicals in the evidence room

Solvents are frequently included in drug-bust evidence. Our fume hoods with activated carbon filters are often specifically purchased to capture solvent fumes and odors.

We tested the effectiveness of our hood and filtration media at capturing Ethylene Glycol Monobutyl Ether (EGBE), a common solvent.

Test results indicate a 99% efficiency rating of the air cleaner against EGBE fume.

With a HEPA filter to trap particles, and carbon filtration to trap odors and chemical fumes, intake in the evidence room environment becomes manageable and less hazardous.

If your evidence intake process starts in the field, investigate how our modular, compact hoods and fume extractors can play a significant role in a mobile situation.

Ambient Air Cleaners

Model 700 Ambient Air Cleaner

Model 700 Ambient Air Cleaner

Evidence storage facility managers should consider ambient air cleaners because not every piece of evidence can be handled within a containment hood. Even without being handled, some materials can off-gas as they sit in storage. The Model 700 shown at the left can be suspended from the ceiling, located on a shelf, or situated on a dedicated stand.

In this horizontal orientation, room air containing contaminants is pulled into the Model 700’s pre-filter on the left, though the filter chamber. Filters trap the contaminants, returning cleaner air to the room via the outlet on the right. To see the interior, check out the photos in this blog post about a Model 700 being prepared for shipment.

If none of those installation choices are appropriate for your building, the Model 700 is very adaptable. Talk with our applications specialists about other possible locations, such as atop a bank of lockers, or positioned vertically on a wall.
Inside, you can specify filters to trap both particles and chemical fumes.

Why room air exchanges are costly

ss-340-dch3Sometimes, a specific number of room air exchanges is recommended as a method to keep clean air in the room.
It’s called dilution ventilation and it’s an expensive notion because the air being pushed out of the room is conditioned air, the air that has been dehumidified and heated or cooled, depending upon the season.

In contrast, ductless hoods and fume extractors supply local exhaust ventilation. The air they filter has contaminants removed and it stays in the room. The need for expensive conditioned replacement air is eliminated.

Convenient filter replacement

Our containment hoods and ambient air cleaners are designed with easily removed and replaced filters.

Improve the safety of your evidence facility! If you need a cost-effective solution for the hazardous air in your evidence room, contact our applications specialists at 800.799.4609, email them at, and fill out our Contact Form on our website.

Visit our website to learn more about all our products –

Resources & More Information

• The Biological Evidence Preservation Handbook: Best Practices for Evidence Handlers

• Industrial Hygiene Report: Control of Glycol Ether Solvent Fumes Using Activated Carbon Filter Media

• Mobile laboratories need modular, compact fume extraction solutions

• Ambient air cleaner will remove cigarette smoke from popular bar and grill

• Need a lab on site NOW?

• Air Purification Equipment for the Forensics Lab