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October 07, 2015
Respiratory protection: New online tool can help you choose the best protection against bioaerosols

When it comes to respiratory hazards in the workplace, the traditional bogeymen are particulates, like cancer-causing asbestos; organic vapors, like toluene and pesticides; fumes, like those generated by welding; and acid mists.

Bioaerosols—organic dusts and droplets of microbial, plant, or animal origin—are a relative newcomer to the category of occupational respiratory threats. In 2009, California became the first state to regulate workers’ exposure to bioaerosols when it adopted General Industry Safety Orders (GISO) Section 5199, Aerosol Transmissible Diseases.

Because this is an emerging hazard category, selecting respiratory protection against bioaerosols can be less clear-cut than for other respiratory hazards. A new online tool created by the Montreal-based Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST, Robert Sauvé Occupational Health and Safety Research Institute) helps employers “choose appropriate, effective respiratory protection against infectious and noninfectious bioaerosols.”

Understanding bioaerosol hazards

In industrial hygiene use, an aerosol is a suspension of tiny particles or droplets in the air—either solids (dusts and fumes) or liquids (mists). “Bioaerosols” are suspended particles or droplets that either contain living organisms (for example, viruses, bacteria, and molds) or originate from living organisms (for example, toxins, plant fibers, bioactive enzymes, and pollen).

They can cause workers a range of health problems, including infectious disease, allergic sensitization, asthma, and a variety of lung diseases; gastrointestinal disease; and skin and eye irritation.

The risk to workers in health care and laboratories has long been recognized, but bioaerosols affect workers in many other industries, too. Recent research has shown that workers in waste recycling and composting are exposed to high levels of potentially hazardous bioaerosols, as are workers in agriculture and those who produce highly purified enzymes for use in food and detergent manufacturing.

Unfortunately, safe exposure limits remain an open question for almost every bioaerosol except wood dusts. Almost no studies establish a dose-response relationship for bioaerosols, and lowest observable adverse effects levels (LOAELs) and no observable adverse effects levels (NOAELs) are in short supply. Even GISO Section 5199 doesn’t try to establish numeric exposure limits for bioaerosols.

The lack of concrete toxicology makes protecting workers problematic. How much do you have to do?

Choosing respiratory protection

Identifying the hazard—workplace exposure to potentially hazardous bioaerosols—is the first step. The next one is putting worker protections in place.

When you have completed the selection process, the IRSST tool lets you print the assessment for your records.

With any airborne hazard, of course, the preferred choice is source control—limiting the amount of the contaminant in the air. But when no safe exposure level has been established, and you can’t completely (or even mostly) remove the contaminant from the air, respirators provide an additional, vital layer of protection. The IRSST tool can help you identify respirators that are effective against bioaerosols.

To use the tool, you’ll need to:

  • Perform a thorough hazard assessment. Understand that the IRSST tool cannot help you select respirators that protect against other hazards, including atmospheres that are immediately dangerous to life or health (IDLH), oxygen-deficient atmospheres, flammable or explosive atmospheres, or chemical and radiological contaminants.
  • Identify your industry. The tool uses different selection methods for healthcare workers than it does for workers in construction, agriculture, and general industry.
  • Identify the risk group. The IRSST tool divides bioaerosols into four “risk groups” based on the risk they pose to individual workers and the community. Guidance within the tool will help you properly classify the bioaerosols you deal with.
  • Identify the level of air quality control in your workplace. If you use ventilation strategies or other control measures to reduce airborne contaminants, the tool will account for that.
  • Identify the bioaerosol generation rate. Are your workers exposed to infectious patients who are coughing and sneezing (a high rate of generation)? Or are they maintenance workers whose work methods give them some control over how much contamination is released into their breathing air (a moderate to low rate of generation)? Again, information is available within the tool to help you assess the generation rate.
  • Find your assigned protection factor (APF). The tool will help you determine your APF, based on your risk group, control level, and generation rate. It will then offer you a selection of respirators that meet the APF requirements of your workplace.
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