The Air We Breathe: Using Personal Protective Equipment to Keep It Safe

Technological advances throughout the 20th century to today have made possible the elimination of many hazards in the workplace. For those situations where exposure to hazards is unavoidable, the use of PPE is a literal lifesaver.

• By Russ Bowman
• Oct 15, 2024

For centuries, humankind has flourished by developing processes that have the unintended side effect of introducing contaminants into the air we breathe. The oldest of these, fire, poses hazards from airborne particulate (such as smoke and soot) and harmful gases (i.e., carbon monoxide, sulfur dioxide and nitric oxide). In the mid-1600s, the concentration of industry in London, England, led to city-wide respiratory problems. In one of the earliest known works on the subject, English writer John Evelyn proposed, in Fumifugium or The Inconvenience of the Aer and Smoak of London, that industry be moved out of the densely populated urban area to the sparsely populated countryside. This was curiously prescient of the Hierarchy of Controls developed by the National Institute for Occupational Safety and Health (NIOSH), in which the most effective means of dealing with a hazard is elimination (i.e., physically removing it from the area). While this protects the general population quite well, workers were still exposed to these hazards. Over the years (centuries, really), other controls were implemented: 

• Substitution: replacing high sulfur bituminous coal with cleaner anthracite coal or natural gas)

• Engineering Controls: ventilation and air purification systems)

• Administrative Controls: hazard training, period health screening, display of warning signs, etc.

It may sound counterintuitive that the least effective control is the first one that many people think of first. It is, however, the one that the user will ultimately be most familiar with. So it’s critical to know if – and when – different Personal Protective Equipment will provide adequate safeguards for airborne hazards. Per OSHA, the responsibility for this rests with the employer:

The employer shall identify and evaluate the respiratory hazard(s) in the workplace; this evaluation shall include a reasonable estimate of employee exposures to respiratory hazard(s) and an identification of the contaminant’s chemical state and physical form. Where the employer cannot identify or reasonably estimate the employee exposure, the employer shall consider the atmosphere to be IDLH (Immediately Dangerous to Life or Health).

The first step is to assess the nature and magnitude of respiratory hazards that personnel may be exposed to. This will include hazards present during normal operations as well as those that may be the result of accidental releases or emergency situations. It’ll also identify the physical state (gas, particulate or both) and chemical form (toxin, corrosive element, carcinogen, biohazard, etc.) of the contaminant(s). Oftentimes, the contaminant is a substance that’s used by the worker. In those cases, OSHA publishes a Hazard Communication Standard (29CFR1910.1200(g)) which mandates hazard identification on Safety Data Sheets. This is a valuable tool and is largely considered to be the primary source of information for any hazards associated with the substance in question. If the contamination is a result or byproduct of an operation, air sampling of the actual environment or objective information from similar operations, might be necessary.

The next consideration will be the factors that might influence the selection of which specific kind of respirator is required. These factors include:

• Physical constraints of the jobsite. This typically won’t be an issue if a simple mask or cartridge filter-type respirators are to be used, but if the environment calls for an independent supply of breathing air, hose fed breathing masks may be needed in tight quarters. Consequently, the use of respirators with air hoses could be limited if there are obstructions in the area and could be downright dangerous around moving machinery. In those cases, a self-contained breathing apparatus will be the better option.

• Certain medical conditions. Many common respirators are classified as negative pressure devices. This means that the wearer has to draw air in through a restriction (like filtration media or chemical cartridges), which means it takes more effort than just “normal” breathing. These aren’t suitable for everyone. For example, they present a very real risk of undue pressure to the heart for someone suffering from lung diseases such as asthma or emphysema. Positive pressure respirators provide a restriction-free flow of breathing air and need to be used in those cases.

• User comfort. It’s not good for anyone to burden workers with awkward or unwieldy PPE of any kind. That can lead to lost productivity, high turnover, and possibly legal action for the employer and a myriad of mental and physical stresses for the employee. Fortunately, technical and material improvements continue to make safety equipment lighter, easier to don, softer on the skin and, many times, even more effective than before.

• Required level of protection. Sanding drywall and cleaning up after an accident at a chemical plant present vastly different breathing hazards and, hence, need vastly different levels of protection. Agencies like the aforementioned NIOSH & OSHA, as well as the American National Standards Institute (ANSI) all have a number of standards and publications on this subject.

Once the appropriate level of protection is determined, select a suitable respirator from two basic categories: air-purifying respirators and atmosphere-supplying respirators.

Air-purifying respirators are self-contained devices, which remove contaminants from the air to make it safe to breathe. Different kinds can remove particulates, vapors or both. They are all classified as negative pressure devices. So they may not be suitable for use by someone with medical conditions as noted above.

• Particulate respirators capture airborne particles in small spaces between the fibers that make up their construction. These include simple masks that cover the mouth and nose and are typically considered to be disposable. They also come in a rigid frame with replaceable filter elements. As particulate accumulates in the fiber, these actually become more effective after some use, but take care to replace them when any resistance or breathing difficulty is noted.

• Vapor respirators use chemical filters (usually in a cartridge or canister), which absorb the vapor. There are different specific types for different vapors; in fact, NIOSH has a color coding chart for them:

• Combination respirators have both particulate and vapor filters. These are especially popular when working with pesticides, as well as other chemical or biological agents that create airborne particulate AND vapor contaminants.

Atmosphere-supplying respirators provide clean breathing air from an outside source, usually an air tank or compressed air system. They’re used when a high concentration of contaminants could foul particulate elements, or expend a vapor cartridge quickly. They may also be needed in areas where the oxygen level could drop below safe levels, such as confined spaces that cannot be adequately ventilated with fresh air. They’re also used for emergency situations to allow personnel to safely evacuate an area where the atmosphere is unexpectedly fouled with smoke or other pollutants. All atmosphere-supplying respirators provide protection against particulate and vapor contaminants and come in three configurations:

• Air-supplied respirators consist of a mask (usually full face with straps to cinch it up for an airtight seal), with a short, low-pressure hose connected to a regulator (usually made to clip on the wearer’s clothing, belt, etc.) which is fed with a hose rated for the supply pressure that has a quick connect for use with breathing air manifolds. These manifolds will normally be strategically located in facilities where contaminated atmospheres require their use. Advantages include their light weight and ability to provide clean breathing air for long periods of time. Disadvantages are limited mobility (the wearer can’t go any further than the supply hose length from a supply manifold) and failure due to hose damage.

• Self-contained breathing apparatuses have the same masks designed for an airtight seal, but are fed with breathing air from a pressurized tank. The wearer has greater freedom of movement – they’re not restricted to the supply hose length of an air-supplied respirator – but they do have finite time limits.

Open-circuit types provide breathing air that the wearer breathes right back out to the atmosphere. These are typically good for 30 to 60 minutes because the larger the tank gets, the more cumbersome it is for the wearer to carry around.

Closed-circuit types recirculate exhaled air through a chemical-activated “scrubber” that removes carbon dioxide and generates oxygen. These are also called “re-breathers” and some are good for up to four hours.

• Combination atmosphere-supplying respirators combine features of the other two types. The primary supply comes from an external source (like the air-supplied ones), but they also include an air tank (like the self-contained ones). The tank is generally smaller on these, as its main purpose is to provide air while the user exits the area. They’re commonly used in confined spaces without adequate ventilation and when working for extended periods in atmospheres that could be immediately dangerous to life and health.

Proper selection and use of respiratory protection is critical to health and safety. Additionally, it’s important to the company’s bottom line. In 2021, OSHA recorded 2,521 violations of respiratory protection standards. This was second only to fall protection violations for that year. The associated fines are commonly compounded per person and per day. Know and understand the hazards you (and/or your employees) will be exposed to. Familiarize yourself with all the different respirator options. Conduct regular training so everyone knows how to protect themselves and others. Fit testing of respirators should be an integral part of that training.

Now take a deep breath. Right now. See how good that feels? It’s certainly worth protecting, right?

This article originally appeared in the October 2024 issue of Occupational Health & Safety.