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Ohio State University Extension


Respiratory Protection

Small Farm and Gardening Safety and Health Series
Agriculture and Natural Resources
S. Dee Jepsen, Associate Professor and State Safety Leader, Agricultural Safety and Health, Food, Agricultural and Biological Engineering
Jeffery Suchy, Graduate Student and Lecturer, Food, Agricultural and Biological Engineering
Farmers and gardeners can often be exposed to hazards in the air:
• Working around heavy dust in barns and greenhouses.
• Working around mold.
• Handling or applying pesticides.
• Using solvents or other chemical irritants.
• Working around allergens (any substance to which a worker is allergic).
Respirators protect against those hazards. Three types of respirators are used during normal work activities:
Particulate respirators use a filter to trap solid particles like dust or mold. They also filter out liquid particles like paint or pesticide mist. They are sometimes called N95 respirators.
Gas/vapor respirators use a cartridge to absorb gases and vapors. They are also called single cartridge respirators. A fit test is required before use.
Combination respirators have a filter for particles and a cartridge for gases and vapors. They are also called dual cartridge respirators. A fit test is required before use.

Safety Data Sheets

Safety Data Sheets (SDSs) also specify respiratory protection. Check SDSs for details on pesticides and chemicals.

General Cautions and Recommendations

• If the hazard appears to be immediately dangerous to life and health, leave the area immediately or do not enter.
• Use a full-face respirator to avoid skin or eye irritation. Otherwise, a half-mask respirator is acceptable.
• A fit test must be performed before a respirator is used to assure proper protection. Respirator use may not be possible if the user has facial hair, scars or an irregularly shaped face or head. 

Selecting a Particulate Respirator

Pesticide or paint mists may contain oil particles. If unsure, use P or HE filters:
• N = Not resistant to oil; do not use with oil.
• R = Resistant to oil; use for up to 8 hours.
• P = Oil proof; use for more than 8 hours.
• HE = High efficiency; use in combination respirators.
Choose a safe level of protection. The percent efficiency refers to the amount of airborne contaminates the mask can remove if used properly. If unsure, choose the highest level of protection, Type 100 or HEPA:
• Type 95 = 95 percent efficient; appropriate for most dust, mold or mist.
• Type 97 = 97 percent efficient; higher level of protection.
• Type 100 or HEPA = 99.7 percent efficient; used with highly toxic substances like asbestos, lead and cadmium.
Note: Disposable dust masks, which typically have only one strap, are not recommended. The protection they provide is unknown. They should only be used for nuisance levels of dust, mold and mist. At a minimum, an N95 respirator should be used.

Selecting a Gas/Vapor Respirator

Choose the correct color-coded cartridge. If unsure, choose Olive Green for maximum protection:
• White = Acid gas.
• Black = Organic vapors.
• Green = Ammonia gas.
• Yellow = Acid gas and organic vapor.
• Olive Green = Multigas combinations.

Overhead view of mask with yellow straps.
N95 Particulate Respirator Gas/Vapor Respirator

Selecting a Combination Respirator

• Combination respirators are similar to gas/vapor respirators but contain additional filters to protect against airborne particulates as well as gases and vapors.
• Choose a color-coded cartridge according to the list above.
• Choose a Type 100 or HEPA filter.

Care and Maintenance of Respirators

• Change filters or mask according to the manufacturer’s instructions or when it becomes hard to breathe.
• Change cartridges according to the manufacturer’s instructions; if a substance taste or smell is noticed; or if eyes, nose, throat or lungs become irritated.
• After use, respirators must be stored carefully in a sealed plastic bag or a container so that they cannot absorb airborne contaminants.


• OSHA Technical Manual (OTM), Section VIII: Chapter 2. Washington, DC: Occupational Safety and Health Administration, 1999.
• General Respiratory Protection Guidance for Employers and Workers. Washington, DC: Occupational Safety and Health Administration, 2009.

Reviewer: Kent McGuire, CFAES Safety and Health Coordinator, Food, Agricultural and Biological Engineering
Originally posted Nov 12, 2015.