Always wear an N95 or P100 respirator when working in high dust concentrated, agricultural environments. A disposable face mask respirator is best when replaced each day, and when a user seal check is performed every time it is worn.
While there are no recommendations for how long (minutes or hours) a respirator will last in agricultural environments, an N-series face mask filter is rated to absorb a total mass of 200mg. The time to reach this level is not known, but is affected by several factors: personal hygiene, breathing resistance and density of the air contaminants. Each job will vary - as will the heat, humidity and other environmental conditions while performing the job.
Treat a disposable N-95 and N-99 respirators similar to the air filter in a vehicle. These masks are made to be disposable and cannot be cleaned or disinfected. Throw them away when:
1. The mask gets clogged beyond a comfortable condition which makes breathing difficult. Likewise, if the inside of the mask becomes dirty, dispose of it.
2. Replace any mask if it becomes wet, torn or the straps are stretched out and will not allow a tight fit.
For cartridge respirators, change the cartridge filters according to the manufacturer’s instructions or if a substance taste or smell is noticed, or if eyes, nose, throat, or lungs become irritated.
There are several factors that affect respirator effectiveness due to the obvious fact that the seal is broken between the mask and the skin. These factors include:
1. Facial hair: beard, mustache, or long sideburns.
2. Deep facial scars or facial shape deformity.
3. Wearing eyeglasses and other personal protective equipment (PPE).
Other factors that determine the ability to wear a respirator is the fitness of the person. A doctor’s advice may be needed before using a respirator in the person has lung disease, heart trouble, or breathing problems.
Before wearing a respirator, it is good to know if the worker has the physical ability to wear a respirator. This can be determined through a Respirator Medical Evaluation Questionnaire completed by the worker. The answers are reviewed by a physician or licensed health care professional. A positive response to any of the questions 1-8 on the Medical Evaluation questionnaire requires a follow-up medical examination. An OSHA Info Sheet can be accessed at: https://www.osha.gov/sites/default/files/publications/OSHA3790.pdf.
Fit testing and user seal checks are also important factors for a good fitting respirator. Read these factsheets for guidance on a proper fitted mask, https://ohioline.osu.edu/factsheet/aex-59132.