Andrew Smith, 15, works summers and after school on his dad's farm and for neighbors near Dickens, Iowa. When his chores require baling and stacking hay, he keeps a two-strap respirator handy.

He's lucky. His aunt, Carolyn Sheridan, clinical director at the Spencer, Iowa, AgriSafe Clinic, has the education and training to select a respirator for maximum protection. Smith and Sheridan are pictured at right.

Sheridan, who also farms with her husband, knows that farm exposures to dusts, molds, gases, pesticides, and other chemicals may cause respiratory conditions, from chronic bronchitis to organic dust toxic syndrome.

"Farmers generally don't smoke," she says. "Compared to other occupations, they still have a high disability rate from respiratory conditions."

Part of Sheridan's job is to provide farmers with personal protective equipment (PPE) to prevent irritants from entering airways and lungs to cause one or all of these symptoms:

• Severe lack of breath with exertion
• Chronic coughing
• Periodic flu-like symptoms
• Sinus problems and nasal drainage
• Tight chest/wheeze after dusty work

But respirators aren't interchangeable. "A dust respirator won't protect you from ammonia," Sheridan says.

Two types of air-purifying two-strap respirators remove particulates, gases, and vapors. One type is disposable; the other has a canister or cartridge that can be replaced.

"If your respirator moves off your face when you breathe in or out, it's not a good fit," Sheridan says. "Even facial hair interferes with the fit." Replace a disposable respirator that loses its shape, is dirty, or difficult to breathe through. The cost ranges from $1 to $8 for a two-strap mask, and $40 for a cartridge respirator, depending on the cartridges needed for the exposure.

"Another type of respirator, a Supplied Air Respirator, has its own air supply for tasks where oxygen is limited," she says. This includes fumigation, silo entry, or a manure pit during pit agitation or pumping.

Below is a quick guide to matching respirators to specific farm respiratory hazards. This listing is not complete.

Storing respirators in a tight container or a sealed plastic bag protects them from dust, sunlight, heat and cold, moisture, and chemicals.

Consult your doctor about wearing a mask if you have heart disease, asthma, emphysema, uncontrolled hypertension, or claustrophobia.

To learn more, contact the AgriSafe Network at 866/213-3002, or visit www.agrisafe.org.

Photograph: Euvonne Sheridan