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Swine Barn Air Quality

Swine buildings concentrate dust, gases and moisture, and workers who spend hours inside can feel it in their lungs. Air quality is a health issue for people and pigs.

What is in swine barn air?

The air in a swine building is a mix of feed dust, dried manure, skin and hair particles, gases such as ammonia and hydrogen sulfide, and microbes and their fragments. Moisture from the pigs and washing adds to the load.

The mix varies with feed type, floor design, manure handling and season. Closed buildings in cold weather tend to be the most challenging because ventilation is turned down to conserve heat.

Official NIOSH and extension materials describe respiratory problems among swine workers. Read them directly for details. Think about handoffs between shifts. When one worker notices that the air is worse than usual, a quick note to the next person or the owner can prevent problems. Make sure that reporting is welcomed. Keep cleaning frequency in mind. Dust that settles on pens, pipes and ledges is stirred up again when pigs move, so regular wet cleaning between groups reduces what is in the air. Consider scheduling. Some tasks that stir dust, such as moving pigs or dry feed handling, can be arranged for when fewer people are inside, and ventilation can be boosted before the work begins. Small changes in timing can lower everyone's exposure.

How can it affect workers?

Cough, phlegm, wheezing, chest tightness, eye and throat irritation and a flu-like feeling after shifts are commonly reported by people who work in confinement buildings. Some develop longer-term breathing problems.

People with asthma or allergies may be more sensitive, so talk with a health care provider before taking on heavy barn work. Tell the provider what you do and how long you spend in the building.

If breathing becomes severe, call 911.

How does it affect the pigs?

Poor air can irritate pigs' airways, contribute to respiratory disease and affect growth. If workers cough, the pigs may be affected too.

Your veterinarian can help you recognize signs and design a herd health plan that includes air quality. Ask about both ventilation and sanitation.

Consistent observation in the barn, by someone who knows what normal looks like, is a good early warning system.

Which gases deserve extra caution?

Ammonia irritates eyes and airways. Hydrogen sulfide from manure can be deadly, especially when pits are agitated, and its smell is not a reliable warning. Other gases and low oxygen are also hazards in pits and tanks.

This guide does not state limits or levels. Look them up from OSHA and NIOSH or ask extension, and use training before any manure pumping.

Never enter a pit, and if someone collapses, call 911 and do not attempt a rescue without training and equipment. See the manure pit guide on this site.

What controls reduce exposure?

Good ventilation that is set and maintained for the season, regular removal of manure and wet bedding, moderate humidity, and attention to dust from feed and dry materials all help.

Some operations use feed or oil-based dust control methods, and equipment makers offer options. Ask your veterinarian and extension specialist about methods that suit your barn, and follow product labels.

Keep fans, inlets and controls clean and maintained, and test alarms and backup power.

• Match ventilation to season and animal needs
• Clean and maintain fans and inlets
• Remove manure and wet bedding on a schedule
• Reduce dust from feed handling
• Test alarms and backup power

When is respiratory protection needed?

For dusty or high-exposure jobs such as washing, cleanout, moving pigs in dusty conditions and handling dry feed, official guidance points to appropriate respirators. A nuisance mask may not be enough.

Select and fit equipment carefully. OSHA rules, where they apply, cover medical evaluation and fit testing. Particle filters do not protect against hydrogen sulfide or low oxygen.

Take breaks in fresh air, and leave the building if you feel unwell.

What should you do about symptoms?

Report recurring cough, wheeze or breathlessness to a provider, and say you work in a swine barn. Early follow-up helps.

Employers and farm owners should make it easy for workers to raise concerns.

Washing and power spray work create mist, noise and slick floors on top of the air concerns. Plan the job so that fewer people are inside, and make sure those who are have suitable protection and a way to call for help.

Last reviewed: November 12, 2026. Written by the Farm Safety Editorial Team. See our editorial policy.