Q2E on measuring air quality on pig farms

In short the answer is:

• Ammonia (NH₃) and carbon dioxide (CO₂) in pig housing pose significant risks to animal welfare, particularly NH₃, which irritates pigs’ mucous membranes and should ideally remain below 20 ppm. CO₂ levels are less critical for pigs but indicate overall air quality and ventilation effectiveness.
• Portable sensors—using electrochemical or optical (infrared) methods—are essential tools for inspectors. NH₃ sensors must detect 0–100 ppm; CO₂ sensors, 400–10.000 ppm. Measurements should be taken at pig level, especially in pens with older animals, where gas levels are typically highest. For best accuracy, sensors must be regularly calibrated and placed away from animal interference. Temperature and humidity must be considered, as they can influence gas detection accuracy.
• Most EU member states follow Directive 98/58/EC, requiring gas concentrations not to harm animals. National thresholds and equipment types vary, but common limits are 20 ppm for NH₃ and 3000 ppm for CO₂.

The full answer:

Introphoto: Ventilator (©WUR)