The project was led by Dr Sanjay Shah and funded by USPOULTRY.

The new ammonia-oxygen monitoring system is portable, weighs less than three pounds and will be relatively inexpensive. While there were portable ammonia measurement methods previously, they either lacked the required accuracy or were too expensive to operate.

The system functions well in the poultry house environment and provides accurate measurements regardless of relative humidity and temperature. This important new tool will help poultry companies and poultry farm managers to continue to improve the environment in poultry houses.

High ammonia concentrations and low oxygen concentrations inside poultry houses can negatively affect bird health and performance.

There is a need to regularly monitor the concentrations of these two gases in poultry houses, particularly during brooding. The new system that can measure concentrations of both of these gases in a poultry house environment could be very useful to poultry farm managers.

The specific objectives of this research project were to:

1. Evaluate several low-cost and commercially-available ammonia and oxygen sensors for their accuracy, sensitivity, stability, measurement range and performance under poultry house temperature, relative humidity (RH) and air quality conditions and select the most suitable sensor for each gas.
2. Assemble the selected ammonia and oxygen sensors into a package system with a suitable power source, scrubbers and electronic interface that will allow display and storage of data. We proposed that the material cost of the system should be less than $500, and its weight should be less than 3 lb.
3. Test the ammonia - oxygen monitoring system in a poultry house environment with a realistic range of temperature, RH and air quality conditions.

Three different metal oxide semiconductor ammonia sensors were evaluated in the laboratory.

Based on lab testing, the Figaro TGS 2444 sensor was selected for use in the sensor system. Similarly, two electrochemical oxygen sensors were evaluated, and the Figaro KE-25 was selected for use in the sensor system.

The sensors were tested in a wide range of ammonia concentrations (using a synthetic gas mixture) and several relative humidity conditions for accuracy, precision, drift and response time.

In order to improve accuracy of ammonia measurement in a poultry house environment, equations were developed for each sensor to compensate for sensor output, relative humidity and temperature.

When tested in a poultry house environment, it was found that in a range of 18-49 parts per million (ppm) ammonia, the ammonia sensor using the relative humidity and temperature compensation equations had a relative error of 6 per cent and a coefficient of variation of 6 per cent.

This performance level is superior to the standard handheld sensor. The oxygen sensor was found to be unaffected by relative humidity and poultry house gases.

The ammonia sensor can be be used for an hour without purging. Purging in fresh air for 2-3 minutes between poultry houses is recommended.