University of Illinois Extension

Using Sensors To Detect Potentially Hazardous
Atmospheres in Production Agriculture

Robert A. Aherin
Leslie L. Christianson
Donald L. Day
Gerald L. Riskowski

Edited by
Randolph E. Fonner

Prepared in Cooperation with the National Agricultural Library, Agricultural Research Service, U.S. Department of Agriculture; Equipment Manufacturers Institute; and the University of Illinois
Beltsville, MD March 1996
Transferring Technologies for Industry No. 6
ISSN 1064-3451

Executive Summary

Hazardous atmospheres exist in agricultural confined spaces, especially manure storage facilities and silos. Methane, hydrogen sulfide, carbon dioxide, and ammonia can exist in manure storage facilities. High concentrations of methane can be explosive, and hydrogen sulfide can reach life threatening levels in seconds. High carbon dioxide levels indicate low air flow exchange rates which may further indicate an oxygen deficiency. Ammonia irritates the eyes and respiratory tract.

Oxides of nitrogen and sulfur dioxide can exist in silos. Of the oxides of nitrogen produced, only nitrogen dioxide and nitrogen tetroxide are medically significant--inhalation can cause sudden death, pulmonary edema, and/or bronchiolitis obliterans. Sulfur dioxide is an irritant.

Riskowski, et al., explains, gases, dust particles, odor, and ions in the air have a detrimental effect on workers and animal health and performance (Chiba et al., 1985a; Donham, et al., 1987)1. From 1980 through 1989, at least 48 worker deaths have occurred as a result of exposure to high concentrations of toxic gases or low levels of oxygen in these facilities.2 It is estimated that several thousand workers have suffered chronic and acute health affects from toxic and irritating gases produced within these facilities.

Farm animals experience prolonged exposure to lower level pollutants including dust particles that are less than one micron in size. Continual exposure to these hazardous gases can cause stress, loss of appetite, and even death. Various acute and chronic diseases, including but not limited to contagious respiratory diseases, can be initiated by exposure to air pollutants or aggravated by them. Such gaseous and particulate stressors on confined animals can lead to increased production costs to farmers. Higher veterinary costs, higher mortality throughout the production cycle, decreased feed efficiency, more days to raise a market animal to the target weight for slaughter, and lower quality carcasses delivered to the packer are all production costs that are passed onto the consumer.

It seems obvious from the above discussion that the ability to identify and measure toxic, combustible, and oxygen-deficient atmospheres is very important for the safety and health of farmers and farm animals and for the economic well-being of the Nation. Monitoring of such atmospheres should detect whether or not hazardous gases exist, what hazardous gases exist, at what levels they exist, and whether there is adequate oxygen.

The question, What gas detection instrument should be used in hazardous atmospheres in production agriculture is not phrased properly. The question should be, In what potentially hazardous atmospheres (locations) will the person be working? Different locations require different types of gas detection instruments and different precautions.

One instrument that is capable of detecting several different gases in multiple farm environments make the most sense for farm production workers. Solid-state sensors are potential solutions to identifying and monitoring hazardous atmospheres. Solid-state sensors are low cost, and they have potential for use in multi-gas monitors for agriculture. From what is known of sensor systems today, personal gas protection multi-gas monitors capable of monitoring continuously for several different gases are the detection instrument of choice, and they are already available commercially.

The caveat to this seemingly ready made solution is that these sensors and monitoring instruments have been developed for use in other fields. While they hold promise for use in agricultural hazardous atmospheres, the have not be tested for such a purpose. To operate in strenuous agricultural environments that are unlike other known environments, any modified sensor system must adhere to the requirements discussed on page 16 of this report. They also must be evaluated to determine: (1) the effects of different gases in the same atmosphere on different sensors; (2) the interference of one sensor with another in providing fast readings: (3) assurance of accurate and reliable readings; (4) the effect of dust as an interferant on sensors; (5) how sealing the instrument from dust may affect its ability to obtaining and accurate and reliable reading, and (6) frequency of sensor re-calibration and/or replacement in multiple gas atmospheres.

In hopes that manufacturers would be interested in testing commercially available systems, the authors of this report have discussed the environmental conditions under which the sensor(s) must operate in agricultural environments. The report includes discussions on current sensor technologies and their advantages and disadvantages in identifying and monitoring toxic and combustible gases in agricultural environments.

The authors also identified four emerging technologies that hold potential for identifying, measuring, and monitoring hazardous atmospheres in production agriculture. The following should be investigated further: Fiber Optic Raman Scattering instrument; Artificial Nose; Gas Microsensor Arrays; and the Trace Atmospheric Carbon Monoxide Sensor.

  1. G.L. Riskowski, et al., Environmental Quality in Animal Housing Facilities - A Review and Evaluation of Alternative Ventilation Strategies. Final Report. (Atlanta, GA: American Society of Heating, Refrigeration and Air-Conditioning Engineers, 1995), in print.
  2. U.S. Department of Health and Human Services, Workers Deaths In Confined Spaces: A Summary of NIOSH Surveillance and Investigative Findings. (Cincinnati, OH: Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 1994), p.18.