Biological Systems Engineering


Date of this Version



Published by University of Nebraska – Lincoln’s Livestock Environmental Issues Committee.


Total Reduced Sulfur Concentration in Beef Cattle Feedlots

In 1997, the Nebraska Department of Environmental Quality amended its Title 129 Air Quality Regulations to establish a regulatory threshold for Total Reduced Sulfur (TRS) concentrations under ambient conditions. These thresholds are set at “10.0 parts per million (10.0 PPM) maximum 1 minute average concentration or 0.10 parts per million (0.10 PPM) maximum 30-minute rolling average”. Two agricultural regions of Nebraska with significant cattle finishing in open feedlots came under scrutiny for possible rule violations. In one situation, area feedlots were asked to prepare and implement a TRS control plan.

This growing scrutiny prompted field survey of TRS levels in the vicinity of typical feedlots in central Nebraska. The intent of this research was compare those observations against current regulatory thresholds for Nebraska, and identify factors that influence TRS concentration. The paper summarizes average TRS concentrations, number of observations exceeding regulatory threshold values, and observed relationships between TRS levels and time of day, air temperature and feedlot surface moisture conditions.