Gas emissions are a very serious problem for animal wastewater lagoons. There are over 400 volatile compounds released from animal wastewater lagoons including: 

Ammonia – In the United States, 80 percent of ammonia emissions come from livestock production. A lagoon can vaporize up to 80 percent of its nitrogen through the reaction: NH4+-N -> NH3 + H+. As pH or temperature increases, so does the amount of volatilized ammonia. Once ammonia has been volatilized, it can travel as far as 300 miles, and at closer ranges it is a respiratory irritant. Acidification and eutrophication of the ecosystem surrounding the lagoons could be caused by prolonged exposure to volatilized ammonia. This volatilized ammonia has been implicated in widespread ecological damage in Europe and is of growing concern for the United States.

Hydrogen sulfide – With averages greater than 30ppb, lagoons have high concentration of hydrogen sulfide, which is highly toxic. A study by the Minnesota Pollution Control Agency has found that concentrations of Hydrogen sulfide near lagoons have exceeded the state standard, even as far away as 4.9 miles. Hydrogen sulfide is recognizable for its unpleasant rotten-egg odor. Because hydrogen sulfide is heavier than air, it tends to linger around lagoons even after ventilation.

Methane – Methane is an odorless, tasteless, colorless gas, which is fatal at high levels. Lagoons produce about 2,300,000 metric tonnes per year, with around 40 percent of this number coming from swine lagoons. Methane is combustible at high temperatures and explosions and fires are a real threat at, or near, lagoons. Additionally, methane is a potent greenhouse gas. The U.S. EPA estimated that 13 percent of all the methane emissions came from livestock manure in 1998, and this number has grown in recent years.