Which gas is released from livestock and manure contributing to air contaminants?

Methane is indeed the correct answer as it is a significant greenhouse gas that contributes to air contaminants, particularly from livestock and manure management. Livestock, especially ruminants like cows and sheep, produce methane during digestion through a process known as enteric fermentation. Additionally, when manure is stored or treated, it can also release methane as a byproduct of microbial activity.

Methane is much more potent than carbon dioxide in terms of its heat-trapping ability in the atmosphere, making it a critical focus for efforts to mitigate climate change impacts. While carbon dioxide is also released from livestock through respiration and combustion processes, it is not specifically a product of manure decomposition. Ozone, on the other hand, is a secondary air pollutant that forms from reactions between other pollutants in the presence of sunlight, and nitrogen dioxide is primarily produced from combustion processes, not specifically related to livestock. Thus, methane stands out as the primary gas released from livestock and manure that contributes to air contaminants.