In addition to temperature and air movement, humidity is another factor to consider when implementing thermal comfort strategies. Humidity is the amount of water vapor in the air, which affects how warm or cool people feel. High humidity can make people feel hotter and more uncomfortable, while low humidity can cause dryness and irritation of the skin, eyes, nose, and throat. Thermal comfort strategies should aim to maintain an optimal level of humidity that balances human comfort and health with energy efficiency and moisture control. The other options are not factors to consider when implementing thermal comfort strategies. Methane off-gassing is the release of methane gas from organic matter decomposition or anaerobic digestion, which contributes to greenhouse gas emissions and climate change. Carbon dioxide concentrations are a measure of indoor air quality that indicates the level of ventilation and fresh air supply in a space. Combustion processes from vehicles are sources of outdoor air pollution that emit carbon monoxide, nitrogen oxides, particulate matter, and other harmful substances. References: LEED Green Associate Candidate Handbook, page 29; USGBC, [Indoor Environmental Quality], page 2.