Pollutant levels refer to the concentration of harmful substances in the environment, particularly in air, water, and soil. These substances can include chemicals, heavy metals, and biological agents that can negatively impact human health and ecosystems. Monitoring pollutant levels helps identify sources of pollution and assess the effectiveness of regulations aimed at reducing environmental harm. High pollutant levels can lead to various health issues, such as respiratory problems and cardiovascular diseases. Organizations like the Environmental Protection Agency (EPA) set standards for acceptable pollutant levels to protect public health and the environment. Regular testing and reporting are essential for maintaining safe conditions in communities.