Particle pollution, also known as particulate matter, is a general term for a mixture of solid and liquid droplets suspended in the air. Particle pollution can be made up of several different components, including acids, inorganic compounds, organic chemicals, soot, metals, soil or dust particles, and biological materials (such as pollen and mold spores) – all of which can have detrimental effects to the human respiratory system.
Yes, the air we breathe indoors and outdoors always contains particle pollution however, some particles are so small they cannot be detected via sight alone – many require a microscope.
The smaller particles generally pass through the nose and/or throat and enter the lungs. Once inhaled, these particles can affect the lungs and heart and cause serious health effects in individuals at greatest risk, such as people with heart or lung disease, older adults, and young children.
Source: United States Environmental Protection Agency, www.epa.gov