Air contaminant

{
  "id": "MLC-T-CHM-000348",
  "term": "Air contaminant",
  "field": "Chemistry",
  "definition": "Any substance present in the atmosphere that is not a natural constituent of pure air, or is present in concentrations exceeding its natural background levels. These substances originate from natural processes or human activities and can exist as gases, aerosols, or particulate matter. Examples include sulfur dioxide, carbon monoxide, and fine dust particles.",
  "subject": "Chemistry and the Environment",
  "see_also": [
    "aerosol",
    "air pollutant"
  ],
  "references": [
    "PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2182 (https://doi.org/10.1351/pac199062112167)"
  ],
  "url": "https://mlchart.com/terminology/chemistry/air-contaminant/"
}