Modifiers matching contamination:

• residual,
• fragile,
• external,
• airborne,
• fecal,
• particulate,
• deleterious,
• inorganic,
• polar,
• penetrating,
• incidental,
• potential,
• organic,
• inert,
• environmental,
• foreign,
• visible,
• heavier,
• biological,
• internal,
• charged,
• animal,
• molecular,
• metal,
• regular,
• possible,
• solid,
• unwanted,
• high,
• toxic,
• hydrophilic,
• soft,
• undesired,
• volatile,
• chemical,
• overhead,
• common,
• colloidal,
• harmful,
• extraneous,
• cross,
• liquid,
• heavy,
• fluid,
• active,
• off,
• regulated,
• minor,
• nonpolar,
• basic,
• salt,
• insoluble,
• microbial,
• industrial,
• atmospheric,
• alkaline,
• natural,
• interfering,
• loose,
• metallic,
• up,
• light,
• irritating,
• physical,
• gross,
• hazardous,
• gaseous,

Simple categories matching overhead:

• hazard,
• charge,
• activity,
• structure,
• system,
• projection,
• surface,
• cover,
• obstacle,
• sport,
• function,
• item,
• object,
• expenditure,
• expense,
• location,
• cost,
• message,
• component,
• operation,
• fixture,
• support,
• solution,
• lighting,
• operations,
• layer,
• construction,
• athlete,
• protection,
• installation,
• work,
• contamination,
• obstruction,
• radiation,
• door,
• foundation,
• lamp,
• motion,
• covering,
• line,
• wire,
• industry,
• action,
• vehicle,
• clearance,
• capital,
• movement,
• resource,
• substrate,
• information,
• predator,
• athletics,
• area,
• light,