Table 2.

Particles and colloids of exogenous origin causing an inflammatory response within the CNS.

Particle origin	Particle constituents	Reference
Combustion products in polluted air	Organic chemicals, minerals	40,42
Combustion products in polluted air	Elemental carbon	45
Disinfection, water treatment	Silver oxide	46
Welding and mining operations	Manganese oxide	38
Medical diagnosis, therapy	Titanium oxide	43,44
Drinking water	Colloidal aluminum salts	51,52