also 7.3.2 Identify signs of potential sources of indoor air pollutants.

• CO: by-product of combustion; no odor; over10 ppm causes drowsiness, 400 ppm can kill by asphyxiation
• CO₂: by product of breathing or combustion; no odor; 5000 ppm can kill
• Mould: Spores are released, which can be toxic or cause an allergic reaction
• Smoke: Tobacco or other combustion creates particulates as well as CO and CO₂
• Radon: Drawn into building from soil where it occurs naturally; carcinogen
• Asbestos: Present in some building materials, insulation and heating systems; known carcinogen if friable
• Lead: Common use in older paints, can be ingested as dust, toxic in high concentrations
• Chemical contaminants: emissions from cleaning products, solvents, and a variet of consumer products.
• VOCs: Household products, building materials; various toxic effects depending on type and concentration.
• SVOCs (semi-volatile contaminants): attach to airborne dust particles and surfaces