| Table I. Measured concentrations of nanoparticles resulting from various common indoor household activities (after Ref. 123). | ||
| Nanoparticle source | Concentration (nanoparticles/cm3) | Estimated source strength (particles/min×1011) |
| Pure wax candle | 241 500 | 3.65 |
| Radiator | 218 400 | 8.84 |
| Cigarette | 213 300 | 3.76 |
| Frying meat | 150 900 | 8.27 |
| Heater | 116 800 | 3.89 |
| Gas stove | 79 600 | 1.3 |
| Scented candles | 69 600 | 0.88 |
| Vacuum cleaner | 38 300 | 0.38 |
| Air freshener spray | 29 900 | 2.34 |
| Ironing a cotton sheet | 7 200 | 0.007 |
| Table II. Particles with proven lung carcinogenic effects in animals and/or humans (adapted from Ref. 40). Some poorly soluble particles are shown to be carcinogenic only in rodents, while epidemiological studies do not clearly indicate human carcinogenicity. Classification in animal studies was done as follows: “+” means positive in more than one animal during inhalation studies, “−” means negative or no inhalation studies, “+/−” indicates inadequate evidence in rats, and “blank” indicates not decided yet. | |||
| Particle | Use/exposure | Carcinogenic effect | |
| Rat | Human | ||
| Particulate matter (PM0.1, PM2.5, PM10) | Ambient | Possibly carcinogenic? (unknown fraction) | |
| NiO | Exhaust | + | Carcinogenic |
| Quartz (crystalline silica) | Constructions | + | Carcinogenic |
| Asbestos | Insulation, mining | + | Carcinogenic |
| Carbon black | Pigments, toner, tires | + | Possibly carcinogenic |
| Refractory ceramic fibers | insulation | + | Possibly carcinogenic |
| Wood dust | Furniture making, saw mills | +/− | Carcinogenic (some types) |
| TiO2 | Pigments, sunscreens | + | |
| Diesel exhaust | Engines, cars | + | |
| Talc | Cosmetics, mining | + | |
| Volcanic fly ash | Ambient | + | |
| Coal mine dust | Mining | + | Not classifiable |
| Rockwool | Insulation | + | Not classifiable |
| Iron oxides | Pigments, paramagnetic diagnostics | +/− | |
| Graphite | Occupational | +/− | |
| Cement | Constructions, buildings | − | Not classifiable |
| Amorphous silica | Cleaning, paints, drugs | − | Not classifiable |
| Table III. AQI values for concentrations of particulate matter with diameters smaller than 2.5 (MP<2.5) and 10 µm (MP<10) (Ref. 122). | |||
| AQI | MP<2.5 (µg/m3) | MP<10 (µg/m3) | Air quality descriptor |
| 0–50 | 0.0–15.4 | 0.54 | Good |
| 51–100 | 15.5–40.4 | 55–154 | Moderate |
| 101–150 | 40.5–65.4 | 155–254 | Unhealthy for sensitive groups |
| 151–200 | 65.5–150.4 | 255–354 | Unhealthy |
| 201–300 | 150.5–250.4 | 355–452 | Very unhealthy |
| Table IV. Nanomaterials, their morphologies, and their relative cytotoxicity index (RCI) on murine macrophage cells (Ref. 112). | ||||
| Material | Mean aggregate size (µm) | Mean particle size (nm) | RCI (at 5 µg/ml) | RCI (at 10 µg/ml) |
| Ag | 1 | 30 | 1.5 | 0.8 |
| Ag | 0.4 | 30 | 1.8 | 0.1 |
| Al2O3 | 0.7 | 50 | 0.7 | 0.4 |
| Fe2O3 | 0.7 | 50 | 0.9 | 0.1 |
| ZrO2 | 0.7 | 20 | 0.7 | 0.6 |
| TiO2 (rutile) | 1 | Short fibers 5–15 nm diam. | 0.3 | 0.05 |
| TiO2 (anatase) | 2.5 | 20 | 0.4 | 0.1 |
| Si3N4 | 1 | 60 | 0.4 | 0.06 |
| Asbestos Chrysotile | 7 | Fibers 20 nm diam., up to 500 aspect ratio | 1 | 1 |
| Carbon black | 0.5 | 20 | 0.8 | 0.6 |
| SWCNT | 10 | 100 nm diam. | 1.1 | 0.9 |
| MWCNT | 2 | 15 nm diam. | 0.9 | 0.8 |