Table 3 Summary of studies with TAS > 10 for MPs reported in indoor and outdoor air for both urban and rural locations
Author | Sample type | Lower size limit (μm) | Particle concentration (average) | Particles in blanks (average) | Particle size (μm) | Predominant particle shape | Predominant polymer type | Quality score (TAS) |
|---|---|---|---|---|---|---|---|---|
Wright et al. [42]) | Deposition | 20 | 712 fibers/m2/d 59 Non-fiber particles/m2/d | 3 cellulose fibres | Fibre diameters of between 5 and 75 and most abundant length 400–500, average 905. Average of non-fibrous particles is 164. | Fibres | 17% of fibres synthetic, dominated by PAN, PET, and Polyamide. 69% of fibres identified as cellulose. | 18 |
Gaston et al. [43] | Air (both in and outdoor) | 20 | 3.3 fibres and 12.6 fragments/m3 (indoor); 0.6 fibres and 5.6 fragments/m3 (outdoor) | 2.4 fibres and 12.2 fragments per filter (indoor) per filter; 0.4 fibres and 6.3 fragments (outdoor) per filter | Fibres lengths indoor 641 μm; outdoor 616 μm; approx. 30% of fibres between 100 and 300 μm; Fragments outdoor 104 μm; indoor 58.6 μm. | Fragments | PS, PET, PE | 15 |
Wang et al. [44] | Deposition | Not defined | 1 MP/100m3 | Not reported | 851.09 ± 578.30 Fibers: measured between 288.20 μm and 2251.54 μm (935.94 ± 556.63 μm) in length | 88.89% fibres | 77% of natural origin, 21% plastic. Natural particles mainly cotton and cellulose, artificial fibers of rayon (50%) and cellophane. Other particles were PE, PET, PP. | 15 |
Klein and Fischer [22] | Deposition | 50 | 275 MPs/m2/d; range 136.5 to 512 MPs/m2/d | 7.3 ± 4.8 MPs/blank | fibes ranged between 300 and 5000 μm; fragments < 63 μm. | 95% of particles identified as fragments | PE (49%), ethylene vinyl acetate copolymer (22%). | 15 |
Bergmann et al. [3] | Snow | 11 | Non-fibrous: 9.8 × 103 MPs/L fibres: 0.043 × 103 to 10.2 × 103 MPs/L | Vary from 256 to 27,243 MPs/L (samples blank corrected) | 80% ≤25 μm, 98% < 100 μm; particle range 11 to 475 μm. Fibre lengths range from 65 to 14,314 μm | Fibres – both natural and synthetic, with MPs accounting for 12% of particles on average. | Acrylates, polyurethane, varnish most frequently detected | 15 |
Vianello et al. [45] | Air (indoor) | 11 | 9.3 ± 5.8 particles/m3 | 7.7 ± 3.8 MPs/blank: data not corrected | 36 and 21 for the major and minor dimension | 13% fibres 87% fragments | 81% PES, 6% PE, 5% PA, 2% PP, and 6% other polymers; non-synthetic - 95% protein, 5% cellulose; MPs = > 4% total particles | 14 |
Liu et al. [46] | Air (outdoor) | 12 | 0.41 MPs/m3 (0 to 2 MPs/m3) | no MPs in one blank collected | 246.52 μm (12.35 to 2191.32 μm) | Fibres (43%), fragments (48%), beads (9%) | PET (51%), epoxy resin (19%), PE (12%), and alkyd resin (8%); fibrous PET = 87% | 13 |
Stanton et al. [47] | Deposition | 38 | Max of 2.9 fibres/m2/d | Synthetic fibres not detected in blanks | Not reported | 100% fibres | 2.1% synthetic | 13 |
Allen et al. [20] | Deposition | 10 | 365 ± 69 particles/m2/d (range 297 to 462) | 3 ± 1 fibres, 1 ± 1 film and 8 ± 1 fragments per filter | majority MPs < 50 μm, predominant fibre lengths of 100–200 μm and 200–300 μm (max. 3000 μm), films 50–200 μm. | Fragments > fibres > films | PS (as fragments) followed by PE | 12 |
Liu et al. [48] | Air (outdoor) | Not reported | 1.42 ± 1.42 MPs/m3 | Not reported | 582.2 μm range between 23.07 to 9555 μm | Fibres (67%); Fragments (30%); granules (3%) | PET, PE, and polyester comprised 49% | 11 |
Dris et al. [5] | Deposition | 50 | 110 ± 96 MPs/m2/d (urban site); 53 ± 38 MPs/m2/d (suburban site) | 1–2 fibres/filter | Fibre length 50–5000 μm (most 200–400 μm); diameter 7–15 μm | 100% fibres | 17% synthetic (PET and polyamide); 21% cellulose; 12% mix of natural and synthetic | 11 |
Zhang et al. [24] | Dust (indoor) | 150 | PET-based MPs ranged from between 29 and 110,000 μg/g PC-based MPs ranged from between < 0.11–1700 μg/g | MQLs of PET and PC were 5.3 and 0.11 μg/g | Not reported | Not reported | Main focus on PET and PC based polymers. | 11 |
Roblin and Aherne [49] | Deposition (Moss) | 30 | 0.6 fibres/g | 24 fibres/g | Fibres ranged between 0.03–30.25 mm; average is 1.02 mm across all sites. 65% < 0.8 mm. | 100% fibres | Not reported | 11 |
Li et al. [50] | Air (outdoor) | Fibres with length > 5 μm and diameter > 3 μm | 5.7 × 10−3 fibres/ml | 1 × 10− 4 fibres/ml | Range between 5 and 20 μm |  | 34.6% total fibres as microplastic | 10 |
Su et al. [51] | Dust (Road) | 20 | range between 20.6 to 529.3 particles/kg | 5.6 particles/kg | Range between 0.08–4.7 mm; average 1.2 mm | 45.7–100% fibres | 58.6% plastic polymers of polyester, PP and rayon. Cotton and cellulose account for 65.4% of non-plastic particles | 10 |