WHERE CERTAINTY ENDS

Knowledge Gaps

A map of what is known and unknown about micro- and nanoplastics: four systems, seven questions, 46 graded findings. Microplastic presence is established in air, water, soil and human exposure; nanoplastic amounts, soil methods and removal from open systems remain the weakest answers.

11 min readUpdated 2026-11-04ReviewedAConsensusBWell supportedCLimitedDDisputedEUnknownPProvenance

Illustration of a narrow beam of light picking out a few amber specks inside a large, dark teal space — Illustration: a narrow beam of light from the upper right picks out a few particles in a dark volume while the rest stays unlit, a metaphor for how little of each system has been measured. Not data; particles enlarged for visibility.Illustration · AI generatedMade with FLUX.1-schnell (fp8, Comfy-Org/Flux-1-Schnell) · ComfyUI (local), tools/content/generate_l3.pySite illustration (AI-generated, Flux)Site original

Some answers about micro- and nanoplastics are settled. Microplastics are in the air of remote mountains, in every ocean basin, in farm soils and in what people eat and breathe. Other answers are barely begun: how much nanoplastic there is, how to extract it from soil, and whether any method removes particles from open air, water or soil.

This map grades 46 checkable findings across four systems (air, water, soil, human body) and seven questions. Microplastics (MP, 1 µm–5 mm) and nanoplastics (NP, below 1 µm) are graded separately wherever their evidence differs, so a weak nano result does not pull down an established micro one.

One number shows how thin the nano layer is. About 27 million metric tons (27 Mt) of nanoplastic in the North Atlantic mixed layer is an extrapolation from nine open-ocean stations sampled on one cruise in November 2020 (level C)¹.

27 Mt

nanoplastic mass estimate, North Atlantic mixed layer

PET, PS and PVC below 1 µm; mixed-layer sum for stations 1–9 (12 stations sampled, three on the European shelf); RV Pelagia cruise 64PE480, November 2020; TD-PTR-MS; spatial extrapolation¹

one transect; polyethylene and polypropylene were not detected

CLimited

283

locations behind the global dataset of airborne microplastics

2,782 concentration and deposition measurements from 76 studies; coordinates rounded to four decimals (one Wenzhou site duplicated by floating-point noise in the raw file)²^,³

the compiled data describe sizes from several µm to several mm

PProvenance

measurement locations on the African mainland in that dataset

our count in the published dataset, 3 November 2026; two Canary Islands sites are coded as Atlantic Ocean³

our calculation; a sampling gap, not evidence of clean air

PProvenance

1.4%

overall recovery of a particle-preserving nanoplastic extraction from soil

Forsyth et al. 2026; palladium-doped nanoplastic spikes; extraction, density separation, filtration below 1 µm and ultrafiltration combined⁴

single laboratory study; the steps alone recovered 38–92%

CLimited

How to read the map

Each row is one finding, stated so that it can be checked: a system, a question, the size class and the claim. Occurrence asks whether particles are present and, in a separate row where it matters, how much; sources, where they come from; transport, how they move (for the human body, uptake and distribution); effects, what they do; methods, whether they can be measured reliably and comparably; removal, whether a tested method takes them out; regulation, which rules exist.

The level grades the evidence for that finding, not whether the news is good or bad. E means not established in the evidence we reviewed, with the search recorded below. Rule rows carry P: they are legal facts checked against the official text, not graded science. The rubric is in Evidence Levels.

The knowledge map: four systems, seven questions

System	Question	Level	Why this level	Sources
air	occurrence · MP: present in outdoor air, from cities to remote and polar sites	AConsensus	Independent studies in Europe, North America and the Arctic; European academies review lists air as contaminated	⁵^,⁶^,⁷^,²^,⁸
air	occurrence · MP: global concentrations quantified	CLimited	283 locations, 35 southern, none on the African mainland; values span orders of magnitude	²^,³
air	occurrence · NP: present in remote snow and ice	CLimited	Alpine snow and polar ice, measured by one research group with one method (TD-PTR-MS)	⁹^,¹⁰^,¹¹
air	sources · MP: land versus ocean emission shares	DDisputed	Emission inventories disagree; models exceed measured concentrations 100- to 10,000-fold	²^,¹²^,¹³
air	transport · MP: long-range transport to remote regions	AConsensus	Remote deposition documented independently on several continents; European academies review concurs	⁵^,⁶^,⁷^,⁸
air	transport · MP+NP: fluxes and residence times	CLimited	Few flux measurements; nanoplastics tracked by one method in snow and ice	¹⁴^,¹⁰^,¹¹
air	effects · MP+NP: direct radiative forcing	CLimited	Three model studies, 2021–2026; sign and size depend on color, size and concentration assumptions	¹⁵^,¹⁶^,¹⁷^,¹⁸
air	methods · MP+NP: comparable ambient measurement	CLimited	No air standard found; compiled studies differ in size windows; nanoplastics only by research instruments	²^,⁹^,¹⁹
air	removal · MP+NP: removal from outdoor air at scale	EUnknown	Not established in evidence reviewed; indoor HEPA filters retain only particles in the air passing through	²⁰^,²¹
air	regulation · rules in force	PProvenance	Euro 7 frames tire-abrasion limits at the source; no ambient-air plastic limit in the EU acts checked	²²
water	occurrence · MP: present in every ocean basin, lakes and rivers	AConsensus	Many independent surveys; European academies (2019) and Thompson et al. (2024) reviews concur	²³^,²⁴^,²⁵^,⁸^,²¹
water	occurrence · NP: present in seawater and fresh water	BWell supported	Independent groups detected nanoplastics in the North Atlantic (2017, 2025) and Chinese surface water and groundwater	²⁶^,¹^,²⁷
water	occurrence · NP: ocean mass inventory	CLimited	27 Mt extrapolated from nine open-ocean stations on one 2020 cruise; PE and PP undetected	¹
water	sources · MP: land and river inputs to the ocean	CLimited	Inputs come from models, not measured budgets	²⁸^,²⁹
water	sources · NP: origin of open-ocean nanoplastics	EUnknown	Authors of the only basin-scale profile call the origin open; no open-ocean source apportionment found	¹^,³⁰
water	transport · MP+NP: sinking, sea-spray and deep fluxes	CLimited	River pathways modeled; sea-spray export from laboratory experiments; deep fluxes sparsely measured	²⁹^,³¹^,³²^,³³^,¹⁴
water	effects · MP: effects on aquatic organisms in laboratory tests	BWell supported	Many tests; a quality review of 105 retains food dilution and physical damage as mechanisms	³⁴^,²¹
water	effects · MP: effects at field-realistic exposure	CLimited	None of 105 aquatic studies met all quality criteria; exposure relevance and size mismatch are main weaknesses	³⁴
water	effects · NP: dose-effect relationships	CLimited	European academies (2019): most nanoplastic designs could not establish a dose-effect relationship	⁸
water	methods · MP ≥ 20 µm: standardized measurement	BWell supported	ISO 16094-2 and the EU method adopted; interlaboratory exercises found spread, largest for small particles	³⁵^,³⁶^,³⁷^,³⁸^,³⁹
water	methods · NP: validated mass measurement	CLimited	Research methods (py-GC/MS, TD-PTR-MS) used by few groups; no standard or interlaboratory study found	¹^,⁴⁰^,²⁷
water	removal · MP: retention by wastewater treatment	AConsensus	WHO (2019) reports removal above 90%; independent plant studies agree	⁴¹^,⁴⁰
water	removal · NP: retention by treatment	CLimited	Three Australian plants cut nano mass 91–96%; pilot filtration retained metal-doped model particles	⁴⁰^,⁴²
water	removal · MP+NP: removal from open water	EUnknown	Not established in evidence reviewed; ocean cleanup targets floating macroplastic	⁴³^,²¹
water	regulation · rules in force	PProvenance	EU method 20 µm–5 mm; California Phase I reports from 50 µm; no limit value; nanoplastics outside both	³⁶^,⁴⁴^,⁴⁵
soil	occurrence · MP: present in soils, including farmland	AConsensus	European academies review and FAO assessment agree with many soil studies	⁸^,⁴⁶^,⁴⁷
soil	occurrence · MP: comparable concentrations across soils	CLimited	Review finds soil methods differ, so concentrations are hard to compare	⁴⁸
soil	occurrence · NP: present in field soil	CLimited	Few field data; polystyrene nanoplastics measured at one compost-amended French site by matrix-matched py-GC/MS (2.57 µg/g in the 200–1,000 nm topsoil fraction, about 28 times a reference plot); a second French field gives only an isotope estimate of the mobile fraction (about 0.25 µg/kg to 55 cm)	⁴⁹^,⁵⁰
soil	occurrence · NP: representative multi-polymer mass across farm soils	EUnknown	Not established in evidence reviewed; the one field quantification we read covers one polymer at one site	⁴⁹^,⁵⁰
soil	sources · MP: sludge, mulch film and compost	BWell supported	FAO covers mulch film and compost; sludge rests on separate studies; amounts are estimates	⁴⁶^,⁵¹^,⁴⁷
soil	transport · NP: uptake into plants	CLimited	Laboratory beads enter crop roots; one field study found polystyrene mostly in roots, shoots below LOQ	⁵²^,⁵³^,⁴⁹
soil	effects · MP+NP: soil structure, microbes and crops	CLimited	Laboratory and outdoor-mesocosm studies; direction varies by polymer, shape and dose	⁵⁴^,⁴⁷^,⁵⁵^,⁵³
soil	methods · MP: standardized, interlaboratory-tested method	CLimited	No published standard or interlaboratory results found; review finds methods incomparable	⁴⁸
soil	methods · NP: validated extraction and quantification	CLimited	Polystyrene-specific py-GC/MS method tested with spikes; particle-preserving extraction recovered 1.4%	⁵⁶^,⁴
soil	removal · MP+NP: removal from field soil	EUnknown	Not established in evidence reviewed; biochar reduced lettuce uptake in one greenhouse study	⁵⁷
soil	regulation · rules in force	PProvenance	EU Soil Monitoring Law allows plastic monitoring, sets no plastic method or limit; REACH restricts products	⁵⁸^,⁵⁹
human	occurrence · MP: present in human tissues	BWell supported	Independent groups using different methods report particles in blood, brain and arterial plaque	⁶⁰^,⁶¹^,⁶²^,⁶³
human	occurrence · MP+NP: tissue mass concentrations	DDisputed	Brain and blood values disputed over lipid interference and contamination; authors defend their data	⁶¹^,⁶⁴^,⁶⁵^,⁶⁶^,⁶⁰
human	sources · MP: exposure through food, water and air	AConsensus	Two WHO assessments and an EFSA panel statement concur	⁴¹^,⁶⁷^,⁶⁸
human	sources · MP: weekly intake mass	DDisputed	Model estimates span about 4 µg to 5 g per week, with different size windows and conversions	⁶⁹^,⁷⁰^,⁶⁷
human	transport · NP: uptake, distribution and clearance	CLimited	Shown with model beads in animals; WHO (2022) found human data insufficient	⁶⁷^,⁷¹^,⁷²
human	effects · MP+NP: association with disease	CLimited	One cohort (257 followed): plaque plastic associated with heart attack, stroke, death; causation unshown	⁶³^,⁷³
human	methods · MP+NP: blood quantification by py-GC/MS	DDisputed	Rauert: unsuitable for PE and PVC in blood; Nardella: detected in all 102, quantified in 20%	⁶⁶^,⁷⁴^,⁷⁵
human	removal · MP: lowering circulating particles clinically	CLimited	One uncontrolled study, 114 patients; tubing shed particles; benefit and nano removal not established	⁷⁶^,⁷⁷
human	regulation · rules in force	PProvenance	No health-based guidance value adopted by WHO or the EU found	⁴¹^,⁶⁷
human	regulation · MP+NP: evidence basis for a guidance value	BWell supported	WHO 2022: insufficient for full assessment; WHO 2019: drinking water low concern, nano data insufficient	⁶⁷^,⁴¹^,⁸

Knowledge map: evidence level of each finding, by system and question

A grid of four systems by seven questions, each cell split into its graded findings. Six findings are A, all about microplastics: presence in air, water and soil, long-range air transport, retention by wastewater treatment and human exposure routes. Six are B, 21 C, four D and five E; the E findings are removal from outdoor air, open water and field soil, the origin of ocean nanoplastics and representative nanoplastic mass in farm soils. Four rule rows are marked P. Source:²¹^,⁸^,⁶⁷^,²^,¹^,⁴⁹^,⁴Grades assigned by this site on 3 November 2026; each cell holds one to five findings, and the sources for each finding are listed in the knowledge-map table. P marks legal facts, not graded science.Nanoplastics ObservatorySite original

Data table

label	value	system	question	size_class
air · occurrence · MP present	A	air	occurrence	MP
air · occurrence · MP quantified	C	air	occurrence	MP
air · occurrence · NP present	C	air	occurrence	NP
air · sources · MP shares	D	air	sources	MP
air · transport · MP long-range	A	air	transport	MP
air · transport · fluxes	C	air	transport	MP+NP
air · effects · radiative forcing	C	air	effects	MP+NP
air · methods · comparability	C	air	methods	MP+NP
air · removal · outdoor	E	air	removal	MP+NP
air · regulation · rules	P	air	regulation	MP+NP
water · occurrence · MP present	A	water	occurrence	MP
water · occurrence · NP present	B	water	occurrence	NP
water · occurrence · NP ocean mass	C	water	occurrence	NP
water · sources · MP inputs	C	water	sources	MP
water · sources · NP origin	E	water	sources	NP
water · transport · vertical and air-sea fluxes	C	water	transport	MP+NP
water · effects · MP laboratory	B	water	effects	MP
water · effects · MP field-realistic	C	water	effects	MP
water · effects · NP dose-effect	C	water	effects	NP
water · methods · MP standard	B	water	methods	MP
water · methods · NP mass	C	water	methods	NP
water · removal · MP wastewater	A	water	removal	MP
water · removal · NP treatment	C	water	removal	NP
water · removal · open water	E	water	removal	MP+NP
water · regulation · rules	P	water	regulation	MP+NP
soil · occurrence · MP present	A	soil	occurrence	MP
soil · occurrence · MP comparable	C	soil	occurrence	MP
soil · occurrence · NP present (field)	C	soil	occurrence	NP
soil · occurrence · NP representative mass	E	soil	occurrence	NP
soil · sources · MP inputs	B	soil	sources	MP
soil · transport · NP plant uptake	C	soil	transport	NP
soil · effects · structure, microbes, crops	C	soil	effects	MP+NP
soil · methods · MP standard	C	soil	methods	MP
soil · methods · NP extraction	C	soil	methods	NP
soil · removal · field soil	E	soil	removal	MP+NP
soil · regulation · rules	P	soil	regulation	MP+NP
human · occurrence · MP present	B	human	occurrence	MP
human · occurrence · tissue mass	D	human	occurrence	MP+NP
human · sources · exposure routes	A	human	sources	MP
human · sources · intake mass	D	human	sources	MP
human · transport · NP uptake	C	human	transport	NP
human · effects · disease association	C	human	effects	MP+NP
human · methods · blood py-GC/MS	D	human	methods	MP+NP
human · removal · plasma exchange	C	human	removal	MP
human · regulation · rules	P	human	regulation	MP+NP
human · regulation · evidence basis	B	human	regulation	MP+NP

Two patterns run across the rows. Microplastic presence reaches A in every environmental system, while every nanoplastic finding sits at B or below.

Removal splits the same way: wastewater treatment retains most microplastics (A) and, in three plants, most nanoplastic mass (C), but in the evidence we reviewed no method has been shown to remove dispersed particles from outdoor air, open water or field soil (E). That matches the 0 / 4 finding in Solutions by System. The human removal row is a different question, a clinical one, and stays at C⁷⁶.

The five biggest gaps

Ocean nanoplastic mass rests on one transect

Ten Hietbrink and colleagues found PET, polystyrene (PS) and polyvinyl chloride (PVC) nanoplastics at about 1.5–32.0 mg/m³ at all 12 stations, surface to bottom (level C)¹. The 27 Mt estimate sums the mixed layer at the nine open-ocean stations, not the three on the shelf. Polyethylene (PE) and polypropylene (PP), about half of global plastic production, were not detected: the authors' "missing PE and PP nanoplastic paradox"¹. We found no second basin-scale profile to test it.

Dark seafloor lit by a robot vehicle, with pale sediment, pink anemones and streams of bubbles rising into blackness — Methane bubbles rise from a seafloor cold seep north of Washington Canyon, offshore Virginia, lit by a NOAA Okeanos Explorer remotely operated vehicle, 31 May 2013; depth not stated. The first basin-scale nanoplastic profile reaching bottom waters came from one 2020 North Atlantic transect.NOAA OKEANOS Explorer Program, 2013 ROV Shakedown and Field Trials (NOAA Photo Library, image expn0686)CC BY 2.0Source ↗

The air map has blank continents and no nano layer

Evangelou and colleagues compiled 2,782 measurements of airborne microplastics from 76 studies at 283 locations (level P)². In the published dataset we count no location on the African mainland, one in South America and 35 in the Southern Hemisphere (our calculation from³). The authors describe reported sizes from several micrometers to several millimeters and ask for measurements extended to smaller microplastics and nanoplastics².

Where airborne microplastics have been measured

World map of 283 published air sampling locations for microplastics: dense clusters in South, Southeast and East Asia, Europe and North America, one point in South America and none on the African mainland. Source:³^,²Our counts of distinct locations per region code after rounding coordinates to four decimals (283 in total, matching the paper; one Wenzhou site appears twice in the raw file, differing only by floating-point noise). Region names are our reading of the dataset codes.Nanoplastics ObservatorySite original

Data table

label	value	unit	measurements
South and Southeast Asia (SAS)	101	locations	501
Europe (EUR)	56	locations	652
East Asia (EAS)	46	locations	406
North America (NAM)	22	locations	751
Antarctica and Southern Ocean (ANT)	20	locations	42
West and Central Asia (WAS)	15	locations	324
Australia and Pacific (AUS)	13	locations	42
Atlantic Ocean (ATL)	9	locations	24
South America (SAM)	1	locations	40
African mainland	0	locations	0

How much plastic is inside a human body

Independent groups using different methods find particles in human tissue (level B). In April 2026 Li and colleagues reported micro- and nanoplastics in 99.4% of 156 brain samples from 113 patients with brain tumors and in all 35 samples from five healthy post-mortem donors, combining infrared imaging (LDIR, O-PTIR) with py-GC/MS and testing operating-room contamination⁶². A correction fixed figure rounding only⁷⁸. Healthy tissue came from five people, and the link to tumor growth is a correlation.

How much plastic is there is disputed (level D). Nihart and colleagues reported brain concentrations by py-GC/MS, supported by infrared spectroscopy and electron microscopy with elemental analysis⁶¹. Critics argue that brain lipids can produce false polyethylene signals⁶⁴. The authors' reply defends the data: per a 2026 summary, the lipid comparison mixes dry- and wet-weight percentages, polymers without known lipid interference rose too, and blanks held no detectable polymer; we could read only the reply's preview⁶⁵^,⁷⁹.

In blood, Rauert and colleagues judged py-GC/MS currently unsuitable for PE and PVC, with extraction recoveries of 7–109%⁶⁶. Nardella and colleagues detected plastic in all 102 blood samples but quantified it in only 20%⁷⁴. Detection is not a validated dose. See Human Body.

Toxicity tests and exposure data describe different particles

The World Health Organization (WHO) found that most occurrence data for water, food and beverages concern particles larger than 10 µm, while most toxicity studies used uniform particles below 10 µm (level A)⁶⁷.

A quality review of 105 aquatic effect studies found the same mismatch between tested and environmental sizes; no study met all 20 criteria, and environmental relevance of exposure was among the most urgent weaknesses³⁴. WHO adds that hazard data after inhalation or ingestion were limited to polystyrene beads⁶⁷.

Soil nanoplastic methods recover little

Field measurements now exist, but they are narrow. In a French floodplain amended with compost for decades, Ryzhenko and colleagues measured polystyrene nanoplastics by matrix-matched py-GC/MS: 2.57 µg/g in the 200–1,000 nm fraction of the topsoil, about 28 times a reference plot, 123 µg/g in grass roots and 32 µg/g in shoots, the shoot value below the quantification limit (level C)⁴⁹. That is one polymer at one site.

At a second compost-amended French field, an isotope estimate put the mobile fraction in soil water at about 0.25 µg/kg down to 55 cm, not the total in soil (level C)⁵⁰.

Methods are the bottleneck: a polystyrene-specific py-GC/MS method has been tested with spiked soils and sediments⁵⁶, while a particle-preserving extraction recovered 1.4% overall, too little for quantitative analysis⁴.

Why the gaps persist

The first reason is size. Methods that identify polymers particle by particle rarely go below about 1 µm; below that, laboratories mostly use thermal methods that report polymer mass without particle size or count¹⁹. Method detail is in How We Measure It.

The second is comparability. When 12 laboratories analyzed the same sample bottles, their results differed widely, most for small particles (here, below 1 mm)³⁷. A drinking-water interlaboratory study also found poorer recovery of small particles³⁹.

The third is contamination. The North Atlantic team ran laboratory blanks and notes that whether clean rooms eliminate plastic contamination at the nanoscale is uncertain¹.

The fourth is access. Human samples come from surgery, autopsy or blood draws, and WHO found too little information to assess how particles are taken up, retained and cleared⁶⁷.

The size windows of current methods show the problem at a glance.

Which particle sizes current methods and rules cover

A logarithmic size axis from 1 nm to 5 mm: the EU drinking-water method starts at 20 µm, California's Phase I reporting at 50 µm (20 µm by Raman) and its planned Phase II at 5 µm, although California's definition reaches down to 1 nm; only research studies such as the North Atlantic transect and the soil extraction study work below 1 µm. Source:³⁶^,⁴⁴^,¹^,⁴^,³⁰Nanoplastics ObservatorySite original

Data table

label	value	unit	range_from	range_to	source
Nanoplastics (site convention)	1	µm	0.001	1	S-017
North Atlantic nanoplastic study: fraction passing a 1.0 µm filter (lower size bound not stated)	1	µm		1	S-067
Soil nanoplastic extraction (Forsyth et al.): filtration below 1 µm	1	µm		1	S-288
California drinking-water monitoring, Phase II (planned, treated water): down to 5 µm	5	µm	5	5000	S-194
EU drinking-water method: particles 20 µm–5 mm	20	µm	20	5000	S-132
California drinking-water monitoring, Phase I (source water): reporting from 50 µm or the method minimum (20 µm by Raman)	50	µm	20	5000	S-194
California definition of microplastics in drinking water	5000	µm	0.001	5000	S-194
Microplastics: upper bound	5000	µm			S-017

The field is also young at the nano scale. In 2019 the European academies found no studies of atmospheric nanoplastic pollution and no analytical method for nanoplastics in soil⁸. Nanoplastics were then reported in Alpine snow in 2020 and 2021 and in polar ice in 2022⁹^,¹⁰^,¹¹. In soil, field measurement of nanoplastic mass is still rare; we read one quantification, from 2026⁴⁹, and one isotope estimate of the mobile fraction, from 2024⁵⁰.

What would close them

Five steps would move the most findings.

Nanoplastic methods validated with orthogonal techniques and reported with confidence levels⁷⁵, including soil extractions that recover enough to quantify⁴.
Effect studies with environmentally realistic particles and exposures, and reference particles that resemble environmental ones, as WHO and the quality review recommend⁶⁷^,³⁴.
Size-resolved air monitoring that extends to smaller microplastics and nanoplastics², with sites outside Europe, North America and Asia (our reading of³).
Repeat ocean transects that test the North Atlantic estimate and look for the missing PE and PP¹.
Human studies whose exposure is measured by validated methods, so that associations such as the plaque cohort can be tested⁶³^,⁷⁵.

Thompson and colleagues add that clear evidence on whether proposed solutions work is now needed²¹. The Lancet Countdown on health and plastics has begun an indicator-based monitoring system that could track some of these gaps over time⁸⁰.

Search record for the E findings

We searched PubMed on 3 November 2026 (publication years 2015–2026, English titles and abstracts), screened every title and read the abstracts of candidates that looked like field-scale evidence. Exact search strings are kept in the claims record of this page.

Removal from outdoor air: 129 records; none tested removal from outdoor air at scale. Excluded: reviews, indoor and wastewater studies, an urban-forest interception perspective.
Origin of open-ocean nanoplastics: 12 records; none apportioned open-ocean sources. One coastal Mediterranean study traced low-molecular-weight PE and silicone debris (retained on a 0.45 µm filter) to sources compatible with wastewater and consumer products; it does not separate nano from micro particles.
Removal from open water: 33 records; none showed removal from a lake, river or ocean. Excluded: laboratory adsorbents and one lake pilot that retained microplastics from pumped water only.
Representative nanoplastic mass in farm soils: 51 records; one field study of one polymer⁴⁹. Excluded: pot experiments, reviews and a 120-field survey that reports total plastic mass below 5 mm without a nano fraction.
Removal from field soil: 54 records; none showed removal at field scale. Excluded: pot, laboratory and review studies.

A missed study would change a grade; please send it.

How this map is maintained

Method

We regrade a finding when a peer-reviewed study, interlaboratory comparison, standard or agency assessment changes what is known; dated change notes are planned, and no regrades have been recorded yet. A finding moves up only with new independent data, not with a press release. You can propose a regrade, with a source, through Corrections & Contact. Last full review: 3 November 2026.

Gallery

Illustration of a row of large amber dots across the middle, many smaller amber specks scattered below to the bottom edge — Illustration: large particles along a detection threshold are easy to count; below it, many smaller particles are harder to see but still there. Smaller does not mean absent. Not data; particles enlarged for visibility.Illustration · AI generatedMade with FLUX.1-schnell (fp8, Comfy-Org/Flux-1-Schnell) · ComfyUI (local), tools/content/generate_l3.pySite illustration (AI-generated, Flux)Site original

Sources

ten Hietbrink S, Materić D, Holzinger R, Groeskamp S, Niemann H (2025). Nanoplastic concentrations across the North Atlantic. Nature. doi:10.1038/s41586-025-09218-1 journal article
Evangelou I, Bucci S, Stohl A (2026). Atmospheric microplastic emissions from land and ocean. Nature. doi:10.1038/s41586-025-09998-6 journal article
Evangelou I, Bucci S, Stohl A (2025). Atmospheric microplastic emissions from land and ocean (dataset: compiled atmospheric microplastic measurements and emission fields). Zenodo. doi:10.5281/zenodo.17660114 dataset open access
Forsyth H, Gnoffo C, Oh S, Sakaguchi-Söder K, Mitrano DM, Frache A et al. (2026). Unearthing nanoplastics in soil: optimising extraction and purification while preserving particle integrity. Microplastics and Nanoplastics 6:7. doi:10.1186/s43591-026-00172-x journal article open access
Allen S, Allen D, Phoenix VR, Le Roux G, Durántez Jiménez P, Simonneau A et al. (2019). Atmospheric transport and deposition of microplastics in a remote mountain catchment. Nature Geoscience. doi:10.1038/s41561-019-0335-5 journal article
Brahney J, Hallerud M, Heim E, Hahnenberger M, Sukumaran S (2020). Plastic rain in protected areas of the United States. Science. doi:10.1126/science.aaz5819 journal article
Herzke D, Schmidt N, Lervik AE, Schulze D, Celentano S, Eckhardt S et al. (2026). Airborne microplastics on the move: Urban Europe as a source to remote regions. Environmental Pollution. doi:10.1016/j.envpol.2025.127380 journal article
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Materić D, Kasper-Giebl A, Kau D, Anten M, Greilinger M, Ludewig E et al. (2020). Micro- and Nanoplastics in Alpine Snow: A New Method for Chemical Identification and (Semi)Quantification in the Nanogram Range. Environmental Science & Technology. doi:10.1021/acs.est.9b07540 journal article
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Evidence levels and provenance

AConsensusUsed on this page: Multiple independent studies or a systematic review plus a statement by a scientific body.
BWell supportedUsed on this page: Several independent studies with concordant findings.
CLimitedUsed on this page: Few studies, narrow conditions, or methodological caveats.
DDisputedUsed on this page: Conflicting results; both sides are shown.
EUnknownUsed on this page: No reliable evidence found; the search scope is stated.

PProvenanceUsed on this page: Provenance: checked against the primary record. A separate category, not an evidence grade: used for bibliographic facts, legal texts, official metadata, definitions quoted from a standard, the site's own arithmetic and statements about the site's process.

Editorial categories of this site. A–E grade scientific findings, per claim, with a one-line rationale; D and E are not lower rungs of the A–C scale. P is not a grade: it marks facts checked against their primary record.