The honest version is more persuasive than the clean one.

PM10 — airborne particulate below ten micrometres in aerodynamic diameter — is the fraction most standards for this problem are written around, because it is small enough to be inhaled and abundant enough near an emissive surface to dominate a monitor reading.

Everything below is organised by how firmly it stands up. Nothing in it is a claim about SoilScrubber, and that is deliberate.

1. What stands up

A health impact assessment published in Atmosphere, looking specifically at exposure to PM10 and dust storms in Kuwait, found particulate levels statistically significantly correlated with acute respiratory disorders and bronchial asthma at p < 0.05.

Peer-reviewed, regional, and about the exact exposure pathway this system addresses. It is the strongest single piece of evidence on this page and it is a correlation in a population, which is what this kind of study produces.

2. The regulatory picture

California's 24-hour PM10 standard is 50 micrograms per cubic metre; the federal standard is 150. The Salton Sea Air Basin regularly exceeds the first and occasionally the second, which is the practical reason a shrinking lake in an air basin becomes an enforcement problem rather than a landscape one.

Reporting on the same basin also describes exposed lakebed containing sulfate and chloride salts, pesticide residue and heavy metals. That characterisation comes from lower-confidence secondary material, so we treat it as indicative and do not build anything on it.

3. What is genuinely contested

The Aral Sea is the case everybody reaches for, and it needs handling with care.

Regional health statistics show elevated asthma: roughly 113 per 100,000 in Khorezm, more than three times the national average, and about 67 per 100,000 in Karakalpakstan, roughly twice it. Those numbers are real and they are grim.

Then read the fieldwork. A controlled study of children across the Aral Sea region, published in the International Journal of Epidemiology, went looking for the link between local dust deposition and respiratory symptoms and did not find it. Its own conclusion is blunter than any paraphrase we would write: asthma prevalence in the area is low, and appears unrelated to dust exposure.

Both of those are on the record simultaneously, and reconciling them is somebody's PhD, not a paragraph on a supplier's website. Elevated regional illness does not by itself establish that lakebed dust caused it. Poverty, drinking water, agrochemical exposure and the capacity of the health system are all present in the same districts and all plausible.

None of that makes Aral dust harmless. It makes the causal chain contested, in print, by people who went and measured. A supplier presenting it as settled has either not read the second paper or has decided you will not.

4. What we deliberately left out

Three figures were available to us, are widely quoted, and do not appear as claims anywhere on this site.

• A 24 per cent childhood asthma rate near the Salton Sea Reported against national rates of 8.4 per cent for boys and 5.5 per cent for girls. Arresting, plausible, and reached our fact base through a summary rather than a full reading of the underlying study.
• COPD and mortality attribution in Ilam, Iran A study covering 2015–16 has been summarised as attributing about 4.9 per cent of COPD hospital visits and 7.3 per cent of respiratory mortality to each ten microgram per cubic metre rise in PM10. Same problem: we have the summary, not the paper.
• Peak PM10 above 7,000 micrograms per cubic metre in Doha Recorded during a severe dust storm. A striking number, sourced the same indirect way.

Each of those would make this page more frightening and therefore, in the short term, more effective. None of them has been read back to source by anyone here. So they sit in this section, labelled, rather than in a headline.

If that standard seems excessive, consider who buys this work. Environment ministries, air quality districts and public health authorities employ people whose job is to check exactly this, and one unsupportable number in a proposal contaminates every supportable one beside it.

5. What we claim about our own system

Nothing on this page. Not one figure above describes SoilScrubber.

What a SoilScrubber programme can demonstrate is a change in emissions from a defined treated area, read on monitors, against an untreated control area, over an agreed period. That is measurable, falsifiable and ours to be accountable for.

Whether reducing emissions from a specific surface produces a measurable change in respiratory outcomes downwind is a public health study. It takes years, it needs controls we cannot supply, and it belongs to researchers rather than to a supplier. We will support one, fund a monitoring contribution to one, and hand over our data. We will not pre-announce its findings.