Germany's missing indoor-air bill

France priced the social cost of indoor air pollution at roughly 19 billion euros a year, about one percent of GDP, for the reference year 2004 (Boulanger et al., 2017, Environment International 104:14-24). The United Kingdom put the first-year cost of poor housing to the National Health Service at 1.4 billion pounds in 2021 (BRE, 2021). Germany has no equivalent figure.

Germany is not short of method. The Umweltbundesamt already prices the damage from German greenhouse-gas and air-pollutant emissions in road traffic, electricity and heat generation, at least 301 billion euros for 2022. Indoor air does not appear in that account at all.

What exists for Germany is partial. There are disease-burden estimates in disability-adjusted life years for single indoor-relevant factors, and a mortality figure of around 2,800 lung-cancer deaths a year from indoor radon (Heinzl et al., 2024, Radiation and Environmental Biophysics 63(4):505-517). There is no aggregate and no Euro figure.

The absence is firmly documented and the comparators rest on primary sources. The reading that the gap is political rather than methodological is my judgment, and the strongest support for it is that German agencies price the air outside the building and leave the air inside it uncounted.

Whoever produces the first German number sets the terms of the debate over who carries the cost.

The carpet at Waterside Mall

In October 1987 the United States Environmental Protection Agency had about 27,000 square yards of new carpet laid in its headquarters at Waterside Mall in Washington. William Hirzy and Rufus Morison documented what followed (Hirzy and Morison, 1991, Advances in Risk Analysis 9:51-61). At least 122 people were affected by the indoor air and the fumes from the new carpet, 17 could no longer work at their normal stations, and at least 6 developed lasting multiple chemical sensitivity. The suspected agent was 4-phenylcyclohexene, a trace compound in the latex adhesive on the back of the carpet. The agency removed the carpet in September 1988, almost a year after laying it. The body charged with protecting the environment could not secure the air in its own building.

The case is well documented and it is one case. It shows that indoor air can carry a measurable health cost. For the size of that cost across a population you need an accounting, and three countries have built one.

What France, Britain and Australia put on the table

France was first. Guillaume Boulanger and colleagues estimated the social cost of indoor air pollution for ANSES, the French agency for food, environmental and occupational safety, based on six pollutants: benzene, trichloroethylene, radon, carbon monoxide, fine particles and secondhand smoke (Boulanger et al., 2017, Environment International 104:14-24). The result lands at roughly 19 billion euros a year for 2004, about one percent of French GDP. Fine particles account for about three quarters of the total, radon next. ANSES frames the figure as an illustrative order of magnitude rather than a final accounting, and it cannot be added to outdoor-air estimates because the exposures overlap. Pierre Kopp, an economist at the Université Paris 1 Panthéon-Sorbonne, led the economic analysis. There is no separate Kopp study. What grey literature occasionally cites as “Kopp 2016” traces back to the same ANSES work.

Britain priced a narrower thing. The Building Research Establishment calculated the cost of poor housing to the National Health Service (BRE, 2021, “The cost of poor housing in England”). First-year treatment costs run at 1.4 billion pounds a year, of which 857 million is attributable to excess cold. The broader social measure, which adds productivity losses and follow-on costs, reaches 18.5 billion pounds. BRE is a commercial research and certification body, and the headline is best read as first-year treatment cost alone, which is how BRE itself frames it. The British Parliament has since cited the estimate in the context of cold and damp homes (House of Commons Library, 2023, Research Briefing CBP-9696).

Australia has a figure too, and it is weaker. Yang Li and colleagues modeled the health gains from eliminating indoor mould in homes (Li et al., 2025, medRxiv preprint). They report a fall in health expenditure of about 78 million US dollars and a rise in income of about 116 million US dollars per million people, accumulated over twenty years and discounted at three percent, not per year. The authors converted these to about 117 and 174 million Australian dollars in a companion article. The work sits in a preprint that has not been peer reviewed, alongside a framing paper from the same group in a journal (Bentley et al., 2025, The Lancet Public Health 10(10):e855-e864). No Australian renovation program cites it. France and Britain carry the comparison. Australia shows that the method travels.

The three rest on different sampling logics: a prevalence-based cost model, a housing survey scored for hazards and a simulation of health-adjusted life years. They do not share data or teams. They converge on the same move, putting a national price on the cost of bad indoor air. Germany has not made it.

Germany counts the air outside and not the air inside

Germany is well equipped to measure indoor air. The Umweltbundesamt runs a Committee on Indoor Air Guide Values, which sets a precautionary value (RW I) and a hazard value (RW II) for individual pollutants, with a method published in the Bundesgesundheitsblatt since 1996 and guideline values updated to the present. A second body, the Indoor Air Hygiene Commission, has advised on the field for about four decades. The infrastructure for naming and limiting indoor pollutants is old and active. What none of it produces is a cost.

The gap is sharper than a plain absence, because the same agency monetizes other environmental harms. The Umweltbundesamt prices the damage from German greenhouse-gas and air-pollutant emissions in road traffic, electricity and heat generation, and reached at least 301 billion euros for 2022, with costing rates on the books for noise as well. Indoor air does not enter the calculation.

What Germany has for indoor air is partial and scattered. Otto Hänninen and colleagues estimated that nine environmental risk factors, among them indoor radon, secondhand smoke and formaldehyde, account for about 5.4 percent of the total burden of disease in Germany, a figure expressed in disability-adjusted life years with no Euro equivalent and no assessment of dampness or mould (Hänninen et al., 2014, Environmental Health Perspectives 122(5):439-446). Myriam Tobollik and colleagues at the Umweltbundesamt later reviewed which environmental burden estimates exist for Germany and found them available for single factors only (Tobollik et al., 2018, Bundesgesundheitsblatt 61(6):747-756). For indoor radon alone, Felix Heinzl and colleagues attribute around 2,800 lung-cancer deaths a year to radon in buildings, a population-attributable fraction of 6.3 percent (Heinzl et al., 2024, Radiation and Environmental Biophysics 63(4):505-517), a figure the Federal Office for Radiation Protection confirms.

The most direct evidence of the gap comes from inside the agency. Myriam Tobollik and colleagues, assessing the environmental burden of disease for German children, found that only five of seventeen relevant factors could be quantified at all, and stated plainly that there are no cost-benefit analyses and no integrated national framework for the indoor-air burden (Tobollik et al., 2026, Frontiers in Public Health 14:1796283). This is not an outside critic but the federal environment agency describing its own missing ledger.

One number that circulates should be kept out of this. The figure of 82 billion euros a year for respiratory disease from damp homes, from the Fraunhofer Institute for Building Physics through the VELUX Healthy Homes Barometer, is a European total across 32 countries and not a German figure. It is not the national accounting Germany lacks, and using it as if it were concedes the ground a real number would hold.

Why the number is missing

There is a real methodological objection, and it is worth stating in full. Aaron Best and Tanja Srebotnjak, in a report for the Umweltbundesamt, argue that aggregating cost estimates across different environmental risk factors is not a trivial task, because pollutants occur in a mix and the contribution of any single component to a health effect is hard to isolate (Best and Srebotnjak, 2021, Umweltbundesamt FKZ 3716 62 2100). They warn that monetized results must be interpreted with care. Indoor air is exactly such a mix, with volatile organic compounds, formaldehyde, mould and radon present at once. A single clean number for indoor air would paper over genuine uncertainty.

The objection is true and it is not a wall. The same authors monetized fine particles, ozone and lead for Germany for 2016. The method works when it is applied. France met the same mixing problem and published an order of magnitude rather than a false precision, which is the honest way to handle it. The German agency has the tools and has used them on outdoor air, not on indoor air.

Position

The gap is political, not methodological. The method exists in three countries and in Germany’s own outdoor-air accounting. The data needed to run it on indoor air is thinner here than in France, which is a real obstacle and a smaller one than it looks. What a national indoor-air number would do is name actors. It would assign a share of the cost to builders, to landlords, to public building managers and to other owners, and it would quantify costs that currently land on the health system. As long as that second side of the ledger stays empty, every renovation debate falls on the first side by default. A renovation costs money now. What a non-renovation costs is not counted. The number is missing because counting it would make a transfer visible, and visibility is the precondition for any argument over who pays.

I hold this as a judgment and not a proof. The absence is documented. The reading of why it persists is mine, and the strongest thing I can put behind it is the asymmetry already on the record: the costed air stops at the front door.

The method exists, the data does not

The templates are settled. The French cost model, the British hazard survey and the Australian simulation are all replicable in their basic logic, and anyone commissioning a German calculation would find working precedents. The real gap is not the arithmetic but the absence of a German indoor-exposure database, a counterpart to the French OQAI housing campaign that ran from 2003 to 2005 and gave Boulanger the inputs to calculate on. France could calculate cheaply because the measurement already existed.

That sets the price of the work, and it inverts the intuition. The cost calculation itself was a desk synthesis of existing exposure and dose-response data, absorbed within the annual budget of the OQAI, which ran between 1.5 and 2.7 million euros for the whole observatory over the decade to 2017 (CGEDD, IGAS and IGA, 2019). The expensive part was the field campaign that fed it, between 3 and 4.6 million euros. Germany has no equivalent campaign. The arithmetic is affordable. The measurement that makes the arithmetic possible is the real bill, and Germany has not paid it.

Beyond the measurement, the open research question is German specificity: how tenancy law, housing-benefit logic and the reimbursement structure of statutory health insurance shape who bears the cost and who could be made to bear it. That is where a German calculation would do its own work rather than copy France, and it is the part no precedent can supply.

Implications

For statutory and private health insurers and their associations

The cost of bad indoor air lands on you, through respiratory and cardiovascular treatment that the building caused. Commissioning the first national calculation is cheap relative to the claims it describes, and the party that puts the first number on the table defines the frame everyone else argues inside. You hold the strongest direct interest and the least reason to wait.

For the real-estate and construction industry

A missing calculation protects you today. When a calculation arrives, and the comparators suggest it will, it will name causes. Trade associations and building guilds can help shape the method while it is still open, or inherit a number built without them.

For foundations and research funders

This is a concrete and fundable gap. The cost arithmetic on existing data is a small item. The real investment is a national indoor-exposure survey, the German OQAI that does not yet exist. Fund the measurement and the calculation follows. Fund only the calculation and it rests on borrowed French exposure data.

For policy and administration

Without a number there is no lever for cause-based responsibility. A national figure is a precondition for the political debate and not a product of it. The European energy-performance framework sets deadlines that Germany will meet at the minimum for as long as the cost of doing more stays uncounted.

Stop doing this

Stop treating the absence of a German indoor-air cost as a data problem that will resolve itself. It will not. The single-factor burden estimates have accumulated for a decade without aggregating into anything a minister can cite. And stop citing the 82-billion-euro European damp-housing figure as a German number. It is European, and reaching for it is the tell that the national figure is still missing.

Methodology

This report rests on primary sources rather than a corpus query. I pinned each headline figure to its origin. The French estimate goes to Boulanger et al. 2017 and the underlying ANSES report. The British figures go to the BRE 2021 report and its parliamentary citation. The Australian figures go to the Li et al. preprint rather than to the Lancet framing paper often credited with them. The German burden estimates go to the Umweltbundesamt and Robert Koch Institute authors who produced them. Where a number drifts in secondary sources, I went back to the original. The EPA Waterside Mall case appears here as at least 122 people affected, the figure in Hirzy and Morison 1991, not the 124 of 2,000 that circulates in later summaries.

The evidence is uneven, which the field dictates. The comparators are solid. The French figure is peer reviewed, the British figure is a primary report from a commercial body and labeled as such, and the Australian figure is a preprint that has not been peer reviewed and is treated as modeled rather than measured. The German side is a documented absence supported by the country’s own agencies. The counter-position, that aggregation across a pollutant mix is hard, comes from a named UBA report and is given in full rather than dismissed. What I cannot show is the size of a German number, because no one has calculated it. That is the subject of the report.

Fourteen sources are named. The thesis has two halves: the absence of a German accounting, and the claim that the absence is political rather than methodological. The first half is verifiable and verified. The second is a judgment, marked as one.