The science behind your Nestwell Score

Why a healthier home starts with understanding.

Home health comes down to exposure — the air you breathe, the water you drink, and everything your skin touches, thousands of times a day, in the place you spend most of your life. Nestwell connects your home’s environmental health to clear, personalized next steps — from air & water quality to mold, moisture, soil, and property risk.

Your Nestwell ScoreYour home
0
Grade C+
Air qualityElevated
WaterPFAS flagged
Hazard sites2 nearby
Measured across three axes
Community

County-level emissions, radon zones, and nearby toxic-release and Superfund sites.

Home

Certified lab results for metals, PFAS, and mold in your air, water, dust, and soil.

Individual

Your biological response over time, as exposures change through critical windows.

The Exposome

Everything your body meets, over a lifetime.

How does exposure to chemicals in the water, air, and soil influence health outcomes ranging from asthma to diabetes to fertility? The exposome1,2 is a framework for studying and understanding the lifetime of lifestyle, chemical, and psychosocial exposures that you come into contact with every day.

A Nestwell home health report listing air, water, radiation, and soil readings with status and target ranges

Why does home health matter?

You spend over half your life in your home, but there can be a variety of hidden environmental factors that are silently contributing to the development of disease over a lifetime. In fact, indoor air quality is often worse than outdoor air.3–5

1 in 4
deaths worldwide are linked to a preventable environmental cause26
World Health Organization
The Environmental Drivers of Disease

Your physical health matters. But so does everything around it.

While your own body and health play a major role in how you feel, the exposome has been implicated in the development of diseases across biological systems such as asthma, heart disease, and developmental disorders. Thus, understanding the environmental drivers of disease you come into contact with every day is paramount for mitigating disease.

Measurements of the exposome range from air pollution metrics6 and targeted chemical measurements7 to broad measurement of all compounds in the blood8 to broad survey questions9 that have all been validated and associated with the development of disease across time. These measurements have different levels of confidence in the specific exposures measured. However, all measurements attempt to identify exposure to a chemical during a critical window10–12 such as childhood, pregnancy, or old age.

Together, the exposome allows for the quantification of these environmental drivers of disease across multiple measurement axes — community, home, and individual.
What Can Address-Level Data Tell Us?

Where you live shapes your health as much as how you live.13

It’s a familiar idea — but what factors beyond social determinants of health are driving the development of disease in different populations? Environmental drivers. At Nestwell, we collect data from trusted sources including the US Environmental Protection Agency, the CDC, and the Environmental Working Group to give you a sense of the exposures in your area.

Bridging the Gap Between Outdoor and Indoor Risk

Geospatial data sources and what each tells us. Tap to expand.

Five EPA datasets anchor the community layer of your assessment:

National Emissions Inventory (NEI) ¹⁴

The EPA's comprehensive count of air pollutant emissions, compiled county by county. We use it to break down which pollutants — and which sources, like on-road traffic — drive your local air quality.

Map of Radon Zones ¹⁵

A county-level geological estimate of radon potential, rated 1 to 3. It tells you the baseline risk for your area, though radon still varies house to house.

Toxic Release Inventory (TRI) ¹⁶

A public database of facilities that release or manage toxic chemicals. We surface the reporting sites nearest your property so you can see what's operating in your area.

Superfund ¹⁷

The EPA's registry of the nation's most contaminated sites and their cleanup status. Proximity to a Superfund site is a signal for elevated soil and groundwater risk.

AirNow ¹⁸

The EPA-led real-time air quality index, drawn from a national network of regulatory monitors. It keeps your air picture current — reflecting today’s conditions, including smoke, not just a seasonal average.

0
out of 100

Percentile-based, benchmarked against homes nationwide. Illustrative data shown.

How Does My Nestwell Score Work?

A single, comparable read on your home.

At Nestwell, we believe you should always know how your home compares to other homes in the country, and what actions you can take to mitigate its risks. The Nestwell Score gives you a baseline understanding of the potential environmental hazards surrounding your home.

To do this, we use a set of simple percentile-based metrics that place you and your home in a distribution of all other measurements in the country — for air quality, specific air pollutants, chemicals in your water such as PFAS, and many more. We average those together to get a full idea of your home’s environment. From there, we find the number of location-based hazards in your area including toxic release inventory sites, Superfund sites, and brownfields, and use that to inform your overall score.

Air quality82th pct
Specific pollutants68th pct
Water — PFAS59th pct
Hazard-site proximity73th pct

Together, this score is further influenced by live events in your area, giving you the industry’s most up-to-date view of current hazards — including wildfire alerts, smoke and air-quality alerts, and exposure events from federally mandated reporting channels.

Live Home Insights

Your baseline, kept current.

Environmental conditions around your home change daily. Air quality changes with the weather, or smoke drifts in from hundreds of miles away. A new NWS alert means something in your air or weather pattern has shifted. These insights and more are provided in real time in your dashboard. Your Nestwell Score captures your baseline, but the Insights map keeps you current.

Available to members, the live Insights map layers real-time and near-real-time data directly over your property: EPA AirNow air quality readings, active National Weather Service alerts, NIFC wildfire perimeters, US Drought Monitor status, USGS seismic activity, and EPA Toxic Release Inventory facilities in your area — all surfaced as soon as the alert reaches the system. A “Right now” strip at the top of the map distills it to the signals that matter most: current AQI, any active alerts, drought class, and nearby fire activity.

See your home’s live map →
Right nowAQI 74 · Moderate1 NWS alertDrought D1Fire 42 mi
Your home
Air qualityWaterHazard sites
From Estimate to Certainty

Your score is a starting point. A test is the truth.

Inferred · Free
Directional confidence

Where to look

Built from your address, your home’s characteristics, and authoritative regional data — air, water, radon, and nearby hazards. A directional estimate that shows you where the risk most likely is.

Lab-confirmed · With a kit
Confirmed confidence

What’s true

A certified lab measures what’s actually in your air, water, dust, or soil — the real reading for your specific home, not a regional average.

A lab result can lower your score (your levels beat the regional baseline) or raise it (it catches what an estimate can’t see). Either way, you stop guessing.
Public Data is Only One Part of the Story

Some exposures can only be found inside your own home.

Despite the rich information geospatial data provides, and all the potential impacts on health outcomes being measured in these ways, there is a wide variety of information that can only be obtained through direct measurement of exposures in your own home. At Nestwell, we bridge that gap with certified lab results from our partners that can measure a wide variety of exposures including metals, PFAS, and mold in your home’s air, water, dust, and soil. By testing your own home, you can identify direct sources of exposure and take steps to remediate it, keeping your family safe.

How your home’s sample becomes a report

The sample from your home is mailed to a certified lab and analyzed under a harmonized protocol.

01
Collect at home

Sample your air, water, dust, or soil with a guided Nestwell kit.

02
Mail it in

Your sample ships to a certified partner lab in prepaid packaging.

03
Certified analysis

Analyzed under a harmonized protocol across our lab network.

04
Your report

Results fold into your Nestwell Score with clear next steps.

Your Exposome Over Time

An important part of the exposome is your body’s biological response to the environment. Because each person has a unique combination of biology, lifestyle, and experiences, the same exposure can affect people differently.24

As your environment and daily habits change over time, so does your exposome — making it a dynamic picture of your health. Nestwell gives you the opportunity to monitor exposures in your area, and to test your home’s exposures over time so you understand the effectiveness of your chosen interventions.

The Research

Grounded in peer-reviewed science.

Framework

Integrating exposomics into biomedicine

The exposome complements the genome — measuring the environmental half of disease risk that DNA alone can’t explain.1,2

Association

An atlas of exposome–phenome associations

Large-scale studies map specific exposures to specific health and disease outcomes across the population.7,9

Timing

Critical windows of exposure

Exposures during childhood, pregnancy, and later life carry outsized, lasting effects on lifelong disease risk.10–12

Our Advisory Team

Nestwell is grounded in peer-reviewed science and a panel of experts across institutions such as Stanford and UCSF. They are experts across medicine and environmental health who help guide Nestwell to properly test your home for environmental exposures and link those to potential health outcomes.

Dr. Malathi Srinivasan
Dr. Malathi Srinivasan
Clinical Professor of Medicine — Primary Care & Population Health
Stanford University School of Medicine
Dr. Mark Cullen
Dr. Mark Cullen
Founding Director, Stanford Center for Population Sciences
Stanford University School of Medicine
Dr. Lauren Eggert
Dr. Lauren Eggert
Associate Professor of Medicine
UCSF Division of Pulmonary, Critical Care, Allergy & Sleep Medicine
Common Questions

Questions, answered.

Both. We evaluate contaminants against federal legal limits (like EPA Maximum Contaminant Levels) and, where the science has moved faster than regulation, against independent health-based guidelines such as the Environmental Working Group’s — which are often stricter. That’s why a home can be perfectly “legal” and still worth addressing.

References

  1. 1.Miller, G. W. & Banbury Exposomics Consortium. Integrating exposomics into biomedicine. Science 388, 356–358 (2025).
  2. 2.Wild, C. P. Complementing the genome with an 'exposome': the outstanding challenge of environmental exposure measurement in molecular epidemiology. Cancer Epidemiol. Biomarkers Prev. 14, 1847–1850 (2005).
  3. 3.US EPA, O. Indoor Air Quality. US EPA https://www.epa.gov/report-environment/indoor-air-quality (2017).
  4. 4.Dris, R. et al. A first overview of textile fibers, including microplastics, in indoor and outdoor environments. Environ. Pollut. 221, 453–458 (2017).
  5. 5.Leung, D. Y. C. Outdoor-indoor air pollution in urban environment: challenges and opportunity. Front. Environ. Sci. 2, 119805 (2015).
  6. 6.Pope, C. A., 3rd, Ezzati, M. & Dockery, D. W. Fine-particulate air pollution and life expectancy in the United States. N. Engl. J. Med. 360, 376–386 (2009).
  7. 7.Patel, C. J., Ioannidis, J. P. A. & Manrai, A. K. An atlas of exposome–phenome associations in health and disease risk. Nat. Med. 1–10 (2026) doi:10.1038/s41591-026-04266-0.
  8. 8.Petrick, L. M. & Shomron, N. AI/ML-driven advances in untargeted metabolomics and exposomics for biomedical applications. Cell Rep. Phys. Sci. 3, 100978 (2022).
  9. 9.Lloyd, D. et al. Questionnaire-based exposome-wide association studies for common diseases in the Personalized Environment and Genes Study. Exposome 4, osae002 (2024).
  10. 10.Nelson, C. A., 3rd & Gabard-Durnam, L. J. Early adversity and critical periods: Neurodevelopmental consequences of violating the expectable environment. Trends Neurosci. 43, 133–143 (2020).
  11. 11.Giulivo, M., Lopez de Alda, M., Capri, E. & Barceló, D. Human exposure to endocrine disrupting compounds: Their role in reproductive systems, metabolic syndrome and breast cancer. A review. Environ. Res. 151, 251–264 (2016).
  12. 12.Barouki, R., Gluckman, P. D., Grandjean, P., Hanson, M. & Heindel, J. J. Developmental origins of non-communicable disease: implications for research and public health. Environ. Health 11, 42 (2012).
  13. 13.Chetty, R. et al. The association between income and life expectancy in the United States, 2001-2014. JAMA 315, 1750–1766 (2016).
  14. 14.US EPA, O. National Emissions Inventory (NEI). US EPA https://www.epa.gov/air-emissions-inventories/national-emissions-inventory-nei (2015).
  15. 15.US EPA, O. The EPA Map of Radon Zones. US EPA https://www.epa.gov/radon/epa-map-radon-zones (2014).
  16. 16.US EPA, O. Toxics Release Inventory (TRI) Program. US EPA https://www.epa.gov/toxics-release-inventory-tri-program (2013).
  17. 17.US EPA, O. Superfund. US EPA https://www.epa.gov/superfund (2014).
  18. 18.AirNow.gov. https://www.airnow.gov/
  19. 19.National Weather Service. Fire Weather. NOAA's National Weather Service https://www.weather.gov/box/fire (2025).
  20. 20.National Risk Index for Natural Hazards. https://www.fema.gov/flood-maps/products-tools/national-risk-index
  21. 21.Environmental Working Group. EWG's Tap Water Database: What's in Your Drinking Water? https://www.ewg.org/tapwater/
  22. 22.The U.S. Drought Portal. Drought.gov https://www.drought.gov/
  23. 23.Home. USGS https://www.usgs.gov/
  24. 24.Niedzwiecki, M. M. et al. The exposome: Molecules to populations. Annu. Rev. Pharmacol. Toxicol. 59, 107–127 (2019).
  25. 25.National Interagency Fire Center. Wildland Fire Open Data — current wildfire perimeters. https://data-nifc.opendata.arcgis.com/
  26. 26.Prüss-Ustün, A. et al. Preventing disease through healthy environments: a global assessment of the burden of disease from environmental risks. World Health Organization (2016).

How healthy is your home, really?

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Nestwell provides environmental information and is not a substitute for professional medical advice.Data: EPA · NWS · NIFC · FEMA · EWG · USGS · US Drought Monitor