Topics Reference

There are 37 topics. They fall into three groups, and each group returns a different shape in value. Read this before you write parsing code.

Natural

18 topics
value is an object with an NRI rating

Proximity

14 topics
value is a number

Measurements

5 topics
value is a measurement object

Natural (18)

Backed by the FEMA National Risk Index (NRI), which scores hazard risk by US census tract. value is an object:

{
  "title": "Wildfires",
  "rating": "Relatively High",
  "score": 62.4,
  "frequency": 0.83
}

Field	Type	Meaning
`title`	string	Human-readable topic name
`rating`	string	NRI risk category (see below)
`score`	number	NRI numeric risk score
`frequency`	number	Annualized event frequency for the tract

rating is one of: Very Low · Relatively Low · Relatively Moderate · Relatively High · Very High · No Rating · Insufficient Data · Not Applicable

Not Applicable is common and expected — e.g. avalanche in Manhattan. It means the hazard doesn’t meaningfully apply to that tract, not that the lookup failed.

Topics:

Slug	Topic	`details`
`avalanche`	Avalanche	`null`
`coastalFlood`	Coastal Flood	`null`
`coldWave`	Cold Wave	`null`
`drought`	Drought	`null`
`earthquake`	Earthquake	Object — nearby seismic records
`hail`	Hail	Array — historical hail reports
`heatWave`	Heat Wave	`null`
`hurricane`	Hurricane	Array — historical storm tracks
`iceStorm`	Ice Storm	`null`
`landslide`	Landslide	`null`
`lightning`	Lightning	`null`
`riverineFlood`	Riverine Flood	`null`
`strongWind`	Strong Wind	`null`
`tornado`	Tornado	Array — historical tornado reports
`tsunami`	Tsunami	`null`
`volcano`	Volcanic Activity	`null`
`wildfire`	Wildfire	Object — fire perimeters and incidents
`winterWeather`	Winter Weather	`null`

Five of these (earthquake, hail, hurricane, tornado, wildfire) pair the NRI rating with a live detail feed. The other 13 return the NRI rating only.

Proximity (14)

Counts of features near the location. value is a plain number.

{
  "value": 60,
  "details": [
    {
      /* GeoJSON features */
    }
  ]
}

details is a GeoJSON FeatureCollection of the individual records that were counted — useful if you need the specific sites, not just how many.

Slug	Topic	Counts
`brownfield`	Brownfields	EPA-tracked brownfield sites
`superfund`	Superfund Sites	Superfund / NPL sites
`toxicReleaseInventory`	Toxic Release Inventory	TRI-reporting facilities
`solidWasteLandfill`	Landfills	Solid waste landfill facilities
`ustFacility`	UST Facilities	Underground storage tank facilities
`ustRelease`	UST Releases	Recorded UST leak/release events
`oilGasWell`	Oil, Gas & Fracking Wells	Wells
`naturalGasPipeline`	Natural Gas Pipelines	Pipeline segments
`powerPlant`	Power Plants	Generating facilities
`nuclearReactors`	Nuclear Reactors	Reactor sites
`highVoltageLine`	High Voltage Lines	Transmission line segments
`cellTower`	Registered Cell Towers	Registered towers
`alternativeFuels`	EV Charging Stations	Alternative fuel / EV stations
`park`	Parks	Parks

A count of 0 is a valid answer — it means no features were found near that location. It is not an error.

Measurements (5)

Each returns a domain-specific object. These do not share a common shape — handle each individually.

`airQuality`

Annual air quality summary for the county.

{
  "metric": "Unhealthy for Sensitive Groups",
  "progressValue": 101,
  "additionalInfo": {
    "daysWithAqi": 366,
    "goodDays": 107,
    "moderateDays": 221,
    "unhealthyForSensitiveGroupsDays": 31,
    "unhealthyDays": 6,
    "veryUnhealthyDays": 1,
    "hazardousDays": 0,
    "maxAqi": 208,
    "medianAqi": 59
  }
}

details is null.

`ozone` · `pm25` · `pm10`

Current pollutant concentration at the coordinates.

{
  "measurement": { "value": 116.83, "unit": "µg/m³" },
  "rating": "Good",
  "timestamp": "2026-07-14T16:31:55.009Z"
}

Field	Meaning
`measurement.value`	Concentration
`measurement.unit`	Always `µg/m³`
`rating`	AreaHub air quality classification
`timestamp`	When the measurement was taken

details is null.

rating is an AreaHub risk rating or an official EPA AQI Category where applicable. For EPA-compliant AQI, compute the AQI from measurement.value — that raw concentration is the authoritative field.

`radon`

EPA average radon zone designation for the county.

{
  "title": "Radon Zones",
  "value": "Low",
  "caption": "Low potential",
  "description": "Radon Zones helps national, state, and local organizations implement radon-resistant building codes..."
}

details is null.

The description field is EPA’s standard advisory text. It is identical on every response and does not vary by location.

Which topics are in which bundle?

Bundle	Topics	Credits
Standard	18 natural topics	15
Enterprise	All 37	35

Any topic can also be requested individually via GET /v1/{slug}/risk for 1 credit.

Update frequency

Topic	Cadence
`alternativeFuels`	Daily
`ozone`, `pm25`, `pm10`	Near real-time
`brownfield`, `superfund`, `toxicReleaseInventory`	Rolling — records update as agencies report
All NRI hazard ratings	Per FEMA NRI release cycle
`nuclearReactors`	Static snapshot

Getting Started

Core Concepts

Reference

Natural

Proximity

Measurements

Natural (18)

Proximity (14)

Measurements (5)

`airQuality`

`ozone` · `pm25` · `pm10`

`radon`

Which topics are in which bundle?

Update frequency

Natural

Proximity

Measurements

​Natural (18)

​Proximity (14)

​Measurements (5)

​airQuality

​ozone · pm25 · pm10

​radon

​Which topics are in which bundle?

​Update frequency

Natural (18)

Proximity (14)

Measurements (5)

`airQuality`

`ozone` · `pm25` · `pm10`

`radon`

Which topics are in which bundle?

Update frequency