Methodology

Last updated: January 2026

Quick summary

Arounded is a free map for tracking environmental signals over time. We use public datasets, label sources clearly, and prefer “unknown” over guessing. If you’re making an urgent decision (health, evacuation, emergencies), always rely on official alerts first — Arounded is designed for context and patterns.

Smoke
NOAA daily plume polygons
Air + Weather
Facilities
EPA datasets (layer-dependent)
Maps
Mapbox tiles + geocoding

What Arounded shows

Arounded helps you understand what’s happening around a location — and what’s been happening over time. Instead of only showing “right now,” it’s built to surface patterns like smoke days over the last month or repeated AQI spikes.

We pull from public sources and present the results on a map. In a few places, we compute simple derived signals (like “smoke day”) to make history consistent and easier to interpret.

Smoke

Source: NOAA HMS Smoke Product

Smoke plume data comes from NOAA's daily satellite analysis. It's published as GeoJSON polygons and commonly includes density categories (Light, Medium, Heavy), when available in the source dataset.

Arounded refreshes smoke data daily and displays it as an overlay on the map.

What “smoke day” means

A "smoke day" means a NOAA smoke plume polygon overlapped a saved location at least once on that day. We calculate this using geometry-based detection (point-in-polygon), then log it daily for saved places.

This is a consistent signal for pattern tracking — it does not measure indoor exposure or duration.

Notes: Satellite interpretation can miss low-level smoke or fast-changing events. Conditions can change quickly within a day.

Air quality

Source: Open-Meteo Air Quality API

Arounded shows PM2.5 and US AQI values for a location. PM2.5 refers to fine particulate matter. US AQI is a standardized scale that converts pollutant levels into a single number that's easier to interpret (higher = worse air quality).

For saved places, we log daily values once per day so you can see history over the last 7/30 days.

Notes: Air quality values can be based on a mix of station observations and models. Local micro-conditions may differ from the nearest estimate.

Weather

Source: Open-Meteo Weather API

Weather includes temperature and daily highs/lows (and may include wind/humidity depending on the view). These values help explain context around air quality and smoke conditions.

Notes: Forecasts are model-based and can vary by elevation, proximity to water, and urban heat effects.

Facilities & data centers

Source: EPA Facility Registry Service (FRS)

Facility locations come from EPA datasets (coverage depends on the layer). These may include regulated facilities, monitoring sites, and other environmental infrastructure. We display locations and basic attributes provided in the source data.

Notes: EPA datasets can lag real-world changes (openings/closures) and records may be incomplete in some areas.

Compiled from multiple public sources. Coverage varies by region.

Arounded highlights data center locations as a focused infrastructure layer. Data center records may come from a mix of public datasets and maintained listings, depending on what's available for a region.

Notes: "Data center" can mean different things (hyperscale vs. smaller facilities). If you're using this for advocacy or planning, we recommend verifying a specific site through local permitting, zoning, or operator documentation.

Update frequency

Different layers update at different intervals:

  • Smoke layer: refreshed daily (NOAA daily plume update)
  • Saved place history: logged once per day for your saved places
  • Facilities: updated when source datasets refresh (varies by dataset)
  • Air + weather: fetched on demand when you view a location (Open-Meteo)

How to use Arounded responsibly

Arounded is best for context and patterns — not split-second decisions. If you're deciding whether to evacuate, whether it's safe to be outdoors during an emergency, or managing serious symptoms, always use official alerts and medical guidance first.

For everyday planning, the history view can be genuinely helpful: smoke days over the last month, repeated AQI spikes, or seasonal changes in heat and air quality.

Limitations

Environmental conditions can change quickly. Any map-based view is an approximation of a complex world. Arounded prioritizes consistency and transparency over "perfect precision."

Smoke data is based on satellite interpretation and reflects where plumes were identified. "Smoke day" means plume overlap — it does not measure exposure duration, indoor air quality, or personal health impact.

Air quality estimates may differ from on-the-ground measurements, especially at very local scales. Facilities and infrastructure layers can contain omissions or out-of-date records depending on the source.

If something looks wrong, treat it as a signal to verify — not a final answer.

Not medical advice

Arounded provides environmental information for educational purposes. It is not medical advice.

If you have health concerns related to smoke or air quality, follow guidance from a healthcare professional and official public health agencies.