BREATH

An air quality intelligence construct for the Echelon prediction market framework, built on constructs by Soju. Ridden by Loa.

What it does

BREATH ingests real-time air quality data from PurpleAir's 30,000+ sensor network and EPA AirNow federal monitoring stations, runs prediction markets on AQI outcomes across configurable time windows, and exports Brier-scored RLMF training certificates. It is the third construct in the TREMOR → CORONA lineage, adapting the proven seismic prediction market architecture to the air quality domain.

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Why air quality

• Ground truth oracle — BREATH uses AirNow current observations as its settlement authority for low-latency market resolution (category_number >= threshold_category_number closes the market). AirNow observations are preliminary — final regulatory data lives in AQS/AirData and may differ. Normal-condition drift between AirNow and AQS is likely modest but has not been directly quantified. This is an explicit product trust-policy choice: fast settlement over regulatory finality.
• Binary structure — EPA AQI category breakpoints (51, 101, 151, 201, 301) create natural threshold gates. Every question has a crisp YES/NO resolution.
• Fast cycles — AQI updates hourly. Theatres resolve in 4–72 hours. High-frequency RLMF data generation.
• Exogenous — Predictions do not affect air quality. No reflexivity. Clean RLMF signal.
• Dense network — 30,000+ PurpleAir sensors enable sensor-to-sensor corroboration. Localized phenomena (divergence, dropout) are detectable before EPA stations report.

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Quick start

import { BreathConstruct } from './src/index.js';

const bc = new BreathConstruct({
  apiKeys: {
    purpleair: process.env.PURPLEAIR_API_KEY,
    airnow:    process.env.AIRNOW_API_KEY,
  },
  purpleair: {
    bboxes: [{ nwlng: -123.0, nwlat: 38.0, selng: -122.0, selat: 37.5, label: 'sf-bay' }],
  },
  airNow: {
    regions: [{ lat: 37.77, lon: -122.41, radius_miles: 25, label: 'sf-bay' }],
  },
});

// Open a prediction market
bc.openAqiThresholdGate({
  region_name:   'San Francisco Bay',
  region_bbox:   [-123.0, 37.5, -122.0, 38.0],
  aqi_threshold: 151,    // Will AQI reach Unhealthy (>=151)?
  window_hours:  24,
});

bc.start();                        // Begin polling (PurpleAir every 2m, AirNow every 60m)
const state = bc.getState();       // { construct, running, stats, theatres }
const certs = bc.getCertificates(); // RLMF training certificates
bc.stop();

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Architecture

src/
  index.js              BreathConstruct, SensorRegistry
  processor/
    aqi.js              NowCast, breakpoints, AQI categories
    quality.js          Channel consistency, freshness, density scoring
    uncertainty.js      Doubt pricing, threshold crossing probability
    settlement.js       Evidence class: provisional -> ground_truth
    bundles.js          EvidenceBundle assembly
  oracles/
    purpleair.js        PurpleAir API v1 (120s cadence)
    epa-airnow.js       EPA AirNow API (60m cadence)
  theatres/
    aqi-gate.js         T1: AQI Threshold Gate
    sensor-divergence.js T2: Sensor Divergence
    wildfire-cascade.js  T3: Wildfire Cascade
  rlmf/
    certificates.js     Brier scoring, certificate export
spec/
  construct.json        Constructs Network spec

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Settlement architecture

BREATH uses a two-tier oracle model:

Tier	Source	Cadence	Role
Signal layer	PurpleAir	120s	Early warning — updates Theatre position probability
Settlement authority	EPA AirNow	60m	Ground truth — resolves Theatre YES/NO

PurpleAir bundles never resolve a Theatre directly; they blend position toward thresholdCrossingProbability. EPA AirNow bundles resolve immediately based on category_number >= threshold_category_number.

AirNow bundles are always processed before PurpleAir bundles in each poll cycle to ensure settlement signals resolve markets before signal-layer updates can affect post-resolution positions.

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Theatre templates

Template	Type	Question format	Window	Resolution
aqi_threshold_gate	Binary	Will AQI reach category X in region R?	4–72h	EPA AirNow confirmation or expiry
sensor_divergence	Binary	Will sensors A and B diverge by >N AQI for K consecutive readings?	4–24h	Self-resolving (consecutive counter) or expiry
wildfire_cascade	Multi-class (5 buckets)	What fraction of sensors will exceed AQI 151?	Up to 72h	resolveWildfireCascade at window close

Wildfire cascade buckets: 0–10% | 10–30% | 30–50% | 50–70% | 70%+

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Calibration edge cases

EPA AirNow hourly delay — AirNow publishes observations on the hour, not in real-time. A theatre that should resolve at 14:00 may not see the confirming bundle until 14:05–14:15. closes_at should account for this lag; using window_hours >= 1 is always safe.

PurpleAir A/B divergence — PurpleAir sensors have two independent measurement channels. When |pm25_a - pm25_b| / avg > 0.7, the bundle is classified channel_inconsistent and does not update Theatre position. This prevents degraded sensors from corrupting market prices.

Sensor dropout — Sensors absent from the PurpleAir API response for > 2× poll cadence are flagged dropout in SensorRegistry. Dropout bundles have evidence_class: 'sensor_dropout' and are not forwarded to Theatres.

AQI breakpoint discontinuities — EPA breakpoint tables have a gap at category boundaries (e.g., PM2.5 12.0 = AQI 50, PM2.5 12.1 = AQI 51). BREATH uses <= on Chigh per the official formula. A PM2.5 of exactly 12.0 maps to AQI 50 (Good), not 51 (Moderate). Values are truncated, not rounded, per EPA specification.

Wildfire smoke transport lag — Local and regional fires (under ~200 km) can reach downwind sensors in roughly 2–12 hours. Long-range transport events can take 12–72+ hours depending on atmospheric conditions. T3 window_hours should reflect the event type: 72h is reasonable for short long-range or snapshot-style events; regional fire sieges may need 72–168h. The low-exceedance prior [0.40, 0.25, 0.15, 0.12, 0.08] reflects the observation that low-exceedance outcomes are more common; bucket probabilities converge as sensors report.

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Settlement trust policy

AirNow current observations are used as settlement authority for fast-cycle markets. These are preliminary values — AQS is the final regulatory system of record and may publish revised data. BREATH intentionally uses AirNow for low-latency settlement because market resolution speed matters more than regulatory finality for RLMF training. Normal-condition drift between AirNow preliminary and AQS final is likely modest, but has not been directly quantified in this construct. If your use case requires final regulatory truth, implement a deferred reconciliation path against AQS/AirData.

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Calibration status

Many threshold values and scoring weights in the processor pipeline are engineering estimates awaiting empirical calibration. These are marked with // TBD: empirical calibration needed in the source code. See the audit report for the full list.

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Dependencies

Zero. Node.js 20+ only.

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License

AGPL-3.0