# Detroit / Air Studies

Seven original p5.js compositions of a single EPA AQS daily PM2.5 snapshot, January 1–March 31, 2026. Retrieved October 19, 2026: 548 observations, seven Detroit stations, 82 absent station-days. Latest matching Detroit observation in the selected archive: March 31. This is recorded playback, not live monitoring.

The current entry point is dist/index.html. It loads gallery.js, guide.js and viewport.js. Each art-embed.html iframe loads the locally bundled p5.js, detroit-2026-data.js and instrument-art.js. Fonts: IBM Plex Mono regular and medium, bundled under OFL.

## Seven linked readings

1. Monthly seven-station register and quarter availability strip.
2. Seven categorical layered traces and pairwise Pearson correlation matrix.
3. Departure from primary quarter median, with trailing seven-day mean.
4. Twelve concentration bins filled by actual observation numerals, with quantiles.
5. Daily station comparisons on one fixed quarter scale, plus station history.
6. Chronology-to-concentration-rank connectors and first differences.
7. One circular quarter calendar: day angle and concentration spoke length.

Primary: 26-163-0097, New Mt. Herman Church, 48217, complete 90 days. Southwest 0015 has 43 readings; gaps remain absent. Units µg/m³ local conditions. Network-wide maximum 43.4. Primary median 6.45. Quantiles use type-7 linear interpolation. Correlations use overlapping reported dates. Neither is a new measurement, exposure estimate or source-attribution claim.

## Presentation

Fixed screen, swipe/arrows, seven unique designs, shared date, 650 ms soft dissolves, light/dark palette, in-frame guide. Playback begins at latest observation, then advances one actual date every two seconds. The cursor updates at display cadence (up to 60 fps); station rows settle over 800 ms with zero endpoint velocity and acceleration. Only cursor position and station rank placement move between dates; concentrations are never interpolated. Guide and hidden tabs pause playback; reduced motion starts held. Space holds/resumes, F fullscreen, S exports a PNG. The slider holds at a chosen date. Portrait uses a dedicated 1080×1440 layout; landscape uses 1920×1080. Export doubles those dimensions.

## Reproduce and verify

Download https://aqs.epa.gov/aqsweb/airdata/daily_88101_2026.zip and run scripts/extract-detroit-air-2026.py with its path. Exact filtering and archive hash are in dist/data/manifest-2026.json and dist/data-notes-2026.html. Selected unmodified EPA rows are in dist/data/epa-detroit-pm25-2026.csv.

Run node scripts/verify-instrument.cjs and node scripts/verify-presentation.cjs. Native Canvas render QA covers all seven portrait and landscape compositions. Earlier standalone 2025 prototypes remain for source history; the seven-work main presentation uses only the 2026 snapshot.
