A choropleth-free bubble map displays air quality index measurements across the United States, with circles overlaid on state boundaries rendered via `d3.geoAlbersUsa` and `d3.geoPath`. A brushed time-series histogram beneath the map uses `d3.brushX` and `d3.bin` to filter the circles by collection date, updating the map dynamically. Data comes from a CSV of ozone readings, while state outlines derive from TopoJSON via the `feature` and `mesh` APIs. SVG elements render all visuals within a React framework.