This map plots EPA air quality monitoring sites across the United States, with each site represented by a circle at its geographic coordinates. The visualization uses `d3.geoAlbersUsa` projection with `d3.geoPath` to render state boundaries and interiors as SVG paths, while React manages the component hierarchy. The site data, loaded via `d3.csv`, includes latitude, longitude, and AQI values, though the circle radius is currently fixed at 5 pixels despite a `scaleSqrt` being configured. The map uses a teal color scheme for states with light gray interior borders, and semi-transparent blue circles for the monitoring locations.