A scatter plot displays air quality measurements, with dropdown menus allowing users to select which pollutant attribute (pollutant, PM10, ozone, or PM2.5) drives the x- and y-axes. Built with React and D3 v5, the visualization uses `scaleLinear`, `extent`, and `max` from d3 to map data to SVG coordinates. Axes are rendered by custom React components, and circles include native SVG `<title>` tooltips. Data loads asynchronously from a CSV using d3's `csv` method.