{"version":"1.0","type":"rich","title":"Two Decades of Pollution in US with menus","description":"This interactive choropleth map displays PM2.5 concentration across US counties for each year from 2000 to 2004, with a React-driven dropdown menu to switch between annual datasets. The visualization uses Vega-Lite’s `markGeoshape` with an Albers USA projection, joining county-level pollution data from a CSV via `vl.lookup`, and encodes concentration values with a clamped color scale. React’s `useState` and a custom `Dropdown` component control the selected year, triggering a re-render of the Vega view. The underlying data comes from the PM2.5 by County dataset, with styling drawn from d3’s `hcl` color utilities.","provider_name":"VizHub AI Studio","provider_url":"https://vizhub.com","html":"<iframe src=\"https://vizhub.com/viz/619549533f824270948a933056a63986?mode=embed\" width=\"960\" height=\"500\" scrolling=\"no\" frameborder=\"0\"></iframe>","width":960,"height":500,"cache_age":3600}