{"version":"1.0","type":"rich","title":"Fork of Fork of Hello VizHub","description":"This heatmap shows daily mean concentrations of four air pollutants (NO2, O3, SO2, and CO) over time, with color intensity indicating pollution levels. The visualization uses D3.js v6 to read a CSV file of EPA air quality data, parse dates, and render an SVG with a color scale based on the `d3.scaleSequential` with the YlGnBu interpolator. Each cell represents a pollutant-date combination, and hovering reveals a tooltip with the exact date and value. The chart employs `d3.axisTop` and `d3.axisLeft` for labeled axes.","provider_name":"VizHub AI Studio","provider_url":"https://vizhub.com","html":"<iframe src=\"https://vizhub.com/viz/1219e7d28f2d4d49a011640da56ac625?mode=embed\" width=\"960\" height=\"500\" scrolling=\"no\" frameborder=\"0\"></iframe>","width":960,"height":500,"cache_age":3600}