The horizontal axis shows the number of people who live in census tracts where typical individuals have an upper-bound lifetime cancer risk above certain levels. The vertical axis shows each individual carcinogenic pollutant. To the right of each pollutant name is a symbol that indicates the relative level of overall confidence in the emissions information in the National Emissions Inventory, the ASPEN dispersion modeling, and the HAPEM5 exposure modeling for that pollutant. The horizontal bar for each chemical shows the number of people in census tracts exceeding the specified risk thresholds. For example, for arsenic (a known carcinogen), the bar on the first set of charts indicates that about 18 million people live in census tracts where the upper-bound arsenic-associated inhalation risk to a typical individual exceeds 1 in 1 million. On the second set of charts, the bar indicates that about 600,000 people live in census tracts where such risks exceed 10 in 1 million. The last set of charts shows that about 30,000 people live in census tracts where such risks exceed 100 in 1 million. Note that the populations are inclusive in that they include populations in higher risk level (e.g., for arsenic, the 30,000 exceeding 100 in a million and the 600,000 exceeding the 10 in a million threshold are also included in the counts for people exceeding the lowest risk threshold of 1 in a million).