Executive Summary

Introduction

National and Regional Analyses

Populations at Risk in the U.S.

• Table 1: Estimated Populations at Risk from Short-term Particle Pollution (24-Hour PM2.5)
• Table 1a: Estimated Populations at Risk from Year-Round Particle Pollution (Annual PM2.5)
• Table 1b: Estimated Populations at Risk from Ozone 

Most Polluted Cities in the U.S.

• Table 2: People at Risk in 25 U.S. Cities Most Polluted by Short-term Particle Pollution (24-Hour PM2.5)
• Table 2a: People at Risk in 25 U.S. Cities Most Polluted by Year-Round Particle Pollution (Annual PM2.5)
• Table 2b: People at Risk in 25 Most Ozone-Polluted Cities

Most Polluted Counties in the U.S.

• Table 3: People at Risk in 25 Counties Most Polluted by Short-term Particle Pollution (24-Hour PM2.5)
• Table 3a: People at Risk in 25 Counties Most Polluted by Long-term Particle Pollution (Annual PM2.5)
• Table 3b: People at Risk in 25 Most Ozone-Polluted Counties

Most Polluted Counties in Each State

• Table 4: Counties with the Worst Particle Pollution (PM2.5 24-Hour and Annual Averages) in Each State
• Table 4a: Counties with the Worst Ozone Air Pollution in Each State

Cleanest Cities

• Table 5: Cleanest U.S. Cities for Short-term Particle Pollution (24-Hour PM2.5)
• Table 5a: Top 25 Cleanest U.S. Cities for Long-term Particle Pollution (Annual PM2.5)
• Table 5b: Cleanest U.S. Cities for Ozone Air Pollution

Cleanest Counties

• Table 6: Cleanest Counties for Short-term Particle Pollution (24-Hour PM2.5)
• Table 6a: Top 25 Cleanest Counties for Long-term Particle Pollution (Annual PM2.5)
• Table 6b: Cleanest Counties for Ozone Air Pollution

Health Effects of Ozone and Particle Pollution