Heavy smoke from wildfires more frequently chokes the skies over the Western United States, but cities farther to the east ...

For this study, researchers tracked wildfire smoke using satellite data and ground-level measures of particle ... The smokiest city with more than a million people was Sacramento, Calif.

NEW YORK — Residents across New York City awoke to a thin brown haze ... temperatures led to an inversion that trapped smoke near the ground. Several air quality readings have degraded into ...