May 21 on The Story: Because of emissions standards that have gradually tightened across the United States, air quality should only be getting better. But even as cars and industries get cleaner, climate change is making wildfires worse, particularly in the western U.S. A recent study shows that those fires have erased two decades' worth of air quality gains in our region — and the kind of pollution that wildfires produce is particularly unhealthy, creating particulates that can travel deep into the lungs and even enter the bloodstream. As a result, being prepared for "smoke season" is more important than ever. Watch more The Story videos: http://bit.ly/watchTheStory Follow The Story on Twitter: https://twitter.com/TheStoryKGW Follow The Story on Instagram: https://instagram.com/thestorykgw