Air pollution can create a haze that affects visibility, dulling national park views by softening the textures, fading colors, and obscuring distant features.

Air pollution remains a significant threat to U.S. national parks in 2026, with the National Parks Conservation Association (NPCA) reporting that nearly 97% of parks suffer from unsatisfactory levels of pollution. The most visible effect is haze, which consists of fine particulate matter from power plants and vehicles; on average, park visitors miss out on roughly 50 miles of scenery due to reduced visibility. Furthermore, nitrogen and sulfur deposits from the air acidify soil and water, harming delicate alpine ecosystems and native fish populations. Ground-level ozone (smog) also stunts the growth of trees and plants, particularly in heavily impacted areas like Sequoia and Kings Canyon. While recent regulations have reduced emissions from coal plants, wildfires have become a leading source of smoke-related pollution, threatening both the health of visitors and the integrity of the natural landscapes.