IMPROVE Documentation

Data Quality Report & Advisories

Data Quality Subtle, long-term progress requires top-notch data

The goal of the U.S. EPA’s 1999 Regional Haze Rule is to return visibility to natural levels in most of the nation’s national parks and wilderness areas by the year 2064. With this 65-year timeframe, incremental changes that occur during the rule’s 5-year study periods can be so subtle that distinguishing real change from background noise requires data of the highest caliber and reliability.