Appropriate Methods to Monitor Urban Visibility for Use in a Secondary PM Standard

摘要

The visual appearance of and ability to see through the atmosphere are the primary ways that people judge air quality conditions, and visual air quality is known to be influential in affecting public wellbeing. Human observations, plus optical and scene characterization methods to monitor visibility have existed for many decades and continue to be developed. The relationships between air quality and visibility are much better known than for other air pollution effects (e.g., health effects). Despite these facts, there are no widely accepted standard approaches that adequately monitor visual air quality in populated areas.