•Providing air toxics data of sufficient quality to identify trends, characterize ambient concentrations in representative areas, and evaluate air quality
•Providing tools and guidance that enable consistent, high certainty measurements.
•Using these consistent measurements to facilitate measuring progress towards national emission and risk reduction goals.
•Considering all NATTS sites to be NCORE level 2 sites, thereby providing rich data sets to address
NCORE level 2 sites are “backbone” sites providing consistent, long-term data for multiple