•Air toxics measurements have been collected across the
country since the 1960s as part
of various programs and measurement studies.
•National monitoring efforts have included programs
specific to air toxics:
–National Air Toxics Trends Stations (NATTS)
–Urban Air Toxics Monitoring Program (UATMP)
•Some ambient monitoring networks are designed for other purposes but also provide air toxics data:
–Photochemical Assessment Monitoring Station (PAMS)
program
–Chemical Speciation Network (CSN) which includes the
Speciation Trends Network (STN)
–Interagency Monitoring of Protected Visual Environments
(IMPROVE)
•State and local agencies have also operated long-running
monitoring operations
and special studies to understand air toxics in their communities.