EPA retroactively applied the approved modification of the federal equivalent method designation for the teledyne advanced pollution instrumentation model T640 particulate matter (PM) mass monitor to all of the concentration data for PM2.5 from the T640 and T640X monitors in the EPA’s air quality system that was reported prior to the modification. 

SIP Proposal: Wisconsin (miscellaneous changes). 

SIP Proposal: Wisconsin (miscellaneous changes). 

SIP Proposal: Wisconsin (miscellaneous changes). 

SIP Proposal: Wisconsin (miscellaneous changes). 

SIP Approval: California (issuance of permits for stationary sources and the preconstruction review and permitting of major sources and major modifications in the San Luis Obispo County Air Pollution Control District). 

SIP Approval: California (issuance of permits for stationary sources and the preconstruction review and permitting of major sources and major modifications in the San Luis Obispo County Air Pollution Control District). 

SIP Approval: California (issuance of permits for stationary sources and the preconstruction review and permitting of major sources and major modifications in the San Luis Obispo County Air Pollution Control District). 

SIP Approval: California (issuance of permits for stationary sources and the preconstruction review and permitting of major sources and major modifications in the San Luis Obispo County Air Pollution Control District). 

SIP Approval: California (issuance of permits for stationary sources and the preconstruction review and permitting of major sources and major modifications in the San Luis Obispo County Air Pollution Control District).