EPA is extending the start date for the updated Photochemical Assessment Monitoring Stations (PAMS).  The PAMS network measures ozone, the pollutants that form it, and meteorology to better understand ozone formation and to evaluate national and local ozone-reduction options. On October 1, 2015, in conjunction with establishing the 2015 National Ambient Air Quality Standards for ground-level ozone, EPA took final action to streamline and modernize the PAMS network.  This revision extends the start date to June 1, 2021.  This action gives states two additional years to acquire the necessary equipment and expertise needed to successfully make the required measurements at the required PAMS sites.  

• Final Rule: Extension of Start Date for Revised Photochemical Assessment Monitoring Stations (PDF)(14 pp, 254 K)
  (Pre-publication Federal Register Notice)
• Fact sheet: Final Extension of Start Date for Revised Photochemical Assessment Monitoring Stations (PDF)(2 pp, 143 K)