Rhode Island has discontinued lead (Pb) monitoring in the state due to the extremely low levels of lead concentrations monitored over the past few years. In 1997, three sites were monitored for nitrogen dioxide (NO2). Two of these sites were photochemical assessment monitoring stations (PAMS) and operated during the summer season. None of the sites experience any violations of the NAAQS. The Rockefeller Library site in Providence reported the highest annual arithmetic mean of 0.025 ppm or 50% of the NAAQS. The ten-year trend graph shows that NO2 levels have remained stable.
In 1997, of the four ozone sites, only the Alton Jones site experience a violation of the NAAQS. The Alton Jones site had the highest 1-hour second maximum value of 0.115 ppm or 96% of the NAAQS. None of the sites reported levels above the NAAQS in 1996. It appears that ozone levels have remained fairly constant over the past few years.
None of the PM10 sites in RI had any violations of the annual or 24-hour standards in 1997. The Allens Avenue site had both the highest 24-hour second maximum value of 62 µg/m3 or 41% of the standard, and the highest annual arithmetic mean of 33 µg/m3 or 66% of the standard. The ten-year trend graph shows no discernable trends at either Providence or Pawtucket.
Three sites were monitored for sulfur dioxide (SO2) this year. There were no violations of the annual, 24-hour, or 3-hour NAAQS at any of the three sites. Rockefeller Library in Providence reported the highest annual arithmetic mean of 8 ppb or 27% of the NAAQS. Rockefeller Library also reported the highest 24-hour second maximum of 37 ppb or 26% of the NAAQS. Both Providence-Rockefeller Library and Pawtucket-Summit Street reported the highest 3-hour second maximum of 61 ppb or 12% of the NAAQS. The ten-year trend graph shows a downward trend.