Seven of the eleven ozone (O3) sites operating in ME had violations of the O3 NAAQS in 1997. This compares with none of the sites reporting ozone levels above the NAAQS in 1996 and seven sites reporting at least one day above the NAAQS in 1995. In 1997, the Two Lights State Park in Cape Elizabeth and the Ocean Ave site in Kennebunkport had the highest 1-hour maximum values of 0.154 ppm or 128% of the standard.
In 1997, none of the sites in ME reported air quality levels above the particulate matter (PM10) NAAQS. The Post Office site in Lincoln reported the maximum daily concentration of 88 µg/m3 or 59% of the NAAQS. There were no violations of the annual standard in 1997. Tukey's Bridge in Portland reported the maximum annual arithmetic mean of 29 µg/m3 or 58% of the standard. The ten-year trend lines continue to show a downward trend.
There were not any violations reported at the thirteen sulfur dioxide (SO2) sites in 1997. The highest annual arithmetic mean was reported at the Shelter sites in Madawaska and Portland at 5 ppb or 17% of the NAAQS. The Shelter site in Portland reported the highest 24-hour second maximum of 23 ppb or 16% of the standard. The US Post Office site at Madawaska reported the highest 3-hour second maximum of 64 ppb or 13% of the standard. The ten-year trend graph shows that sites are well below the NAAQS and are relatively stable. Since 1992, the trend line for the Madawaska US Post Office site has shown a significant downward trend.