June 6, 2011-by John Blair, valleywatch.net editor
After failing to notify the public last week when Ozone levels soared to unsafe levels on Thursday as they are required to do under an agreement with the Federal Government, the City of Evansville did issue a warning that zone levels were expected to exceed those considered safe under the National Ambient Air Quality Standards for the chemical Ozone on Tuesday June 7.
Levels significantly exceeded the health based standard on Thursday, June 2, averaging 79.38 parts per billion over eight hours at a monitor in St. Phillips, well over the standard of 75 PPB. In that event, levels reached as high as 85 PPB over one hour.
Ozone is formed when pollutants know as volatile organic compounds or VOC and Nitrogen Oxides are emitted from industries and vehicles which combine with sunlight to form the poisonous gas Ozone which has three oxygen atoms (O3). Animals, including humans require an oxygen molecule (O2) to breathe.
People can help reduce the level of ozone formation by not doing those things that release either NOX or VOC. In Evansville, for instance, people can ride public transit for free on Ozone alert days. Other measures include reducing energy use, not filling your gas tank until the evening when the sun does not cook Ozone.
Other measures like refusing to use drive-up windows are also useful.
Evansville air quality has improved over the last two decades due mostly to Federal action to reduce nitrogen oxides from the region’s numerous power plants. In the 1990s, it was not unusual for levels to be higher than 120 PPB. At that time the standard was also higher and as the standard has ratcheted down-now it is set at 75 PPB over eight hours, regional levels have improved.
EPA is due to release a new standard that will fall somewhere between 60 PPB and 70 PPB in the near future.
Much of SW Indiana has also experienced numerous days with high levels of fine particles during 2011 after having somewhat better air in 2009 and 2010 as utilities reduced their coal electric output due to the global recession. So far there have been no “alerts issued for fine particles and in fact, the State of Indiana has asked the Federal government to declare us in compliance with the fine particle standard although there is a question about the Federal “enforceability” of such a move, which Valley Watch may challenge in court.