Wednesday, June 25, 2008

Two Air Quality Alerts in a Row...

I've heard from a lot of people lately about the air quality issues. Fortunately, this is a topic I am well-versed in (for the last 20 years) and I'd like to bring my expertise to this important issue on Commission.

The EPA determines the relative health hazard by looking at two pollutants- ozone and find particulate matter (PM). The data is available in near real-time on the EPA's web site (, and some links on there explain in detail what the different alert levels mean and how they are computed. An orange day ("Unhealthy for Sensitive Groups") mean that people with asthma, COPD, etc should stay indoors, and everyone should limit strenuous outdoor activity.

Knox County also has a phone number you can call and get the latest AQI without a computer. I believe it is 215-5925 (but it doesn't seem to be working this AM).

Two things that aren't on the EPA site, though:
  1. The Air Quality Index (AQI) is calculated by looking at the risk of the two pollutants independently, and taking the highest of the two (and discarding the lower entirely). Thus, not all "yellow" or "orange" days are really the same. There's a big difference between a day with "orange" ozone / "orange" particulate and a day with "orange" ozone and "green" particulate. There are studies that show synergistic effects, so my advice to anyone with breathing disorders or heart disease should try to find the concentration levels of ozone and PM and look at them both during yellow or orange alert days.
  2. The ozone standard for compliance was lowered from 80 parts per billion to 75, but it was noted at the EPA conference that the science pointed them to lowering the standard all the way down to 60. Of course, this was politically untenable, so the EPA compromised with 75. But it was interesting to note that the studies showed, for the first time, damage to the respiratory system of healthy adults at levels over 60 ppb. Thus, this is no longer an issue just for people with asthma, COPD, etc.
What can we do? Other areas have programs that click into place on ozone action days encouraging carpooling, lowering highway speed limits in down, anti-idling regulations, dropping the bus fare (or making rides free). There's a lot of good programs in other counties we can examine and consider adopting. As an individual, it's quite astounding what changing your house lights over to compact fluorescents (CFL) will do (less power generation = less ozone). Reduce unnecessary car trips on hot summer days (not a problem with gas prices).

Be safe.

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