The heat and sunshine of our latest heat wave are driving up smog levels to heights not often seen in the last few years in Illinois, and as a result health warnings have been issued for "sensitive populations."
According to Illinois EPA, not only most of the Chicago area, but also Metro East, Champaign-Urbana, Springfield, Bloomington-Normal, Decatur are forecast to have "unhealthy" air Wednesday. Pollution levels will cause "Increased likelihood of respiratory symptoms and breathing discomfort in sensitive groups." The state recommends "Active children and adults, and people with respiratory disease, such as asthma, should limit prolonged outdoor activity."
There are basically two types of pollution of particular concern on these dog days. Smog, or ozone, is a gas that forms when many different types of pollution cook in sunlight. In unhealthy concentrations, it can cause something like sunburn on the inside of your lungs, and cause asthma attacks and other health problems. Particulate matter refers to fine particles of pollution that get past our bodies defenses and lodge deep in our lungs. These also cause respiratory problems and even death on days like today. For instance, particulate pollution from Illinois' coal-burning power plants has been linked to 1350 deaths every year in Illinois.
Unfortunately pollution levels climb with the temperatures. In addition to the heat and sunlight creating ideal conditions for smog formation, our coal-burning power plants are often generating at peak capacity on days like to day to meet electricity demand. Since these plants don't have scrubbers or other modern pollution controls, a hot day that is simply uncomfortable for most of us can be deadly for many.
You can now see maps online that show current pollution levels, and time-lapse animation that shows how and where they grow during the course of the day.
You can see the daily map for ozone (smog) at:
And for particulate matter at:
IEPA's daily conditions & forecast are at: