Your Body Almanac

Illinois

High-radon soil, dark winters, cold snaps and deadly summer heat waves.

More than half of Illinois counties have high radon potential. Winters are cold with weak sun, and summer heat waves can be deadly; the 1995 heat wave was Chicago's worst weather-related disaster.

01

Radon

EPA places 56 of Illinois' 102 counties in Zone 1, its highest radon-potential category, and only three in the lowest zone. Radon is the second leading cause of lung cancer in the US. A test kit is cheap, and it is the only way to know your home's level.

SourcesEPA Map of Radon Zones and Supplemental Information (US EPA)Health Risk of Radon (US EPA)
Test your home for radonAs neededRadon is invisible and odorless, so a simple test is the only way to know your level. Fix it at 4 pCi/L or higher.
02

Weak winter sun and vitamin D

Chicago is at almost exactly Boston's latitude, where a classic study found winter sun made no vitamin D in skin from November through February. Southern Illinois is farther south and fares a bit better, but most of the state gets little vitamin D from sunlight for a few months.

SourcesInfluence of season and latitude on the cutaneous synthesis of vitamin D3 (Webb, Kline and Holick, 1988)Vitamin D — Health Professional Fact Sheet (NIH Office of Dietary Supplements)
Get vitamin D from foodDailyEat fatty fish, fortified milk and UV-exposed mushrooms so you are not relying on the sun alone. Ask your doctor about vitamin DYearlyIf you get little sun or few vitamin D foods, ask at your checkup whether testing or a supplement makes sense for you.
03

Summer heat waves

A humid heat wave in July 1995 led to 465 heat-related deaths in Chicago. Most of those who died were older people, many of them isolated and living alone. Humid heat, hot nights and city pavement are the combination to watch for.

SourcesNatural Disaster Survey Report — July 1995 Heat Wave (NOAA National Weather Service)Heat Safety and Preparedness (National Weather Service Chicago)
Stay safe in the heatAs neededOn hot days, drink water often, take breaks in the shade and plan hard work for the cooler parts of the day. Rehydrate when you sweatAs neededDrink regularly during hot work or long workouts, and add electrolytes when you sweat for more than two hours. Make time for peopleWeeklyReach out to friends, family or neighbors each week, and build in regular shared activities.