Hennepin, Minnesota vs Cook, Illinois Air Quality
Side-by-side air quality comparison using 10 years of EPA monitoring data. Hennepin, Minnesota has the edge with an Air Quality Grade of C (64/100).
| Metric | Hennepin, Minnesota | Cook, Illinois |
|---|---|---|
| Air Quality Grade | C (64/100) | D (49/100) |
| Current Median AQI | 52 (Moderate) | 57 (Moderate) |
| 5-Year Average AQI | 47 | 57 |
| 10-Year Trend | ↓ Improving (0) | → Stable (-2) |
| Unhealthy Days/Year | 4 | 18 |
| Primary Pollutant | Fine Particulate Matter (PM2.5) | Fine Particulate Matter (PM2.5) |
Side-by-Side Analysis
Hennepin, Minnesota outperforms Cook, Illinois on overall air quality with a Grade C (64/100) versus D (49/100). Hennepin, Minnesota's 5-year median AQI of 47 sits in the "Good" range, while Cook, Illinois averages 57 ("Moderate") — a 10-point gap that shows up consistently in year-over-year readings, not just in a single year.
The two cities are moving in opposite directions: Hennepin, Minnesota is improving (-0.6 AQI/yr) while Cook, Illinois is stable (-0.1 AQI/yr). Over time, today's ranking may flip if these trends hold.
What's in the Air
Both cities share the same dominant pollutant: Fine Particulate Matter (PM2.5). These cities' dominant issue is fine particulate matter — typically driven by combustion (vehicles, wildfire smoke, industry, residential wood burning). PM2.5 is the air pollutant most strongly linked to long-term cardiovascular and respiratory disease because the particles penetrate the bloodstream.
Health Implications
Over a 5-year window, Hennepin, Minnesota averages roughly 4 unhealthy air days per year (AQI above 100, where sensitive groups should limit outdoor exertion) versus 18 for Cook, Illinois. That 14-day gap matters most for residents with asthma, COPD, heart disease, or pregnancy — and for outdoor workers, who accumulate the most cumulative exposure. The city with fewer unhealthy days offers a meaningfully different baseline risk picture for sensitive populations. For long-term residents, the cleaner-air city is associated with measurably better outcomes on respiratory disease, cardiovascular events, and life expectancy — Harvard cohort research consistently finds 0.5 to 1.0 years of additional life expectancy for each 10-µg/m³ reduction in long-term PM2.5 exposure.
Frequently Asked Questions
Hennepin, Minnesota has better air quality with a Grade C (64/100) compared to Cook, Illinois's Grade D (49/100). Hennepin, Minnesota has a current median AQI of 52 and is improving over the past decade.
Hennepin, Minnesota averages 4 unhealthy air days per year (5-year average), while Cook, Illinois averages 18. Unhealthy days are those when AQI exceeds 100 and sensitive groups should limit outdoor activity.
Hennepin, Minnesota's primary pollutant is Fine Particulate Matter (PM2.5), while Cook, Illinois's is Fine Particulate Matter (PM2.5). Both cities share the same dominant pollutant.
Source: EPA Outdoor Air Quality Data, 2026.
Comparing Hennepin, Minnesota and Cook, Illinois on U.S. air quality and AQI history requires lining up the underlying EPA Air Quality System data data side by side. The table above runs the comparison on the canonical fields; the narrative below identifies the factor or factors that drive the most meaningful difference between the two.
For households or analysts using this comparison as a decision input, the right framing is usually not "which is better" in aggregate but "which is better for the specific decision in front of you." EPA Air Quality System data captures the raw data; the framing depends on whether the question is investment, residency, planning, or research.