Air Quality in Chicago, US

Yesterday AQI: Fair ⚠️ (2 of 5)

Tomorrow AQI: Fair ⚠️ (2 of 5)

UV Index: Not available

Pollutant Levels in Chicago (μg/m³)

• CO: 157.27 (0–12400 µg/m³) – Carbon Monoxide – a colorless gas that limits oxygen delivery in the body. – Produced by incomplete combustion from vehicles, stoves and wildfires. High exposure reduces oxygen transport and can be life-threatening. (Low)
• NO: 0 (0–200 µg/m³) – Nitric Oxide – reactive gas that contributes to ozone and smog formation. – Short-lived gas from fuel burning. Although unstable, it contributes to ground-level ozone and secondary pollutants. (Low)
• NO2: 4.04 (0–200 µg/m³) – Nitrogen Dioxide – toxic reddish gas, linked to asthma and lung irritation. – Strongly traffic-related pollutant. Long-term exposure is associated with asthma, reduced lung function, and cardiovascular risk. (Low)
• O3: 52.83 (0–180 µg/m³) – Ozone – harmful near the ground, formed when sunlight reacts with traffic and industrial emissions. – Unlike protective ozone in the upper atmosphere, ground-level ozone is harmful. It causes chest pain, coughing and worsens bronchitis. (Low)
• SO2: 0.35 (0–250 µg/m³) – Sulfur Dioxide – pungent gas from coal and oil combustion, triggers respiratory issues. – Major contributor to acid rain. Short-term exposure irritates eyes, nose, throat and can trigger asthma attacks. (Low)
• PM2_5: 11.38 (0–55 µg/m³) – Fine Particles (PM2.5) – microscopic dust and smoke that enter deep into the lungs. – Particles smaller than 2.5µm – from smoke, coal burning and vehicle exhaust. They bypass body filters and reach the bloodstream. (Low)
• PM10: 12.34 (0–250 µg/m³) – Coarse Particles (PM10) – larger dust, pollen and ash particles affecting breathing. – Particles up to 10µm – from construction dust, pollen and ash. Aggravates respiratory conditions like COPD and asthma. (Low)
• NH3: 3.04 (0–1000 µg/m³) – Ammonia – gas mainly from agriculture and fertilizer use. – Emitted by livestock farming, fertilizers and some industry. Can form fine secondary particles when combined with NOx and SO2. (Low)

About Air Quality in Chicago

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Chicago Pollution & Air Quality Highlights

Real-Time Air Quality: Currently, Chicago maintains a Good air quality with an AQI around 35–36. PM2.5 levels are approximately 5–7 µg/m³, and PM10 around 16–26 µg/m³ :contentReference[oaicite:0]{index=0}.

Seasonal AQI Trends: In 2025, AQI values have ranged from a low of 28 in May to a high of 54 in June — making summer the most polluted period :contentReference[oaicite:1]{index=1}.

Extreme Events: On June 5, 2025, Chicago experienced one of its worst pollution episodes in recent memory—AQI soared to ~160, becoming the second-worst air quality among major global cities due to wildfire smoke from Canada :contentReference[oaicite:2]{index=2}. The event triggered air quality alerts and health warnings across the region :contentReference[oaicite:3]{index=3}.

Environmental Justice & Long-Term Concerns: Polluted air and industrial exposures significantly contribute to chronic health disparities, including a pronounced life expectancy gap across Chicago communities :contentReference[oaicite:4]{index=4}. Grassroots groups like Neighbors for Environmental Justice (N4EJ), based in McKinley Park, are advocating against localized pollution sources such as asphalt plants, which disproportionately affect vulnerable neighborhoods :contentReference[oaicite:5]{index=5}.

Comparative Air Quality Rank: With an annual average PM2.5 of ~8.08 µg/m³, Chicago ranks around **124th** globally for least particulate pollution among cities listed — positioning it in a moderate mid-tier category :contentReference[oaicite:6]{index=6}.

Proactive Response: While carefully managing typical air quality levels, the city faces growing risks from wildfire events. Sustainable strategies and community advocacy remain critical to ensure healthier, more equitable air for all residents.

More US Cities

• Air Quality in New York
• Air Quality in Los Angeles