Insights: Michigan City-La Porte, IN metro. Aggregated EPA AQS monitors across this Core-Based Statistical Area logged a median Air Quality Index of 43 over 365 measured days in 2025, which corresponds to a Good band and a Moderate metro-wide health grade. The monitored-day split lands at 230 Good days (63%), 123 Moderate (34%), and 11 Unhealthy-for-Sensitive-Groups (3%). The 90th-percentile AQI finished at 72 while the highest single-day reading hit 153 (Unhealthy). Metro residents averaged roughly 18.9 clean-air days per 30-day window across the reporting year.

Across the 2020–2025 trend window, the share of monitored days rated Good shifted by -15.9 points and the median AQI moved +5 points, which classifies the multi-year trajectory as worsening. The annual record contains 1 day at Unhealthy or worse. On that day, the EPA recommends that sensitive groups limit prolonged outdoor exertion. Metros with comparable AQI profiles include Ashtabula, OH (81.2% good, AQI 43); Bloomington, IN (67.7% good, AQI 43); Champaign-Urbana, IL (65.8% good, AQI 43).