Louisville’s streak of good air days has been broken.

The city recorded its first bad ozone day since 2012 on Friday, when levels were high enough to count as an exceedance of the federal government’s 8-hour standard.

Air Pollution Control District spokesman Tom Nord says the highest reading was 93 parts per billion at the District’s monitor on Cannons Lane.

This translates to 145 on the federal Air Quality Index, which means the air was unhealthy for sensitive groups like children, the elderly, and people with heart and lung problems.

Usually, the APCD tries to predict which days will have poor air quality, and officials issue Air Quality Alerts to inform the public. But ozone wasn’t forecast to be a problem that day, so the exceedance took regulators by surprise.

Erica Peterson is WFPL's News Director.