In the land of 10,000 lakes and sky-blue waters, there appears to be a lot of dirty air. A new determination by the Environmental Protection Agency shows there’s more bad air than we first thought in Minnesota.

The EPA recently lowered the threshold for ground-level ozone or smog because scientific tests show the bad air is more harmful at lower levels than first thought. That will translate to a lot more air quality alerts this year in Minnesota.

The smog can generally occur in the summer when ozone is a threat on hot sunny days and in the cooler months when air inversions keep particulate matter suspended for longer periods of time. As a result, the state issues air quality alerts warning that the elderly, small children or those with asthma and other respiratory problems limit their exposure. But even healthy adults are supposed to limit rigorous outdoor activities.

It’s hard to imagine Minnesotans not being able to go hiking on one of the hundreds of beautiful state trails because the air isn’t good to breathe. It’s hard to imagine city softball leagues halting the game because the outfielders are hacking and wheezing.

But that’s the reality that faces us.

In fact, despite Minnesota’s reputation for a clean environment and pristine lakes, air quality is only considered “good” less than half the year in the state’s largest metro area, according to Pollution Control Agency measurements. Last year the Twin Cities had 178 good air days, 178 moderate air days, and nine unhealthy air days. Cities around the state including Rochester and Mankato had also been included in several bad air alerts last year.

The causes are not surprising, of course. We know driving, running lawnmowers and ATVs and even burning wood fires can hurt air quality. Cleaner burning fuels like ethanol have helped but, according to the American Lung Association, those benefits have mostly been offset by longer commutes, more drivers and sitting in traffic longer.

The number of air quality alerts we have this year will stand as a reminder that if we choose convenience and pleasure over doing our part to keep the air as clean as possible, we may be paying the price with our health.