Summer in the city not always a breath of fresh air

The Milwaukee skyline on a clear evening.

The Milwaukee skyline on a clear evening.

Summer is here! The furnace is off, coats are in storage, shorts have replaced jeans, and my pale white legs blind the neighborhood every time I mow the lawn. In Wisconsin we cherish the summer months. We make up for lost time spent huddled in our homes as snow piles up outside our windows (well, not this winter). But a few days each summer our warm atmosphere can be a burden on those sensitive to poor air quality, especially when that summer breeze becomes stagnant.

Fortunately the air quality in southeast Wisconsin isn’t as bad as other parts of the world. We rarely see days when the air quality gets to a point where a normal healthy person feels the symptoms. In Mexico City 21 million people live in a valley surrounded by mountains. Even the valley floor sits around 7,300 feet above sea level (about 2,000 feet higher then Denver, CO). Exhaust from cars and factories accumulate in the bowl formed by the mountains while sunlight (low latitude + high altitude means strong solar rays) plays a major role in the chemical reaction turning certain exhausts into ozone.

In southeast Wisconsin we have our own geographic feature that can raise pollution levels. That cool lake breeze can also trap exhaust. Here’s an example:

We get a warm, humid summer day with little or no wind. The cool air over Lake Michigan drifts over land. Exhaust from cars, factories, and power plants collect in the cooler, shallow airmass but cannot rise into the warmer air above. It remains trapped under an “inversion”. These are the few days when southeast Wisconsin’s air quality becomes a concern.

For most of us this isn’t a major problem. But for asthma sufferers, those dealing with respiratory illnesses, the young, and the old it’s a different story. So how do you keep watch on air quality? With this website:

WWW.AIRNOW.GOV

This EPA website provides current conditions as well as forecast for the entire country. You can also click on Wisconsin to see our air quality close up. The site provides air quality on a numerical and color scale. 0 to 50 (green ) is good, 51 to 100 (yellow) is moderate. Both levels indicate little or no problems for everyone. 101 to 150 (orange) is unhealthy for sensitive groups.  This is the level where those with respiratory illnesses / conditions may start to feel symptoms during prolonged exposure. On very few days do we ever reach 151 to 200 (red) which is the unhealthy level. At this point anyone can feel symptoms during prolonged exposure. The levels do go higher but since we almost never exceed the levels we just covered I’ll let you explore for yourself.

One final tip, our air quality is typically at its worst in the late afternoon and early evening. If you’re planning a long jog and want to breathe easy, head out in the morning or after sunset (with flashlight of course) to keep the oxygen flowing.

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