We may have been lulled by the wet, relatively mild spring we've had so far, but yesterday provided a reminder that summer is fast approaching - and with it worsening air quality, aka "smog."  Time to pay attention, especially if you have compromised breathing already.

Ozone in the air reached "Code Orange" unhealthful levels on Monday in Padonia, north of Baltimore city, for children and adults with respiratory and heart ailments, who are likely to be more sensitive to pollution.

It's not uncommon to have "bad air" days in summer, as strong sunlight is all that's needed to make ozone from the pollutants spewing from car and truck tailpipes, power plant smokestacks and a whole range of other sources.

Ozone is a good thing in earth's upper atmosphere, where it helps shield us from skin cancer by blocking out some of the sun's ultraviolet rays; closer to the ground, though, it can "burn" our lungs and bronchial passages if inhaled in the air we breathe.  High levels of ozone can cause coughing and wheezing, shortness of breath, chest pain, headaches and nausea, and eye and throat irritation. Even for health adults, exercising in ozone-polluted air may make it painful to take deep breaths. 

Last year, there were 25 bad ozone days in the Baltimore area.  Normally, they peak in June and July, though they can happen earlier, in May or even sooner.  The first Code Orange days this year actually hit during a brief warm spell on April 25 and 26.

When ozone levels soar on sweltering days, it's best to keep kids - and yourself - indoors, especially if you have health conditions already.  You can get daily air-quality forecasts and even check ozone levels real-time here.