The Mid Ohio Regional Planning commission has issued an air quality alert for today. The hot, dry weather will combine with pollutants from vehicles and factories to produce unhealthy levels of smog. The alert covers Delaware, Franklin, Knox, Licking and Madison counties.The agency advises the elderly, young children, and those with breathing difficulties to monitor and limit their outdoor activities. This is the 12th air quality alert issued this year, equaling the total from all of last summer.