As intense heat continues to move across the eastern two-thirds of the nation throughout the week, air quality will likely suffer as a result.
The cities plagued most by the heat will be St. Louis, Kansas City, Chicago, D.C. and Philadelphia.
Air quality will deteriorate in these areas, with most of the East and Midwest facing moderate health concern as a result of the air quality.
According to the air quality index at airnow.gov, a moderate health concern means that 'air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.'
Areas of more serious concern include Atlanta, Pittsburgh, St. Louis, Chicago, Detroit, Cleveland and Cincinnati.
These areas have been temporarily deemed unhealthy for particularly sensitive groups. According to airnow.gov, "Members of sensitive group may experience health effects."
The general public is not likely to be affected, the site explains.
It's not a coincidence that poor air quality usually accompanies heat waves.
"When you get a large area of high pressure promoting widespread heat, you also get a large zone of stagnant air," said AccuWeather.com Meteorologist Meghan Evans.
"Smoke and ozone can be trapped in the atmosphere, leading to poor air quality."
For the full story on the heat, click here.
The Bardarbunga volcano erupted Friday in Iceland, according to the Icelandic Met Office.
A great white shark was spotted at Duxbury Beach in Massachusetts earlier this week, forcing the evacuation of the water.
While Marie will stay well offshore from Los Angeles, it will continue to produce dangerous surf along many Southern California beaches through Friday.
It's been a tumultuous week on both the East and West coasts as two hurricanes induced rough surf and a high risk for rip currents.
There is the risk of severe weather, including tornadoes on Sunday from the northern and central Plains to part of the Upper Midwest.
After a brief cooldown late this week, very warm and humid air will bounce back during the Labor Day weekend.
Anchorage, AK (1989)
A total of 9.6 inches of rain -- wettest August on record.
New England (1816)
"Year in which there was no summer", otherwise known to weather historians as "1800 and frozen to death" killing frost once again damages sparse corn corp in northern New England...loss of this and other crops led to severe famine in much of New England that winter...and helped spur western migration in spring of 1817.
New England (1965)
A total of 2.5 inches of snow on top of Mt. Washington set an August record. Vermont had a reading of only 25 degrees, while Nantucket had a chilly 39 degrees. Earliest freeze on record at many stations.