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.
Dry conditions and above-normal temperatures are expected for Super Bowl Sunday in Santa Clara, California.
The new week will bring more opportunities for snow to create slick travel in the northeastern United States, starting with a winter storm set to sideswipe New England on Monday.
Cold and snow showers are in store for the New Hampshire primary on Tuesday but should not significantly impact voter turnout.
As the Denver Broncos and Carolina Panthers clash for the Super Bowl 50 title in Santa Clara, California, on Sunday, they will do so in one of the most energy-efficient stadiums in the world.
A magnitude-6.4 earthquake shook southern Taiwan shortly before 4 a.m. local time on Saturday, according to the U.S. Geological Survey.
In some circumstances climate, environmental factors and weather have led to some of the most exciting, mysterious and academically important discoveries of all time.
Albuquerque, NM (1986)
6 inches of snow.
Louisville, KY (1998)
22.4 inches of snow (4th-6th).
Lee-Shore snowburst dropped an estimated 6ft.