Current air quality outlook

Department meteorologists use monitoring data along with weather predictions to determine when and where an air quality notice is needed. The meteorologists submit daily air quality forecasts for eight Wisconsin cities to EPA's AirNow website [exit DNR]. Below is the current air quality forecast, which will be updated as needed.

Monday, May 13 - Monday, May 20, 2013

Ozone

Starting out in the Good Air Quality Index (AQI) range, then increasing to mid-to-high-Moderate range by Tuesday, followed by decreasing to low-to-mid-Moderate range for Wednesday through Monday.

Particle pollution (PM2.5)

Starting out in the Good AQI range, then increasing to mid-Moderate range by Tuesday, followed by decreasing to Good-to-low-Moderate range for Wednesday through Monday.

Weather outlook

The forecast week starts out with Wisconsin witnessing ozone and particle pollution (PM2.5) levels in the Good range as the state positioned directly under a surface high pressure system that is slowly advecting seasonably moderate temperatures and moisture into the state from the west direction. This high pressure system will continue to move eastward – quickly drawing much warmer, humid air into the area by Tuesday (May 14), which will be more conducive to the production of higher levels of ozone and PM2.5 - into the mid-to-high Moderate AQI ranges.

During early Wednesday (May 15) an advancing cold front from the North will bring some scattered rain followed by drier, cooler air into the state. This clean Canadian air mass will predominate in Wisconsin until mid-Thursday, reducing ozone and PM25 levels to the Good-to-low-Moderate range.

During late Thursday (May 16) through Sunday (May 19), Wisconsin will be positioned in a slightly unstable air mass north of a stalled front. This will result in much of Southern Wisconsin witnessing modest increases in temperature, clouds, rain and wind speeds. These conditions will yield mostly increases in PM2.5 and ozone (less so for the former) to the mid-Moderate AQI range.

During early-to-mid Monday (May 20) a cold front will pass through the state. The front-induced rain and subsequent drier, cooler air will lower ozone and PM2.5 levels back towards the Good range.

Air Quality Index (AQI) ranges

For more information, see the U.S. EPA's Air Quality Index - A Guide to Air Quality and Your Health [exit DNR].

Color coded chart showing ozone and fine particle concentration ranges for each AQI level

AQI Levels of Health Concern	Numerical Value	8-hr Ozone (ppb)	24-hr PM2.5 (ug/m3)
Good	0-50	0-59	0.0 to 12.0
Moderate	51-100	60-75	12.1 to 35.4
Unhealthy for Sensitive Groups	101-150	76-95	35.5 to 55.4
Unhealthy	151-200	96-115	55.5 to 140.4
Very Unhealthy	201-300	116-374	140.5 to 210.4
Hazardous	> 300	> 374	> 210.4