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 Action Day
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Air Quality Index (AQI)
observed at 14:00 EDT
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Health Message: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors. |
Note: Values above 500 are considered Beyond the AQI. Follow recommendations for the Hazardous category. Additional information on reducing exposure to extremely high levels of particle pollution is available here. |
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| Air Quality Index (AQI) |
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Moderate |
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Health Message: Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors. |
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| Air Quality Index (AQI) |
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Unhealthy for Sensitive Groups |
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Health Message: Active children and adults, and people with lung disease, such as asthma, should reduce prolonged or heavy exertion outdoors. |
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ACTION DAY |
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Forecast Discussion: FORECAST SUMMARY: Thursday, May 24th, 2018 through Friday, May 25th, 2018 ...AIR QUALITY ACTION DAY ADVISORY FOR FRIDAY MAY 25TH… THE ACTION DAY ADVISORY IS IN EFFECT FOR THE FOLLOWING MICHIGAN COUNTIES: IN WEST MICHIGAN: ALLEGAN... BERRIEN… CASS… KENT... MUSKEGON... OTTAWA… AND VAN BUREN COUNTIES IN SOUTHEAST MICHIGAN... LENAWEE… MACOMB... MONROE... OAKLAND... ST. CLAIR... WASHTENAW... AND WAYNE COUNTIES Ozone: 8-hour Ozone concentrations are expected to mostly Moderate Thursday with isolated USG possible. More widespread USG levels are possible Friday. PM-2.5: 24-hour Fine Particulate concentrations will range from upper Good to middle Moderate. FORECAST DISCUSSION: High pressure positioned southeast of the state will produce plenty of sunshine and warm temperatures the next two days. Temperatures warm both at the surface and upper levels and that, coupled with plenty of sunshine and a southwest wind, will produce an environment conducive for ozone development. Levels begin increasing Thursday, but most locations should remain Moderate. As levels build into Friday, more widespread USG is anticipated both along the west Michigan lakeshore mainly from Muskegon south, and in southeast Michigan. With the threat for higher ozone concentrations, we have decided to issue an Action Day for ozone Friday in those locations. Outside of those areas, Moderate ozone is expected. Fine particulate will also begin climbing and with readings from upper Good to middle Moderate. EXTENDED FORECAST: Models show increased moisture as we start the holiday weekend and the question is when/where storms may develop. This leads to a tricky forecast as areas that remain dry could see increased pollution levels. With the uncertainty, we are holding another regional forecast call Friday to discuss expected pollution for the coming holiday weekend. Forecast updated by Stephanie Hengesbach: Thursday, May 24th, 2018 Next forecast update: Friday, May 25th, 2018 |
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AQI: Good (0 - 50)
AQI: Moderate (51 - 100)
AQI: Unhealthy for Sensitive Groups (101 - 150) 
AQI: Unhealthy (151 - 200) 
AQI: Very Unhealthy (201 - 300)
AQI: Hazardous (301 - 500)
National Parks/Monuments
Tribal Boundaries
