Elevated fine particle air pollution levels were recorded across east-central Iowa yesterday. Levels have fallen, and are expected to continue to fall through the remainder of today, as a cold front moves through the state and winds increase.
The EPA’s 24-hour health threshold for fine particles in the air is 35 micrograms per cubic meter. Several monitoring sites recorded exceedances of the health threshold Dec. 3. Monitors in Cedar Rapids, Clinton and Iowa City recorded 24-hour fine particle levels of 40.0, 36.8 and 36.9 respectively. Monitors in Davenport recorded values of 40.4 and 37.7.
At 10 a.m. today, daily average levels ranged from 5.6 in Emmetsburg up to 27.2 in Davenport. Levels in eastern Iowa are expected to continue to improve when the cold front passes through this evening.
Monitors that have exceeded EPA health levels this year can be found at: www.iowadnr.gov/Portals/idnr/uploads/air/insidednr/monitoring/iowa_naaqs_2013.pdf .
Fine particles are emitted by vehicle traffic and other combustion sources and are formed by chemical reactions in the atmosphere. Stagnant air masses do not allow fine particles to disperse, so pollutant levels rise.
EPA’s national air quality map is available online at www.airnow.gov.
For more informaction, contact Chris Maiers, Air Quality Ambient Monitoring, 515-494-6412.