title: Uncontrolled combustion of shredded tires in a landfill -Part 2: Population exposure, public health response, and an air quality index for urban fires.
abstract: The Iowa City Landfill in eastern Iowa, United States, experienced a fire lasting 18 days in 2012, in which a drainage layer of over 1 million shredded tires burned, generating smoke that impacted the surrounding metropolitan area of 130,000 people. This emergency required air monitoring, risk assessment, dispersion modeling, and public notification. This paper quantifies the impact of the fire on local air quality and proposes a monitoring approach and an Air Quality Index (AQI) for use in future tire fires and other urban fires. Individual fire pollutants are ranked for acute and cancer relative risks using hazard ratios, with the highest acute hazard ratios attributed to SO2, particulate matter, and aldehydes. Using a dispersion model in conjunction with the new AQI, we estimate that smoke concentrations reached unhealthy outdoor levels for sensitive groups out to distances of 3.1 km and 18 km at 24-h and 1-h average times, respectively. Modeled and measured concentrations of PM2.5from smoke and other compounds such as VOCs and benzo[a]pyrene are presented at a range of distances and averaging times, and the corresponding cancer risks are discussed. Through reflection on the air quality response to the event, consideration of cancer and acute risks, and comparison to other tire fires, we recommend that all landfills with shredded tire liners plan for hazmat fire emergencies. A companion paper presents emission factors and detailed smoke characterization.
authors.affiliation: Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242.
authors.forename: Ashish
authors.initials: A
authors.lastname: Singh
authors.affiliation: Public Policy Center, University of Iowa, Iowa City, IA 52242.
authors.forename: Scott N
authors.initials: SN
authors.lastname: Spak
authors.affiliation: Department of Chemistry, University of Iowa, Iowa City, IA 52242.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Stone
authors.affiliation: Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242.
authors.forename: Jared
authors.initials: J
authors.lastname: Downard
authors.affiliation: Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242.
authors.forename: Robert
authors.initials: R
authors.lastname: Bullard
authors.affiliation: Public Policy Center, University of Iowa, Iowa City, IA 52242.
authors.forename: Mark
authors.initials: M
authors.lastname: Pooley
authors.affiliation: Johnson County Department of Public Health, Iowa City, IA.
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Kostle
authors.affiliation: State Hygienic Laboratory-Coralville, University of Iowa, Coralville, IA 52241.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Mainprize
authors.affiliation: State Hygienic Laboratory-Coralville, University of Iowa, Coralville, IA 52241.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Wichman
authors.affiliation: Department of Occupational and Environmental Health, University of Iowa, Iowa City, IA 52242.
authors.forename: Thomas
authors.initials: T
authors.lastname: Peters
authors.affiliation: Johnson County Department of Public Health, Iowa City, IA.
authors.forename: Douglas
authors.initials: D
authors.lastname: Beardsley
authors.affiliation: Chemical and Biochemical Engineering, University of Iowa, Iowa City, IA 52242 ; IIHR Hydroscience and Engineering, University of Iowa, IA.
authors.forename: Charles O
authors.initials: CO
authors.lastname: Stanier
keywords: Iowa City; air quality index; hazard ratio; tire fire