Characterization of Fine Particle Concentrations in an Engine Plant

Transcription

1 Characterization of Fine Particle Concentrations in an Engine Plant William Heitbrink, Ph. D. CIH 1 Thomas Peters, Ph. D. 1 Douglas Evans, Ph. D 2 Thomas Slavin 3 1 University of Iowa, Iowa City, IA; 2 CDC (NIOSH), Cincinnati, OH; 3 Navistar-International, Warrenville, IL.

2 Acknowledgements We greatly appreciate the support and collaboration from the International Truck and Engine Corporation, The United Automobile Aerospace and Agricultural Implement Workers of America (UAW), and NIOSH.

3 Background Epidemiological studies link adverse health effects with inhalation of respirable particles Respiratory: inflammation, asthma, etc. Cardiovascular: heart-rate variability, increased BP Toxicological studies show ultra fines (d < ~150 nm) more toxic than larger particles

4 Goal To characterize very fine particle concentrations in an engine machining and assembly center

5 Mapping Procedures Verify instruments operating similarly Sample one-minute at each position Coarse grid (60 points) Fine grid (200 points) Compute number / mass concentration Very fine particle number concentration estimate = CPC OPC (300 nm 1 µm) Respirable mass estimated from OPC Create aerosol maps

6 Laptop Mobile Sampling Cart Aerosol Photometer Respirable PM-2.5 Pumps Battery Charger Diffusion Charger Diluter Power Inverter Battery TSI CPC nm 1 um 1 channel Condensation Particle Counter Optical Particle Counter Grimm PDM µm 15 channels

7 Engine Machining and Assembly Center 1000 engines produced per day New Enclosures; Gas Heat Retrofitted Enclosures; Steam Heat Empty Cam Block Head Rod Outside Crank Assembly 870 ft x 1,200 ft 10 6 ft 2

8 enclosures in the CAM-Crank area of the plant were re open; allowing aerosol to escape into the plant.

9 Block-Head-Rod Lines had nearly complete enclosure appeared to completely control the mist generated by machining operations.

10 Click link to the portrait slides/

11 Findings From Maps Very fine particle concentration varies with season and area. Season affect due to natural gas burners Some generation of fines in the older area of the plant Respirable mass concentration varies with area, but not season. Mostly generated in the CAM Crank area due to incomplete enclosures.

12 Source Characterizations August 2005, February 2006 ELPI was used to measure particle number distributions OPC used to infer mass distributions. Locations In air handling units during burner operations On roof, near inlets to air handling unit Near selected machining operations.

13 Gas Heaters Major Ultrafine Source Low Efficiency Filters Outside Air Exhaust Air Gas-Fired Burners Chiller Plant Ceiling Dampers to control Fraction of recycle And outside air Return Air Conditioned Air to Plant 18 Air Handing Units 50,000 cfm each

14 Inside Air Handling Unit Direct-fire natural gas burner Dampers control fraction of recycled air and outside air

15 Burner Operation Increases Very Fine Particle Concentration In Supply Air very fine particle concentration (partilcles/cm 3) Burner on Burner off roof

16 Burner Operation Does Not Affect Respirable Aerosol Concentration In Air Supplied To Plant respirable aerosol (mg/m 3 ) Burner on Burner off roof

17 Burner Produces Aerosol Under 0.05 µm C n / ln(d p ), particles/cm 3 10x x x x x x10 6 4x10 6 3x10 6 2x10 6 1x10 6 Instrument: ELPI burner on-after chiller burner on before chiller diameter (µm)

18 Burner Findings Burner operation creates large quantities of particles smaller than 0.05 µm. Burner does not affect respirable mass concentration Background outside plant may affect upon very fine particle concentration during warm weather. Inadvertent recirculation from air cleaners?

19 Transfer to portrait slides

20 Findings From Source Characterization Burner operation creates large quantities of particles smaller than 0.05 µm. Some machining operations can produce particles smaller than 0.1 µm. During summer operations, the very fine particle concentration in the incoming air is important. Air pollution? Inadvertent recirculation?

21 Discussion and Conclusions Direct-fire, natural gas heaters generate very fine particles. Some machining operations can generate very fine particles. Possible mechanisms: Evaporation/condensation? Spray atomization? Thermal decomposition? Respirable mass may not be a good indicator of very fine particle concentration.

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