The Health Effects of Combustion Generated Ultrafine Particles

1
The Health Effects of Combustion Generated
Ultrafine Particles
Angelina Padilla, David Baston, Bing Guo,
Michelle Werner, Cort Anastasio, Michael
Denison, Ian Kennedy Department of Mechanical
Engineering Department of Environmental
Toxicology Department of Atmospheric Science
University of California, Davis, CA 95616
Abstract Dioxin-like compounds, including
polychlorinated dibenzo-p-dioxins, are generated
in combustion processes and can be adsorbed and
transmitted by particulate matter such as soot
particles generated in the combustion processes.
Transformation and/or transportation of the
dioxin-like compounds carried by soot particles
in the earths atmosphere can affect toxicity
levels and have subsequent health effects. In
order to discover the effect of the atmosphere on
polyaromatic hydrocarbons and dioxins transformed
by reactions induced by sunlight and other
factors in the atmosphere, samples were generated
under specific, controlled, combustion conditions
and were analyzed prior-to and after an
atmospheric aging process. In the atmospheric
aging chamber, soot samples were exposed to
controlled levels of ozone, ultraviolet light,
nitric oxides, humidity and a specified pH-value.
All of the samples were analyzed by means of a
bioassay and their corresponding toxicities were
compared. The bioassay demonstrated evidence of
dioxin-like activities in the samples generated
in this experiment.

• Introduction
• Reactions of particles in the earths atmosphere
  can have an effect on the toxicity and health
  effects of ultra fine combustion generated
  aerosol particles that might be inhaled by a
  human. Specifically, polyaromatic hydrocarbons
  and dioxins can be transformed by reactions in
  the atmosphere and by sunlight.
• Dioxins are known to have carcinogenic potential
  1
• Dioxins have a half-life of 7-10 years and are
  environmentally stable1
• Hydrocarbons seem to be formed in the
  post-combustion zone due to incomplete
  incineration of chlorinated plastics 2
• Experimental
• Burned controlled levels of Methyl chloride in a
  laminar diffusion flame
• Preliminary results were collected around 2.5
  inches above a propane fueled flame
• Later results were collected at room temperature
  with a ethylene fueled flame
• Particles were collected on a Teflon filter for
  a duration of 3 to 4
• The samples analyzed by means of bioassay (cell
  culture) for four hours
• Aging of the samples included exposure to
  specified levels of ozone, ultraviolet light,
  nitric oxides, humidity and a specified pH-value

• Results
• Preliminary results have both indicated
  dioxin-like activity and no dioxin-like activity.
  Although the data does not demonstrate a clear
  relationship it does imply a decrease in
  dioxin-like activity after aging.
• Overall the amount of dioxin-like activity is
  low both before and after aging
• Higher chlorine concentrations yielded greater
  dioxin concentrations
• Lower chlorine concentrations demonstrated
  negligible results
• Aging seems to reduce the amount of dioxin-like
  activity
• The first graph is of a preliminary sample
  against the standard it indicates positive
  results for dioxin-like activity. The second
  graph is of an unaged sample and its
  corresponding aged sample is number 21 in the
  third figure.

Figure 2 Graph of an unaged sample against the
standard.
Standard Curve
Aged sample
Figure 3 Graph of an unaged sample and one aged
sample against the standard.
Acknowledgements Thank you to Professor Kennedy,
Bing Guo, Dave Baston, Mercedes Piedra and the
UCLEADS Program for all of their guidance and
support. Thank you to Hewlett Packard.
Literature Cited 1) Murkerjee, D. Journal of the
Air and Waste Management Association 1998, 48,
157-165. 2) Sidhu, S. S. Maqsud, L. Dellinger,
B. Mascolo, G. Combustion and Flame 1995, 100,
11-20.
Figure 1 Graph of a preliminary sample against
the standard.