|
Initial Development of a Semicontinuous Monitor of Particle and Gas Phase Reactive Oxygen Species in the Urban Atmosphere
Start Date 08/15/2006
End Date 09/30/2007
Primary Partner: Clarkson University
Primary Contact: Hopke, Philip - Director of CARES
Project Type: CARTI I
Technical Description:
There is one major hypothesis for the observed health effects for which there are very little data. The species in question are peroxides and related oxidants present on the surface of inhaled particles. These reactive oxygen species (ROS) are concentrated on the particles and thus, deliver a concentrated dose to the tissue on which the particle deposits. Such ROS could explain the relative constancy of the health effects observed for fine particulate matter in spite of the significant differences in the bulk composition of the particulate matter. Our group has made measurements in both the summer and winter and found the presence of significant quantities of particle-bound ROS. However, the sample processing and analysis must be done immediately and thus, it is not currently practical to use manual methods for making sufficient exposure measurements to be able to assess the potential health effects.
Expected Outcomes:
It is the purpose of this pilot project to do the development that would lead to a prototype instrument to collect and analyze ROS on a continuous basis.
Accomplishments:
Several ROS quantification methods have been used and described in the literature. The development of an automated ROS monitor involves the selection of the best available analytical approach to quantify the ROS, and the subsequent integration of the best analytical approach to a suitable sampling system. Several methods for detecting ROS were evaluated and compared in terms of their strengths, limitations, and ease of automation.
The particle-into-liquid sampler (PILS) (Weber et al., 2001; Orsini et al., 2003) was chosen for use in our system because it was an inlet system that could be purchased (Metrohm).
Calibration of the instrument was performed with standard H2O2 solutions of concentrations ranging from 50 to 800 nM, prepared by serial dilutions of a 30% stock solution of H2O2, with water serving as a blank.
Benefits:
The development of an instrument that can continuously collect, measure, and analyze ROS will help clarify the health effects of inhalation of particles to which these are attached.
For more information: http://www.clarkson.edu/cares/
Publications
Development and Evaluation of a Particle-Bound Reactive Oxygen Species Generator, P. Venkatachari and P.K. Hopke, J. Aerosol Science and Technology. (In press, 2007).
Development and Laboratory Testing of an Automated Monitor for the Measurement of Atmospheric Particle-bound Reactive Oxidative Species (ROS), P. Venkatachari and P.K. Hopke, Aerosol Science and Technology. (Under review, 2007).
Schematic of the integrated ROS sampling-analysis system
Image Credit: Philip Hopke, Clarkson University
Back To Research Projects List
|
