AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
A Portable and Automated On-Line Instrument to Quantify Health-Relevant Aerosol-Bound Reactive Oxygen Species (ROS)
FRANCIS WRAGG, Markus Kalberer, University of Cambridge, UK
Abstract Number: 318 Working Group: Health Related Aerosols
Abstract Epidemiological studies have linked urban aerosol levels with mortality and hospital admissions due to respiratory and cardiovascular disease. It is often hypothesised that these negative health effects could be due to particle-bound reactive oxygen species (ROS), and subsequent oxidative stress of lung cells.
Fuller et al. (2014) presented a first version of our on-line instrument, based on fluorescence spectroscopy and a reaction system combining 2,7-dichlorofluorescein (DCFH) fluorescence probe with catalytic enzyme horseradish peroxidase, and demonstrated that traditional off-line techniques might severely underestimate total ROS concentrations. This instrument furthered concepts previously described by Wang et al (2011) and King and Weber (2013) in that it allowed both fully continuous measurement and capture of ROS components under mild conditions.
This study describes the further development of our instrument into a compact on-line ROS instrument capable of automated and un-manned continuous measurement over 12 hours. It exists in a compact structure, is designed for field deployment, allows capture of aerosol under mild conditions, and requires minimal or no user interaction. The instrument has a detection limit of under 2 nm[H$_2O$_2] equivalents per m$^3 air and a time resolution of under 10 minutes, values which should be suitable for detection at many measurement sites in polluted and urban areas. Examples of ROS concentration data obtained in laboratory-generated secondary organic aerosol experiments, as well as at an urban ambient site, are presented.