10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Usefulness of Stable Carbon Isotope and Other Chemical Tracers to Distinguish between Primary and Secondary Carbonaceous Sources of PM2.5 Particles over a National Park in Central India
SHILPI SAMIKSHA, Ramya Sunder Raman, Indian Institute of Science Education and Research, Bhopal
Abstract Number: 840 Working Group: Carbonaceous Aerosol
Abstract Carbonaceous aerosols were investigated by measuring the stable carbon isotopic ratio, δ13C in bulk PM2.5 particles. In this study, ambient PM2.5 samples were collected over Van Vihar National Park in Bhopal, central India over a period of two years (01 January, 2012 to 31 December, 2013). 12 hour integrate samples were collected on to Teflon, Nylon, and quartz fiber filter substrates. Punches of the quartz fiber filters were analyzed for organic and elemental carbon (OC/EC) using a thermal-optical-transmittance/reflectance (TOT-TOR) analyzer operating with a 632 nm laser diode.
Punches of the quartz filters were further analyzed for concentrations of total carbon (TC) and their δ13C were measured using elemental analyzer (Flash 2000) interfaced to isotope ratio mass spectrometer (EA-IRMS). The CO2 produced was introduced into a MAT 253 isotope ratio mass spectrometer (IRMS) via a Conflo IV interface to determine the carbon isotopic ratio. Standard (Acetanilide and CH-3 cellulose) were measured after every 4 samples and every tenth sample was analyzed in duplicate. Duplicates were analyzed such that they covered the entire concentration range of the samples. A routine precision of ~ ± 0.1‰ was obtained.
This study will present preliminary results on the seasonal variations δ13CTC in PM2.5 particles collected over the study site. We also investigate the relationships between δ13CTC concentration and the concentrations of other chemical tracers (mono and di-carboxylic acids, K+), their seasonal variations, and associations with air parcel back trajectories. These relationships will be used to estimate the relative importance of primary and secondary organic aerosols at the study location. Further, isotope-mixing models (e.g., ISOSOURCE) will also be used for organic aerosol source characterization.