10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Health Detrimental SVOC Uptake by Infiltrating Ambient Particels Measured with Soot Particle Aerosol Mass Spectrometry
AXEL C. ERIKSSON, Christina Andersen, Anette Krais, Jacob Klenø Nøjgaard, Per Axel Clausen, Aneta Wierzbicka, Joakim Pagels, Ergonomics and Aerosol Technology, Lund University, Sweden
Abstract Number: 1306 Working Group: Indoor Aerosols
Abstract Indoor air contains a multitude of health relevant SVOCs originating from active and passive sources. Human exposure occurs continuously, through the relative importance of different exposure routes, some including aerosol particles as intermediate steps, are uncertain. We have studied aerosol particle uptake of a SVOC compound with known adverse health effects; Di(2-ethylhexyl) phthalate (DEHP), from vinyl flooring using in-situ aerosol mass spectrometry. We sampled particles passing through a 1.2 liter aluminum chamber containing 2 dm2 of vinyl flooring with DEHP content of 176 mg /cm3. Mean particle residence times were varied in the interval 1-12 minutes by means of adjusting the flow through the chamber. We used particles infiltrating the aerosol laboratory in Lund for our experiments. We compare our measured aerosol composition with aerosol speciation monitor (ACSM) data from the regional background station Hyltemossa, located approximately 50 km from Lund, in order to separate regional transport from local sources (e.g., particles originating inside the building or city). Furthermore, we injected laboratory generated ammonium sulfate particles for comparison. Our main instrument, used to measure the chemical composition of particles passing though the chamber, was the soot particle aerosol mass spectrometer (SPAMS). We deployed two units in order to investigate the reproducibility of the measurements. We used the "dual vaporizer" mode of SPAMS operation, where the laser vaporizer, which enables soot detection, is periodically disengaged, thus yielding "normal" AMS data intertwined with the SPAMS data. The relative importance of soot containing particles vs non-soot containing particles is thus probed, albeit resulting in non-trivial difficulties in terms of quantification. We used a single particle soot photometer (SP2) to further elucidate the role of soot in the uptake. We used a scanning mobility particle sizer (SMPS) to estimate the surface area available for adsorption. The environmental parameters relative humidity and temperature were monitored. Preliminary results show that the DEHP to total organic aerosol ratio was 5-15% throughout the study period, a total of three weeks. Infiltrating ambient particles were about five times more efficient than laboratory generated ammonium sulfate particles by mass, which we tentatively attribute to increased absorption by the more abundant organic aerosol fraction. Infiltrating particles include a serendipitous event with transported wildfire emissions from the Iberian peninsula (in October 2017), approximately 3000 km upwind our experiment. In addition, there were several events where organic aerosol originating from renovations of the building housing the laboratory was sampled, and what appears to be fresh traffic emissions occurring in the immediate vicinity of the fresh air intake supplying the laboratory. We find that aerosol mass spectrometry is a suitable tool to study the process of health detrimental SVOC uptake by aerosol particles, even in the comparatively clean (PM1 is typically below 5 µg/m3) laboratory air. It is our aim to add more health relevant compounds besides DEHP to coming investigations.