Influence of airborne particles' chemical composition on SVOC uptake from PVC flooring - time resolved analysis with aerosol mass spectrometry

We sampled ammonium sulfate particles and indoor particles of outdoor origin through a small chamber covered with polyvinyl chloride (PVC) flooring. We measured the uptake of semi-volatile organic compounds (SVOC) by the airborne particles in real time. The particles acquired SVOC mass fractions up to 10%. The phthalate ester DEHP (di(2-ethylhexyl)phthalate), a known endocrine disruptor, contributed by approximately half of the sorbed SVOC mass. The indoor particles acquired higher DEHP fraction than laboratory generated ammonium sulfate aerosol. We attribute this increased uptake to absorption by organic matter present in the indoor particles. Using a thermodenuder to remove volatile components, predominantly organics, reduced SVOC uptake. Positive matrix factorization applied to the organic mass spectra suggests that hydrocarbon-like organic aerosol (typically fresh traffic exhaust) sorbs DEHP more efficiently than aged organic aerosol. SVOC uptake is one of the processes that modifies outdoor pollution particles after they penetrate buildings, where the majority of exposure occurs. Particles from indoor sources, typically dominated by organic matter, will undergo such processes as well. Aerosol mass spectrometry improves the time resolution of experimental investigations into these processes, and enables experiments with lower, relevant particle concentrations. Additionally, particle size resolved results are readily obtained.