Thread by @Poppendieck

#IndoorAir2022. YIng Xu. Plenary. Targeted analysis of samples can miss lots of emerging chemicals. Lots of false positives in non-targeted analysis (NTA) of unknown samples. NTA is typically a slow, manual process. New NTA method is 50 times faster and more accurate. 1/

Large number of chemicals found in NIST test dust that were not previously identified.

Emission Characterization: VOC emission is primarily limited by internal control (e.g. diffusion through the material). SVOC emission is controlled primarily by external control 2/

(e.g. the concentration in the air above the material, or "y0"). Methods to measure y0 can take days-weeks, have fitting uncertainty, and be complicated to measure. New micro-emission cell and sampling methods can reduce times and increase accuracy. 3/

Found linear relationship between yo/vapor pressure and mass fraction in product (this is cool! and took a decade of work to prove) allowing prediction of critical parameter y0. 4/

Transport of SVOCs. Modeling indicates direct transfer of SVOCs from products to dust. Process is controlled by dust mass loading, y0 and the partition coefficient (Koa). Important for young children. 5/

Exposure modeling can show the relative contribution from dermal (air), inhalation, direction contact and ingestion (pubs.acs.org/doi/full/10.10…). Exposure results can be higher than biomonitoring data. 6/

Hazard quotient (HQ) = exposure/reference dose. When compared to cancer risk can all of prioritization of chemical exposure data indoors. 7/

When all above is combined you can go from product concentration to body burden of SVOCs to evaluate population scale health risks. When compared with NHANES biomonitoring data, the combined effort above results in order of magnitude comparisons. 8/

Ying's talk was a really cool big picture road map approach to screen our exposure to SVOCs and achieve a "healthy and sustainable indoor environment." 9/9