Thread by @Poppendieck

#indoorair2022. Tunga Salthammer. Plenary.
WARNING: "If you don't have a strong background with music and hard rock music this talk will be challenging." 1/

Guidelines and reference values are very different. Guidelines can be the result of health effect, or hygine. Health effect guidelines can be cancerous or non-cancerous. Reference values are the results of statistical analysis of large population data sets. 2/

Tunga highlighted the @isiaq STC 34 guidelines website. ieqguidelines.org/map.html. National guidelines can vary by three orders of magnitude. Found 43 guidelines for formaldehyde that varied 10-10,000 ug/m3. 3/

One problem is everyone has the right to define guidelines. Example Germany has guidelines for alpha-pinene is from 5 ug/m3 and the highest value is 2 mg/m3. These guidelines do not include reaction products. 4/

German guidelines: Guideline value I (GVI): no evidence of any health effect. Guideline value II (GVII): effect known, might want to run out. BUT then there is a big grey area in between those values. Each guide value has its own paper. 5/

Tunga highlighted his leading work (he is always five years ahead of everyone) with Tobias Schripp on vaping demonstrating large emissions of the solvent propylene glycol. 6/
onlinelibrary.wiley.com/doi/abs/10.111…

Germany quickly estimated exposure concentrations from passive vaping (160-395 ug/m3). Resulted in guide values of GVI of 0.06 mg/m3 to GVII 0.6 mg/m3.

Far exceeded by hard rock player who steps into propylene glycol cloud 30 times per concert. 7/

CO2 and TVOC values are hygiene based guidelines. But how you measure TVOC measurements are widely varied all giving different TVOC values (my comment, there is no health impact of TVOC). You must define measurement technique when defining guideline. 8/

"Having good air quality in schools is EASY." Just measure CO2 and make corrections and you can solve 95% of school IAQ problems. 9/

New WHO guidelines from 2021 are also applicable to the indoor environment. 10/

There are problems with guidelines . e.g. formaldehyde. Guidelines range from 9-100 ppb (higher value is WHO). But real world can have elevated concentrations as high as 50-150 ppb OUTDOORs. /11

Tunga strongly supports guidelines. But "Is the lowest guideline always the best guideline." or "Does the benefit always justify the effort?" Cost increase exponentially, while benefits flatten or decrease (other compounds may impact benefit). /12

"Everyone cares about formaldehyde. No one cares about radon." Both cause cancer.

If you publish guideline value you need to define the conditions which it can be applied (long term, short term, measurement technique, etc.) 13/