Discover and read the best of Twitter Threads about #indoorair2022
Most recents (15)
#IndoorAir2022. Toby Carter. How do ozone and hydrogen peroxide interact with surfaces and impact IAQ? Oxidants deposit on surfaces and can release secondary VOCs. Secondary emissions are a function of deposition velocity, reaction yield, oxidant concentration and volume. 1/3
Room relevant material surface to volume ratios are important (very different for offices and bedrooms). Most deposition for ozone was on plastic/paint/skin/soft fabrics. 2/3
Hydroxyl radical concentration vary with time of day and space (highest in kitchen). Concentrations of formaldehyde and decanal increased when modeled people were introduced as a result of hydrogen peroxide and ozone reactions. 3/3
Goodbye Kuopio,goodbye #IndoorAir2022. Thank you @isiaq and all the organisers for a wonderful conference with great venues, great science, great food and lots of conversations 1/
After 2 years of working under enormous pressure, this week has been the biggest mental reset I’ve had in a very long time. Being able to share experiences and have time to reflect on the future research has been amazing 2/
I’ve met up with many #IAQ friends who I last saw in 2018 and it has been great to catch up on the work they’ve been doing and all the social aspects 3/
#IndoorAir2022. Andrea Burdack-Freitag. Do Air cleaning devices produce unintended byproducts? Tested UVC and ionization/plasma units (120-1000 cfm). Analyzed PM (nm), O3, NOx, VOCs (GCMS/LCMS). Nebulized phi6-bacteriophage. 1/3
One UVC unit reduced 2-20 nm PM, one had no effect. "We did not reach zero value (viral load) because we had to abort this measure, because we reached a very, very high level of ozone and it was too dangerous..." (600 ppb in 30 min, plasma unit). 2/3
Byproducts measured: Ozone 0-8 ug/m3. VOCs 0-87 ug/m3. Highest VOC acetone. Next added VOCs to room (isobutanol, acetophenone, limonene, hexanal, pentanoic acid, at 275-850 ug/m3). Acrolein and formaldehyde measured. 3/3
#IndoorAir2022. @licinadusan. Plenary. Can we feel as good indoors and out? Can our buildings predictively respond to outdoor changes? Can our indoor environments not impact the ecological health of the planet? 1/14
Green certified buildings attempt to achieve these goals. hundreds of certifications globally. Certification schemes started during 1970s energy crisis (BREEAM). Existing certifications focus on building energy, less emphasis on occupants, IEQ and much less on human health.2/14
We consume huge amounts of energy on non-certified buildings and have poor occupant satisfaction (highest complaint is noise). Certification improve, but don't solve occupant satisfaction issues. Improvements still don't reach expected satisfaction of other industries. 3/14
#IndoorAir2022. Michael Scholand, Piet Jacobs. Is cooking with natural gas a public health risk? "This is like living with a tailpipe in your kitchen". Gas stoves emit NO2, CO, ultrafine particles. 1/
European effort to get data to support EU/UK actions. Emulating @RockyMtnInst study. What happens if you increase hydrogen content of gas to IAQ? "You can't regulate something if you can't measure it." 2/
Phase 2 is a field campaign in winter 22-23 in EU kitchens with gas and electric stoves. What component of IAQ is gas/versus cooking? 3/
#IndoorAir2022. Plenary Discussions. @CathNoakes, Giorgio Buonanno, Arsen Melikov. Lidia Morawska. Does Monkey Pox have airborne transmission? @CathNoakes "Quite Uncertain" But potential. 1) Before pox show, with fever. Not much data. 2) Lesions. Evidence of mouth lesions.1/6
3) skin flakes could transmit in places like bedding. Potential for airborne transmission (especially from lesions), but may not be a major route. But ventilation and airborne transmission guidelines should be followed in hospitals. 2/6
Lidia: "once it (monkey pox) is in the respiratory fluid there is no limit on what is going to happen." Giorgio: paper on classroom ventilation was important as it communicated to the epi world by using epi language from data engineering studies. 3/6
#IndoorAir2022. Arsen Melikov. Plenary. Increasing ventilation rates is expensive, requires energy. Air cleaning also use energy and placement can impact performance. CFD modeling shows variability in ventilation type impacts Infection probability by up to factor of 7. 1/
Personal ventilation is best, supply air as close to breathing activities as possible, e.g. air curtains. Should consider occupant activities when making recommendations. 2/ 
Source control via ventilation. Clean air at mouth. 3/
#indoorair2022. Giorgio Buonanno. Plenary. In 2020, airborne modeling tools "came out like mushrooms". Most all tools used Wells-Riley and box models and assumed accurate input parameters. 1/4
Quantum = dose of airborne particles required to cause infection in 63% of individuals. Experimental validation demonstrated that volume of particle emission is main contributor to uncertainty. 2/4
Retrospective study in Italy of >10,000 classrooms. Classrooms with ventilation 1.4-10 L/s/person and >10 L/s/p. Risk reduction was 80% in higher ventilated classroom. 3/4
#indoorair2022. @CathNoakes. Plenary. Breathe is a jet for 30-50 cm, then rises due to temperature, then starts to mix through turbulence. Aerosol production goes up breathe>sing>cough. BUT orders of magnitude differences between people. 1/
Respiratory aerosols are liquids that evaporate over time. Impacts virus viability and aerosol size. Aerosols 20-100 microns get smaller fast and concentrate high concentrations of virus. Variation of size and virus numbers can vary 4-5 orders of magnitude. 2/
Fomites also can have orders of magnitudes of dose. People are not stationary, we move around. But also with wide variability in our rates of interactions with other people. Does/response have orders of magnitudes differences for all aerosol diseases. 3/
Check our presentation of a novel air disinfection method at #IndoorAir2022.
Permanent infrastructure needs to address the problem sustainably.
Throwing ACHs won’t hit ESG benchmarks because the power requirement is enormous.
Permanent infrastructure needs to address the problem sustainably.
Throwing ACHs won’t hit ESG benchmarks because the power requirement is enormous.
Filters in HVAC don’t move the needle much: its too late by the time pathogens make it to the filter.
How do we know?
Because we studied this, came up with a comprehensive air equation— and built a tool to compare mitigation measures that yields a time to infectious dose.
How do we know?
Because we studied this, came up with a comprehensive air equation— and built a tool to compare mitigation measures that yields a time to infectious dose.
#indoorair2022. @specandthecity. (with @jenna_ditto!) Heterogeneous oxidation of THC, aka thirdhand smoke reactions with ozone. Cannabis smoke is distinct from tobacco smoke, but not as well characterized due to legal status. 1/3
Noted most cannabis is consumed inside, potential exposure to kids. Smoke was injected for 30 minutes into 1 m3 Teflon chamber containing cotton samples. Cotton then place in chamber and exposed to ozone. 2/3
Extracted and analyzed on LC-MS/MS. THC decayed slowest on cotton compared to glass. THC on glass decay to 5% of initial after 1 w, 10% on cotton. THC-20 and THC-30 byproducts seen on surfaces. 3/3
#IndoorAir2022. Congratulations to the new @isiaq board of directors members.
I am proud that @KerryKinney14 will be our FOURTH straight female president when she serves from 2024-2026.
I look forward to working with you all.
I am proud that @KerryKinney14 will be our FOURTH straight female president when she serves from 2024-2026.
I look forward to working with you all.
@JamesAMcGrath, @JamesAMcGrath and Tunga Salthammer discuss how money money should we have in reserve as a society.
@polsiewski congratulates @isiaq for tackling gender issues within the society. President Corinne Mandin noted that we now need to deal with geographic diversity and expand our reach to Africa/South America and India.
#IndoorAir2022. @CJWeschler. Indoor non-body (inanimate objects) reactions of ozone has a reaction rate constants of about 2.0 h-1. Body reactions about 0.9h-1. Gas phase losses is about 0.1 h-1. So about 1/3 of ozone loss is on-body surfaces. 1/5
"What fraction of ozone removal by off-body surfaces is attributable to reaction with skin oil constituents?" We emit tons of skin flakes daily. Skin oil is distinctive in that is has omega-10 acyl groups (not in cooking oils, etc). These groups result in decanal. 2/5
Hence, decanal is a good tracer for ozone-skin oil reactions. Decanal yield with skin oil is about 5%. Off body yields is about 1%. Roughly 20% of ozone removal by off-body surfaces is attributable to reactions with off-body skin oil. 3/5
#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/
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/
#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/
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/
