I have held off discussing ASHRAE 241 until I saw a final version. First of all, this a big step and I want to thank the 40+ person development team.

Among the many new procedures ASHRAE 241 requires in this is a one hidden item that might prove a big starting point.

1/7

https://twitter.com/ashraenews/status/1672665938267709440

241 requires air cleaning equipment to be tested for "Chemical Analytes Released by Air Cleaning Systems or Resulting from Chemical Reactions in the Air." Specifically, ozone, formaldehyde, and particulate matter.
2/7

Ever wonder what the ventilation is like at ASHRAE headquarters in Atlanta? Turns out it is pretty good in the conference rooms at typically occupancy.

Does the use of 222 nm Germicidal UV lamps (GUV) impact indoor air quality?

Some new research in three just released preprint articles suggests it does.

(Image credit Michael Link)
1/ A primary mechanism to impact indoor chemistry is the generation of ozone. Ozone can initiate a cascade of chemical reactions that can lead to health impacting formaldehyde and nanoparticles indoors.

2/

What is the easiest way to estimate air change rate from carbon dioxide data for a space?

Simply measure how long it takes for the CO2 concentration to fall from 1200 ppm to 800 ppm an empty room:
/1 Once the air change rate has been estimated the overall ventilation rate can be determined by multiplying by the space volume. /2

So how did the ventilation community come up 1000 ppm for CO2 as rule of thumb (albeit poor) for "adequate ventilation"?

The reason stinks.

According to Dr. Andy Persily you can find the answer here:
aivc.org/sites/default/…
1/ Basically, after a series of chamber tests in the 1980's it was determined the roughly 20% of people were dissatisfied (80% satisfied) by the odor of "human bioeffluents" when the CO2 concentration exceed 650 ppm above outdoors concentrations. 2/

What is the next step to improve Indoor Air Quality (IAQ)?

After the White House summit on Indoor Air Quality (#WHIAQ) many people asked what is next?
1/ This thread explores EIGHT actions that federal, state, and/or local jurisdictions, along with standard and codes bodies can do NOW to improve IAQ.
2/

#WHIAQ. Innovations in IAQ

Stephanie Guerra. OSTP. Assistant Director for Health Security and Biodefense.

- Responsible innovation of technologies can help improve IAQ in a wide spectrum of indoor environments.
1/ @CorsIAQ. It is not going to require rocket science to improve IAQ. We have the tools to do it now. If we do it we will get better health outcomes. We need to make sure we don't leave any community behind. We need accessible tech for IAQ.
2/

#WHIAQ. Clean Air Benefits Everyone.

Taryn Williams. Ass. Secretary of Labor for Disability Employment Policy. Improving IAQ in schools, homes and workplaces is an issue of equity (YES). Those who vulnerable are more likely to be affected by poor IAQ.
1/ Kenneth Mendez. Asthma and Allergy Foundation of America. 25 Million Americans have Asthma and 4,000 people die per year (1:13 people). 5 Million children. Asthma is leading cause of missed school days. Cost is up to $82 billion (?). Need better IAQ to reduce triggers.
2/

#WHIAQ. Why improving IAQ makes good business sense.

Jordan Silberman. Monumental Sports (Capital One Arena in DC). Baseline post pandemic now thinks about more than just security. Created a system to track safety AND IAQ through building wide monitoring.
1/ Michele Schneider. Salesforce. 6 million sq feet management. Workplace design focused on well being in the past. Now IAQ is on the list and a core value.

Kevin Kampschroer. GSA. The only reasons buildings exist is to take care of people in them (YES).
2/

#WHIAQ Schools. Alex Marrero. Denver County Public Schools Superintendent.

Jesus Jara: Clark County School District Superintendent.

(Lost the intro thread.... But both have districts that with 10,000s of staff/teachers and 90,000 plus students). 1/ - Clark County has 10,000 homeless students.

- Marroro. Funding and policy. Has spent $25 million on IAQ (MERV 13 filtration as standard and IAQ monitoring). What happens when money ends? Filters need to exchanged. 2/

#WHIAQ. @j_g_allen.

- Our indoor age is 0.9x(age).

- The person who manages your buildings (including your homes) has a bigger impact than your doctor
1/ - Standards for ventilation are bare minimums when they are actually followed.

- Give buildings a tune up.
Take pulse of buildings regularly (CO2).
- Increase ventilation
- Upgrade filtration
- Need Ventilation METRICS (YES!)
We have enough data to move now.
2/

#WHIAQ. @ashishkjha

- Indoor air quality is the next front for public health.

- Drinking water improvement was a long term systematic change. We need the same effort for IAQ.

- It becomes harder to imaging how our health care system can manage respiratory diseases. 1/ - The single biggest structural change we can make to address respiratory transmission is to improve indoor air quality.

- We need health buildings, because we need healthy communities. 2/

#AAAR2022. Plenary: @IAQinGWN

- A story about filters....

- How to improve indoor air cleaner
1- Keep it dry
2- Source control
3- Ventilation
4- Air cleaning

- Filtration (air cleaning) has the shortest history. Only 50-100 years use in buildings.
1/ - ASHRAE standard 52.2 for filtration is only 23 years old.

- Measured CO2 and PM2.5 decay in a classroom that was supposed to be operated at 6 air changes per hour with ventilation and filtration. But it was actually at ~2 air change per hour.
2/

#AAAR2022, @IAQinGWN.

- Lots of reasons filtration is not optimal.
> energy cost
> too noisy
> filtration replacement cost

1/ - Trade offs between performance and runtime.

- Can they improve on the concentration threshold approach for running the portable filter?

-Unlikely to be universal threshold due to sensor and environment variability.

2/

#AAAR2022. @SarahRHaines

- Indoor dust can be resuspended by human activity. Dust can be use as a tracer to determine the presence/absence of RNA (i.e. SARS-COV2).

1/ - Deployed indoor air cleaners in homes/classroom where people who COVID positive.

- In home cleaners placed in isolation room, outside and in the main living area. After 1-2 weeks dust was removed from filters => extracted => qPCR analysis.

2/

#AAAR2022. @LioraMael

- How do homes recover when impacted from wildfires.

- @LioraMael notes that her home burned down in the Marshall fire the day before she was to move in. #RealworldImpacts
1/ - Looked particulate matter in a house on the edge of the Marshall fire roughly one month after the fire.

- Cleaning activities increased the particle concentrations in the home.
2/

#AAAR2022. Xiaochen Tang.

- Does long term exposure of Tobacco Specific Nitrosamines (TSNAs) lead to negative health impacts.

- Previous research shows TSNAs stick to surfaces. TSNAs hard to measure due to reactivity (esp NNN, NNK).
1/ - Added HONO enriched air to chamber with cloth coated with nicotine to create TSNA. Examined cellulose and cotton with/without sweat and skin oil.
2/

#AAAR2022. @ProfPeteD. ALPACA Project Overview

- ALPACA - Investigation in artic air quality in urban artic environments.

- When it is -14F(?C) people are inside. But in Fairbanks there is a high prevalence of wood burning stoves.

1/ - What happens when you move polluted air from outdoors indoors with a 50 C temperature difference?

- In general outdoor PM10 concentrations higher outdoors than indoors, EXCEPT when pellet stove was used inside the house. 2/

#AAAR2022. @etgall

- Can you use consumer grade sensors be used to estimate particle infiltration.

- Survey asking what mitigation method they used during wildfires: main response stay indoors and keep windows and doors shut.
1/ - Corrected Purple Air sensor measurements to reference station.

- Outdoor PM2.5 concentrations varied by over a factor of 2 outdoors over 25 km during wildfire.

- Indoor concentrations varied from equal to outdoor data to order of magnitude lower than outdoor.
2/

#AAAR2022. Pradeep Prathibha. USEPA

- Do DYI filters help during wildfire events?

- For this study looked a 1 filter taped to a fan (not 4 filters and fan of #CorsiRosenthalBox) 1/ - Looked a Hoopa tribe spring/fall interventions in Northern CA at 8 homes.

- Compared two weeks of no air cleaner/DYI/commercial air cleaners. 2/

#AAAR2022. @EarthMechanic

- What happens on surfaces when wildfire smoke comes indoors?

- Indoor surface films are complicated, diverse, chemical mixtures, patchy and remain for periods longer than the air change rate (weeks/months).

1/ - Gas surface reactions can happen. But so can reactions WITHIN the condensed phase film.

- You can find third hand smoke tracers in houses of people who don't smoke.

2/