A residential ventilation system can meet its whole-house airflow target while an occupied bedroom receives too little outdoor air overnight.

Disclosure: I work with MENRED, an HVAC manufacturer. We recently put together a guide on this issue, focusing on room-level checks rather than selecting equipment from its maximum airflow rating.

The main checks are:

• Sleeping occupancy, including two people sharing a room.
• Actual bedroom airflow at the intended nighttime setting.
• The supply, extract and transfer paths with the door closed.
• Filter condition and room balancing.
• Noise and drafts that may lead occupants to reduce fan speed.

Overnight CO₂ trends can help, especially when logged with door/window positions and fan settings. They do not establish overall air quality or measure particles and other pollutants.

A practical commissioning question is whether the system was tested under the conditions people actually use overnight.

For people designing or commissioning residential ventilation: what most often explains an under-ventilated bedroom—air distribution, a restricted transfer path, or reduced nighttime fan speed?

Our guide and selection questionnaire:
https://www.menred-hvac.com/newsdetail/bedroom-ventilation-why-whole-house-airflow-may-not-be-enough

I'm moving into a brand-new apartment in Los Angeles (weho) that finished construction a few months ago. When I initially toured it, there was a noticeable but tolerable chemical/new-construction smell, which raised concerns about VOC off-gassing from paint, flooring, adhesives, cabinetry, etc.

Since then, I've had the windows open for approximately 3 weeks (i haven't moved in yet) and hired a company to perform post-construction cleaning, HVAC duct cleaning, and brief air scrubbing.

I've also been taking measurements with a Temtop LKC-1000S+ (which I understand isn't laboratory-grade).

With windows open: - TVOC: 0.05 mg/m³ - Formaldehyde (HCHO): 0.01 mg/m³ - PM2.5: 3.7 µg/m³ and AQI of about 15

After approximately 48 hours with windows closed: - TVOC: 0.38 mg/m³ (peaked at .45 and settled at .36) - Formaldehyde (HCHO): 0.08 mg/m³ (~65 ppb) - PM2.5: 2.1 µg/m³

The chemical/new-building smell was still noticeable after those 48 hours with the windows closed.

My main concern is long-term exposure once I move in and start living normally with the windows closed for extended periods.

I have very bad health anxiety and I'd really appreciate input from you guys as well as any industrial hygienists or indoor-air-quality professionals on a few questions:

Are these readings typical for a newly constructed apartment, or should i be worried? Do they warrant further investigation?

Would professional laboratory testing for this be justified, or would you consider ordinary ventilation sufficient?

If testing is recommended, what specific sampling methods would be most appropriate for a residential apartment?

I do struggle with severe OCD/health anxiety especially in how my brain could be damaged in regards to toxic exposure, so I'm trying to distinguish an objectively warranted environmental concern from excessive precaution. I'd especially appreciate evidence-based advice rather than speculation or worst-case scenarios.

Thanks in advance!

With the temperature changing and the heat coming on I’ve had a massive increase in VOCs in my basement unit. Terrible sleep and headaches overnight. I have an air purifier running but I don’t think I should be seeing numbers this big. Any thoughts or advice would be grateful.

Wondering.

Why you probably shouldn't rely on your air purifier's automatic mode.

A nation of nearly 300 million people, with fires everywhere. Are ordinary people destined only to suffer?

No comment needed

A year ago a clip went viral regarding the cutting of Mangroves of Mumbai. The citizens raised their questions about ‘How will it affect the life of people?’ ‘For whom exactly is this development for?’ ‘The AQI problem it might raise really worth the development?’ and ‘Are we ready to counter the problems deforesting the Mangrove might raise?’ but the members of the bench who were supposed to answer and ensure their citizens with fullproof plan and honesty in their work smilingly said “Whatever it is atleast it is not as bad as Delhi" and guess what exactly a year later Mumbai’s AQI is as worse as Delhi even more at that!

#MumbaiAQI #CuttingMumbai’sLifeline #CuttingMumbai’sMangrove

I live in India and this seems to be not getting any better.
At evening it just climbs up like 600+ ug/m3

I'm drawn to AirGradient Go as it's open source (both software and hardware) and has PM2.5 and CO2 sensors. However, the uHoo Caeli can provide additional CO, NO and O3 sensors with active sampling.

Which do you recommend? How important is it to have CO, NO, O3 sensors at home?

Comparison Table

uHoo Caeli: https://getuhoo.com/home/caeli/

AirGradient Go: https://www.airgradient.com/shop/#!/AirGradient-Go-Portable-Monitor-P-1PSG-Fully-Assembled-&-Tested/p/822277003

I've got an Air Gradient Go and a gen 1 Atmo Tube pro, and I like having portable air quality meters that measure multiple parameters, but I've not seen a credible consumer meter than includes PM and ozone, yet Vernier managed to include a 2ppm ozone sensor in their educational sensor.

https://www.vernier.com/product/go-direct-air-quality-sensor

• PM1.0
• PM2.5
• PM10
• CO2
• NO2
• SO2
• O3
• VOC Index
• Temperature
• Relative Humidity
• Barometric Pressure
• Station Pressure
• Latitude
• Longitude
• Altitude

Does anyone know of a consumer unit with a similar suite of sensors?

Has anyone had issues with their sofas offgassing for weeks?

We purchased a Crate and Barrel sofa, delivered 7 weeks ago. Initial weeks there was a strong offgassing odor, now it's very subtle.

But I still get headaches, dizziness and tingling/itchy face. That's from just living in the same space, I haven't even sat on the sofa.

Our airthings VOC sensor detects high levels. But when actively venting out room air, VOC levels drop. It's getting too cold to keep fans and windows open now.

This is already sofa number 2. We bought and returned another sofa for the same issue. Any advice?

A few people in my last post mentioned surprisingly high CO₂ levels in closed rooms, and one said opening their bedroom door or window helped with morning headaches.

That got me curious about sleep.

I recently saw someone share a pretty bad sleep score despite getting around 8 hours of sleep. They suspected a hot, poorly ventilated bedroom with rising CO₂.

Obviously, one sleep score doesn't prove anything. But has anyone here actually tested this?

If you monitor CO₂ in your bedroom:

• - How high does it get overnight?
• - Did improving ventilation make a noticeable difference to your sleep or how you felt in the morning?
• - Or did the numbers improve without you feeling any different?

Curious about real experiences, especially if you've compared several nights rather than just one.

I have a job that keeps me right next to a busy street (in-town main street in a large town/small city going 20-30mph) for an hour a day. I also seem to be acquiring a health condition that is both hereditary/in my family but can be caused by super high pollution. I'd like numbers to make my decisions on- is there such a thing as a personal/small air quality monitor that I could use for a week or so while on the sidewalk to assess the amount of air pollution?

I'm trying to understand what is happening in my bedroom every morning. I wake up the Sun comes through the window which is closed and I immediately smell some sort of chemical burnt odor. my air purifier is always on. I leave for the day and I come back and the odor gone. I thought it was either the air purifier or one of the outlets burned out so I tried sleeping without any plugs and the odor was still there. it's not there at night when the air purifier is still plugged in so I don't think it's that. it's driving me crazy and I have to escape my room as fast as possible in the morning but it's causing me breathing issues and headaches.

How bad would u say the VOC is from adhesive glue and the rubber board? My body is sensitive and it smells very strong I’m worried for my health

I swear I’m color blind when it comes to these cards. Can anyone help me read it? Thanks!

Looking for a low level co detector. Looking at true safety ones. Any recommendation

I'm so conflicted based on research I have done.

Our home was built in 2021 thats is very tight and efficient. In the summer, our AC does a good job of keeping RH in our home to about 50% on main level and 60% in basement. We live in Wisconsin.

In the winter, we deal with higher humidity - mid 60% when furnance is running. This causes a good amount of condensation on our bedroom windows, especially when outdoor temps get in the teens.

I had a HVAC contractor out here and he recommended an ERV. Now, I dug around the Internet and everything I am finding is using an HRV as it helps reduce humidity in the winter? An ERV is better in the summer?

Can someone please help me understand why I would go ERV over HRV?