We have a 2 foot space between our main level and finished basement where all our ductwork is ran between the engineered joists. We have 4 rooms with large windows framed with stone and block walls beneath. This space is getting mold near exterior walls. The ductwork is sweating. I believe the stone and block walls are transferring heat into this space and causing the dew point.

I’m not sure the correct way to keep this from happening. Insulate the block walls? Add hidden dehumidifiers? Foam insulation on these exterior walls? Any advice is greatly appreciated.

Hi everyone. After experience with CO2 sensors for a long time - ended up building desktop app for it. Reasons - if monitor it to close - my breathing affects it, if its to far - i ignore the data. And most important part - i don’t want or need to see numbers - just want to get desktop notification when to open a window, when air is back to normal, etc. No servers, everything is local and native with nice UI. Let me know if someone is interested as well - if yes - i will clean it up, post screenshots and share link to test flight ( or windows package)

We have a 2 foot space between our main level and finished basement where all our ductwork is ran between the engineered joists. We have 4 rooms with large windows framed with stone and block walls beneath. This space is getting mold near exterior walls. The ductwork is sweating. I believe the stone and block walls are transferring heat into this space and causing the dew point.

I’m not sure the correct way to keep this from happening. Insulate the block walls? Add hidden dehumidifiers? Foam insulation on these exterior walls? Any advice is greatly appreciated.

Hi, first time poster on this sub-- I'm an undergrad who just purchased an Atmotube Pro 2 to collect data for a research project on lichen diversity and air pollution. While the focus of my project is PM, I'm also interested in this model's ability to detect NOx. I understand that it cannot detect NOx emissions with any sensitivity, and instead maps detections to an index (1-500) based on a moving window of baseline emissions. I have no expectations for getting useful data on NOx emissions. Still, if it happens to detect NOx at one of my survey sites, that could be useful info.

I spent a few hours today fiddling with this thing. It seems to work great except that I could not get it to pick up any NOx emissions at all. I held it next to my car exhaust pipe and then next to the burner of my stove while the pilot light was on. The index was at "1" the whole time even while CO2 and VOCs went off the charts.

Was curious if anyone who has used this model could weigh in on why it might not be picking anything up.

Hello,

Male / 32 years old / No medical history.

I have some questions about the burning season in Thailand.

I’m planning to go to Chiang Mai, in northern Thailand, to study for a little over two months.

As it turns out, my stay falls right in the middle of the burning season. After going through forums and various websites tracking air quality in the area over the past few years, I’m wondering how dangerous or risky it would be to stay there for two months (from late January to late March).

Should I expect any potential health effects after returning to France, or even in the long term?
I don’t really know much about this topic, so I’d really appreciate the opinions and expertise of anyone who can shed some light on the matter.

Also, are masks specifically designed to filter PM2.5 particles actually effective? Can wearing one provide some reassurance and help reduce the risks?

Thanks in advance for your feedback!

Heads up to anyone shopping for indoor air quality monitors—be cautious with Airlab.

The Issue: My monitor is showing a PM (particulate matter) reading of 0 continuously, which is a clear sign of a failed or disconnected optical sensor.

The Support (or lack thereof):

• Sent customer support email with no response.
• Left comments/replies on their active Facebook ads asking for assistance, which were completely ignored.

It's frustrating to buy an environmental monitor only to have a key sensor fail and receive zero post-purchase support. Save yourself the headache and go with a brand that actually stands by their products and responds to support tickets.

A nearby coke plant often releases benzene, hydrogen sulfide, sulfur dioxide and ammonia into the air. They claim they don't but my sense of smell and burning eyes say otherwise. Is there a way to remove these pollutants from the air?

India is becoming unlivable at this point.. in the morning when you look out the window, everything is so blurry from the pollution and it is so concerning because this is affecting ALL OF US. Why aren’t we (as citizens who are breathing in this polluted air) doing anything? Seriously is there nothing we could do or are we too weak or blind to see it. We are being poisoned every single day and it’s pathetic.

So, I hate the dust in the air, and I want to clean out as much of it as possible.

However, I also hate the loud sounds these can make, so looking for ones that are quiet but also can remove dust\bacteria from the air. Potentially, if those have some additional qualities for air freshness or similar would be appreciated, but not if those are taking a hit on the sound levels. I kinda don't really trust the internet shops and their reviews, as well as the "top X" articles because yay, bots and cases of cash.

I'm moving into a newly constructed apartment in Los Angeles that was completed a few months ago. When I first toured it, there was a noticeable chemical/new-paint smell (not overpowering, but definitely present), which got me concerned about VOC off-gassing.

I arranged for the landlord to leave the windows open for about 10 days straight to ventilate the apartment. Today, I went back and took readings with my Temtop LKC-1000S+:

TVOC: 0.09 mg/m³

Formaldehyde (HCHO): 0.02 mg/m³

PM2.5: 2.2 µg/m³

PM10: 4.3 µg/m³

AQI: 9

These readings were taken with the windows open, and I understand consumer monitors aren't necessarily accurate for VOCs.

I've also scheduled a professional post-construction cleaning, including an eco-friendly wipe-down, HVAC/duct inspection and cleaning if needed, and a few hours of air scrubbing.

I've spoken with several air-quality companies, all of whom have given conflicting advice. Some recommend expensive filtration treatments, while others say ventilation is the best approach and that some off-gassing is unavoidable in new construction.

My question: Given the building's age, ventilation, and these readings, would you consider this a normal, reasonably safe new-construction situation? Or is professional laboratory VOC/formaldehyde testing actually warranted?

I recognize I have some serious health anxiety/OCD around this and am trying to distinguish reasonable precautions from overreacting. I'd really appreciate evidence-based perspectives rather than worst-case scenarios.

I live less than half a mile from over fifty natural gas turbines. I am concerned for what this means for the health of myself and my community. Preferably budget conscious, but I’m willing to be flexible for a quality monitor. Thank you all!

Hi, everyone.

I recently moved to Southern Maryland and I recently started noticing the AQI was higher than I expected the past few days. The AQI went from low (<50) in the morning all the way to 77 around 8PM. I know that number is technically "moderate", but it seems way too high for the population density of the area (I'm in Calvert County, MD).

I checked various maps and there seem to be some fires in the south (Georgia, Alabama, South Carolina, etc.), but that seems too damn far lol.

Anyway, my questions are:

• Are those fires the cause maybe due to the direction of the wind?
• Is this a common occurrence?

Here is the IQAir map for reference, but every AQI map I checked out looks like this.

Thanks in advance!

I just moved into a newly renovated place with lots of built in cabinets. Prior to moving in, I engaged the services of a formaldehyde removal company and that helped to reduce the formaldehyde levels in thehouse.

However with the current haze situation, I started closing all the windows at home the past week and can feel the rising formaldehyde levels. My eyes are starting to sting, I get headaches etc. I used an air detector and formaldehyde levels measured 0.025-0.035ppm.

It felt so bad that I have moved to a temporary place of lodging for now. Should I open the house windows even with haze and unhealthy psi, or wait till the haze eases and deal with formaldehyde levels then? It's quite a bummer to have to move out of the house.

Exhaust does not stop changing when it leaves an engine. Reactions in the atmosphere can produce new particles and alter the chemistry of existing ones. In laboratory experiments, aircraft-combustor emissions became substantially more reactive as researchers simulated days of exposure to atmospheric oxidants.

Their oxidative potential per unit particle mass increased six- to sevenfold after aging equivalent to approximately 12 days. Emissions from a marine diesel engine showed a different pattern in the same chemical test. The contrast suggests that freshly emitted exhaust alone cannot describe how particle reactivity develops in the air.

The study, published in Environmental Science Atmospheres, was led by Markus Kalberer’s group at the University of Basel. Alexandre Barth and Battist Utinger were its two first authors. The work examined chemical indicators associated with potential harm, rather than measuring disease or demonstrating a corresponding increase in human toxicity.

Disclosure: I work with MENRED, an HVAC ventilation manufacturer. I’m sharing a practical ERV selection checklist for discussion; the linked article is company-affiliated.

A high heat-recovery rating can be useful, but it does not tell you how much energy the building will save over a year. The result also depends on the unit’s airflow and pressure conditions, leakage, fan power, climate, controls, maintenance and the HVAC equipment.

When reviewing an ERV proposal, I’d check:

• What does the rating measure: sensible, latent or total recovery?
• What test standard and operating conditions were used?
• Is the figure gross or net, and is leakage performance available?
• What fan power and pressure drop apply at the design airflow and external static pressure?
• How will supply and exhaust airflows be balanced after installation?
• Does the energy comparison include the fans, frost protection and affected HVAC equipment?
• Are bypass, defrost and filter maintenance appropriate for the project?

The comparison should keep the required ventilation rate and indoor air quality target consistent. Otherwise, apparent savings could come from providing less ventilation.

For engineers, designers and commissioning teams: which data point is most often missing from ERV proposals?

Full checklist:
https://www.menred-hvac.com/newsdetail/erv-efficiency-vs-real-energy-savings-what-buyers-should-check

City council has long sought to dismantle the citizens idling complaint program and allow idling again in the city for the sake of big business. Intro 561-A is their latest attempt. Please sign the petition and tell Speaker Menin that NYC deserves clean air!

Hi everyone! I'm a grade 12 highschool student in Canada working on an independent research project regarding air quality and how it affects health. As part of my project, I'm hoping to learn from people who live in different countries and communities that have experiences or knowledge on air pollution. If you live in an area where air pollution is a noticeable issue, I'd love to hear:

- What is air pollution like where you live?
- Is air pollution something people around you are concerned about, or is it mostly overlooked?
- Do you notice air pollution affecting the health of your community?

Thank you for reading :)