CO2 and Indoor Air Quality, school me please

[gruesome]

I think you are overly concerned about CO2. To be actually unpleasant (not dangerous or deadly, just unpleasant) the concentration would have to be in the percent region, assuming oxygen is still at 21%. (If I remember correctly, they were debating running some longer term space missions at a few percent, but that could make for a very unpleasant time adjusting to that level.) At 1000 ppm (parts per million) you are still a factor 10 below 1%. As others pointed out, the global average has crept up to 420ppm this year, so you can't really hope for anything lower indoors. The better your house is sealed, the higher the CO2 will go. I wouldn't worry about twice the outdoor value (800 ppm).
If it goes beyond 1000 ppm (0.1%, 1 permille) people can get tired/sleepy; that can easily happen in meeting rooms if the HVAC doesn't control for CO2 concentration.
This all assumes that your indoor oxygen levels are normal. If oxygen drops significantly below 21%, that is a reason to worry.


CO (one O) is a completely different thing (OSHA limit 50 ppm); are you sure you are not confusing the two?

 

[begreen]

It sounds like C02 levels could be much higher in the fall then as plants die off or go dormant.

 

[EbS-P]

It sounds like C02 levels could be much higher in the fall then as plants die off or go dormant.

About a 3 month lag in the mid level of the atmosphere.

Watching Earth Breathe: The Seasonal Vegetation Cycle and Atmospheric Carbon Dioxide | AIRS

In this animation, NASA instruments show the seasonal cycle of vegetation and the concentration of carbon dioxide in the atmosphere.

airs.jpl.nasa.gov

 

[begreen]

About a 3 month lag in the mid level of the atmosphere.

Watching Earth Breathe: The Seasonal Vegetation Cycle and Atmospheric Carbon Dioxide | AIRS

In this animation, NASA instruments show the seasonal cycle of vegetation and the concentration of carbon dioxide in the atmosphere.

airs.jpl.nasa.gov

I'd be interested to see the graphs from February.

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[stoveliker]

I am surprised that the seasonal photosynthesis effects seem to be larger than winter-heating fossil fuel emissions. At least in the explanations of these videos they mention the former but not the latter.

 

[EbS-P]

I am surprised that the seasonal photosynthesis effects seem to be larger than winter-heating fossil fuel emissions. At least in the explanations of these videos they mention the former but not the latter.

Do we drive less in the winter?

 

[stoveliker]

Do we drive less in the winter?

Maybe not but we do heat more. Including electrically.

Hard to get good data, but transportation is less than "residential and commercial" direct and indirect (i.e. electric generation) emissions.

But that's not heating only.

Sources of Greenhouse Gas Emissions | US EPA

Sources of greenhouse gas emissions, inculding electricity production, tranportation, industry, agriculture, and forestry.

www.epa.gov

My point is that heating is not insignificant (unless in the south...) for emissions, and it goes up exactly when plants don't consume CO2.

 

[dougstove]

Hi; Eddy Flux Covariance uses gas monitors for local CO2 and CH4, and anemometers to measure air movement in 3D. Then mathematics can back out whether an area is releasing, or taking up, the gas from the local atmosphere.

Part of the global seasonal pattern is more landmass in the northern hemisphere, so northern summer causes a temporary pull down of CO2. Photosynthesis is still big, compared to emissions. cheers from a windy Nova Scotia, hoping our local Eddy Flux tower does not blow over...

 

[crstrode]

Greta Thunberg said we would all be dead by now.

 

[crstrode]

United States Occupational Safety and Health Administration (OSHA)
and National Institute for Occupational Safety and Health (NIOSH) have established a time-
weighted average limit value of 5000 ppm v for airborne exposure in any 8-hour work shift during
a 40-hour workweek and 30,000 ppm v as a short-term exposure limit, i.e., a 15-minute time-
weighted average that should not be exceeded at any time during a workday. ASHRAE Stan-
dard 62.1 has not contained a limit value for indoor CO 2 since the 1989 edition of the standard.
Misunderstanding of previous editions of the standard continue to lead many to incorrectly attri-
bute a 1000 ppmv limit to ASHRAE.

An indoor CO2 concentration below 1000 ppm v has long been considered an indicator of
acceptable IAQ, but this concentration is at best an indicator of outdoor air ventilation rate per
person. This value of 1000 ppmv has been used for decades without an understanding of its
basis, which is its link to the perception of human body odor by building occupants. This misun-
derstanding of the significance of 1000 ppmv has resulted in many confusing and erroneous
conclusions about IAQ and ventilation in buildings. The use of CO2 as an indicator of outdoor
air ventilation must reflect the fact that outdoor air ventilation requirements depend on space
type, occupant density, and occupant characteristics (e.g., age, body mass, and activity levels).
Therefore, a single CO2 concentration does not apply to all space types and occupancies for
the purposes of assessing the ventilation rate. Also, CO 2 concentrations can vary significantly
within a building or space based on the details of how ventilation and air distribution are imple-
mented.

 

[begreen]

Greta Thunberg said we would all be dead by now.

When and where did she say this?

 

[stoveliker]

When and where did she say this?

https://www.factcheck.org/2023/06/viral-posts-distort-greta-thunberg-tweet-warning-about-climate-change/

 

[crstrode]

When and where did she say this?

At a Holiday Inn - 2018

 

[begreen]

At a Holiday Inn - 2018

I thought so.