Cooking with gas - health and environmental concerns

As does the USA since a disaster in 1937, and I suspect any country with NG infrastructure.

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I don’t see that measuring leaks at any one place is that useful for this purpose. I am more interested in the broader questions of fugitive emissions across gas infrastructure, including but not limited to home stoves, and health consequences of combustion particulates.

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I suspect you are correct. Whether the amount leaked that was detected in the linked study was above or below that amount a person can smell I cannot say.

IE network loses

UAFG, refer to section 6 of the AER Gas Network Performance report might be a starting point for an upper estimate of the loses, excluding behind the meter.

https://www.aer.gov.au/system/files/AER%20-%202021%20Gas%20Network%20Performance%20Report%20-%20December%202021_0.pdf

No assurance this offers a concise answer, but for the AER and ACCC it matters in respect of the direct cost to consumers.

More than that. There are losses during drilling and fracking, from well heads, field lines and processing plants before any gas gets to the network.

Dare to reference Steven Fry and the BBC’s program QI, ‘No one really knows!’ Is the answer to many great questions.

The National Accounting of Green House Gas Emissions assumes certain values.

There are considerable differences of opinion between those who believe the scientific estimates are reliable and other scientists who suggest that due to a lack of measured data the estimates cannot be relied upon.

Which problem deserves the greater effort and resolving?
In any comparison the volumes of gas leaked in the average residential home are likely inconsequential compared to the losses in production, transportation, processing and distribution.

The difference in changing how we use energy in homes will make a small difference. Will it solve the greater problem?

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Surely a correctly installed gas appliance has no gas leaks, so where is this methane coming from?
Refrigeration mechanics are regularly installing pipework which does not leak, and holds operating pressures exceeding 2500kPa (~363PSI).
It beggers belief that a plumber would be incapable of installing a non-leaking system to hold 1.7kPa (0.25PSI).

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Probably why I never needed ventolin with puffers and nebulisers until I moved into this house. I’m going to have a plumber remove the old stove and cap the inlet before I die here.

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The study is from the USA. There are differences between Australia and the USA as well as similarities.

The study is thorough in it’s measurement of emissions and leakage. It did not extend to identifying the individual sources of leakage. Further work would be more meaningful in understanding the conditions. Note, for Australia all work on residential gas is regulated by the state and territory governments.

The more detailed report is linked within the ABC article.

For the background methane leakage the report stated,

The data for steady-state-off measurements were long-tail skewed, with the top 5 stoves (9% of sampled units) emitting half (49%) of all steady-state-off emissions.

Which suggests there are maintenance factors or quality/installation factors involved. All installations revealed some leakage, although at levels up to ten times lower than those top 5. The relevant graphs in the report use a log scale which compresses the data points.

Is there cherry picking of the results to emphasise the environmental impact and personal health risks? It has certainly gained attention. Assuming similar in Australia the US reported gas usage in the home for cooking as approximately 1/10th of the gas used for hot water. Also note that not all Australian gas stoves have gas ovens, while a gas oven is more common based on the US tests.

In total, previous inventories report that natural gas residential indoor cooking appliances use 113 billion cubic feet (bcf) of gas per year in the United States, …space heating (2677 bcf per year) and water heating (1019 bcf per year).

The method of measurement of leakage and combustion losses/products required a sealed room. The method did not measure or attempt to determine personal exposure levels. There are established scientific methods using personal exposure meters or sampling units. Some caution required in how the report is referenced, for those purposes.

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I have no answer to how the gas leaked, it may have been faulty plumbing or faulty or worn stoves. If you want to say the study was incompetent then by all means show us the flaws in their methodology for detecting gas or show that what they detected came from elsewhere. Assuming it is wrong doesn’t work for me.

The comparison with other technology doesn’t help as there is nothing similar about them other than there are pipes carrying gas to devices. The pipes, the gases, the devices and the technicians and their training are all different. It is true that higher pressure requires different measures to contain it but that tells us nothing about the success or failure of the technology required to do so under field conditions.

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I could be corrected, and it is locale dependent in the USA, but as a general statement my memory is anyone can DIY a gas cooker/over replacement installation, or almost anything else in most places.

Our ‘licensed tradies’ deliver varying levels of quality but are at least trained and licensed rather than ‘educated’ by a youtube how to. Investigating whether our installs are always of higher standard than an American DIY would be another issue. Our houses are generally not as air tight, either.

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I measured gas pollution in my kitchen and this is what I found (yikes)

Half a dozen times, the monitor showed the amount of tiny PM2.5 particles in our kitchen soared to the same levels as the toxic air people were breathing in Sydney during the Black Summer bushfires. Yikes.

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This is a US-based study from the American equivalent to CHOICE regarding gas cooktops and health. While it might not be directly comparable to our local cooktops, it is interesting as the testing was conducted in house at Consumer Reports:

https://www.consumerreports.org/appliances/indoor-air-quality/is-your-gas-range-a-health-risk-a6971504915/

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Anecdotally* typical US gas hobs are roughly 10% +/- more powerful than most EU type appliances that could explain some of it, eg more gas = more pollution.

* I randomly compared a few US vs EU speced cook tops including my own; the US models (or brand stable equivalents) usually had more capacity. It might counterbalance their lack of proper 240v kettles.

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The article was silent on the type of gas used or assessed in the study (e.g. LPG or propane/butane ratios, CNG etc). It would have been useful to know and if different gas types produce different emissions/have different risks. This might then assist with applicability to the Australian market.

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Agree it is interesting in the test arrangement used and the commentary on the results. It asks a number of important questions. There is a reminder that effective ventilation is important with indoor gas cooking. Also true of most cooking to minimise moisture and airborne fats accumulating in the near kitchen area.

But in several tests we recorded elevated levels of carbon dioxide and, even more concerning to Kapoor, nitrogen dioxide, one of the NOx gasses CR measured. Those gases are “more potent with respect to acute toxicity,” she says

One question I’d ask is whether the lab analysed the source gas used prior to combustion for the presence of the measured combustion products? NOx and CO2 are both gases associated with coal and petrochemical production chains. It should not take away from the result to know whether the levels recorded have been influenced by the gas supply. The US is a significant producer of CSG. Australian sources vary by region. Many Australian homes cooking with gas use LPG which has a different base gas and production profile compared to NG which includes CSG.

Notes:
A difficulty with any of these types of tests is correlating the result to real life exposure. For urban dwellers the background levels of NOx and particulates are always a concern. Recognised high intensity sources include ICE road vehicles and industrial processes. It’s important to put into context the relative exposure from all sources.

Nitrogen dioxide (references SWA) has a very low occupational threshold with a TWA of 3ppm and STEL of 5ppm. Carbon dioxide has relatively high acceptable levels, TWA 5000ppm and STEL 9000ppm. These would apply in a commercial kitchen or workplace for an 8 hr shift. It would be informative to know more about the actual results from the USA tests to be able to compare.

For those interested in knowing more about NOx.
https://www3.epa.gov/ttncatc1/dir1/fnoxdoc.pdf

The following from the reported results may surprise some, notable for the low levels of products commonly discussed in relation to gas use in the home.

We then performed 24 tests, for each of the two ranges, to measure levels of not only NOx but also carbon monoxide, carbon dioxide, and particulate matter. We also measured oxygen levels to see whether they dropped dangerously low.
None of our testing revealed dangerous levels of carbon monoxide or particulate matter, nor did oxygen drop to unsafe levels.

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This issue is making it to the mainstream media - which is a good thing.

Here is and article from the SMH Gas stove culture warfare hits the fan

It is mainly good stuff except there is a somewhat technical error:

Another US study published a year earlier found nitrogen levels associated with gas cooking exacerbated asthma symptoms.

That is not what the study found, it found the levels of nitrogen dioxide not nitrogen were dangerous. The air we breath is about 4/5 nitrogen.

Then there is the fun part:

“If the maniacs in the White House come for my stove, they can pry it from my cold dead hands. COME AND TAKE IT!!” tweeted Texas congressman Ronny Jackson, the beginning of an online outpouring that would have impressed the National Rifle Association.

Who cares about science or facts, policy is based on gut feeling and whatever you can make people believe. The ‘cold dead hand’ quote is clearly a reference to the NRA performance by Charlton Heston, apparently Congressman Jackson has a dictionary that does not contain the word “irony”.

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For those looking to make the change.

Some useful advice for those with gas appliances looking to change over.

But if you are switching from gas, you are likely to need some work done, as it probably won’t be OK to run the new stove from an existing circuit, explained Malcolm Richards, an electrician and chief executive of Master Electricians Australia.
“You will probably need to run a new circuit from the switchboard to the electric cooktop to make sure it can run on its own circuit,” he said.
“Then you do need a licensed contractor who can do the calculations to ensure the rest of the wiring in the home can accommodate the additional load.”
Most homes will be able to take the extra load. But older apartments can be trickier.
“In some cases, you may need to talk to your plumber — your gas expert — to remove the old gas plumbing,” Mr Richards said.

Safely disconnecting the gas connection in our experience will require a gas fitter/plumber (licence requirements as prescribed state by state/territory). Also to ensure the gas connection/s are decommissioned securely.

To determine the costs to install the electrical circuit and connect a new induction cooktop plus electric oven to replace an all gas set up. It will require a detailed quote from a local electrical contractor.

For those noting the reference to ‘Master Electrician’ it’s a reference to membership of a trade association,

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11 posts were merged into an existing topic: Are New Home Builders being compelled to connect to Gas?

A new topic has been created to further discussion on when and why new homes are being connected to gas. This is broader than the concerns some have expressed over using gas for home cooking.