Dear X-Men, There may be new tech option to eliminate a LOT of the dirty air in the world’s cities, which I have already sent all over the Internet with little or not interest or replies. The FAA, or Federal Aviation Administration, invented a Nanotube air filter, now inside of all passenger jet airplanes, which separates outside air, into its gas elements of pure Oxygen, and pure Nitrogen. The Nitrogen obtained this way is piped into the plane’s emptying fuel tanks, because there was a disaster, where static electricity sparked a lethal explosion in an airliner’s fuel tank. Because Nitrogen is an INERT gas, unlike Oxygen, the static electricity, which they could not eliminate, CANNOT ignite an explosion in the emptying fuel tanks. ANYWAY, why not retrofit these devices into all semi-trailer trucks, and all of the passenger ships in the world, because these filters can CHEAPLY provide a lot of Oxygen from outside air, to put into the diesel engines, to enable TOTAL combustion of their ‘dirty’ diesel fuel, to enable better mileage, and also burn up ALL of the tar, etc. that makes the SOOT causing the air pollution in our cities. This option might also present the big passenger ships from emitting soot that is indirectly warming the Earth’s polar ice caps by covering the black soot particles over the icecaps, so they absorb more solar heat and melt faster. That covers it.-Robert Schreib
Welcome to our community Robert! @rgschreib
Thank you for sharing your input on a proposed solution to clean up the air.
@akb, @hopkepk, @djaffe, @DanBowden @jamesburbridge
I feel you all may have more insight here on the proposed solution shared by Robert. Please join the discussion!
If air could be readily separated into a nitrogen stream and an oxygen stream then this might provide an opportunity to improve combustion engines.
Removing nitrogen from the engine intake would prevent the formation of nitrogen oxides (NOx) - a significant pollutant.
Plus an increased oxygen content in the engine intake would probably enhance the combustion efficiency and reduce those pollutants caused by incomplete combustion (carbon monoxide, volatile hydrocarbons, and particulates). However, the engine management system would have to be re-calibrated for this oxygen rich intake. It may also require significant changes to some aspects of the engine and exhaust control systems.
So potentially, such a device could be beneficial - if the device can be deployed in a viable manner (e.g. low cost, and low energy requirement).
Looking at the long-term picture, forward looking countries are now committing to the removal of combustion powered (petrol and diesel) vehicles and replacing them with zero emission vehicles [by 2030, 2040 or 2050, depending on the country]. So technologies to reduce the emission levels partially, can’t compete with the forthcoming zero emission vehicles. In other words, such solutions are perhaps just a short-term fix.
@akb I tend to agree with your parting thoughts on the transition from ICE to EV, although depending on where you get your power from this could lead to more SOx or NOx from coal-fired power gen, mostly in the developing world.
@rgschreib I do love the idea of applying new tech like the nanotube air filter to combat urban air pollution. We’ve heard of some interesting interesting reactions between types of air pollution and certain catalysts, for example tropospheric ozone and gold. Are there other cutting edge or novel approaches to reducing urban air pollution either of you can think of?
@akb - the goal of zero emissions vehicles is a good and necessary one, but is currently beyond our technological capacity for jet airliners. That said, perhaps hydrogen-based jet fuel is being developed by some lab somewhere.
As for carbon nanotubes…scalable manufacturing of 3D graphene structures (nanoscale tubes or other architectures) at the macro scale is NOT cheap, but rather costly, right now (e.g., graphene ‘sieves’ for separating waste by-products). This will change as more efficient and scalable nano-to-macro scale manufacturing processes (such as mass chemical vapor deposition) come on line.
Further, there is the issue (often neglected) of carbon nanotube pollution; CNTs can easily penetrate cells, and, while the data on cell/tissue toxicity is mixed (largely due to inconsistent testing on in vitro cell cultures versus in vivo/ex vivo analyses)…there is reason to be cautious about their wide-spread use – especially in the context of air-filtering (wherein we are inhaling the CNT-filtered air that probably contains airborne nanoparticles).
Also: I am not sure what is meant be he term “pure” here as far as Nitrogen and Oxygen goes…atmospheric Nitrogen and Oxygen (the presume sources of the air to be filtered) are actually N2 and O2 (mostly, with a small % of single-atom ionic forms) which are more stable forms.
There seems to be some confusion here. If we are talking about particulates, then miscellaneous sources are the greatest contributor to atmospheric concentrations in the US. EVs are not going to make much difference to particulate concentrations. If we are talking about CO2 emissions, then EVs will help, provided the source of electricity is low, or no, carbon. Since fossil fuels still generate nearly 2/3 of our electricity, that is not currently the case. Further, for issues of grid stability alone, both fossil plants and renewables will be needed as we go forward.
Regarding combustion efficiency, in the US, combustion efficiency is already 99.8+%. The concept of separating oxygen from air for use in combustion won’t do much to increase combustion efficiency, which is primarily a physical mixing problem. The problem with combustion in pure oxygen is that the combustion temperature would be such as to melt the various machines that would be doing the combustion (ie boilers, IC engines, gas turbines, etc.) Oxygen firing has been tested as a means of generating a concentrated CO2 stream, which was accomplished by recirculating CO2 so as to get a synthetic mixture with the same temperature profile as air firing. NOx generation from thermal formation may be reduced, but NOx generation from fuel bound nitrogen will be about the same. Sulfur compounds, particulates, mercury, and heavy metals would still be the same. Handling pure oxygen requires some safety consideration that are not part of present day combustion systems for air.
Good point @jamesburbridge : “EV, although depending on where you get your power from this could lead to more SOx or NOx from coal-fired power gen, mostly in the developing world”.
Like @marz62 I’d also echo the desire for plenty of research into the potential impacts on health of carbon nanotubes.
[Adopting the precautionary principle.]
Throughout the history of science and innovation we have often pushed forward without adequately researching the health and environmental implications until decades later - often at great cost.
Air pollution is a complex subject, and it has a number of perspectives as @carlbozzuto touches on. One perspective that is relevant to the health of populations living in urban areas is the particulate pollution from vehicles, particularly diesel vehicles. In pollution hot-spots, particulate pollution represents a significant health problem. In that sense the introduction of low/zero emission vehicles (such as electric vehicles) represents a significant health improvement.
On a wider scale, and from a CO2 perspective, we also have to consider how the electricity for those vehicles is generated. We would probably advocate the use of clean renewable sources of energy. “Clean” should also include the lifetime impact of the products and processes involved.
[It’s also worth reflecting on the fact that not all particulates are equal: not all types have the same health impact. Relevant factors include: particulate size, internal chemistry, and chemicals adsorbed on their surface. We discuss this in the particulate monitoring topic in this community.]
Hello again @carlbozzuto and @akb
The conversation going on here is one we’ve had internally almost from the beginning of the project. Personally, this problem generally gets solved by replacing fossil fuel power generation with renewables and electrifying EVERYTHING. Yes, we would still have to deal with agricultural pollution, and some of the miscellaneous sources Carl mentioned, but by and large, the end of fossil fuel burning for heat and energy would take care of the problem.
However, we live in the real world and renewable installation and grid expansion of the scale we are talking about just isn’t going to reach the developing world any time soon. So what do we do in the meantime? We have a pretty good understanding of where air pollution comes from and that capability is getting better by the day almost. Emission controls are the optimal answer, but require strong governance and compliance mechanisms, something that I reckon we can’t always rely on given competing priorities. That leaves us with pollution removal, an unbelievably daunting task that borders on impossible, except that we know it is possible to remove some pollution from the air, just not at the scale necessary to make a major impact. We can calculate the air mass necessary to clean and the amount of PM to remove, now we need to start building off what we already know and can do and work toward scaling up what is possible!
Who’s with me!!!
(Forgive me for the run-on sentences…)
I fully agree with that overview of the challenge we face @jamesburbridge and I’m with you!
Two additional thoughts spring to mind: scenarios; and deployment.
Perhaps two types of scenario might be relevant here: modern (wealthy) cities; and poor urban/rural areas. We can imagine a high tech costly solution for those cities and perhaps an alternative approach for other areas that cannot afford that technology (their need is as great, and perhaps greater from an health perspective). [And there’s also the opportunity to address those burning (wood) indoors and suffering from indoor air pollution.]
Deployment times for infrastructure are notoriously slow (although China sometimes excels at this). So a rapid automated deployment of the winning solution would be a relevant and useful factor in the XPRIZE challenge. It’s likely that it might also reduce the cost of deployment; and if we’re very lucky, it might make the solution applicable to both scenarios.