DRAFT Air Pollution Removal Prize Parameters

Hello all,

Here is a draft of what a broad, technology agnostic air pollution removal prize design could include. Please note that this is strictly a draft version meant to stimulate discussion. It in no way reflects a decision of or commitment by XPRIZE to move forward with this type of design. We look forward to all of your feedback!

Click here for the Draft Air Pollution Removal Prize Parameters

Ambient air impacts are going to be difficult to measure directly. There are too many variables that will impact ambient air. The test facility will not likely treat enough ambient air to impact the actual level, perhaps even locally. Net negative carbon is not practical for this exercise. If we are going to deal with ambient air, then we need to think about how an appropriate test set up would likely work. There are already any number of filtration devices that can be tested. The question is how to get enough volume of ambient air treated to make a difference. One could conceivably do some ambient air modeling to try to estimate the amount of particulate removal at some smallish area and then look at the downwind concentrations to see if there would be a noticeable difference. However, the real goal is to reduce the amount of particulates in ambient air. The basics are the amount of air treated and the amount of particulates removed. If ambient air is currently 12 micrograms/m3 in the US and we would like to get it down to 9 micrograms/m3, we would need to remove 3 micrograms/m3. That figure (ie 3 micrograms/m3) should be the primary target. Whatever system gets tested, the amount of ambient air treated and the amount of particulates collected should average out to at least 3 micrograms/m3. The assumption there would be that eventually, all of the air in the country would be treated. This may or may not be the case. Some assumptions would have to be made about how much air can eventually treated with the proposed system. If only half the air can be treated, then the target figure would get doubled.
Reliability would be a major consideration. A test period of at least 6 months with an “on stream” factor of at least 85% should be required for a demonstration. Stick with particulates. Other gases will be a distraction from the main goal. Some consideration needs to be given to waste disposal (ie land fill) vs incineration. At this point, dust in the air is not likely to be particularly useful, especially since we don’t really know what is in the dust. That would be a “nice to have”. Capex, at this point will be very difficult. No one is going to know the actual cost of building a system until one is built that is demonstrated to work reliably. My company built the first SO2 scrubber for $2/Kw. It didn’t work. By the time we got done with development, the system cost $200/Kw. Energy, water, and other consumables need to be accounted for. At this point, I don’t think we know enough to put a limitation on the system. These will have to be scored in some way.
As an example, one can go online and buy a room air cleaner for around $200. The amount of air treated is on the order of 7,000 ft3/hr. The system uses an activated carbon bed to adsorb certain chemicals, a HEPA filter to remove dust down to 0.3 microns (99.97% removal), and a TiO2 plate that is activated by UV light to destroy VOCs, germs, viruses, mold spores, and anything else that is organic in nature. The TiO2 is an oxidation catalyst that works in the presence of moisture and UV light. It will also oxidize CO, SO2, and NOx to CO2, sulfates, and nitrates (ie particles). A 5 speed fan draws the room air into the device and cleans the air. The average air turnover for the room is 5 times. The performance benefits are obvious. The question is how to scale up such a system to treat vast quantities of ambient air. For example, a good size power plant produces 70 million ft3/hr and that certainly does not use all of the air in the country. That should give you some things to think about. If I did my estimates right, there are about 7 e17 lb air sitting over the US, or 1 e19 ft3.

Great stuff @carlbozzuto, much appreciated. We’ve been thinking quite a bit about how testing for this style of competition might look, harboring some of the exact same reservations about testing in ambient air. More work to be done.

Hi @hopkepk , @Ananya_Roy , @bartc , @kchance , @DanBowden , @alanDRI , @mccubbin ,
We would love to have your inputs and feedback on the prize design parameters. Please join the discussion. Thanks.

I see the mention of “net negative carbon footprint”.

This is the first I have heard of this important metric.

I assume this means performing a life-cycle analysis (LCA) using some established basis?

@KeithDPatch good catch, we didn’t intend for that to read ‘carbon’ but rather ‘pollution footprint’. The thinking there is that a potential solution shouldn’t release more pollution over the course of its lifecycle than it can capture, validated via LCA.
We have a similar requirement in the Carbon Removal Prize Design.

Hi @paulwuebben , @Cerruti , @Sierramtz , @rohan9602 , @dwcollins1960 , @cnoonan , @hannusalmela , @Chandra_Bhushan ,
We are keen to have your feedback on our preliminary prize design. Please join the discussion. Thanks.

Good Afternoon Everyone,

Exciting topic and really appreciate the many prior comments - especially concerning LCA and the critically important considerations around embedded energy and the importance of holistic thinking (@carlbozzuto).

From our experience around the world, we find the challenge with air quality management is not actually a lack of solutions, but that there is too little data to understand where/how/what is the best solution for a given community. These political/economic risks often result in limited action (investments and/or legislation) - especially in the resource constrained geographies of the world.

A few challenges and comments I see with the current prize design parameters:

  1. Local vs Regional Pollutants: **
    One of these key challenges with particulate air pollution (PM1, PM2.5, PM10, etc.) is that many cities/regions are struggling with transboundary sources. For instance, even if Singapore was running on 100% clean energy and operating solely zero emission vehicles throughout the city (dream big?) Singaporeans would still struggle with significant the smoke haze several weeks/months a year from the agricultural practices of neighboring countries. This doesn’t mean that a local solution impacting local sources isn’t working, but your design of experiment for particulate matter will be a significant challenge.

On the other hand, Nitrogen Dioxide (NO2) can frequently vary rapidly over only a few meters. This is a key reason Clarity Movement has been focused on deploying dense networks of low-cost sensors that can measure NO2 in real-time. Frankly, the existing regulatory monitoring infrastructure in most cities today is completely insufficient for really understanding what is happening with NO2 when they modify transportation access or close roads. Unfortunately, without proper alternatives we’ve often found that cars are simply re-routed to smaller roads that have even less capacity to handle the volume of vehicles. Moving the problem is not the same as solving the problem.

2) Project Duration & Maintenance/Calibration Considerations:
The draft parameters suggest days/weeks/months long evaluation time frames which can be quite problematic for air quality management. As per the prior Singapore example, many communities/cities struggle with highly seasonal pollution episodes that can only be compared year-over-year. It is likely one would want to understand the “test area’s” baseline pollution for one year and then perform your comparison (with lots of measurement) to ensure a proper A-B evaluation of the selected solution.

As far as maintenance/calibration, air sensing (especially gases) is quite complicated - especially if you want data that can achieve some level of comparison with regulatory measurements. We believe it is absolutely essential to ensure that appropriate, ongoing QA/QC is being implemented such that decisions (that impact lives and health!) are being made on accurate data. Too often projects are being funded as “Innovation Theater” only to have their applications languish as the solutions are not properly maintained or insufficient budgets to continually maintain the “solution”. This is a key reason we’ve focused on working directly with governments/businesses and included continuous maintenance and QA/QC with our measurement fixed-price service.

Regardless of the solution selected it is essential to have a credible evaluation plan for the duration of the project.

3) Scaling Market-Based Solutions:
I strongly believe that the prize should focus on innovative applications/approaches to apply existing solutions at the largest scale possible. There is substantial funding available through the U.S. (SBIR, NSF, DOE, DHS, etc.) and EU (H2020) for R&D to help lower TRL solutions grow/improve developing technologies. The world needs clear case studies to understand the return on investment of the solutions they are making. When the economics of clean(er) air are clear that investment in zero emission fleets, designated bike lanes, cleaner energy generation portfolios will become common sense.

It is imperative that the solutions are economically-viable and market-based. One of my first suggestions to new cleantech/environmental startups is “Don’t sell your morality - sell the value ($$$) of your solution.” Cleaner air can save governments and businesses lots of money in the big picture. For better or worse, it’s easier to trust such entities to act far more urgently in their immediate financial interests than out of a moral obligation to future generations.

Looking forward to your thoughts and comments!


@swihera , @jamesburbridge
Let’s think a little bit more about scale. I mentioned that a good sized power plant generates about 70 million ft3/hr, most of which comes from air. That means that there is sufficient fan capacity to move that much air. Further, each plant has a particulate control device. Let’s just take the fan, the particulate control device, and the stack as our air cleaning system. We can make the size of the plant a little bigger and fans are very reliable, so 8000 operating hours should not be a problem. That would give us 1 trillion ft3/yr of air cleaning capacity. If we wanted to treat all of the air in the US in one year, we would need 10 million such units. Of course, we don’t really have to treat all of the air in one year. Let’s say 10 years. That would imply 1 million units. After that, we should be on maintenance. While this represents a lot or equipment, it is doable. The approach would be to make this a utility function, just like water treatment facilities. There are some 20,000 cities and towns in the US. Each one would need 50 of these units on average. Citizens would be taxed or charged for the clean air produced. For the sake of argument, let’s assume that the particulate control device is a bag house. The collected particles could then be easily collected and land filled. There would be no chemical additives. Operating costs would consist of the power to run the fans and the bag house controls. Over time, the bags tend to deteriorate, so that would be an operating cost to be factored in. By the way, this estimate would hold for any air capture technology (ie SO2 removal, NOx reduction, CO2 capture, etc.). There is just a lot of air to be treated.

Hi @Alessandra , @Simonyu , @gzeg , @Adaryani , @devinny , @jwangjun , @peterstyring , @oscarr , @ET_Tony , @Robert_Tulip , @JimGaston , @chrisfrider . @hlee
We would love to have your feedback on the uploaded preliminary prize parameters.
Please join the discussion. Thanks.

Hello @yousotchik , @hyungjoo_lee , @mskoehle , @asbock2 , @Mehta , @Lyz ,
We look forward to your feedback on parameters of preliminary prize design.
Please join the discussion.

Hi @jamesburbridge great work.
The draft Prize Design shows a great deal of thought has gone into this complex and challenging topic (air pollution). It identifies many key points and parameters, and poses some interesting questions.

Some initial thoughts to this are presented below.

The phrase “prevention is better than cure” can be applied to air pollution generally, in the sense that it is usually much easier to capture emissions at source, or not generate them in the first place (rather than trying to suck out pollutants over a vast area).

Given that this challenge attempts to do the latter the above paragraph is still useful because it allows us to consider the following:

  1. How long will it be before most emissions at source are prevented? (years)
  2. Over what area would a solution actually be deployed? (hot spots, selected roads, wider areas)
  3. What types of environment would the solution be deployed in? (urban, suburban, rural)

The XPRIZE community have shown that removing pollutants from ambient, outdoor, air represents a huge technical challenge. This is what XPRIZEs focus on (audacious challenges) but with point 1 in mind: how long would it actually take to deploy a fully working infrastructure and would project completion dates pass the point at which emissions at source have been prevented - thus rendering the approach obsolete before its completion?

For example, emissions from vehicles will be significantly reduced (in clean zones) within the next 10 years, and significantly reduced in many urban areas within 20 years (thanks to low and zero emission vehicles, e.g. electric). Assuming an XPRIZE challenge of 3 years, legal and urban planning of 3 years, and a contractual and construction time of 3 years, the first solutions deployed might only deliver ~10 years of useful service across a wide urban area before they were no longer needed (due to emissions at source being eliminated). In the case of clean zones they might be obsolete before installation has been completed. Other emission sources exist, of course, but it is reasonable to assume that these too will be prevented within the next 10 to 20 years - via technological and policy based solutions.

If, on the other hand, we assume time to deployment is not an issue then we can consider points 2 and 3. These ambitious projects might have more chance of success if their scope is focused on a few limited areas where the greatest environmental/health impact is expected: hot spots where many pedestrians are exposed to pollution. Pollution levels, from traffic, can be higher near busy roads and intersections; and in street “canyons” (streets with high buildings both sides of the road, trapping air pollution). Pollutant concentrations are also greatly affected by the weather, particularly the wind and vertical air currents. On days with no air movement pollution levels escalate. So potentially a limited number of hot spots could have their pollutant concentrations kept below legal limits. If the operational factors (e.g. energy and cost) were high then the devices might only be activated when those locations exceed legal limits (e.g. at times of high traffic flows and unfavourable weather).

Having said that, the above overlooks those scenarios where wide spread pollution is produced by a combination of factors from different emission sources (e.g. traffic locally and further afield, industry, power generation, secondary pollution (photochemical smog), and agricultural and forest fires). This might require a much larger and expensive deployment of the proposed technology. That challenge might be too great (but we don’t know unless we try).

With the above in mind, here are some comments on specific aspects of the draft prize design…

Re: AQI to <50

Different countries have different air quality index algorithms and values, and these are subject to change as epidemiological studies learn more and national governments make their own intreprations of what is “safe”. Recommendation: use specific values and units (e.g. micro-grams per metre cubed) for each pollutant concentration to avoid those ambiguities. Using international values might be useful: WHO air pollution limits / recomendations.

Re: Total PM removed
● Metric = micrograms of PM removed from ambient air
● Alternatively, or in conjunction, could be measured as a rate (i.e. PM removed per minute or hour)

Assuming the technology presents a given area to the polluted air (e.g. as a fan’s intake, or a static surface), it has to extract pollution at a comparable rate to that of the (local) emissions source, or the rate of pollutant delivery (by wind and diffusion). For example, a canyon type street (with no wind) might have to extract pollutants at a similar rate to the total vehicle emissions on that street - but if only part of the street has the clean air technology fitted then it might have to extract pollutants at a faster rate. Admittedly, this complicates matters because we have to know how the technology will be deployed spatially. So rate of extraction might be required, e.g.:
micrograms of pollutant per unit surface area (of the technology’s interface) per minute.

Re: Total Gases removed

Similar to PM (above).

Re: Minimum Length of Time Tested

To test durability and operation under a wide range of weather conditions the longer the better. Testing in extremes of weather is relevant (summer, sun, hot, winter, cold, windy, no wind, atmospheric inversion layer, fog). Yes: include maintenance (and pollutant removal) aspects in the test cycle.

Re: Energy usage

Yes: assess energy consumption (per mass of pollutant extracted?) and the technology’s own environmental impact (emissions, etc.).

Re: Land Use / Footprint

Needs to be assessed (and see example above with canyon street).

Re: Waste Disposal

It might be useful to know how the collected waste is extracted from the device, how easy it is to do, and how often. For example, would a lane on a street have to be closed while the waste is extracted? Is the process risk free? What are the costs?

Re: Water Usage

If a technology proposes flushing the waste down the drains then the environmental impact of that should be considered [consult the relevant waste water authority].

Re: Cost

All costs are of interest (capital, installation, operation and maintenance), but it’s always difficult justifying whether a proposed environmental solution is worth it. For the purposes of the challenge, if all other factors are equal amongst competitors’ solutions then cost might be the deciding factor. Perhaps a maximum viable cost could be crudely estimated by looking at something like the London congestion pricing and its new emissions related charge (specifically) and using that as a guide to derive a maximum cost for a technology. [Assuming a scenario where vehicle emissions are the primary concern. Not sure how to approach other (more complex) scenarios.]

Re: Monitoring - Reporting - Modeling

This might be a separate, but worthwhile, XPRIZE. It could be independent of the air cleaning technology prize. Although the infrastructure for an air cleaning approach would need to monitor that the air cleaning technology is working efficiently and air quality levels are maintained as expected.

Re: Waste Conversion Bonus Prize/Points

In the “upcycling” world we might want to turn the waste into a useful form. (Whilst being careful what it is used for, as some pollutants are toxic and will probably remain so.) Depending on the actual scale of deployment though, the quantity of waste might be relatively small.

Hi @akb, sorry your comment didn’t go through earlier. It’s up now.

Thanks @NickOttens

On reflection of my above post…
“Yes: include maintenance (and pollutant removal) aspects in the test cycle.”

On the other hand we might want to be careful. How robust is the prototype when it is not maintained? Could it be that the competitor uses the “maintenance” opportunity to make up for some limitation in their prototype?

In the Carbon XPRIZE, we are only looking at operating cost. For early stage developments, capital cost is a wild card. In our discussions, we decided that complexity could be considered when comparing two otherwise successful competitive teams. The more complicated a process is, the more likely it is that the capital cost will be high. For most new technologies, you don’t know the capital cost until you build it.
In the US, point source emissions of particulates are estimated to be 20 million tons/yr. Open source emissions (dirt roads, construction activities, wind erosion, wild fires, paved roads, tillage, and mineral extraction) are estimated to be 390 million tons/yr (according to EPA). Ratcheting down another 50% on point sources would only reduce overall emissions by around 2%. Of course, this is in the US. The EU and Japan likely have had similar progress on point source controls. Other parts of the world have not been as diligent.

Thanks @akb and @carlbozzuto for your excellent feedback and inputs.

Using drone to purify indoor air. See www.RoboticVectorControl.com my own patented method.

Great stuff as always @akb and @carlbozzuto . The pollutant removed per unit of surface area is a good one for us to think about. We’ve been thinking about it in terms of time, but haven’t been certain how to include area, only that we need to include it somehow. We’ll be sure to post any updates to the parameters/metrics as they come up.

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