One exciting thing from over the holidays is that the Int'l Civil Aviation Organization (@ICAO) and aircraft engine manufacturers for the first time publicly released quantitative emissions indices for particle # and mass emitted per unit fuel burn! 🧵 1/

https://t.co/zXuFN66SWe

Up until now, certification data for aircraft engine particle emissions have been reported in terms of a "smoke number", which is derived from the change in reflectance of a Whatman 4 filter after collecting 16.2 kg/m² exhaust. 2/

https://t.co/6fa9Kkdupr
One challenge with the smoke number measurement is that the filter doesn't capture all of the particles -- especially small ones. Is the decrease in smoke number over time because we are trading a few large soot particles for many more smaller soot particles? 3/
While smoke numbers are not particularly helpful for quantitatively assessing particle emissions impacts on air quality & upper tropospheric composition, they have been a huge success in motivating the reduction of unsightly exhaust plumes! 4/

Photo credit: flickr/dsleeter_2000
The new EI data are much more useful for #AirQuality and #Climate modeling efforts seeking to understand the environmental impacts of aviation. Since they're collected at ground conditions, the data are most relevant to AQ, but maybe can be extrapolated to cruise conditions? 5/
Of course, we still need to understand how well the certification EIs capture real world, near-surface emissions impacted by fuels, engine maintenance, and human behavior (e.g., reduced thrust takeoffs). 6/

Leipzig/Halle: https://t.co/ITMszAGSej

LAX: https://t.co/fSADIkoXEw
We also know that "spreading contrails and the cirrus clouds that evolve from them -- collectively known as contrail cirrus -- have a greater radiative forcing today than all aviation CO2 emissions since the first powered airplane flight" - B. Kärcher 7/

https://t.co/zLXnWyDCwc
If we can reduce engine soot particle emissions at cruise enough to fall below the soot-rich emissions regime (threshold ~ 10¹³ to 10¹⁴ per kg fuel) then that would translate into a reduction in climate-altering, aviation-induced cloudiness. 8/

https://t.co/Pi22W6Gw4Y
There are a number of promising approaches for meeting these targets in the short term including the use of sustainable, bio-based jet fuels as well as introduction of lean-burning combustion technologies. 9/

https://t.co/FSZWr27Tmg
Models of contrail formation and persistence provide the key to targeting these efforts when the economics might not make sense for widespread adoption of advanced (& expensive) biofuels. We can focus on large "contrail outbreaks" to have big impact! 10/

https://t.co/j3SmQwl0yy
The new ICAO aircraft engine particle emissions data released on Dec. 23rd are fertile ground for understanding how changes in engine technology (particularly advanced, lean-burning combustors) will impact the environment both near the ground and high above! 11/11
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I want to share my thoughts, as someone who has been so alarmed by the so-called "dissident" scientists like Gupta, Heneghan, Kuldorff, Bhattacharya, & Ioannidis who consider themselves brave Galileos unfairly treated by "establishment scientists." I will try not to swear. 1/n


I want to talk about 3 things:
‼️Their fringe views are inhumane, unethical junk science that promotes harm
‼️They complain that they've been marginalized but this is simply untrue
‼️I am sick of people telling me we have to "listen to both sides." There aren't 2 sides here 2/n

These 'dissident' scientists have consistently downplayed COVID-19, urging policymakers not to take aggressive control measures. They claim it is not a serious threat. Gupta even went on TV saying people under 65 shouldn't worry about it!

RECEIPTS

They have consistently argued that policymakers should just let the virus rip, in an attempt to reach herd immunity by natural infection. Kuldorff *continues* to argue for this even now that we have many highly effective, safe vaccines.


We've never controlled a deadly, contagious pandemic before by just letting the virus spread, as this approach kills & disables too many people. In Manaus, Brazil, 66% of the city was infected & an astonishing *1 in 500* people died of COVID-19
All modern research questions frame your mindset and self-frame research paradigm. Broad thinking: how little of everything can a citizen survive on; how cheap can your upkeep be? /1


When an American patient lands in an Austrian hospital for a back problem, a doctor tells him to perform a set of exercises.

- How many?
- Do you have anything else to do? /2

This interchange illustrates two mindsets colliding at bedside. How little can I get away with vs there is no limit to effort when it comes to your wellness. /3

When you were robbed of movement, somebody started selling you exercise. To understand that digging a ditch, to build a house, or to carry a child around, or waking to your grandparents for an hour is not the same as jogging on a treadmill... will reveal what research hides.
/4

When I talk about doing a purposeful activity outdoors, I look at complexity of movement, purpose, meaning, sun, and air, even an opportunity to meet a neighbor... that is now reduced to a calcium pill, vitamin D, an antidepressant, an osteoporosis shot, and an oxygen tank. /5

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