Libby H. Koolik
@libbyhkoolik.bsky.social
(she/her) UC Berkeley environmental engineering PhD candidate | MIT '17 and '18 | air quality & equity scientist | amateur vegan chef | https://lkoolik.github.io/
I feel so lucky to have a team of intelligent and kind collaborators on this perspective. Our team represents folks from both academia and EJ community advocates. Thank you all for your support on this work! (10/10)
December 5, 2025 at 7:01 PM
I feel so lucky to have a team of intelligent and kind collaborators on this perspective. Our team represents folks from both academia and EJ community advocates. Thank you all for your support on this work! (10/10)
That’s great for people in states like CA, but not for folks in less EJ-inclined states. My hope is that the good people in local government find our insights helpful and can identify small wins like moving a bus line to reduce traffic in a community or siting EV chargers in polluted areas. (9/)
December 5, 2025 at 7:01 PM
That’s great for people in states like CA, but not for folks in less EJ-inclined states. My hope is that the good people in local government find our insights helpful and can identify small wins like moving a bus line to reduce traffic in a community or siting EV chargers in polluted areas. (9/)
Still, a key finding of our work is that land use and transportation planners have a really important role in mitigating air pollution exposure disparities. These decisions happen at local and community scales, and are even more important without federal support. (8/)
December 5, 2025 at 7:01 PM
Still, a key finding of our work is that land use and transportation planners have a really important role in mitigating air pollution exposure disparities. These decisions happen at local and community scales, and are even more important without federal support. (8/)
In the year since I started this project, the regulatory landscape for environmental policy has changed a lot (understatement). Without a federal government pushing for place-based infrastructure changes or emission mitigations, it will be hard to apply this framework at scale. (7/)
December 5, 2025 at 7:01 PM
In the year since I started this project, the regulatory landscape for environmental policy has changed a lot (understatement). Without a federal government pushing for place-based infrastructure changes or emission mitigations, it will be hard to apply this framework at scale. (7/)
The idea was born from this question from my vehicle analysis: why do huge emission reductions not yield equivalent reductions in disparity? What we found was exactly what EJ groups have been advocating for: structural changes to the distribution of emissions sources. (6/)
doi.org/10.1126/scia...
doi.org/10.1126/scia...
PM2.5 exposure disparities persist despite strict vehicle emissions controls in California
Decades of California’s strict exhaust emissions controls reduced PM2.5 exposure but not relative racial-ethnic disparity.
doi.org
December 5, 2025 at 7:01 PM
The idea was born from this question from my vehicle analysis: why do huge emission reductions not yield equivalent reductions in disparity? What we found was exactly what EJ groups have been advocating for: structural changes to the distribution of emissions sources. (6/)
doi.org/10.1126/scia...
doi.org/10.1126/scia...
We also apply our conceptual framework to the results that other great scientists in the field have produced to identify key components of successful policies. I am really appreciative of the open science & kindness of these other researchers – please go check out their great publications! (5/)
December 5, 2025 at 7:01 PM
We also apply our conceptual framework to the results that other great scientists in the field have produced to identify key components of successful policies. I am really appreciative of the open science & kindness of these other researchers – please go check out their great publications! (5/)
In fact, we use a simple Gaussian plume model to demonstrate why we really should design policies that do all three at the same time! Only when we meaningfully relocate the center of mass of emissions do we fully mitigate disparities before eliminating 100% of emissions. (4/)
December 5, 2025 at 7:01 PM
In fact, we use a simple Gaussian plume model to demonstrate why we really should design policies that do all three at the same time! Only when we meaningfully relocate the center of mass of emissions do we fully mitigate disparities before eliminating 100% of emissions. (4/)
Consider this highway system example (A). Some policies reduce emissions in-place (B), some move emissions away from everybody (C), and some meaningfully eliminate the unfair source distribution (D). While real policies do these together, different regulators tend to control each term. (3/)
December 5, 2025 at 7:01 PM
Consider this highway system example (A). Some policies reduce emissions in-place (B), some move emissions away from everybody (C), and some meaningfully eliminate the unfair source distribution (D). While real policies do these together, different regulators tend to control each term. (3/)
In our perspective, we introduce a conceptual framework to mitigate exposure disparities that does two things. 1: it decomposes why different policies have different outcomes mathematically. 2: it builds an intuition for which policies should be successful at reducing exposure disparities. (2/)
December 5, 2025 at 7:01 PM
In our perspective, we introduce a conceptual framework to mitigate exposure disparities that does two things. 1: it decomposes why different policies have different outcomes mathematically. 2: it builds an intuition for which policies should be successful at reducing exposure disparities. (2/)
I feel so lucky to have a team of intelligent and kind collaborators on this perspective. Our team represents folks from both academia and EJ community advocates. Thank you all for your support on this work! (10/10)
December 5, 2025 at 6:57 PM
I feel so lucky to have a team of intelligent and kind collaborators on this perspective. Our team represents folks from both academia and EJ community advocates. Thank you all for your support on this work! (10/10)
That’s great for people in states like CA, but not for folks in less EJ-inclined states. My hope is that the good people in local government find our insights helpful and can identify small wins like moving a bus line to reduce traffic in a community or siting EV chargers in polluted areas. (9/)
December 5, 2025 at 6:57 PM
That’s great for people in states like CA, but not for folks in less EJ-inclined states. My hope is that the good people in local government find our insights helpful and can identify small wins like moving a bus line to reduce traffic in a community or siting EV chargers in polluted areas. (9/)
Still, a key finding of our work is that land use and transportation planners have a really important role in mitigating air pollution exposure disparities. These decisions happen at local and community scales, and are even more important without federal support. (8/)
December 5, 2025 at 6:57 PM
Still, a key finding of our work is that land use and transportation planners have a really important role in mitigating air pollution exposure disparities. These decisions happen at local and community scales, and are even more important without federal support. (8/)
In the year since I started this project, the regulatory landscape for environmental policy has changed a lot (understatement). Without a federal government pushing for place-based infrastructure changes or emission mitigations, it will be hard to apply this framework at scale. (7/)
December 5, 2025 at 6:57 PM
In the year since I started this project, the regulatory landscape for environmental policy has changed a lot (understatement). Without a federal government pushing for place-based infrastructure changes or emission mitigations, it will be hard to apply this framework at scale. (7/)
The idea behind this framework was born from my first dissertation chapter: why do massive emission reductions not yield equivalent reductions in disparity? What we found was exactly what EJ groups have been advocating for: structural changes to the distribution of emissions sources. (6/)
December 5, 2025 at 6:57 PM
The idea behind this framework was born from my first dissertation chapter: why do massive emission reductions not yield equivalent reductions in disparity? What we found was exactly what EJ groups have been advocating for: structural changes to the distribution of emissions sources. (6/)
We also apply our conceptual framework to the results that other great scientists in the field have produced to identify key components of successful policies. I am really appreciative of the open science & kindness of these other researchers – please go check out their great publications! (5/)
December 5, 2025 at 6:57 PM
We also apply our conceptual framework to the results that other great scientists in the field have produced to identify key components of successful policies. I am really appreciative of the open science & kindness of these other researchers – please go check out their great publications! (5/)
In fact, we use a simple Gaussian plume model to demonstrate why we really should design policies that do all three at the same time! Only when we meaningfully relocate the center of mass of emissions do we fully mitigate disparities before eliminating 100% of emissions. (4/)
December 5, 2025 at 6:57 PM
In fact, we use a simple Gaussian plume model to demonstrate why we really should design policies that do all three at the same time! Only when we meaningfully relocate the center of mass of emissions do we fully mitigate disparities before eliminating 100% of emissions. (4/)
Consider this highway system example (A). Some policies reduce emissions in-place (B), some move emissions away from everybody (C), and some meaningfully eliminate the unfair source distribution (D). While real policies do these together, different regulators tend to control each term. (3/)
December 5, 2025 at 6:57 PM
Consider this highway system example (A). Some policies reduce emissions in-place (B), some move emissions away from everybody (C), and some meaningfully eliminate the unfair source distribution (D). While real policies do these together, different regulators tend to control each term. (3/)
In our perspective, we introduce a conceptual framework to mitigate exposure disparities that does two things. 1: it decomposes why different policies have different outcomes mathematically. 2: it builds an intuition for which policies should be successful at reducing exposure disparities. (2/)
December 5, 2025 at 6:57 PM
In our perspective, we introduce a conceptual framework to mitigate exposure disparities that does two things. 1: it decomposes why different policies have different outcomes mathematically. 2: it builds an intuition for which policies should be successful at reducing exposure disparities. (2/)
Our key recommendation is still important and possible: we need to prioritize reducing emissions in the most overburdened areas at a rate that outpaces the emissions reductions from the overall on-road fleet turnover. I'm excited to keep looking ahead and thinking creatively about how to do this 👩💻
September 12, 2025 at 1:05 AM
Our key recommendation is still important and possible: we need to prioritize reducing emissions in the most overburdened areas at a rate that outpaces the emissions reductions from the overall on-road fleet turnover. I'm excited to keep looking ahead and thinking creatively about how to do this 👩💻
One thing that keeps me optimistic: many of these land use and transportation decisions are made locally. We don't necessarily need to rely on the federal government to design transit-oriented and/or sustainable cities that keep traffic away from people 🌃.
September 12, 2025 at 1:05 AM
One thing that keeps me optimistic: many of these land use and transportation decisions are made locally. We don't necessarily need to rely on the federal government to design transit-oriented and/or sustainable cities that keep traffic away from people 🌃.
We also discussed the importance of paradigm shifts in how we think about mitigating transportation emissions. Land use or transportation policies that can change the spatial patterns of vehicles may be a really important next step for reducing disparities in exposure (more on this soon! 👀).
September 12, 2025 at 1:05 AM
We also discussed the importance of paradigm shifts in how we think about mitigating transportation emissions. Land use or transportation policies that can change the spatial patterns of vehicles may be a really important next step for reducing disparities in exposure (more on this soon! 👀).
In our discussion of our article, we praised some of California's great rules and regulations that drove (ha!) this reduction in pollution from cars and trucks. In the last year, these policies (such as Advanced Clean Trucks) have been under attack by the federal government 😞.
September 12, 2025 at 1:05 AM
In our discussion of our article, we praised some of California's great rules and regulations that drove (ha!) this reduction in pollution from cars and trucks. In the last year, these policies (such as Advanced Clean Trucks) have been under attack by the federal government 😞.
Our major finding: air pollution from California's on-road fleet (🚗 🚚) reduced dramatically, but the relative inequality in exposure for people of color and residents of overburdened communities remained nearly constant. While we want everyone to breathe better air, we also want to close the gap!
September 12, 2025 at 1:05 AM
Our major finding: air pollution from California's on-road fleet (🚗 🚚) reduced dramatically, but the relative inequality in exposure for people of color and residents of overburdened communities remained nearly constant. While we want everyone to breathe better air, we also want to close the gap!