Dan Westervelt

What’s Up With New York’s Bad Air Quality This Week?

This week's air quality dip in NYC is connected to temperature fluctuation, says LDEO expert @dwesty.bsky.social. Recent cold/snow created a "temperature inversion" where temps near ground became cooler than those above, causing pollutants to build up. Via @nytimes.com. https://nyti.ms/3OADZty

Ambient air quality and health impacts of PM2.5 from US residential wood combustion Air pollution from residential wood burning contributes to thousands of premature deaths annually, with unexpected urban impacts.

The study itself can be found open access here: doi.org/10.1126/scia...

New wheels! Our first EV, the Kia EV6. Plugged in at the @lamont.columbia.edu charging point conveniently located right outside of my office!

Blessing us with dirty air today as well! bsky.app/profile/dwes...

Could clearly see the polluted boundary layer while going across the George Washington Bridge today!

screenshot of AQI from AirNow. Green = good. Yellow = moderate. Orange = unhealthy for sensitive groups

Textbook winter temperature inversion across the mid-Atlantic today impairing air quality (yellow = moderate AQI). A 20+ ºF swing in warmer temperatures today versus the last few days means warmer air aloft than at the surface (air has a lower heat capacity).

Save NCAR from being dismantled today! The Trump Administration has vowed to dissolve the center that provides critical extreme weather and climate data for our nation.

The Trump Administration's plan to dismantle the @ncar-ucar.bsky.social is senseless & dangerous.

It would weaken weather forecasting, climate research, & the science that keeps people safe.

We urge that this plan be abandoned.

Call Congress to #SaveNCAR today. buff.ly/7ka1BQA

Also if you are at AGU this week, we have a poster on this topic on Thursday, details here: agu.confex.com/agu/agu25/me... (4/4)

with some evidence of spillover effects increasing NO2 or PM pollution outside of the tolling area, possibly due to traffic rerouting. Currently in review at Scientific Reports, with the preprint available here: www.researchsquare.com/article/rs-8... (3/4)

when things like causality, equity/environmental justice, and other types of pollutants are considered, the picture is not as clear. Our new work finds uneven short-term air quality impacts of congestion pricing, (2/4)

There has been a decent amount written thus far on the air pollution response to New York City's congestion pricing policy, most of which has been overwhelmingly positive. While PM2.5 concentrations are indeed down at most locations in NYC, (1/4)

In case you're working on NSF COA

Our new article out today takes a hard look at some practical limitations on stratospheric aerosol injection and what they means for the riskiness of this approach. @mcneill-lab.org w/ @gwagner.com & @steingart.bsky.social @climate.columbia.edu @columbiaseas.bsky.social

Here's the press release:

Group dinner

Columbia Dinner 🩵🩵🩵 with Westervelt Group @dwesty.bsky.social , @mcneill-lab.org past and present, @aqtoolbox.org and some additional @climate.columbia.edu friends! #AAAR2025

😱

Nice profile in Columbia News related to the Climate Week event we hosted Monday @aqtoolbox.org @mcneill-lab.org

We sat down with V. Faye McNeill to discuss her work co-leading the Clean Air Toolbox for Cities Initiative. Her upcoming event, happening during #ClimateWeek, will showcase pioneering work by researchers paving the way towards cleaner air and a sustainable climate.

https://bit.ly/46bc2iq

Image of heatmap for Ghana showing air pollution data trends using a heatmap.

The GRASP dataset is expanding access to air quality data across the continent.
Update: Ghana’s dataset is now live, providing daily PM2.5 trends from the early 2000s through 2024. A powerful tool to inform research, policy, and action for #CleanAir4Africa.
🔗 Explore here: bit.ly/42mk99m

📣 A new #AirQuality dataset for Ghana from @dwesty.bsky.social & colleagues

Register today:

Data and Partnerships for Global Clean Air and Climate

Join us during #ClimateWeek @Columbia for an @aqtoolbox.org event,
"Data and Partnerships for Global Clean Air and Climate"

@columbiaseas.bsky.social @climate.columbia.edu @climategroup.bsky.social @openaq.org @columbiauniversity.bsky.social @lamont.columbia.edu @dwesty.bsky.social

Secondary organic aerosol in urban China: A distinct chemical regime for air pollution studies In the past decades, China has witnessed high air pollution associated with rapid economic development, although regulatory efforts have alleviated the situation since 2013. Haze events characterized ...

Sometimes patience pays off... This paper has been in the works since I was still in my 30s 🤣

It was a pleasure to travel to Xian and work with @amgcarlton.bsky.social and other friends and colleagues on this

Effects of germicidal far-UVC on ozone and particulate matter in a conference room The application of 222 nm light from KrCl excimer lamps (GUV222 or far-UVC) is a promising approach to reduce the indoor transmission of airborne pathogens, including the SARS-CoV-2 virus. GUV222 inac...

Happy to see this one out!

TL;DR: under the right conditions* GUV lamps aren't too bad for air quality in a real-world conference room

*only use the minimum necessary GUV intensity for the space, preferably have good ventilation

journals.plos.org/plosone/arti...

Canadian wildfires are impacting air quality in the U.S. Canada is having its second worst wildfire season yet. Two scientists explain what a red air alert means and how anyone living in impacted areas can protect themselves.

In the past, emissions from power plants or vehicles were bigger drivers of bad air quality. Now, wildfires are pretty much the whole story when it comes to air quality problems in the US, says @lamont.columbia.edu climate scientist @dwesty.bsky.social. Via @npr.org.

in line to submit AGU abstract

Tough scene for us last minute abstract submitters! #AGU

Cleaner air has increased the number of city heatwaves Reducing air pollution is critical for improving public health, but it has brought big climate trade-offs

New study finds that cleaner air has accelerated the increase in heatwaves. "The findings are compelling and add to a growing body of literature on how aerosols can have out-sized impacts on climate extremes," says @lamont.columbia.edu climate scientist @dwesty.bsky.social. Via @newscientist.com.

Nice article on a recent insightful paper, featuring a quote from me

New research from a large team including myself pointing to aerosol reductions in East Asia being responsible for recent observed acceleration in global warming. In particular we find this to be a bigger driver than the oft-mentioned shipping sulfur emissions reductions.

How Fireworks Impact The Environment - Videos from The Weather Channel Fireworks are synonymous with the Fourth of July, but they come with a hidden cost. Beyond the bright colors and loud booms, they release pollution and harmful chemicals that can impact both the envir...

"If you look at a time series of the entire year of data, you can almost instantly pick out July 4th because there'll be a huge spike in particulate matter concentration," says @lamont.columbia.edu expert @dwesty.bsky.social‬, with implications for the environment & health. Via The Weather Channel.

If they close all these research labs, you can't just undo it four years later.

Decades of expertise and tons of specialized equipment will be scattered to the wind. Rebuilding would take ages.