Ronald C. Cohen | Research UC Berkeley

Research Expertise and Interest

climate, greenhouse gases, air pollution, atmospheric chemistry, environmental chemistry, analytical chemistry, ozone, nitrogen oxides, CO2, clouds, Atmospheric Aerosol

Research Description

Ronald Cohen's research aims to describe and understand the connections between human activities, greenhouse gas emissions and poor air quality. In his research project, BEACO2N, he and his team are operating a neighborhood scale long-term observing system for tracking CO2 and air quality: http://beacon.berkeley.edu/about/. This project was one of three “Climate Data in Action” efforts recognized in the Obama administration’s Climate Data Initiative in summer 2014. The project is following trends in CO2 and related gases and aerosol in cities including the Bay Area and Los Angeles in California, Providence, RI and Glasgow, Scotland. The project is reporting on trends in CO2 emissions with short lag times, km scale resolution and the ability to pinpoint emissions by economic sector. In other research his fundamental chemical research on organic nitrates established that these molecules are the main path for removal of atmospheric nitrogen oxides on the continents. His research using satellite measurements of nitrogen oxides has established new methods for achieving accurate interpretation of trends in urban chemistry: http://behr.cchem.berkeley.edu/. He has published extensively on the links between high temperatures and poor air quality--identifying key aspects of atmospheric chemistry that are unimportant most of the time but play the primary role in governing what people are breathing when it is hot.

In the News

a charging cord inserted into the port of a white electric drive car

EVs Are Lowering Bay Area’s Carbon Footprint

An extensive CO2 monitoring network set up around the San Francisco Bay Area by a Berkeley professor has recorded the first evidence that the adoption of electric vehicles is measurably lowering the area's carbon emissions.

masked scientists and policymakers gathered around GHG sensor

Using Berkeley Technology, Glasgow Debuts New GHG Monitoring Network

UC Berkeley’s Ronald Cohen was beaming behind his mask as he joined governmental officials from Scotland and California today (Nov. 3) at the 2021 Climate Summit (COP26) in Glasgow to demonstrate a sensor network he pioneered to provide realtime monitoring of greenhouse gas emissions in cities.

With drop in LA’s vehicular aerosol pollution, plants emerge as major source

California’s restrictions on vehicle emissions have been so effective that in at least one urban area, Los Angeles, the most concerning source of dangerous aerosol pollution may well be trees and other green plants, according to a new study by University of California, Berkeley, chemists.

aerial photo of Bay Area, showing empty freeway

Drop in pandemic CO2 emissions previews world of electric vehicles

In the six weeks after the San Francisco Bay Area instituted the nation’s first shelter-in-place mandate in response to the growing COVID-19 pandemic, regional carbon dioxide emissions dropped by 25%, almost all of it due to a nearly 50% drop in road traffic, according to new study from the University of California, Berkeley.

Coronavirus impact: Maps show pollution has dropped in the Bay Area since shelter-in-place orders

Air quality researchers predicted, and the EPA recently confirmed a more than one-third year-to-year drop in significant pollution levels around San Francisco.

Six UC Berkeley faculty elected AAAS fellows

Six scientists are among the 396 newest fellows elected to the American Association for the Advancement of Science (AAAS) for “advancing science applications that are deemed scientifically or socially distinguished.”

Berkeley air-monitoring project wins White House nod

The White House has given a public nod to a ground-breaking UC Berkeley air-monitoring project and its new collaboration with a Colorado public media platform, which aims to build a citizen-science story-corps to help monitor carbon emissions in the Bay Area.

UC Berkeley Chemists Installing Carbon Dioxide Sensors in Oakland

Using inexpensive detectors that can fit inside a shoebox, UC Berkeley chemists are installing carbon dioxide and other air pollution sensors in 40 sites around Oakland to explore how detailed, neighborhood-by-neighborhood information can help communities monitor greenhouse gas and other harmful emissions.

There’s something in the California air

UC scientists built and worked in towers — some as tall as 1,500 feet — as part of the largest single atmospheric research effort in the state. The data they’ve collected will guide policymakers dealing with air pollution.

Featured in the Media

Please note: The views and opinions expressed in these articles are those of the authors and do not necessarily reflect the official policy or positions of UC Berkeley.

April 4, 2024

Electric vehicles cutting carbon footprint in Bay Area, new study says

NBC Bay Area

Christie Smith

We observed that the total emissions of CO2 over a five-year period from 2018 to 2022 and the total emissions decreased a little less than 2%. And we attribute that change to the tremendous increase of electric vehicles on the roads here in the Bay Area,” said Ronald Cohen, professor of atmospheric science. This study was reported on Berkeley News.

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November 16, 2020

Drop in Bay Area Air Pollution From COVID-19 Lockdown Previews World of Electric Cars

ABC-7

Dan Ashley and Tim Didion

The Bay Area's popular commuter corridors are also generators of carbon dioxide and micro pollutants. So what happened when COVID-19 forced most commuters off the road and into their homes? "...We saw this incredible change. The amount of CO2 released into the atmosphere in the Bay Area was 25% lower in that period than just before the lockdown six weeks before," says UC Berkeley professor Ron Cohen. "So we've been thinking about this as a model for the electric car." For more on this, see our press release at Berkeley News. A story on this topic also appeared in Science Daily.

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April 29, 2020

L.A. coronavirus clean air streak has already come to an end. Here's why

Los Angeles Times

Tony Barboza

If I could wave my magic wand and we all had electric cars tomorrow, I think this is what the air would look like, says chemistry and earth and planetary sciences professor Ron Cohen, an air quality researcher, referring to the beneficial side-effect of improved air quality during the COVID-19 shutdown. He and his team are monitoring air quality, and through an analysis of satellite measurements they've found a 32% decline in levels of nitrogen dioxide pollution over the first three weeks of shelter-in-place rules in Southern California, compared to the prior three weeks. They also, however, found a 26% reduction between the same periods in 2019, suggesting that spring weather contributed to the effect. "Driving is dramatically lower," he says, "but differences in weather between this year and last still make it hard to put numbers on how much cleaner the air is because of the shelter-in-place." Expressing dismay about how the pandemic is helping his research, he says: "It's terrible to get that view by people getting sick. ... It's not at all how we would design the experiment if we had a choice."

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April 8, 2020

Coronavirus impact: Maps show how much pollution has dropped in the Bay Area since shelter-in-place orders

KGO TV

Tim Didion

After China began its COVID-19 quarantine, a satellite map highlighted a dramatic reduction in air pollution over the country. When chemistry and earth and planetary sciences professor Ron Cohen, an air quality researcher, saw the image, he predicted a similar effect in the Bay Area. Now the EPA has confirmed that pollution levels around San Francisco have decreased by more than one third over last year. "It's much bigger than drops of anything else we've ever looked at," Professor Cohen says. He and his team have investigated the numbers for nitrogen dioxide, one of the key pollutants, finding that its levels were roughly cut in half from the week before the shelter-in-place order to the next week. He says they'll learn a lot more as new data becomes available. It will help the researchers not only confirm pollution levels in the air, but also what its sources are. "We think we know how much comes from cars, how much from trucks, how much from industry. And all of those things suddenly changed by different amounts. So we'll be able to check," he says. Link to video.

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