City skyline with visible air pollution haze
London, UK skyline with air pollution haze taken from tall measurement tower.
Samuel J. Cliff
Postdoctoral Researcher

Samuel J. Cliff, PhD

Advancing air pollution and climate change mitigation through high precision meteorological and atmospheric characterisation. Focussed on translating research into policy action and community education.

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A mobile laboratory tour at the West Oakland Environmental Indicators Project (WOEIP) community group.

Tracking emissions implications from local air quality to global climate

I am a Postdoctoral Researcher at the University of California Berkeley in the Department of Civil and Environmental Engineering, working with Professors Allen Goldstein and Josh Apte. My research focuses on air pollution and climate change mitigation.

My work consists of making multi-dimensional, high resolution measurements of the atmosphere to identify and quantify emissions sources. I am especially interested in translating research findings into actionable insights for policymakers and affected communities. My studies target over burdened communities, or locations facing specific mitigation actions that require evaluation.

I completed my PhD Chemistry at the University of York in 2024, where I worked on urban air pollution emissions quantification. Prior to that, I received my Master's of Chemistry from the University of York where I made gas phase atmospheric measurements onboard the UK's large atmospheric research aircraft all around the world.

University of California Berkeley Goldstein and Apte Research Groups
Hohenpeissenberg Meteorological Observatory, Germany
Hohenpeissenberg Meteorological Observatory, Germany.

Recent Projects

Mobile laboratory tour

The CalMAPLab out measuring in the field in South San Francisco, California.

01

Statewide Mobile Monitoring in Disadvantaged Communities

Many communities in California are overburded with air pollution but have minimal or no monitoring in the area to fully understand the sources. I deploy the recently developed CalMAPLab in 20 disadvantaged communities in California for over 1000 hours of mobile monitoring in 2025. With a public-engaged approach, we work closely with local community groups and use lived experiences to drive our measurement strategy.

Coming Soon
Bird at WWTP

A California Gull relaxing on a primary clarifier in a wastewater treatment plant.

02

Investigating urban methane emissions with a multi-platform approach

Urban methane emissions in the U.S. are consistently underestimated in emissions inventories. We use long-term eddy covariance measurements from a tall tower in Berkeley, CA, and target individual facilities with mobile monitoring to try and reduce this discrepancy.

Coming Soon
CalMAPLab in the field

Live time series and geolocated data streams during a sampling drive in the UC Berkeley Mobile Air Pollution Laboratory (CalMAPLab).

03

Design, operation and characterisation of a mobile laboratory for community-scale atmospheric research

Air pollution exposure is spatially heterogenous and exhibits hyperlocal variability largely uncaptured by regulatory monitoring sites. I designed and built the UC Berkeley Mobile Air Pollution Laboratory (CalMAPLab) equipped with research grade instrumentation for measurements of over 600 gas and particle phase compounds in the atmosphere. This facility enables real-time quantification and mapping of air pollution at meter level resolution.

Coming Soon
Caltrain electrification

The last diesel trains operating out of the Caltrain depot in San Francisco, California, before electrification.

04

Quanitifying the air quality benefits of rail electrification

In August 2024, the diesel-powered trains on the Caltrain commuter rail system between San Francisco and San Jose were fully replaced by electric models over a six week period. I deploy pop-up stationary monitoring sites and perform on-board measurements to quantify the significant air quality benefits of this transition.

BT Tower Atmospheric Observatory

Landscape view of the BT Tower Atmospheric Observatory in London, UK.

05

Evolving urban air pollution sources from direct emissions measurements

London, UK, is a world leader in road transport emissions mitigation policy. I make long-term eddy covariance emissions measurements from a tall tower in central London to study the impact of low emissions zones on urban NOx emissions and the sources of emerging importance left in their stead.

FAAM Airborne Laboratory

The FAAM Airborne Laboratory sampling ship plume emissions during a campaign in the summer of 2019.

06

Airborne investigation of oil and gas, shipping and wetland emissions

Aircraft-based measurements unlock locations and spatial scales inaccessible to other measurement strategies. I operate the core chemistry instrumentation on > 40 research flights onboard the UK's large atmospheric research aircraft all around the world in 2019 and 2020. Studies ranged from quantifying the importance of Scandanavian wetlands for global CH4 emissions to investigating the pollution and climate impact of new marine diesel sulfur content regulations.

Smoke haze in Maine, US, following wildfires in Canada
Smoke haze in Maine, US, following wildfires in Canada 2025.

Publications

2025

Quantifying blackcarbon emissions from traffic and construction in central London using eddy covariance

Cheng, Z., Hu, D., Flynn, M., Nemitz, E., Langford, B., Drysdale, W., Helfter, C., Cliff, S. J., et al. — Environ. Sci.: Atmos., 5, 7, 785-800

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2025

Dramatic air quality improvements after the complete electrification of a commuter rail system

Cliff, S. J., McNamara-Byrne, H., Goldstein, A. H., Apte, J. S. — Environ. Sci. Technol. Lett., 12, 5, 587-592

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2025

Evidence of heating-dominated urban NOx emissions

Cliff, S. J., Drysdale, W. S., Lewis, A. C., Moller, S. J., Helfter, C., Metzger, S., Nemitz, E., et al. — Environ. Sci. Technol., 59, 9, 4399-4408

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2023

Unreported VOC emissions from road transport including electric vehicles

Cliff, S. J., Lewis, A. C., Shaw, M. D., Lee, J. D., Flynn, M., Andrews, S. J., Hopkins, J. R., Purvis, R. M., Yeoman, A. M. — Environ. Sci. Technol., 57, 8026-8034

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2023

Pandemic restrictions in 2020 highlight the significance of non-road NOx sources in central London

Cliff, S. J., Drysdale, W. S., Lee, J. D., Helfter, C., Nemitz, E., Metzger, S., Barlow, J. — Atmos. Chem. Phys., 23, 2315-2330

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2023

Flaring efficiencies and NOx emission ratios measured for offshore oil and gas facilities in the North Sea

Shaw, J. T., Foulds, A., Wilde, S. E., Barker, P., Squires, S., Lee, J., Purvis, R. M., Burton, R., Colfescu, I., Mobbs, S., Cliff, S. J., et al. — Atmos. Chem. Phys., 23, 1491-1509

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2022

Eddy covariance measurements highlight sources of nitrogen oxide emissions missing from inventories for central London

Drysdale, W. S., Vaughan, A. R., Squires, F. A., Cliff, S. J., Metzger, S., Durden, D., Pingintha-Durden, N., et al. — Atmos. Chem. Phys., 22, 9413-9433

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2022

Airborne quantification of net methane and carbon dioxide fluxes from European Arctic wetlands in Summer 2019

Barker, P., Allen, G., Pitt, J. R., Bauguitte, S. J. B., Pasternak, D., Cliff, S. J., France, J. L., et al. — Philos. Trans. Royal Soc. A, 380, 2215

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2021

Ozone production and precursor emission from wildfires in Africa

Lee, J. D., Squires, F., Sherwen, T., Wilde, S. E., Cliff, S. J., Bauguitte, S. J. B., Reed, C., Barker, P., et al. — Environ. Sci.: Atmos., 1, 524-542

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2020

Airborne measurements of fire emission factors for African biomass burning sampled during the MOYA campaign

Barker, P. A., Allen, G., Bannan, T. J., Nisbet, E. G., Pitt, J. R., Bauguitte, S. J. B., Pasternak, D., Cliff, S. J., et al. — Atmos. Chem. Phys., 20, 15443-15459

Read Paper
2020

Characterizing the particle composition and cloud condensation nuclei from shipping emission in Western Europe

Yu, C., Pasternak, D., Lee, J., Yang, M., Bell, T. G., Bower, K. N., Wu, H., Liu, D., Reed, C., Bauguitte, S. J. B., Cliff, S. J., et al. — Environ. Sci. & Technol., 54, 15604-15612

Read Paper
In Review

Design, operation and characterization of a mobile laboratory for community-scale atmospheric research

Cliff, S. J., et al. — Submitted, Atmospheric Measurement Techniques

In Review

Urban Natural Gas Seasonality is Associated with Commercial Areas in Berkeley, California

Byrne, H. M., Katz, E., Cliff, S. J., et al. — Submitted, Environmental Science & Technology

In Review

Field-based quantification of non-exhaust emissions using gas dilution and machine-learning techniques

Sheehan, A., Hicks, W., Tremper, A. H., Preistman, M., Punter, P., Kelly, F., Font, A., Alastuey, A., Minguillon, M. C., Querol, X., Via, M., Guervara, M., Allan, J., Coe, H., Flynn, M., Watson, N., Bloss, W., Hou, S., Harrison, R., Cliff, S. J., et al. — Submitted, Transportation Research Part D: Transport and Environment

News & Media

News story image
April 2025

Electric trains are quieter, more reliable than diesel. New study finds they're healthier, too.

UC Berkeley News

News story image
November 2024

Unequal burden: Addressing air quality disparities through data and policy

UC Berkeley Engineering

News story image
February 2023

Pollutionwatch: London Ulez cuts traffic fumes but heating is concern

The Guardian

Curriculum Vitae

Education

2024
Ph.D. in Chemistry
University of York
2020
Master of Chemistry
University of York

Awards & Fellowships

2023
Kathleen Mary Stott Prize
University of York
2020
Whinfield Medal
University of York
2020
Graduate Researcher Fellowship: £90k
National Environmental Research Council

Experience

2024–Present
Postdoctoral Researcher
University of California Berkeley
2020–2024
Graduate Researcher
University of York
[2019]–[2020]
Research Student
Facility for Airborne Atmospheric Measurements

Skills & Methods

Computing & Data Analysis
R, Python, Linux, SQL/DuckDB, Git, Docker, HPC
Measurement Techniques
Mass spectrometry, optical spectroscopy, chromatography, electrical mobility spectrometry

Contact

samcliff@berkeley.edu
Office
Davis Hall, Room 628
University of California, Berkeley
Research Group
Goldstein and Apte Labs
Department of Civil and Environmental Engineering