You are here

Annual Report 2022

A Message from the Chair

HEI Board Chair Richard Meserve reflects on HEI's progress in 2022 and its ongoing commitment to innovative science for lasting impact. Read more

Thank You to Our Peer Reviewers

HEI thanks all the experts who offered their time and expertise in 2022 to provide thoughtful, high-quality comments and feedback on research applications as well as final reports. Read more

Section Overview


To advance science that guides stakeholders, HEI brings communities, industries, policy makers, and scientists together to exchange ideas, voice concerns, and find common ground. Our role as a convener is critical to our ability to ask the right questions — and find the right answers. Read more


Three recent HEI research reports shed new light on the potential health impacts of low levels of air pollution. These studies come at an important moment as governments across several global regions consider tightening pollution regulations. Read more


Get details on our annual expenditures and funding support from government, industry, and foundation sponsors. Read more


While hailed as a great success, the strides made in reducing tailpipe emissions have been uneven around the world, with traffic pollution rising rapidly in many low- and middle-income countries. HEI research is providing important data on both tailpipe and non-tailpipe emissions, which influence health and disease everywhere. Read more


Air pollution is a global problem with local consequences. Learn how HEI’s publication of several new reports is helping to inform policies for cleaner air in many countries and cities. Read more

Convening Communities

Everyone has a stake in clean air because everyone benefits from it. To advance science that guides stakeholders, HEI brings communities, industries, policy makers, and scientists together to exchange idea, voice concerns, and find common ground. Our role as a convener is critical to our ability to ask the right questions — and find the right answers.

Vital Conversations

How can we learn what issues are of greatest concern to people and their communities? How do we know what types of evidence will be most useful for decision makers? To bring out the core questions that are important to stakeholders — and identify where investments in science can make the biggest impact — requires honest, productive conversations among people with diverse experiences and interests. HEI brings together people and organizations from across all sectors of society for meaningful discussions about air pollution, its sources, and its impacts.

The public is both stakeholder and beneficiary when credible science is applied to policy making. HEI is committed to ensuring that the benefits of our work impact all communities, especially those that have been historically marginalized. To inform a growing nationwide effort to better serve communities experiencing disproportionate burdens from pollution, HEI hosted a two-day workshop on “New Science to Inform Environmental Justice” in the fall of 2022. The event forged new connections among a broad array of environmental justice stakeholders from community and nongovernmental organizations, academic institutions, government, and industry. It represented an important first step in identifying priorities, barriers, and possible solutions to address the environmental health challenges many historically marginalized communities face.

HEI also places a high priority on engaging people who live and work in areas that are the focus of our research programs. HEI Energy hosted two open-house events in the spring of 2022 to engage local communities in its research program on exposures related to unconventional oil and natural gas development across the United States. The public events — held in person in Longmont, Colorado, and virtually for communities in the Permian and Eagle Ford regions in Texas — provided residents and other stakeholders with an opportunity to meet research teams, ask questions, and learn about the purpose of the research and how to stay up to date. More community engagement events are planned as the research program continues moving forward.

Sharing Science

U.S. EPA Deputy Administrator Janet McCabe

U.S. EPA Deputy Administrator Janet McCabe gave the keynote address at HEI’s Annual Conference 2022 in Washington, D.C.

For nearly four decades, HEI’s Annual Conference has been a hallmark of our role as a convener. In 2022 the conference, held in person again after taking place virtually in 2020 and 2021, featured U.S. Environmental Protection Agency (EPA) Deputy Administrator Janet McCabe as keynote speaker and welcomed attendees from the EPA, industry sponsors, academic institutions, and nongovernmental organizations. Participants shared the latest scientific findings and policy developments on setting ambient air quality standards, emerging trends in mobility, relationships between climate and ozone levels, environmental justice, air pollution’s effects on the immune system, and much more.

Prioritizing Diversity, Equity, and Inclusion

Addressing inequities requires consistent, intentional action. HEI recognizes that we have a key role in addressing inequities and a responsibility to promote diversity, equity, and inclusion (DEI), both through our work and our organizational culture.  

We have been excited to welcome an increasingly diverse group of people to the HEI network in the past year, including newcomers to our staff as well as Annual Conference speakers who joined us from around the world. In addition, we launched a new DEI Committee consisting of five HEI staff members who volunteered to help develop and move forward HEI’s official DEI plan, set annual goals and communications objectives, facilitate dialogues and learning, and evaluate HEI’s progress in implementing these measures.

In 2022 HEI also launched a new Summer Fellowship Program, which aims to encourage undergraduate students from backgrounds that are underrepresented in the environmental health sciences to explore research opportunities in this area. The program, a collaboration between HEI and the International Society of Exposure Sciences and the International Society for Environmental Epidemiology, will support its first cohort of summer fellows in 2023.


HEI's Diversity, Equity, and Inclusion Committee

In 2022, five HEI staff members volunteered to serve on the DEI Committee. From left: (top row) Elise Elliott, Amy Andreini, and Anna Rosofsky; (bottom row) Lissa McBurney and Jacqueline Rutledge .

Insights on Low Exposure

Three recent HEI research reports shed new light on the potential health impacts of low levels of air pollution. With their large sample sizes and rigorous scientific methods, these studies offer powerful insights and test long-held assumptions about what pollution levels are safe.

One study, led by Harvard researcher Francesca Dominici, examines mortality trends among more than 68 million older Americans and links pollution exposure with an increased risk of death even at concentrations below the current U.S. National Ambient Air Quality Standards (NAAQS). According to the findings, a slightly lower air quality standard for PM2.5 — 10 micrograms (µg) per cubic meter instead of the current standard of 12 µg/m3 — would have saved more than 143,000 lives over the course of a decade. The researchers used five different analytical approaches to conduct their study over four years, strengthening their confidence in the findings and bolstering the case for a likely causal effect between long-term pollution exposure and mortality.

In another study, University of British Columbia researcher Michael Brauer and colleagues combined satellite data, air monitor data, and atmospheric modeling to assess the relationship between pollution and mortality in over 7 million Canadian adults. Their results link long-term outdoor exposures to fine particle air pollution as low as 2.5 µg/m3 with an increased risk of death, underscoring the opportunity to yield further health gains from cleaner air even in a country such as Canada, which has some of the lowest pollution exposures in the world.


Map figure from the study in Canada by Brauer and colleagues

Figure from the HEI study conducted in Canada by Brauer and colleagues shows estimates of fine particulate matter (PM2.5) annual means averaged over the entire study period (1981–2015). City-level estimates for the largest cities are shown in the circles.


A third study, led by Bert Brunekreef at Utrecht University in the Netherlands, found that exposures to relatively low levels of three pollutants (fine particulate matter, black carbon, and nitrogen dioxide) were significantly associated with death from all causes, heart disease, respiratory disease, and lung cancer, but that exposure to ozone was not linked to an increased risk of death from these causes. The study analyzed data from over 28 million people across 11 European countries and suggests these three pollutants may adversely affect health at concentrations below current European Union air quality limit values.

Informing New Standards

These studies come at an important moment as governments across several global regions consider tightening pollution regulations. When the study led by Dominici was published, the New York Times reported, “Older Americans who regularly breathe even low levels of pollution from smokestacks, automobile exhaust, wildfires and other sources face a greater chance of dying early, according to a major new study.” Based in part on these findings, the EPA subsequently proposed a draft rule to lower the annual NAAQS from 12 µg/m3 to 9–10 µg/m3 and is expected to issue a final rule in 2023. In Europe, findings from Bert Brunekreef and colleagues have contributed to a new European Commission proposal to lower its PM2.5 Air Quality Limit Value to an annual limit of 10 µg/m3, a level that is substantially below the current value of 25 µg/m3.

Based on recent research, such actions could likely be expected to reduce harmful exposures and yield further health benefits for millions of people.

Traffic & Health: Steps to Knowledge

In many higher-income countries, a dramatic reduction in tailpipe emissions over the past several decades has been hailed as one of the great successes in air pollution control. Technological improvements by industry, along with regulations on fuels and vehicle emissions, have contributed to a steady decline in some air pollutants in many places. However, worldwide progress has been uneven. Population growth, urbanization, and economic activity have increased traffic congestion, counterbalancing some of the air quality gains seen in some places while worsening pollution in others.

HEI’s Special Report 23, Systematic Review and Meta-analysis of Selected Health Effects of Long-Term Exposure to Traffic-Related Air Pollution, presents a new landmark review of scientific literature, offering a detailed look at the health effects of long-term exposure to traffic-related air pollution and insights on global trends.

Why Our Health Is (Still) Tied Up in Traffic

Vehicle emissions continue to drop in many places thanks to increasing vehicle emissions control, a growing adoption of electric vehicles, and other trends, but this is not enough to fully offset the fast-growing number of vehicles on the road globally. Traffic pollution is rising rapidly in many low- and middle-income countries, where increasing rates of car ownership are contributing to congestion and many older, higher pollution-emitting vehicles remain on the roads. As a result, according to the HEI report, both tailpipe and non-tailpipe emissions remain key sources of pollution that influence health and disease worldwide.

Illustration with silhouetted pregnant woman, father, and small child and list of health outcomes associated with traffic-related pollution

Figure from HEI Special Report 23.

Conducted by a panel of 13 renowned experts who reviewed 353 published studies, the report represents the largest and most comprehensive scientific review on the topic to date. It updates and builds upon HEI’s widely cited 2010 report on traffic-related air pollution with an analysis of studies spanning four decades.

The Consequences of Congestion

The report concludes with a high level of confidence that exposure to traffic-related air pollution is strongly linked with early death from any cause, including cardiovascular diseases. It also reports moderate to high confidence in linkages with death from lung cancer and asthma onset in adults, as well as asthma onset and acute lower respiratory infections in children. Associations identified with moderate confidence include low birth weight, diabetes, and early death from respiratory diseases in adults. Exposures at the local level (within one kilometer of a major roadway) provided the greatest potential in determining the health effects of traffic-related air pollution.

To date, almost all traffic pollution regulations target tailpipe emissions. The report highlights continuing questions about non-tailpipe sources of emissions generated by traffic, including road dust, abrasion of the road surface, and wear from brakes and tires, which can release heavy metals such as iron and copper. In 2022, HEI held a competition for targeted studies of these emissions and funded two new studies in London and Toronto.

The Road Ahead

In the fall of 2022, informed by the findings of Special Report 23, HEI issued a request for applications focused on assessing health effects of traffic-related air pollution in the context of a changing urban transportation landscape. In 2023 the program will allocate $5 million to a small number of studies using novel or improved methods to evaluate pollution exposures and effects as technologies and fuels change, the vehicle fleet turns over, mobility transforms, and electrification makes greater inroads around the world.

Conducted by a panel of 13 renowned experts who reviewed 353 published studies, HEI's new Special Report on traffic-related air pollution represents the largest and most comprehensive scientific review on the topic to date.

Advancing Global Health

Air pollution is a global problem with local consequences. It sweeps across geopolitical borders, mountain ranges, and oceans; it drifts through urban centers and rural landscapes; and it affects people in all walks of life. To help inform policy for cleaner air, HEI communicated widely in 2022 — through webinars and in person in Brussels, Bulgaria, Beijing, Delhi, and elsewhere — to draw connections between global air pollution exposures and health impacts for people the world over.

Data Wherever You Live

Three recent special reports of HEI’s State of Global Air initiative drew locally relevant insights from global trends in air pollution exposures and health impacts. One report, How Does Your Air Measure Up Against the WHO Air Quality Guidelines?, focused on how fine particulate matter (PM2.5) air pollution levels compare to air quality guidelines established by the World Health Organization (WHO). It found that no countries meet the WHO guidelines for healthy air (5 µg/m3) and that a majority of the world’s population is exposed to levels of PM2.5 pollution higher than WHO’s least stringent interim air quality target, 35 µg/m3, a level that puts many at risk for serious health impacts.

A second State of Global Air report, Air Quality and Health in Cities, provided a detailed examination of pollution in urban areas, which suffer some of the poorest air quality on the planet. According to the analysis, cities saw 1.7 million deaths linked to fine particle air pollution exposure in 2019, with urban areas in Asia, Africa, and Eastern and Central Europe seeing the worst disease burdens. Rapid urbanization around the world puts cities at the forefront for taking actions to reduce the health effects of air pollution, especially in low- and middle-income countries. 

A third report, How Does Air Pollution Affect Life Expectancy Around the World?, quantified air pollution’s harsh impact on health in terms of decreased life expectancy. Globally, the analysis estimated that recent air pollution levels reduce the average person’s lifespan by about 1.8 years, with reductions of 2 to 3 years in more heavily polluted countries. In 2023, State of Global Air expects to issue a new comprehensive report with updated analyses of air pollution and its health impacts for more than 190 countries.

What’s Producing All the Pollution?

To design effective interventions to reduce air pollution, decision makers need to know the major sources of pollution in a particular area. These sources vary considerably from place to place, from pollutant to pollutant, and from source to source. HEI’s Research Report 210, Global Burden of Disease from Major Air Pollution Sources (GBD MAPS): A Global Approach, provided the first comprehensive analysis of pollution sources for every country in the world. The report documented the key role fossil fuel combustion plays as a primary source of air pollution — linked with more than 1 million deaths globally in 2017 — and in particular the continuing burden of disease from coal combustion. Underscoring the continuing impacts from fuel combustion despite dramatic increases in clean-energy technologies, the findings can help guide approaches to simultaneously improve air quality and mitigate climate change around the world.

Marrakeck market


Regional Insights for Targeted Action

Two recent HEI reports drilled deeper into air pollution trends in particular regions in order to guide evidence-based action. A special State of Global Air report on Southeast Europe, as well as reports focused specifically on Serbia and Bulgaria, revealed that this region suffers a rate of death due to air pollution nearly four times higher than the rate seen in Western Europe. The report highlighted energy poverty and access to clean energy as key issues to address if the region is to reduce air pollution and its associated disease burden.

A second regional report focused on air pollution trends in Africa and drew attention to the high disease burden of household air pollution, which is generated from burning solid fuels such as coal, wood, and charcoal for cooking. This source of pollution is associated with particular health impacts for newborns and young children, with air pollution accounting for nearly 1 in 6 deaths in children under 5 across Africa. Fine-particle air pollution from energy production, vehicles, and industrial activities also combines with windblown dust (a natural pollution source) in some parts of Africa, contributing to some of the highest pollution levels in the world.

World map

The 21 regions, as defined by the Global Burden of Disease project, along with the number of cities analyzed in each region.

Air Quality and Health in Cities provides a detailed examination of pollution in urban areas, which suffer some of the poorest air quality on the planet.

Financial Summary 2021-2022

Statements of Financial Position

    June 30, 2022   June 30, 2021

Cash and cash equivalents

  $6,454,725   $6,089,019

Restricted cash

  147,962   147,962

Contributions and accounts receivable

  3,609,717   1,645,968

Unbilled incurred costs on grants

  5,500,000   4,504,834

Prepaid expenses

  43,788   84,841

Office equipment, office furniture and fixtures, and leasehold improvements, net

  24,815   54,097
Total Assets   $15,781,007   $12,526,721
Liabilities and Net Assets        



Contracted research payables




Accrued contracted research

  2,769,329   1,934,203

Deferred rent payable

  36,019   51,185

Other accounts payable and accruals

  1,675,543    1,070,663
Total liabilities   4,792,948   3,503,522

Net Assets:


Without donor restrictions

  722,041   656,243

With donor restrictions

  10,266,018   8,366,956
Total net assets   10,988,059   9,023,199
Total Liabilities and Net Assets   $15,781,007   $12,526,721

Statements of Activities

    June 30, 2022   June 30, 2021

Revenues and support:


EPA grants for the Health Effects of Air Pollution Program

  $5,744,711   $5,950,844

EPA contracts for Energy Research

  3,421,866   651,100

Industry contributions

  5,399,530   5,161,046

Other non-federal grant and contract revenue

  449,080   678,918

Other revenues

  65,798   39,737
Total revenues and support   15,080,985   12,481,645



Research programs:


Research studies

  5,940,177   4,687,594

Research planning and study selection

  642,306   618,614

Scientific study management

  342,818   276,929

Scientific study review

  300,276   285,174

Scientific publication and communication

  1,153,281   858,358
    8,378,858   6,726,669

Special Scientific projects:


Energy research

  1,048,193   655,620

Traffic studies review

  329,993   459,428

Global health science

  1,042,768   992,904
    2,420,954   2,107,952

Total research and scientific expenses

  10,799,812   8,834,621


  2,316,313   1,938,294
Total expenses   13,116,125   10,772,915
Net increase in net assets   1,964,860   1,708,730
Net assets at beginning of year   9,023,199   7,314,469
Net assets at end of year   $10,988,059   $9,023,199

The HEI Financial Statement and the Mayer Hoffman McCann P.C. Auditors’ Report may be obtained by contacting Jacqueline C. Rutledge.


HEI made significant progress in fiscal year 2022 toward the objectives of the Health Effects of Air Pollution program by completing research on possible health effects from low levels of exposure and examining the potential effects of traffic exposure in its broader context. We have also made progress in expanding our efforts to produce and communicate Global Health Science. These activities were made possible by funding from our core government and industry partners with additional funding from government, industry, and foundation sponsors. Separate funding has also allowed us to move forward with our Energy Research Program. The significant balance in Temporarily Restricted Net Assets ensures we will have funds to continue and expand our current targeted research initiatives in future years.

Insights that Endure: Investing in Science for Lasting Impact

A Message from the Chair

Richard Meserve Headshot

Richard A. Meserve, Chair, HEI Board of Directors

It is rare for any single new scientific finding to quickly inform public and private decisions on individual and community health. In reality, scientific knowledge builds over time until there is a consensus among experts in a range of relevant disciplines. To that end, HEI has always sought to build Insights that Endure, the theme of this year’s report. For decades, HEI’s trusted independent research has identified top priority scientific and policy questions in environmental health, built strategic plans to answer those questions, and invested in innovative science for lasting impact.

This past year is no exception. Questions about the lowest levels at which air pollution might affect health arose in HEI’s strategic plans, and HEI invested in wide-ranging studies of millions of U.S., Canadian, and European citizens. The findings are now at the center of active public discussions in the United States and the European Union about setting new health-protective air quality standards.

Much the same can be said of HEI’s longstanding efforts to understand the effects of and solutions to exposures from vehicle traffic. HEI science informed a series of public and private decisions, along with technology advances, that resulted in every vehicle entering the marketplace today being dramatically cleaner than its counterparts of 10–20 years ago. But challenges remain. In the past year HEI issued its latest systematic review of the world’s literature on traffic and health, which noted improvements but identified key continuing questions that HEI will now pursue to ensure lasting progress.

Long-term investment has been essential as well in the efforts of HEI’s Global Health program to advance understanding of air pollution and health around the world. Starting some two decades ago in Asia, the Global Health program’s dedicated synthesis of existing research, capacity strengthening among local scientists, and effective communication — in particular, through its State of Global Air initiative — have resulted in a growing community of scientists who are advancing understanding in China and India. In 2022 HEI also made new investments in building scientific networks in East Africa as countries there grapple with air pollution.

This progress comes at a time when the world is increasingly turning its attention to an even bigger challenge: promoting an energy transition that will reshape the ways we use energy in transportation, industry, our homes, and every other aspect of our lives. With these changes come opportunities for substantial additional health benefits, but also the challenge of identifying potential unintended consequences for health. Even as it moves forward with new energy research across the United States, HEI Energy is reaching out to sponsors and to the broader community to identify key new directions, such as exploring the health impacts of increased roles for hydrogen and carbon capture and storage. The institute is taking the first steps toward building capability to produce research that will inform the energy transition over the long term.

HEI also recognizes that it must undertake efforts to include scientists from a range of backgrounds and communities that have historically been underrepresented in science and, more specifically, in environmental health fields. HEI’s Diversity, Equity, and Inclusion initiative is actively broadening how HEI recruits scientists to its staff, Board, and committees; encourages and receives proposals from underrepresented scientists; and seeks to build a pipeline of young scientists engaged in environmental health.

But HEI’s efforts have not stopped there. 2022 brought active engagement with community leaders from marginalized communities, scientists who have been working successfully with those communities, and government agencies. The aim was to identify the best ways that HEI can build programs that have lasting impacts in advancing cleaner air in marginalized communities that have endured disproportionate adverse health effects.

It is sometimes a challenge to convince sponsors of science that, while their investments may not have immediate impact, a well designed, strategic research program can make a long-term difference. HEI is fortunate to have ongoing support that enables it to make enduring contributions that matter.




Richard A. Meserve
Chair, HEI Board of Directors

Thank You to Our Peer Reviewers in 2022

We would like to thank all the experts who offered their time and expertise to HEI in 2022. We are grateful for their thoughtful, high-quality comments and feedback on our various projects. Thanks also to our quality assurance audit teams, our Research Committee, Review Committee, Global Health Oversight Committee, and the Traffic Literature Review Panel. We would not succeed without the help of all these individuals.

Core Program

Alexandra Monteiro, Universidade de Aveiro, Portugal

Alvaro Osornio-Vargas, University of Alberta, Canada

Cole Brokamp, University of Cincinnati

Denise L. Mauzerall, Princeton University

Edmund Seto, University of Washington

Edson Severnini, Carnegie Mellon University

Éric Lavigne, Health Canada

Erik Melén, Karolinska Institute, Sweden

Hwashin Shin, Health Canada

James Hammitt, Harvard University

John S. Ji, Tsinghua University, China

Joshua Warren, Yale University

Jun Wu, University of California, Irvine

Lea Hildebrandt Ruiz, University of Texas at Austin

Li Fan, Duke University

Marcus Cooke, University of South Florida

Massimo Stafoggia, Lazio Region Health Service, Italy

Meng Wang, University at Buffalo, The State University of New York

Paul Villeneuve, Carleton University

Peter J. Adams, Carnegie Mellon University

Phil Hopke, University of Rochester

Rachel Nethery, Harvard University

Randall Guensler, Georgia Institute of Technology

Shinichi Enami, Institute for Environmental Studies, Japan

Stacey Alexeeff, Kaiser Permanente Division of Research

Tao Xue, Peking University, China

Tiantian Li, Chinese Center for Disease Control and Prevention, China

Washington Junger, Universidade do Estado do Rio de Janeiro, Brazil

Zhanghua Chen, University of Southern California

Global Program

Anca Nemuc, National Institute for Research and Development for Optoelectronics, INOE, Romania

Andrea Bizberg, C40 Cities

Antigona Ukëhaxhaj, Fehmi Agani University, Kosovo

Baerbel Sinha, Indian Institute of Science Education and Research, India

Bertrand Tchanche Fankam, Alioune Diop University, Senegal

Bhargav Krishna, Centre for Policy Research, India

Branislava Matič, Institute of Public Health of Serbia, Serbia

Cathryn Tonne, ISGlobal, Spain

Dan Westervelt, Columbia University

Dang Espita-Casanova, Clean Air Asia

Dima Tsanova, Medical University of Pleven, Bulgaria

Eduardo Peralta, C40 Cities

Evangelia Samoli, National and Kapodistrian University of Athens, Greece

Everlyn Tamayo, Clean Air Asia

Ivaylo Hlebarov, Za Zemiata, Bulgaria

Kevin Lane, Boston University

Michael Brauer, The University of British Columbia, Canada

Nataša Dragic, Institute of Public Health of Vojvodina, Serbia

Patrick Katoto, University of Cape Town, South Africa

Ravindra Khaiwal, Postgraduate Institute of Medical Education and Research (PGIMER), India

Reneta Dimitrova, Sofia University “St. Kliment Ohridski”, Bulgaria

Samir Lemes, University of Zenica, Bosnia and Herzegovina & Balkans United for Clean Air Campaign

Seneca Naidoo, C40 Cities, South Africa

Shally Awasthi, King George's Medical University, India

Simon Sambou, C40 Cities, Senegal

Srdjan Kukolj, Health and Environment Alliance, HEAL, Serbia 

Sumi Mehta, Vital Strategies

Tibebu Assefa, C40 Cities, Ethiopia

Vasil Zlatev, Independent Consultant, Bulgaria

Vivian Pun, C40 Cities, Singapore

Zoe Chafe, C40 Cities

Zorana Andersen, University of Copenhagen, Denmark