Kirk's legacy

PROFESSOR KIRK R. SMITH 1947-2020

Kalpana Balakrishnan, Ajay Pillarisetti, Sumi Mehta, Santosh Harish, Sarath Guttikunda, Ajay Mathur, Ambuj Sagar

The Collaborative Clean Air Policy Centre (CCAPC) joins the global public health and scientific community in mourning the loss of Professor Kirk R. Smith, an exemplary researcher, colleague, mentor, friend and, most of all, an iconic champion of clean air for everyone, especially the poor. Prof. Smith worked tirelessly to highlight the widespread health impacts of air pollution and explore ways to reduce them. We are deeply saddened by his unexpected death on June 15, 2020, at his home in Berkeley, following a stroke and cardiac arrest. Dr. Smith, Professor of Global Environmental Health at University of California, Berkeley’s School of Public Health, was the founding director of CCAPC.

Prof. Smith worked on household air pollution related issues with a level of insight, engagement, and passion that has no parallel.  His science was inherently collaborative; he worked consistently and constantly with colleagues over 40 years to make a difference in the lives of millions of poor women and children struggling with the impacts of using solid cooking fuels. The CCAPC was his latest brainchild, emerging from his conversations with some of us – KB, AM, AS – about the necessity of bringing the best scientific analysis into policy-making.  In fact, the name of the Centre embodies what he deeply valued  – collaboration and clean air – and recognized policy as key to achieving the latter. Prof. Smith’s dedication to CCAPC and its mission was evident by his spending four to five months every year living and working in Delhi to shepherd the Centre and work on vital issues of air pollution exposure and related health effects and policy interventions. Notably, even though he had numerous distinguished affiliations at many prestigious institutions across the world, he chose to highlight his newest role at CCAPC in his email signature.

Among many accolades, he shared the Nobel Peace Prize in 2007 along with other Intergovernmental Panel on Climate Change scientists, and received the Tyler Prize for Environmental Achievement in 2012. In recent years, Prof. Smith’s focus shifted to (1) translating complex science into policy changes in developing countries and in India in particular, where he sought ambitious policy to fully transition households to clean energy sources, and (2) building infrastructure for serious, policy-oriented science and capacity building. The CCAPC was set up to fulfil this mission. 

He shaped the lives of a substantial fraction of the now large community of researchers working on household air pollution throughout the world. To all of us who knew him and worked with him, he was not just a mentor but also a selfless collaborator who was deeply committed to advancing science and building capacity.  Prof. Smith was a gentle guide, offering his students a bright star to guide them, and providing introductions to colleagues to help kick-off research partnerships, but never insisting on a specific path to be taken. Many of us in India have experienced his energy, enthusiasm, and sheer brilliance over the last four decades. We remember with gratitude how he not only treated women colleagues as equals himself, but also publicly corrected others who displayed chauvinistic attitudes. 

His demonstrated commitment to fostering and sustaining collaborative and collegial working relationships paved the way for establishing a long-term network of colleagues in India, with Prof. Smith as a central node. There is an unspoken understanding, trust, and shared commitment among his colleagues which serves as the basis for strong and sustained partnerships; this invaluable legacy must be continued.  Whether we worked together decades ago, or starting just last year, we will remember fondly his easy-going nature, quirky sense of humour, and supposed lack of jet lag, not to mention his dedication, intellectual rigor and keen sense of observation.   As we continue to work together, we will empathise with how he was, at times, understandably grumpy and impatient in the face of slow progress, and will aspire to stay motivated for the cause.

We cannot find adequate words to describe all that he has meant for India and the field of air pollution, but we want to dedicate this tribute to his favourite paradigms (adapting from Smith 2015). These “mantras” were not only responsible for revolutionising the field but have transformed the thought processes of the community interested in making a difference for millions without access to clean air.  They will also continue defining CCAPC’s actions in the years to come as we try to continue his formidable legacy.

Paradigm #1: Absence of evidence is not evidence of absence

While ubiquitous, smoke in the kitchen was not recognized as a health hazard. Many considered woodsmoke as natural and thus harmless – including both populations using solid fuels, and also scientists (even in the 1980s) immersed in the air pollution risks causes by modern sources like vehicular and industrial emissions. Prof. Smith during travel through Asia and Latin America observed the high levels of smoke observed in homes and hypothesized that it must be unhealthy. In 1981, as a young researcher who had recently received his PhD from UC Berkeley and had then founded the Energy program at the East-West Center in Hawaii, he set about generating objective evidence to prove his hypothesis. He toured the villages of Kheda District in Gujarat to conduct personal, micro-environmental, and ambient monitoring, and show that the pollution levels both indoors and outside were staggeringly high (Smith et al 1983). No one had attempted to look for this evidence before! Methods that he used to gather this evidence under extreme field conditions are truly remarkable and continue to provide the framing for exposure assessment for major studies some 40 years later. And thus was born a quest for pursuing a public health hazard that we now recognize as one of the largest threats to health. “Never assume evidence doesn’t exist. Have you looked for it?” he would say to the uninitiated air pollution researcher.

Colleagues then at TERI (Veena Joshi, Chandra Venkataraman, VVN Kishore and Uma Rajarathnam), NIOH Ahmedabad (AL Aggarwal) and IGIDR (Jyoti Parikh and Kirit Parikh) share many memories of his visionary enthusiasm from his first field studies in India and of their earliest efforts in creating an emissions inventory for the cooking sector. 

Paradigm #2: Follow the risk

This was perhaps the most famous of Prof. Smith’s maxims. While he started his career focused on nuclear risk assessment, he soon shifted his focus to household energy because he believed it was a much larger concern. "Most people have accepted the fact that sticking burning stuff in your mouth is bad for you. Now think of a thousand cigarettes an hour burning in the kitchen.  Babies don’t smoke, but babies are in kitchens,” he said at the 2012 Tyler Prize Laureate Lecture.  Prof. Smith recognized early on that while he had identified this neglected hazard in the kitchen, documenting the health risks associated with cook-fuels would take decades. He followed up his initial studies in India with studies in China, Nepal, Tibet, Mexico and most famously in Guatemala, where he conducted the first ever intervention trial for reducing household air pollution (HAP) exposures (Smith et al 2011).

Kalpana Balakrishnan (SRIHER, Chennai), Sumi Mehta (then at UC Berkeley), Uma Rajarathnam (then at TERI, Delhi) and their teams have conducted numerous large–scale exposure measurements in India under his guidance (e.g. see Balakrishnan et al 2004). He collaborated with colleagues at PGI Chandigarh (SK Jindal, D Behera, D Gupta) and several other medical professionals at KEM Lucknow and KEM Mumbai to generate the epidemiological evidence for health effects of solid fuels (using demographic survey or categorical fuel use data, even before exposure measurements were being made). In 2000, ITRC Lucknow (Prahlad Seth and Qamar Rahman) organised a seminal conference, where Prof. Smith made a case in point for HAP to delegates from 21 countries. 

Numerous papers had already been published on the health effects of HAP before he led the first efforts to estimate its disease burden as part of the Comparative Risk Assessment (CRA) and Global Burden of Disease (GBD) Assessment conducted by The World Health Organisation (WHO). Kalpana Balakrishnan and Sumi Mehta, who were part of the WHO HAP working group, vividly recall his persuasive arguments supporting the strength of the evidence base compared to other well-known risks including smoking, salt, high cholesterol, blood pressure) (see Smith et al (2004) and Smith et al (2014)). Much of the evidence from his “RESPIRE” trial would come years later, but his meticulous preparation in consolidating the evidence from the field won the argument and HAP was recognized as a leading risk factor for public health for the first time; for an early example of this consolidation of evidence, see Smith (2000) for the first estimate of the burden of disease due to indoor air pollution in India. His contributions through exposure-response information generated from the RESPIRE trial continue to guide intervention trials throughout the world and the GBD exercise to date.

 “You just have to follow the risk, don’t get diverted, always do good science and focus on the things that are going to help people, even though it is not easy to do in the academic environment,” he said on numerous occasions (e.g. in his opening remarks at Peking University in 2015), especially to thousands of starry eyed students and young researchers who came up to him at the end of his lectures.

Paradigm #3: You don’t get what you expect, you get what you inspect

Prof. Smith stressed on the importance of investigating what was and was not working in actual use with technologies being proposed as HAP interventions, using his experience from numerous field studies to guide his thinking. He was part of the group that designed the 2009 National Biomass Cookstove Initiative (NCI) of the Ministry of New and Renewable Energy that sought to provide quality of energy services from cookstoves comparable to that from other clean energy sources such as LPG.

 “The motto of my group is you don’t get what you expect, you get what you inspect. There have been an awful lot of programs around the world introducing so-called improved stoves, but they haven’t done any inspecting and consequently, didn’t achieve anything verifiable. But there are so many parameters that you have to do an awful lot of monitoring and evaluation or regular checking to see what’s happening and modify the program accordingly” he said in a 2012 interview in PNAS.

To address this, he developed sensors he dubbed “small, smart, cheap and fast”: rugged devices to monitor the use and performance of stoves and related parameters (Pillarisetti et al 2017). He deployed them at dozens of sites throughout the world. Sankar Sambandam and Krishnendu Mukhopadhyay at SRIHER (Chennai), Rajinder Prasad at IIT Delhi, and Karabi Dutta at ARTI (Pune) were part of the earliest improved cookstove assessments including the ones certified by the NCI. More recently, he guided the long-term deployment of stove use monitors at sites in Palwal, Haryana and Junnar, Maharashtra led by Ajay Pillarisetti (then of UC Berkeley) and colleagues at INCLEN (Delhi), KEMHRC (Pune), and SRIHER (Chennai).  

The findings from these studies collectively showed that the so-called “improved cookstoves” failed to achieve health relevant exposure reductions. His keen eye for inspection led him to introspect, and he went on to champion the cause of “clean cooking” and question the meaning of “improved”!

Paradigm #4: Make the clean available, instead of waiting to make the available clean

Initiating a dramatic paradigm shift, in 2015, Prof. Smith and Ambuj Sagar (IIT Delhi) described a new strategy for rural India to escape from the age-old practice of dirty cookstove and solid fuel use – a phenomenon they dubbed the Chulha Trap (Smith and Sagar 2014). They recognized that while many rural communities in India had made progress on several development indicators, they still remained “stuck” using solid fuels in traditional cookstoves. They provided compelling arguments to move away from so-called improved biomass cookstoves – including the inability of solid fuels to burn cleanly in cheap (affordable) devices, the failure of these stoves to satisfy household cooking requirements, and the need to achieve really low levels of pollution to truly protect health. LPG was a familiar fuel for a third of India already, with an impressive supply infrastructure. “Needed is a new agenda to make the ‘clean available’, i.e., to vigorously extend these clean fuels into populations that are caught in the Chulha Trap” (Smith and Sagar (2014), p. 410).

Years of dedicated science provided Prof. Smith the ammunition to argue for an ambitious programme to increase clean fuel access to millions of poor women in India. In a historic meeting with Vivek Rae, then Secretary, Ministry of Petroleum and Natural Gas (MoPNG), he outlined the framework for what would go on to become the Pradhan Mantri Ujjwala Yojana (PMUY). He served on the PMUY Task Force for the MoPNG as well as the Indian Council of Medical Research. He re-located to Delhi for up to six months in a year just to be able to meet with colleagues and take the work of the task force ahead.  He guided studies led by Sanjay Juvekar (KEMHRC, Pune) and NK Arora (INCLEN, New Delhi) and colleagues at UCB and SRIHER to pave the way for targeted LPG schemes for pregnant women and other vulnerable groups.

Prof. Smith remained an untiring champion for the health of millions of poor women and children in India.      

Paradigm #5: It is a health problem! 

Prof. Smith was a physicist by training, an aerosol and exposure scientist by field experience, and an epidemiologist by practice.  Rarely can the field of public health see all the skills embodied in equal measure in one individual. He started his career as an energy professional but spent much of his working years as a champion of public health. He would constantly draw upon the successes and failures of other public health programs to scope air pollution actions. Principles of equity dominated his thinking while framing any new idea to advance this field.

Prof. Smith’s perspective on scaling public health solutions evolved with the increasing evidence base on the health benefits of clean cooking – even after his own flagship randomized control trial in Guatemala indicated that improved biomass stoves could substantially reduce severe child pneumonia rates, he was not satisfied with merely recommending a sub-optimal solution to the poor.  He often used the vaccine analogy for cookstoves: “You don’t have an inferior vaccine for the poor and a superior one for the rich— we just need to find a way to make the best vaccine available at the most affordable price. We just need to make clean fuels accessible and affordable”.

As patterns of disease evolved, Smith expanded his earlier focus on protecting child health to include links with non-communicable disease.  This work also epitomized his belief that “absence of evidence is not evidence of absence”, and in short-course, air pollution, and household solid fuel use, soon became acknowledged as a leading risk factor for non-communicable diseases, particularly in low- and middle-income countries.  With Prof. Smith’s influence, WHO’s SEARO region passed a ground-breaking resolution in 2013 to emphasize that HAP should be considered a leading risk factor for NCDs in the region.  In 2014, he contributed to a seminal report produced by a high level Steering Committee, constituted by the Ministry of Health and Family Welfare, under the guidance of Srinath Reddy (PHFI) and Ambuj Sagar. Together with Indian colleagues, including those focused on non communicable diseases, he helped articulate a vision for India to lead the way by following a health-centred strategy for air pollution based on a new paradigm of exposure management, instead of concentration management, to prioritize policies and actions.

Prof. Smith was also one of the first people to realize the importance of articulating the broader benefits of clean cooking to households and the community at large – quantifying the health and climate co-benefits (Goldemberg et al 2018), as well as the connection between household and ambient air pollution (Chafe et al 2014). Alongside colleagues in IIT Delhi (Sagnik Dey and Sourangsu Chowdhury) and UrbanEmissions (Sarath Guttikunda) he elegantly modelled the feasibility of achieving the Indian national air quality standard for PM2.5 on average throughout the country by just controlling household emissions (Chowdhury et al 2019). His long-term collaborators at SRIHER are currently participating in the first multi-country Household Air Pollution Intervention Network (HAPIN) LPG trial that is expected to provide important insights for expanding clean fuel access and use among rural communities.

He often remarked that intervening on household sources would be the lowest hanging fruit for air quality and health actions in India.

The final tribute

Long-term colleague Dr. T.K. Joshi (Special Advisor to MOEF, Government of India) aptly described his passing as “Ek yug ka anth” (the end of an era). The vision of clean cooking and clean air for millions in India has been enriched over the last 40 years by the contributions of Professor Kirk R. Smith. No one could have served the cause of household air pollution better and in more impactful ways. He leaves a lasting legacy for researchers, students, and policy makers to carry forth his unfinished agenda. The CCAPC hopes to continue Professor Kirk Smith’s journey until his dream of achieving clean air for everyone and everywhere is fulfilled. 

Some of Prof. Smith’s classics

Balakrishnan L, Mehta S, Kumar P, Ramaswamy P, Sambandam S, Kumar SK, Smith KR. 2004. Indoor air pollution associated with household fuel use in India: an exposure assessment and modeling exercise in rural districts of Andhra Pradesh. Report. Washington, DC: World Bank 

Chafe Z, Brauer M, Klimont Z, Van Dingenen R, Mehta S, Rao S, Riahi K, Dentener F, Smith KR. 2014. Household cooking with solid fuels contributes to ambient PM2.5 air pollution and the burden of disease Environ. Health Perspect. 122:1314–20 doi: 10.1289/ehp.1206340

Chowdhury S, Dey S, Guttikunda S, Pillarisetti A, Smith KR, Di Girolamo L. 2019. Indian annual ambient air quality standard is achievable by completely mitigating emissions from household sources. Proceedings in the National Academy of Sciences: 116 (22) 10711-10716

Pillarisetti A, Allen T, Ruiz-Mercado I, Edwards R, Chowdhury Z, Garland C, Hill LD, Johnson M, Litton CD, Lam NL, Pennise D, Smith KR. 2017. Small, Smart, Fast, and Cheap: Microchip-Based Sensors to Estimate Air Pollution.  Sensors 17, 1879 doi: 10.3390/s17081879

Smith KR, Aggarwal AL, Dave RM. 1983. Air Pollution And Rural Biomass Fuels In Developing Countries: A Pilot Village Study In India And Implications For Research And Policy. Atmospheric Environment 17 (11):2243-2362

Smith KR. 2000. National burden of disease in India from indoor air pollution. Proceedings of the National Academy of Sciences 97(24):13286-13293

Smith KR, Mehta S, Maeusezahl-Feuz M. 2004. Indoor air pollution from household use of solid fuels. In Comparative Quantification of Health Risks: Global and Regional Burden of Disease due to Selected Major Risk Factors, Vol. 2, ed. M Ezzati, AD Rodgers, AD Lopez, CJL Murray, pp. 1435–93. Geneva: WHO

Smith KR, McCracken JP, Weber MW, Hubbard A, Jenny A, et al. 2011. Effect of reduction in household air pollution on childhood pneumonia in Guatemala (RESPIRE): a randomised controlled trial. Lancet 378:1717–26

Smith KR, Bruce N, Balakrishnan K, Adair-Rohani H, Balmes J, Chafe Z, Dherani M, Hosgood HD, Mehta S, Pope D, Rehfuess E; HAP CRA Risk Expert Group. 2014. Millions dead: how do we know and what does it mean? Methods used in the comparative risk assessment of household air pollution. Annu Rev Public Health 35:185-206 doi: 10.1146/annurev-publhealth-032013-182356. PMID: 24641558.

Smith KR, Sagar A. 2014. Making the clean available: Escaping India’s Chulha Trap Energy Policy 75 410–414

Smith KR. 2015. Changing Paradigms in Clean Cooking. EcoHealth 12:96–199