2001 Haagen-Smit Award Winners
The committee for the selection of the Haagen-Smit Award, given annually to two outstanding papers published in Atmospheric Environment (AE), has considered all nominations and made their final determination. We are very pleased to announce that the winners of the AE 2001 Haagen-Smit Award are:
R. Atkinson, Gas-Phase Tropospheric Chemistry of Organic Compounds, Atmospheric Environment, 24A, 1-41 (1990).
J. J. Schauer, W. F. Rogge, L. M. Hildemann, M. A. Mazurek, G. R. Cass and B. R. T. Simoneit, Source Apportionment of Airborne Particulate Matter Using Organic Compounds as Tracers, Atmospheric Environment, 30, 3837-3855 (1996).
With this announcement we would like to congratulate the authors and the nominators of these selected papers. These are indeed contributions that we can all be proud of. We would also very much like to thank all the other nominators for their effort and note that unsuccessful nominations are eligible for consideration again next year.
We further take this opportunity to acknowledge the hard work of the selection committee, made up of members from six countries, in arriving at a clear and timely decision.
Hanwant B. Singh and Peter Brimblecombe
R. Atkinson, Gas-Phase Tropospheric Chemistry of Organic Compounds, Atmospheric Environment, 24A, 1-41, 1990.
This is one of the most celebrated papers published in Atmospheric Environment and has been widely used. There were 447 citations as of January 2001 that place this paper in an extremely select category. Behind this outstanding paper is a scientist who is highly regarded for his innovative and extensive scientific contribution to atmospheric chemistry.
Let me elaborate on my choice of this paper for this award. Studies of Atmospheric Chemistry are critically dependent on accurate knowledge of chemical rate constant data for a very large number of chemicals. Air quality models, used in the development of environment policy all over the world, depend on the validity of these reaction rates. Unfortunately, these rates are often incorrect, internally inconsistent, and conflicting. Prof. Atkinson is a word class kineticist and has measured many of the rate constants widely used today. He has also led the effort to make some sense of the wide variety of kinetic data available. Because of his special expertise he is able to select the best available rate data and also provide knowledge of uncertainties to a vast user community. He has been especially successful in this effort because of his high credibility in the scientific world and his ability to continually collect, compile, and update these data.
It is in this context that I nominate this paper. It was among the first to present, in a concise way, a view of what was known ca 1990 concerning the atmospheric chemistry of Volatile Organic Chemicals (VOCs). It was primarily aimed at being useful to air quality/atmospheric chemistry modelers and experimentalists. It has clearly met that objective evident from its wide use and extensive citation. It highlighted areas of uncertainty in the atmospheric chemistry of VOCs, which needed further study, and provided an overall view of atmospheric chemistry of organics. This paper was updated in a 1994 review and evaluation in J. Phys. Chem. Ref. Data (Monograph 2, pp. 1-216, 1994) and more recently as one of the NARSTO Ozone Assessment critical reviews published in Atmospheric Environment ("Atmospheric Chemistry of VOCs and NOX", Atmospheric Environment, 34, 2063-2101, 2000). In this context, Prof. Atkinson's efforts and the subject paper have provided an outstanding service to the scientific community.
Dr. Roger Atkinson has a consistent record of outstanding scientific research with many of his publications appearing in Atmospheric Environment. He is presently a professor at the University of California, Riverside and received his undergraduate and graduate education from the University of Cambridge, UK.
For all of the above reasons, I believe that the subject paper and its author, Prof. Roger Atkinson, make an excellent choice for the Haagen-Smit award.
Nominator: Hanwant B. Singh, NASA Ames Research Center, California, USA
JJ Schauer, WF Rogge, LM Hildemann, MA Mazurek, GR Cass, and BRT Simoneit, Source apportionment of airborne particulate matter using organic compounds as tracers, Atmospheric Environment, 30, 3837-3855, 1996.
Airborne particles have a major influence on the character of our atmospheric environment. They are a rich and diverse set of species, varying over broad ranges of size and chemical composition. Their sources are many and their dynamic behaviors are complex.
As a class of air pollutants, particulate matter has a long history, and yet much remains to be learned. Interest has grown explosively as a consequence of the epidemiological studies that are consistently showing an as-yet-unexplained association between ambient concentrations of particulate matter and an array of adverse health outcomes. Evidence suggests that the fine particles may be disproportionate contributors. Based on this evidence, new federal standards have been promulgated for PM2.5 in the United States. It is apparent that some areas will be declared "nonattainment" with respect to these new standards. When that happens, plans will have to be developed to reduce concentrations. These plans will necessarily call for reduced emissions from sources. And the question will have to be answered: which sources and by how much?
The paper we are nominating makes an enormous contribution to our understanding of the sources of fine particulate matter in the Los Angeles area, historically one of the world's most polluted air basins. It is a tour de force, representing the culmination of a line of investigation initiated by Professor Cass almost two decades ago, and pursued with courage, determination, creativity, and insight. Professor Cass deserves special praise for initiating this line of research long before epidemiological evidence of fine particle health effects and PM2.5 air quality standards were established. The paper in Atmospheric Environment delivers an analytical approach and insights that will serve us well in assessing the origin of fine particles in the atmosphere.
The key challenge that this paper addresses can be stated simply: how much do different emission sources contribute to the atmospheric burden of fine particulate matter? This is a challenging question to answer. The chemical mass balance method of receptor modeling, widely used for source apportionment of PM10, is difficult to apply to the case of fine particles. Why? Because much of the fine particulate matter is organic, and so the elemental source signatures are broadly similar from one source to another. Motor vehicles (since lead was eliminated from gasoline), wood smoke, and meat cooking are all major contributors to urban air particle pollution. However, these sources cannot be readily distinguished on the basis of their elemental compositions.
The breakthrough achieved by the Cass group in this paper was to use the molecular composition of organic molecules in particles as the source fingerprint. A similar idea was previously developed for use in apportioning emissions of organic gases, but, to our knowledge, the present paper is the first to develop and apply the idea for particle source apportionment.
The challenges faced were many and substantial. Analytical methods for measuring trace quantities of high molecular weight species are difficult. Extensive field sampling was required to collect samples that were representative of annual conditions basinwide. Samples had to be collected and analyzed for a large battery of emission sources. These and other challenges were solved by the Cass group in the predecessor papers. The paper we are nominating successfully integrates this information in the framework of the chemical mass balance method to reach important conclusions about fine particulate matter in the Los Angeles air basin.
The conclusions are rich. Only a few key findings are repeated here. Four sources dominate as contributors to fine primary organic particulate matter: diesel exhaust, gasoline-powered vehicle exhaust, meat cooking operations, and wood combustion. Secondary organic aerosol can contribute no more than 15-18% of the total fine organic aerosol at central sites and less than 31% at the downwind Rubidoux station. Meat cooking is the primary source of oleic acid and nonanal in fine particulate matter; gasoline vehicle emissions contribute most of the PAHs. Perhaps the most significant finding is this: "Once these primary aerosol source contributions are added to the secondary sulfates, nitrates and organics present, virtually all of the annual average fine particle mass at Los Angeles area monitoring sites can be assigned to its source."
The impact of this work is profound and wide-ranging. Researchers studying biomass burning, secondary organic aerosol formation, polycyclic aromatic hydrocarbons, fossil fuel combustion, and health effects of atmospheric aerosols have noted this work.
Less than five years after publication, the paper has been cited more than 80 times (ISI Web of Science). Of great importance is the number of research projects and regulatory efforts that have commenced in the past several years that will apply the methods first presented in this paper. Efforts are now underway in the United States, Europe, Asia, and South America to use molecular organic tracers to study urban air pollution, remote tropospheric aerosols, and even personal exposure samples.
In summary, because of its substantial and timely contributions to our understanding of the sources of airborne fine particulate matter, a major issue of concern in the atmospheric environment, we believe this article is richly deserving of Atmospheric Environment's Haagen-Smit award.
Nominators: WW Nazaroff and RA Harley, University of California, Berkeley
*-pictures of first authors shown