Link to Abstracts

Question #1

Question #2

Question #3

Question #4

Question #5

Topic Leader Abstracts

The abstracts set an initial context for discussion and help participants prepare for the open-floor session and the break-out group session.

We will have up to three hours per topic to articulate key opportunities for advancing atmospheric science. What are the opportunities? When, where and how can they be engaged? A brainstorming session will offer additional time to refine some key ideas and bring out new issues.

Abstracts

Question #1
What are commonalities and differences between carbon emission inventory needs for visibility, health, and climate?

William Pennell, Topic Leader (contact)

NARSTO has recently completed an assessment of the status of emission inventories in North America (available at http://www.narsto.org/), and it offers a prioritized list of suggestions for improving them. The assessment focused primarily on the needs of air quality management; however, it does include some consideration of greenhouse gases. The topic leader will use the NARSTO assessment – particularly its critique of the strengths, weaknesses, and priority suggestions for improvement – as a platform for launching a discussion of the commonalities and differences between carbon emission inventory needs and the needs of the air quality management and research communities. The objective will be to assess the NARSTO recommendations from a climate perspective and to offer any revisions to these recommendations that may be required.

Question #2
What properties of carbonaceous PM emissions should be measured?

Jacob McDonald, Topic Leader (contact)

Carbon (organic and black carbon) accounts for 40 % or more of urban Particulate Matter (PM), and has been implicated in effects on climate, ecosystem, haze, visibility, and human health. Although carbon emissions are not directly regulated, they are an important component of a major criteria pollutant (PM) and most of the Toxic and Hazardous Air Pollutants are organic species. Data on carbon emissions are relatively sparse, and there is a large amount of uncertainty (at least a factor of 2) in the data that exist. This lends to a high degree of uncertainty in the impact of carbon on the environment and human health. The data that do exist on carbon emission characteristics have been compiled in useful forms and databases (e.g., EPA SPECIATE, AP-42) and have been reviewed and described recently by NARSTO (2005) and others (e.g., Bond et al., 2004). In addition to the deficiencies addressed in those reviews with respect to emission inventories, there are also many deficiencies and uncertainties in our understanding of environmental and human health impacts of particulate matter. To address topic 2, we will briefly touch on the current knowledge of the characteristics of carbonaceous PM and address what is the state of the science on understanding carbonaceous PM and human health linkages. Rationale for potential (scientific, philosophical, budgetary) reasons for deficiencies in both will be presented for discussion. Research “needs” will be defined in context of plausibility considering limitations in budgetary and other resources. Ultimately, the goal of this session will be to facilitate discussion to define tangible benchmarks for improving our understanding of carbon in the environment.

Question #3
How should source testing methods be modified to better represent carbon emissions from point, area, and mobile sources?

John Watson, Topic Leader (contact)

Abstract available soon.

Question #4
How can carbon emission inventories by evaluated and how can their uncertainties be assessed?

Tami Bond, Topic Leader (contact)

Two environments determine the composition and nature of ambient particulate matter: generation and processing within the source, and reactions and formation in the atmosphere. We can define an emission inventory thus: “A tabulation of particle and precursor quantities and properties that are governed by sources.” Given this definition, the inventory developer becomes responsible not only for emitted quantities, but for properties that affect the answers to key questions. Likewise, the task of evaluating inventories requires assessing not only particulate mass, but also the critical properties defined under Topics 1 and 2.

Quantities and properties can be tested at least at four “checkpoints:” (1) In the exhaust or immediate surroundings of the source itself; (2) in source-dominated microenvironments such as highway tunnels; (3) in urban airsheds; and (4) in regional or continental plumes or backgrounds. We will discuss the types of measurements that are most common in each environment, and brainstorm methods of expanding those measurements to provide inventory evaluation with constrained resources.

When measurements are taken far from sources, it is difficult to attribute variations in aerosol properties to one particular type of source. However, when measurements are taken near sources, the possibility is greater that the measurement is dominated by unrepresentative units. To address the former problem, we will discuss possibilities for correlating critical properties with source markers; for example, perhaps light absorption or toxicity could be correlated with molecular tracers or other source-apportionment techniques. To address the latter issue, discussion will focus on establishing representativeness of individual sources or environments used in source profiling.

Question #5
How should data repositories be established to facilitate carbon inventory improvement and dissemination?

Michael Hays, topic leader (contact)

Source emissions repositories are critical components of air quality management and modeling. The task of coordinating repositories that accurately reflect all spatially relevant source emissions activity is immense and currently incomplete. For the sake of future air pollution research, it is essential that data repositories be continually modernized and restructured with the aim of developing and disseminating improved carbon and chemical inventories. A core Workshop precept is to place the matters affecting inventory development under consideration with respect to the views of its aerosol and atmospheric scientist participants. To establish a framework for constructive discussion in this area, the topic leader will offer appropriate topic definitions and provide examples of previously assembled inventories. In an effort to further motivate dialogue, source emissions factor ratings and the potentially limiting effect of poorly characterized or highly variable emissions sources on carbon inventories will be evaluated. Possible outcomes of the interchange are: (i) the identification of carbon emissions sources in need of further testing, (ii) simplified criteria for rating repository data quality, (iii) the recognition of novel, useful organic chemical measurements for repositories (e.g. single particle-chemical data or organic carbon particle microstructure) and (iv) the eventual elimination of subjectivity evident in inventories and caused by missing, inadequately assembled, or eroding emissions factor data.

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