Ron Wyzga, SC. D., FASA Senior Technical Executive

AWMA Annual MeetingJune 25, 2014

Commentary on the Critical Review Public Health and Components of Particulate Matter:

The Changing Assessment of Black Carbon

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Critical Review

• Good compendium of literature• Rightfully points to role for BC• Needs to go beyond BC

– other components– surrogacy– BC, OC as mixtures

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Rohr – Wyzga Paper

• Reviewed literature through February 2012

• Epidemiology, toxicological, human clinical studies

• Acute studies only (exposures ≤ 1 week)

• No judgments about study methods, analyses

• Studies had to consider at last 2 components and PM2.5

• Quantitative results were presented

• Considered the most significant positive result

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Results – Epidemiological Studies Overall

• 39 studies considered PM2.5 and at least 2 components

• CVD response

21/39 significant association and at least with PM or component

2/39 significant association with PM, but not component

17/39 significant association with components, but not PM

Carbon-containing components gave more significant associations than PM2.5

24/28 studies considering carbon-containing particles found significant associations

9/35 studies considering sulfates found significant associations

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Results Epidemiological Studies II

• Respiratory responses

15/26 studies for carbon-containing particles

12/27 studies for sulfates

• Asthma

7/20 studies for carbon

• Not much consideration of metals in epi studies– Ni, V, Cu, Si, K found greatest effects

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Limitations/Caveats

•Considered any significant positive results

•Methodologies not evaluated

•No consideration of measurement error

•Multiple comparison issue

•Surrogacy issue

•Two pollutant models not addressed

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Ito et al Results

150 Cities(components)

64 Cities (components)

YearWarm

SeasonCold

SeasonYear

WarmSeason

Cold Season

PM2.5 x x x x - x

Sulfate - - - - - x

OC x x x x - x

EC x - x x - x

Nitrate x - - - x -

x = statistically significant

150 Cities(components)

64 Cities (components)

YearWarm

SeasonCold

SeasonYear

WarmSeason

Cold Season

x - x x x x

- - - x x -

x x x x x -

x - x x - x

- - - - - -

CVD Hospitalizations Respiratory Hospitalizations

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Overall Conclusion

• No major component is exonerated

• More evidence for carbon-containing particles– Definition needs to be clarified– Need to go beyond EC

• Some concern for metals, especially Ni, V with cardiovascular and respiratory; Al, Si with respiratory endpoints

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Health Analyses of Thermal Desorption Data

Atlanta & Birmingham (2006 - 2009), Dallas (2006 – 2007)

Health Data:– Medicare enrollees (>64 yr)– Total emergency CVD and respiratory related hospital admissions

Air Pollution Data:– PM2.5 condensed-phase primary OC species (TD-GCMS)

grouped by their chemical structure• At least 75% non-missing observations• At least 50% above the LOD• IQR/median > 0.3• All criteria satisfied in all 3 cities

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Thermal Desorption Data: Atlanta, Birmingham, Dallas Combined Total CVD

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Conclusions

• EC, OC are mixtures

• Some components may be more important in predicting health effects than others

• Need more detailed measurements to unravel air pollution – health issue

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Possibilities for EC

• EC bad actor• EC, others bad actors• EC + other bad actors• EC a surrogate