EAC2007 COST 633 session

Flemming R. Cassee

Some consideration• Any new proposed metric should be poorly correlated with PM10/2.5

• Additional indicator does not necessarily have to be promoted to a standard to guide policy in reducing health effects

• Not per se temperal but spatial. E.g. soot, black smoke shows more spatial variability which is needed for observational studies

EAC2007 COST 633 session

Flemming R. Cassee

ZW= black smoke

EAC2007 COST 633 session

Flemming R. Cassee

Some consideration• Any new proposed metric should be poorly correlated with PM10/2.5

• Not per se temperal but spatial. E.g. soot, black smoke shows more spatial variability which is needed for observational studies

• Consider other dimensions than mass, e.g. oxidative or genotoxic potential that are presumingly more health relevant

• Are there components that are not capture by routine PM monitors that are still health relevant, e.g. semi volatile organics

EAC2007 COST 633 session

Flemming R. Cassee

Scenarios• A Yes, supporting evidence from toxicology (and

epidemiology) that low mass components can induce significant toxicity, UFP, There are dosimetric reasons to classify UFPs as a separate fraction and also that UFP can induce different health effects than larger PM

• B Difficult with changing source composition in time but also while being transported to a receptor. Yet important to know what are the most toxic source emissions: is woodsmoke just as toxic as diesel soot?

• C Little evidence apart from adjuvant action of bioaerosols and diesel exhaust or PM in general. Tox studies are usually not designed to detect synergy

EAC2007 COST 633 session

Flemming R. Cassee

Scenarios• D Sulfate itself may not be very harmful but it is still a result

of anthropogenic emissions and might be good indicator. Recent studies using other constituents suggest that sulfate is less relevant.

• Sea salt: allowed to subtract from measurements in Europe; this opens opportunities to increase level of the more toxic fraction

EAC2007 COST 633 session

Flemming R. Cassee

PM10 composition

5 512

9 9

13

-

50

1 2 3

ug/m

3

No-ToxMild ToxModerate ToxToxic

Standard

Abatement strategy: focus on toxic part of PM

EAC2007 COST 633 session

Flemming R. Cassee

Scenarios• D Sulfate itself may not be very harmful but it is still a result

of anthropogenic emissions and might be good indicator. Recent studies using other constituents suggest that sulfate is less relevant.

• Sea salt: allowed to subtract from measurements in Europe; this opens opportunities to increase level of the more toxic fraction

• E. Gas – PM interactions? Very little information. Suggestion NO2 increase due to catalic particle traps cause increased tox. Yet, also evidence for the opposite effect.