ABSTRACT
Abbreviations ............................................................................................................................... 221
References .................................................................................................................................... 221
The burning of fossil fuels generates fine and ultrafine airborne particles, which contain a large
amount of organic compounds including polyaromatic hydrocarbons (PAH). These particles must
be taken into account as they are considered to be among the most abundant components of
particulate matter 2.5 mm (PM
) in urban areas. Most of them are produced by diesel engine-
powered cars and diesel exhaust particles (DEP) constitute, on average, 40% of the PM
in a city
such as Los Angeles (Diaz-Sanchez 1997), and in a kerbside station in Paris more than 50% of
particles were close to the ultrafine range (%0.26 mm), likely due to the influence of the traffic
(Baulig et al. 2004). Chemical analysis between PM
collected in a kerbside and a background
station in Paris revealed that PAH are twice as important in the kerbside station. The results are
more relevant with heavy PAH than light PAH, due to their higher stability. We have also observed
variations of PAH according to the seasons, probably due to chemical reactions with atmospheric
oxidants. However, PAH are only a part of the organic component and they do not greatly influence
the soluble organic fraction (SOF) measured after dichloromethane extraction that appear to be
between 10 and 12% of the mass of the particles whatever the station and approximately 45% lower
than the SOF of DEP (20%) (Baulig et al. 2004).
