Environmental Engineering Reference
In-Depth Information
Table 5.1 Summary of characteristics of on-road vehicle emissions.
Modal diameters
Emission factors
References
Exhaust
emissions
Diesel vehicles (1)
Nucleation mode:
6-30 nm
Soot mode:
50-60 nm
Petrol vehicles (2)
No typical
signature
From
2-7
10 14 particles
veh 1 km 1 (3)
2-5
×
(1) Vogt et al. , 2003;
Kittelson et al. , 2006a
(2) Ritovski et al. , 1998;
Maricq et al. , 1999b;
Morawska and Zhang,
2002; Kittelson et al. ,
2006b
(3) Morawska et al. , 2005
and references therein
(4) Beddows and
Harrison, 2008 and
references therein
10 13 particles
veh 1 km 1 (3)
Light-duty vehicles
(mix fl eet)
2-70
×
10 13 particles
veh 1 km 1 (4)
Heavy-duty vehicles
(mix fl eet)
20-730
×
10 nm to
80 nm
<
10 13
particles
veh 1 km 1 (4)
×
Brake-wear
emissions
Not yet known
Not yet known,
depend on braking
conditions
Garg et al. , 2000; Sanders
et al. , 2003
Road-tyre
interface
emissions
15-50 nm
10 12
particles veh 1 km 1
at speeds of 50
and 70 km h 1
10 11 -3.2
Dahl et al. , 2006
3.7
×
×
Peak concentrations of ultrafi ne particles in occupied buildings are generally
associated with indoor activities. Cooking activities strongly enhance indoor par-
ticle number concentrations irrespective the use of gas or electrical stoves. The
increase of ultrafi ne particle concentrations depends on many parameters, such as
the activity type (frying, grilling, stove use, toasting, etc.), the way used to cook (gas
or electrical stove, oven, etc.) and the cooking temperature. As a consequence,
various impacts of cooking are noted in the published literature and results are
highly variable. Indoor particle number concentrations could be increased by
factors ranging from four times to 85 times (He et al. , 2004 ; Hussein et al. , 2005a ;
See and Balasubramanian, 2006). Also, particle modal diameters vary considerably
from one study to another. He et al. (2004) found that particle number size distribu-
tions resulting from cooking activities were always unimodal, with the number
median diameter ranging from 22 to 63 nm, while See and Balasubramanian (2006)
observed smaller modal diameters ranging from 8 to 29 nm.
Various indoor sources have been reported in the current literature. Candle
burning, aroma oil evaporation and aroma lamp activities are other sources of
indoor NPs that generate much less NPs than cooking or smoking; while burning
incense sticks was found to be an intermediate source between candle burning and
smoking (Hussein et al. , 2006). Cleaning activities also greatly affect particle number
concentration levels (Diapouli et al. , 2007), in particular vacuuming (Hussein et al. ,
2005a). A gas clothes dryer generates more than 6
1 0 12 ultrafi ne particles per
drying episode; showing a bimodal distribution with a major peak at the smallest
size measured (9.8 nm) and a secondary peak at 30 nm (Wallace, 2005). Finally,
×
 
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