3 research outputs found
Assessment of Particle Pollution from Jetliners: from Smoke Visibility to Nanoparticle Counting
Aviation is a substantial and a fast
growing emissions source.
Besides greenhouse gases, aircraft engines emit black carbon (BC),
a climate forcer and air pollutant. Aviation BC emissions have been
regulated and estimated through exhaust smoke visibility (smoke number).
Their impacts are poorly understood because emission inventories lack
representative data. Here, we measured BC mass and number-based emissions
of the most popular airliner’s engines according to a new emission
standard. We used a calibrated engine performance model to determine
the emissions on the ground, at cruise altitude, and over entire flight
missions. Compared to previous estimates, we found up to a factor
of 4 less BC mass emitted from the standardized landing and takeoff
cycle and up to a factor of 40 less during taxiing. However, the taxi
phase accounted for up to 30% of the total BC number emissions. Depending
on the fuel composition and flight distance, the mass and number-based
emission indices (/kg fuel burned) were 6.2–14.7 mg and 2.8
× 10<sup>14</sup> – 8.7 × 10<sup>14</sup>, respectively.
The BC mass emissions per passenger-km were similar to gasoline vehicles,
but the number-based emissions were relatively higher, comparable
to old diesel vehicles. This study provides representative data for
models and will lead to more accurate assessments of environmental
impacts of aviation
Size-Resolved Endotoxin and Oxidative Potential of Ambient Particles in Beijing and Zürich
PM<sub>2.5</sub> pollution has become
a global health concern,
however its size-resolved health impact remains to be poorly elucidated.
Here, ambient particulate matter (PM) were collected into 13 different
size ranges (10 nm to 18 μm) and the mass, metal, endotoxin
distributions, and related oxidative potential were investigated in
two regions (Zürich, Switzerland and Beijing, China). Results
showed that the two regions had remarkably different PM distribution
patterns. Swiss urban samples had a mode around 40 nm with 23.3% of
total PM mass, while Chinese samples featured two modes around 0.75
and 4.23 μm with 13.8–18.6% and 13.7–20.4% of
total PM mass, respectively. Two peaks for endotoxin at 40–100
nm and 1–4 μm were observed in different regions. For
PM-borne metals, Chinese samples had 67.6–100% of total Cd,
As, and Pb in the size range of 0.1–1 μm, and Swiss samples
had similar distributions of Cd and Pb but much lower total metals
than Chinese samples. The PM oxidative potential varied greatly with
sizes for different regions. Accordingly, the current practice, i.e.,
sole use of the mass concentration, could lead to inadequate health
protection for one region, but unnecessary economic costs for another
without achieving significant extra health benefits
Size-Resolved Endotoxin and Oxidative Potential of Ambient Particles in Beijing and Zürich
PM<sub>2.5</sub> pollution has become
a global health concern,
however its size-resolved health impact remains to be poorly elucidated.
Here, ambient particulate matter (PM) were collected into 13 different
size ranges (10 nm to 18 μm) and the mass, metal, endotoxin
distributions, and related oxidative potential were investigated in
two regions (Zürich, Switzerland and Beijing, China). Results
showed that the two regions had remarkably different PM distribution
patterns. Swiss urban samples had a mode around 40 nm with 23.3% of
total PM mass, while Chinese samples featured two modes around 0.75
and 4.23 μm with 13.8–18.6% and 13.7–20.4% of
total PM mass, respectively. Two peaks for endotoxin at 40–100
nm and 1–4 μm were observed in different regions. For
PM-borne metals, Chinese samples had 67.6–100% of total Cd,
As, and Pb in the size range of 0.1–1 μm, and Swiss samples
had similar distributions of Cd and Pb but much lower total metals
than Chinese samples. The PM oxidative potential varied greatly with
sizes for different regions. Accordingly, the current practice, i.e.,
sole use of the mass concentration, could lead to inadequate health
protection for one region, but unnecessary economic costs for another
without achieving significant extra health benefits