Posts tagged trees
CU Boulder — LA air pollution has a surprise problem
Mar 2nd
comes to some types of air pollution
The exhaust fumes from gasoline vehicles contribute more to the production of a specific type of air pollution — secondary organic aerosols — than those from diesel vehicles, according to a new study by scientists from the University of Colorado Boulder’s Cooperative Institute for Research in Environmental Sciences, or CIRES, NOAA’s Earth System Research Laboratory and other colleagues.
“The surprising result we found was that it wasn’t diesel engines that were contributing the most to the organic aerosols in L.A.,” said CIRES research scientist Roya Bahreini who led the study and also works at the National Oceanic and Atmospheric Administration’s ESRL. “This was contrary to what the scientific community expected.”
SOAs are tiny particles that are formed in air and make up typically 40-60 percent of the aerosol mass in urban environments. This is important because fine-particle pollution can cause human health effects, such as heart or respiratory problems.
Due to the harmful nature of these particles and the fact that they can also impact the climate and can reduce visibility, scientists want to understand how they form, Bahreini said. Researchers had already established that SOAs could be formed from gases released by gasoline engines, diesel engines and natural sources — biogenic agents from plants and trees — but they had not determined which of these sources were the most important, she said.
“We needed to do the study in a location where we could separate the contribution from vehicles from that of natural emissions from vegetation,” Bahreini said.
Los Angeles proved to be an ideal location. Flanked by an ocean on one side and by mountains to the north and the east, it is, in terms of air circulation, relatively isolated, Bahreini said. At this location, the scientists made three weekday and three weekend flights with the NOAA P3 research aircraft, which hosted an arsenal of instruments designed to measure different aspects of air pollution.
“Each instrument tells a story about one piece of the puzzle,” Bahreini said. “Where do the particles come from? How are they different from weekday to weekend, and are the sources of vehicle emissions different from weekday to weekend?”
From their measurements, the scientists were able to confirm, as expected, that diesel trucks were used less during weekends, while the use of gasoline vehicles remained nearly constant throughout the week. The team then expected that the weekend levels of SOAs would take a dive from their weekday levels, Bahreini said.
But that was not what they found.
Instead, the levels of SOA particles remained relatively unchanged from their weekday levels. Because the scientists knew that the only two sources for SOA production in this location were gasoline and diesel fumes, the study’s result pointed directly to gasoline as the key source.
“The contribution of diesel to SOA is almost negligible,” Bahreini said. “Even being conservative, we could deduce from our results that the maximum upper limit of contribution to SOA would be 20 percent.”
That leaves gasoline contributing the other 80 percent or more of the SOA, Bahreini said. The finding was published online March 1 in Geophysical Research Letters. “While diesel engines emit other pollutants such as soot and nitrogen oxides, for organic aerosol pollution they are not the primary culprit,” Bahreini said.
If the scientists were to apply their findings from the L.A. study to the rest of the world, a decrease in the emission of organic species from gasoline engines may significantly reduce SOA concentrations on a global scale as well. This suggests future research aimed at understanding ways to reduce gasoline emissions would be valuable.
The study was funded by NOAA’s Climate Change and Air Quality Programs, the California Air Resources Board and the National Science Foundation.
CIRES coauthors on the team include Joost de Gouw, Carsten Warneke, Harald Stark, William Dube, Jessica Gilman, Katherine Hall, John Holloway, Anne Perring, Joshua Schwarz, Ryan Spackman and Nicholas Wagner.
Boulderwind cowx 54mph 92mph gusts: trees, lines, transformers, accidents, signs, debris blown
Jan 18th
A tree fell on power line near 11 and Walnut starting a fire.
Nearby homes were evacuated.
In east boulder cattle fences blew down and cattle were on highway.
RTD is reporting some large signs down in city.
City 911 very busy. Dispatch reports
Power outages all over city.
Wind related roll over accidents 2 in last hour.
Some officers have been seen wearing helmets and googles. Good advice to anyone walking around. See weather report below. This does not account for the foothills of Boulder where winds are high
8:20 pm Power lines down on Pennsylvania on hill
8:25pm Tree down at 9th and college impeding traffic
Tiles flying off down town church at Broadway and Spruce
8:45pm Boulder County reports power line down in field at redwood court, sparking with fire and embers.
all fires out at this point, but police report signs, debris flying through air. Power lines are down and there are still power outages.
9:00pm Boulder Airport reports constant wind speed of 54mph Various sources in city report gusts of 71mph to 92mph
Diagonal and Look out road RR crossing sign blew into car causing tow car accident.
9:27pm Boulder Weather Station live reposts Power lines and trees continue to fall at this hour.
High Wind Warning
.HIGH WINDS IN THE MOUNTAINS AND FOOTHILLS THROUGH THURSDAY MORNING…
.VERY STRONG WEST WINDS WILL CONTINUE OVER THE NORTHERN COLORADO
MOUNTAINS…FOOTHILLS AND ADJACENT PLAINS THROUGH THURSDAY
MORNING. THE HIGH WIND WARNING IN THE MOUNTAINS HAS BEEN UPGRADED TO A
BLIZZARD WARNING FOR THE REST OF TONIGHT AS SNOW WILL DEVELOP ALONG
WITH THE CONTINUED WIND.
WIND GUSTS FROM 70 TO 90 MPH WILL BE COMMON IN WIND PRONE
MOUNTAIN AND FOOTHILL AREAS…AND ALSO IN FAVORED AREAS JUST EAST
OF THE MOUNTAINS SUCH AS ROCKY FLATS…BOULDER…AND CARTER LAKE.
THE STRONG WINDS WILL LIKELY CAUSE DOWNED TREES…POWER OUTAGES…
AND MAY BLOW OVER HIGH PROFILE AND LIGHT WEIGHT VEHICLES.
MONITOR THE LATEST WEATHER CONDITIONS AND AVOID TRAVEL IN AREAS
EXPERIENCING VIOLENT WINDS. MAIN AREAS LIKELY TO BE AFFECTED ARE
INTERSTATE 70 IN JEFFERSON AND CLEAR CREEK COUNTIES…THE PEAK TO
PEAK HIGHWAY BETWEEN BLACK HAWK AND ESTES PARK…AND HIGHWAYS AT
THE BASE OF THE FOOTHILLS.
City of Boulder: Nightmare on Pearl St coming.
Jan 13th
The City of Boulder Open Space and Mountain Parks (OSMP) will be removing two damaged cottonwood trees along the west end of Pearl Street. The work is scheduled to begin on Tuesday, Jan. 17, and be finished by the end of the week. This schedule is weather dependent.
Due to several defects these two cottonwood trees have been identified as hazards to the public and to public and private property. While the contractor is on site and working, Pearl Street will be closed from Canyon Boulevard to Third Street.