The study is the first to provide a global estimate of maritime shipping's total contribution to air particle pollution based on direct emission measurements. The authors estimate ships emit about 1,100 tons of particle pollution globally each year.
Ship pollutants affect both global climate and the health of people living along coastlines, according to the study authors. The findings appear online the week of Feb. 23 in the Journal of Geophysical Research.
"Since more than 70 percent of shipping traffic takes place within 250 miles of the coastline, this is a significant health concern for coastal communities," said lead study author Daniel Lack, a researcher with the NOAA-supported CU Cooperative Institute for Research in Environmental Sciences based at NOAA's Earth System Research Laboratory in Boulder.
Earlier research by one of the study's co-authors, James Corbett of the University of Delaware, linked particle pollution to premature deaths among coastal populations.
Commercial ships emit both particle pollution and carbon dioxide, but they have opposite effects on the climate, said the researchers. The particles have a global cooling effect that is at least five times greater than the global warming effect from the ships' CO2 emissions.
The particles affect both climate and health, said the researchers. CO2 from ships makes up roughly 3 percent of all human-emitted CO2 and almost 30 percent of smog-forming nitrogen oxide gases.
During summer 2006, Lack and colleagues aboard the NOAA ship Ronald H. Brown analyzed the exhaust from over 200 commercial vessels, including cargo ships, tankers and cruise ships in the Gulf of Mexico, Galveston Bay and the Houston Ship Channel. The researchers also examined the chemistry of particles in ship exhaust to understand what makes ships such hefty polluters.
Ships emit sulfates, the same particles associated with diesel-engine cars and trucks and which have resulted in tighter regulations regarding on-road vehicle fuel standards, according to the research team. Sulfate emissions from ships vary with the concentration of sulfur in ship fuel, the authors found.
Globally, fuel sulfur content is capped under the International Convention for the Prevention of Pollution from Ships. As a result of the cap, some ships use "cleaner," low-sulfur fuels, while others continue to use the high-sulfur counterparts.
But sulfates make up just under half of shipping's total particle emissions, according to the NOAA-CU study. Organic pollutants and sooty, black carbon -- which make up the other half of emissions -- are not directly targeted by today's regulations. A 2008 study by Lack's team focused exclusively on soot.
Emissions of non-sulfate particles depend on the operating speed of the engine and the amount of lubricating oil needed to deal with wear and tear from burning less-refined fuels, according to the researchers. "Fortunately, engines burning 'cleaner,' low-sulfur fuels tend to require less complex lubricants," said Corbett. "So the sulfur fuel regulations have the indirect effect of reducing the organic particles emitted."
One surprising result of burning low-sulfur fuels was that while total particle emissions diminish, the time the remaining particles spend in the air appears to increase. It's while they're airborne that particles pose a risk to human health and affect climate, according to the study.
Lack and colleagues found that the organic and black carbon portion of ship exhaust is less likely to form cloud droplets. As a result, the particles remain suspended for longer periods of time before being washed to the ground through precipitation.
Daniel Lack | EurekAlert!
Further reports about: > Air Pollution > CO2 > CO2 emissions > Coastlines > Environmental Sciences > Global Climate > SHIP > Ship pollutants > black carbon > cargo ships > coastal communities > emission measurements > maritime shipping > maritime shipping's > particle pollution > premature death > premature deaths among coastal populations
Ice cave in Transylvania yields window into region's past
28.04.2017 | National Science Foundation
Citizen science campaign to aid disaster response
28.04.2017 | International Institute for Applied Systems Analysis (IIASA)
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences