“Usually you can see the ‘super-polluters’ simply just by looking; particularly when they accelerate or climb a hill and a cloud of smoke comes out of the exhaust pipe”, comments the physicist Philip Siegmann, from the Department of Signal Theory and Communications at the University of Alcalá (UAH) and co-author of the study.
“People usually complain about the bad smell and the smoke, but the worst thing is that the nanoparticles that nobody can actually see or smell are always present in Madrid, for example, even when you think that you are breathing in clean air” the researcher points out to SINC.
The new study confirms that the “super-polluters” are, “by far”, the vehicles that emit the largest amount of nanoparticles. The report concludes that were these vehicles removed from the flow of traffic, the “total active surface” (TAS) concentration of the nanoparticles (the particle surface that interacts with the environment) could be reduced by up to 25%, and the concentration of particulate polycyclic aromatic hydrocarbons (PPAH) absorbed by the nanoparticles, which are known toxic substances, could be reduced by up to 48%.
The study, published recently in the review entitled Atmospheric Environment, has focused on distinguishing and quantifying which types of vehicles have a higher emission rate of nano- particles, namely the ultra-fine ones (less than 100 nm in size), that are implicated in the development of different diseases. Their reduced size enables them to be distributed within the body with hardly any detection by the defences of the organism, and can even cross the cell membranes. Some studies have already shown that these small particles stimulate allergic reactions, such as asthma, and the development of multiple sclerosis. Moreover, under continued and prolonged exposure, they can produce cancer, as is the case with tobacco.
The researchers have noted that one of the main emission sources of these ultra-fine particles comes from diesel powered vehicles, but this is less so for petrol powered vehicles. “In any case, it is the super-polluters that pollute the most, since these are usually the ones in poor working condition and with poor combustion” Siegmann points out. The expert considers that these vehicles need to be removed from the traffic flow.
In order to obtain measurements, the scientists had to follow moving vehicles and, through the window, record the data using two sensors located at the end of a tube. The recordings were taken every ten seconds and were made by sucking in the air so that the sensors could pick up the measurement peaks when they entered the trail of smoke emitted by a vehicle. In the case of the “super-polluters”, the PPAH measurement peaks ranged from 100 to 1,000 nm/m3, but in some cases this even exceeded this high quantity.
Less nanoparticle pollution in Madrid
The study data were taken in Madrid in 2001 and 2006 and in Mexico City in 2001, one of the most polluted cities in the world. Although they do not appear in the report, measurements were also taken in Boston (USA). The highest number of emissions of nanoparticles corresponded to Madrid, and the scientists relate the data to the fact that a high percentage of the cars in this city are diesel (nearly 30% in 1999-2001 and 50% in 2006), whereas in Boston there are fewer emissions of this type because nearly all the vehicles travelling on the roads are petrol driven. Mexico City finds itself in the middle, although there is a plethora of “super-polluters” in this city.
Nevertheless, in Madrid, the results confirm that over the last 6 years pollution from nanoparticles has reduced by nearly 65%. The researchers justify this because of the improvements that have been incorporated into new vehicles in order to comply with the European regulations regarding emissions, such as the ‘Euro 4’ level which will be replaced by the ‘Euro 5’ level in 2009.
Despite this, Siegmann recognises that ‘super-polluters’ are still on the roads in this city. “Anybody who is waiting at a bus-stop will have suffered from a cloud of smoke emitted by a bus as it accelerates”, he adds, “and in this cloud of smoke large quantities of all types of particles, including nanoparticles, are being emitted“.
Nanoparticles mainly come from human activities such as the combustion of coal, incinerators, vehicles, burning of rubbish, kitchens, barbecues and tobacco, but they can also be natural in origin, such as those emitted by volcanoes. In any event, the exposure of the human being to these substances has increased as a consequence of the industrial development throughout the 20th century, particularly with the advent of diesel driven cars, with the consequent health problems.
SINC Team | alfa
How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)
Scientists have developed a new method of characterizing graphene’s properties without applying disruptive electrical contacts, allowing them to investigate both the resistance and quantum capacitance of graphene and other two-dimensional materials. Researchers from the Swiss Nanoscience Institute and the University of Basel’s Department of Physics reported their findings in the journal Physical Review Applied.
Graphene consists of a single layer of carbon atoms. It is transparent, harder than diamond and stronger than steel, yet flexible, and a significantly better...
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
30.05.2017 | Life Sciences
30.05.2017 | Life Sciences
30.05.2017 | Physics and Astronomy