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What actually is NOx, and is this gas a climate-change sinner? And where does ozone come into the picture? SINTEF- scientist Mario Ditaranto, an expert on combustion, provides all the answers on flue gases.

“What is NOx?”

“NOx is actually a collective expression that refers to two distinct gases that are subject to quite strict emission limits: NO or nitric oxide, and NO2 or nitrogen dioxide. Both of these gases are formed when practically anything that is combustible is burned. Nitrous oxide (N2O), better known as laughing gas, is also occasionally included in the NOx concept,” explains Ditaranto.

In fact, almost 80 per cent of the air that we breathe, and which is consumed in a fire, is nitrogen. The nitrogen molecule, N2, which is oxidised to NOx during the combustion process, may come from fuels such as wood, coal, biofuel, etc., but also from the air itself.

NOx have long been known as significant pollutants in many sectors, including transport, electricity generation and industry. A number of measures have been introduced to reduce NOx emissions.

“Why are NOx pollutants?”

“NOx are toxic to human beings when they are inhaled, even at relatively low concentrations (tens of parts per million).”

“NOx are present both in vehicle exhausts and industrial chimney smoke.”

“They (especially NO2) are also responsible for smog and the typical brown sky that often covers large cities and reduces air quality. NOx are also the most important source of acid rain. These gases are therefore not only sources of atmospheric pollution, but also contribute to the general acidification of soil and water,” points out Ditaranto.

“Are NOx from vehicles a greenhouse gas?”

“Well, the answer is both yes and no. As I have just mentioned, NOx refers to two different molecules whose relative concentration in exhaust gases depends on the type of combustion involved, that is, whether it is petrol, diesel oil, or wood that is being burned. Diesel cars produce more NOx than petrol vehicles, due to the higher combustion pressures and temperatures in diesel engines.”

Although the most important component of vehicles exhausts is NO, this is rapidly oxidised to NO2, which is not a greenhouse gas itself. That is to say, if we fill a bottle with NO2 and leave it out in the sun, the temperature of the gas will not rise. However, NO2 is responsible for the formation of ozone, which is a greenhouse gas, via secondary reactions with other gases.

Although ozone itself has a short lifetime, measured in hours to days, it influences cloud formation and the absorption of carbon by plants, which in turn has an effect on global warming.

The lifetime of NOx in the atmosphere is therefore influenced by how rapidly it is transformed into other directly dangerous components (acids and ozone), a process that can take place in the course of a few hours or days. The conclusion is that although NOx themselves are not greenhouse gases, emissions of these gases do lead to global warming, points out the SINTEF scientist.

“What is the problem with ozone and solar radiation?”

“Ozone in the troposphere, which is the lowest layer of the Earth’s atmosphere, and in which we live, is a danger to life, and also leads to global warming via the interactions that we have just mentioned. However, ozone is also essential higher up in the stratosphere, because it protects us against ultraviolet radiation from the Sun. Ozone also has a cooling effect in the stratosphere. Unfortunately, however, human activity is leading to a breakdown of stratospheric ozone and an increase in ozone levels closer to ground level.”

“What about the really wicked climate gas; nitrous oxide?”

“N2O, or laughing gas, is also produced during combustion, especially from biomass or coal in certain types of combustion process, but to a lesser extent by vehicles. Unfortunately, N2O reduces stratospheric ozone, which is regarded as “good” ozone.”

“The most important source of N2O emissions is the use of artificial fertilisers. Unlike the other NOx, N2O is a powerful greenhouse gas, 300 times as strong as CO2 in a hundred-year perspective. Furthermore, this gas has a lifetime of about 110 years in the atmosphere. It is responsible for about six per cent of the global greenhouse gas effect, according to the Intergovernmental Panel on Climate Change (IPCC).”

“Which is worse; diesel or petrol, as far as N2O are concerned?”

“As far as vehicles are concerned, there is little to choose between diesel and petrol in terms of N2O emissions. Ironically, laughing gas is largely produced by the catalysts that are used to reduce NOx emissions from cars!

“The global warming effect of N2O is estimated to be in the order of one to ten per cent of total lifetime geenhouse gas emissions from a vehicle”, says SINTEF combustion expert Mario Ditaranto.

So now you know all you need to know about NOx.

(gemini)

A general view of the Klemetsrud incinerator in Oslo, Norway, January 25, 2016. REUTERS/Alister Doyle

Norway’s greenhouse gas emissions rose by 1.5 percent last year, lifted by the oil and gas sector and industry, making it harder for Oslo to keep promises of deep cuts to limit global warming, official data showed yesterday.

Emissions rose to the equivalent of 53.9 million tonnes of carbon dioxide from 53.2 million in 2014, breaking several years of declines, and were above the 51.9 million in the benchmark year of 1990, preliminary Statistics Norway data showed.

In the oil and gas sector, BG Group’s new Knarr oilfield added most to emissions in 2015.

The rise makes the climate goals of the right-wing government’s ever tougher. Last year, Oslo said it would cut emissions by at least 40 percent by 2030 from 1990 levels as part of a U.N. agreement on climate change reached in Paris in December.

Many opposition politicians say the powerful oil and gas sector too often gets priority. Norway has often bought emissions quotas abroad to make up for a lack of progress in cutting domestic emissions.

On Wednesday, Norway awarded 10 oil licences to energy companies in the Arctic, opening new acreage for exploration for the first time in two decades.

(Reuters)

Norway’s foremost institute for interdisciplinary climate research has launched a new initiative pairing scientists with leading investors to better explain climate risk.

The Center for International Climate and Environmental Research – Oslo (CICERO) has launched the Climate Finance Initiative, “a meeting place for climate scientists and leading global investors to improve the understanding of climate risk.” Together, the Initiative hopes to “develop tools to incorporate climate risk in long-term investments, tailored to investors’ needs and inspired by the latest climate science.”

“Climate risk and sustainable investment are ever higher on the agenda in many financial environments, but climate change researchers and financial stakeholders do not always speak the same language,” said Kristin Halvorsen, Director and Former Norwegian Minister of Finance. “Our goal is to bridge that gap and jointly develop solutions.”

Much has been made recently of the need to better tailor future investments to account for both climate risks and the future of the fossil fuel industry. In April, the Institutional Investors Group on Climate Change published a report warning utilities of the threat of climate change, while a report from the Sustainable Finance Programme at the University of Oxford’s Smith School of Enterprise and the Environment concluded that the planned expansion of Japan’s fleet of coal-fired generation plants could end up stranding $56 billion in assets.

Earlier this month, Investment Leaders Group published a new report detailing the massive impact that energy and carbon regulations can have on a company’s bottom line. Investors are increasingly looking to renewable energy for future investment opportunities, at the same time as the global campaign to divest from fossil fuel investments continues to ramp up — highlighted most recently by news that the Bill and Melinda Gates Foundation Trust divested itself entirely from any investments in the super-major oil and gas company BP. Another global energy behemoth, Shell, is also looking forward, having just created its New Energies division, which will focus on investing in new energy such as solar and wind.

With climate change increasing the possibility of extreme weather events, and the ever-increasing shift away from fossil-fuel based energy generation, the Climate Finance Initiative aims to work with investors to provide scientific information to influence investment decisions based on climate risk.

“As we seek to expand our evaluation of the risks portfolios face from climate issues, both from a transition and physical perspective, we look forward to continuing to benefit from CICERO’s climate expertise while sharing with them what metrics are most meaningful to investors,” said Ashley Schulten, Head of Climate Solutions at BlackRock, the world’s largest private investor. “We have worked previously with CICERO on our impact reporting efforts in the green bond space and found they were able to interpret our needs as an investor and help us understand and evaluate environmental metrics.”

“With green bonds issued by the World Bank and others, investors can support climate action through a simple fixed income product,” added Heike Reichelt, Head of Investor Relations and New Products at the World Bank. “CICERO’s second opinion was a key part of the green bond model developed for the first World Bank Green Bond together with SEB in 2008, which has helped the market diversify with integrity. We look forward to continuing our collaboration with CICERO to expand the opportunities for investors to support climate finance.”

Already, BlackRock and the World Bank Treasury, in addition to a number of Scandinavia’s biggest financial actors and leading climate financial experts, have signed up to the Initiative’s Advisory Board which will support the Climate Finance Initiative.

“Climate finance is key to meeting the adaptation and mitigation needs of developing countries. Private climate finance flows to developing countries are already quite significant. However, much more is needed,” said Børge Brende, the Norwegian Minister of Foreign Affairs, which is providing start-up money for the initiative. “CICERO Climate Finance will build on and utilize the nexus of climate finance expertise in Norway, expanding on this experience and extending it to international actors and activities.”

(cleantechnica)