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HCFC, CFC, PFC, HFC – what does it mean?

When looking for information concerning air emissions you probably came across the abbreviations HCFC, CFC, PFC and HFC referred as air pollutant. These combinations of H-s, C-s and F-s create confusion even for experts of environmental statistics. So lets look what is behind of these letters.

All of these abbreviations refer to human made substances mainly used in different kinds of refrigerators and air conditioners. By their chemical compositions all of them are hydrocarbons containing at least one fluorine atom.  But there’s also a significant difference between these compounds and due to that their air emissions are classified under different environmental problems.



Misleading publication about food waste from European Commission

Some time ago our office got an e-mail from one of the governmental establishments with request to comment data published in one publication of European Commission. You can find the online version of this publication here:

This publication is titled “PREPARATORY STUDY ON FOOD WASTE ACROSS EU 27“, Technical Report – 2010 – 054“ and it was compiled by group of experts from different countries. We were asked to comment the table on the page 12.

Summary of this publications say: Around 90 million tones of food waste are generated in the EU each year.”



The evidence of global warming or the Monster in my bedroom

The evidence of global warming or the Monster in my bedroom

Despite talking abou it we usually don’t feel the global warming; the rise of average temperature of atmosphere by about 0.2 oC during 10 years is not perceptible. But there are some back-hand evidences.



Nitrous oxide (N2O)

Nitrous oxide is a colourless non-toxic gas with a faint sweet odor and taste. It’s stable and inert at room temperature; its reactivity increases at higher temperature.

It is also known as laughing gas because inhaling it has euphoric effects. Nitrous oxide has anesthetic and analgesic effects and is used in surgery and dentistry. It has also been used for recreational purposes as a euphoria-inducing inhalant drug.

At higher temperatures nitrous oxide is a powerful oxidizer and is used in racing cars and rockets to increase the power output of engines. In vehicle racing, nitrous oxide (or just “nitrous”) allows the engine to burn more fuel. The nitrous oxide itself is not flammable but it supports combustion releasing more oxygen by breaking down at elevated temperatures and so providing more oxygen than air alone. The result is a more powerful combustion



Lost in zeros aka always look at the units

Some time ago I got a phone call from a Concerned Citizen asking explanation about tremendous increase in arsenic air pollution. He had read about it in a small citys local newspaper. He had already talked to the author of the article and the journalist referred him to statistical data on our website. The Concerned Citizen was well aware with environmental problems of his city and knew that air emissions of sulphur dioxide used to be about 20 tons per year but arsenic is very dangerous substance and should not be emitted into air at all in any considerable quantity. And now the amount of them was about equal. (more…)


Acid rain

One negative impact to ecosystem caused by air pollution is acidified atmospheric depositions. The phenomena is best known as acid rain. Actually it’s not just rain. All other kind of depositions like snow, sleet, hail as well as fog and cloud water get acidified due to air pollution.

The acidity of water (solution) is usually measured in pH units. pH is defined as the decimal logarithm of the reciprocal of the activity of hydrogen ion in a solution. The pH of pure clean water is 7. When acid is dissolved in water, the pH will be less than that of pure water, (pH<7).  When an alkali is dissolved in water, the pH will be greater than that of pure water (pH>7). Measured pH values lie mostly in the range of 0 to 14.)



Air pollutants

Different kind of substances can be found in the databases referring to air emissions. The most commonly these are: SO2 (or SOx), NO2 (or NOx), N2O, CO, CO2, NH3, CH4, O3, VOC-s (or NM-VOC-s), PM (and PM2,5 and PM10), POP-s, PAH-s, heavy metals, HFC-s, PFC-s, SF6, HCFC-s, CFC-s. If you remember something about high school chemistry you’ll see that the most of these are not individual chemical compounds. Actually these combinations of letters and numbers refer to the groups of substances with similar chemical or physical properties. But you hardly find all of them in the same table. Usually different air pollutants are grouped by their main harmful properties: pollutants which impact the ecosystem, pollutants with impact to the climate and pollutants which are harmful to humans.



Air pollution

If asked to name one fruit without thinking most people usually answer “apple”. If they are asked to name one big environmental problem, most people will say „air pollution“.  If you ask them to be more specific and name some the most important air pollutants, they answer: “CO2”. And if asked why CO2 is a problem, aware people will add: “This is about depleting the ozone layer”. At least this is the impression I got after 2 weeks of interviewing candidates for vacancy in our office.

A few weeks ago we got an angry e-mail from one consulting company complaining that out database of air pollutant air emissions does not contain emissions of such importance as CO2. Their company was conducting a project researching an air quality in different cities and they needed data on emissions of CO2 in these cities.

The truth is they were looking for it in the wrong table. They should have looked up “Emissions of greenhouse gases” instead of air pollutants. CO2 is not an air pollutant and by the way, it has nothing to do with depletion of ozone layer.



CO2 equivalents

As a rule data in databases/tables/articles about emission of greenhouse gases is in CO2 equivalent tonnes. These are not the tonnes of emitted CO2. Actually these are not the tonnes of real gases of any kind at all. CO2 equivalent tons are theoretical quantities invented in order to express total greenhouse gas effect caused by all GHG altogether. Why do we need such theoretical quantity and why cant we just add the quantities of all greenhouse gases emissions together?

Using CO2 equivalents enables us to compare different greenhouse effects caused by emissions of different greenhouse gases and to add it together. Different gases have different ability to cause greenhouse effect; global warming potential (GWP) of different substances vary greatly. It depends of three main matters:

1) molecules ability to absorb radiation;

2) the wavelength of radiation absorbed;

3) the timeperiod of which the molecules stays in the atmosphere.

Combination of these characteristics specifies the harmfulness (GWP) of substance. This mean, that substance (gas) with very high GWP gives lot of CO2 equivalent tonnes even when its actual emission in tonnes is quite small. CO2 is taken as standard, its GWP is agreed to be 1; real CO2 emission and its emission in CO2 equivalent tonnes is the same. CO2 equivalent of other greenhouse gases is calculated by multiplying  quantity of gas emission with GWP of this gas. Emission of GHG in CO2 equivalents equals the quantity of GHG multiplied by its GWP.

When emissions of all greenhouse gases are expressed through CO2 we can add them together to indicate the total greenhouse emission. Actually the real emission in tonnes of gases with high GWP (higher than that of CO2) is much smaller than their CO2 equivalents quantities.

So CO2 equivalent is defined as the amount of CO2 that would have the same global warming potential (GWP), when measured over a specified timescale (which is usually 100 years). Carbon dioxide equivalents is used to express  the greenhouse gas emission (flow) into the atmosphere.


Global warming potential

The contribution of different greenhouse gases into greenhouse effect  (and thus into global warming) is different. It depend on chemical and physical properties of the molecule and lifespan of this molecule in atmosphere. A relative measurement unit has been agreed upon in order to compare the greenhouse effect of different gases. It is called global warming potential (GWP). It compares the amount of heat trapped by the particular gas in question to the amount of heat trapped by a similar mass of carbon dioxide during a specific time interval, commonly 100 years. Global warming potential of carbon dioxide is agreed to be 1.


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