About air quality
Why is clean air important?
Clean air is essential for our health. Poor air quality leads to respiratory complaints, cardiovascular diseases, cancer and in some cases even premature death. The World Health Organization (WHO) estimates that 90% of the world's people breathe too many pollutants. Clean air is important to reduce the impact of air pollution on health. That is why we must limit the emission of polluting substances as much as possible.
Air quality and climate are closely linked. After all, sources of air pollution are often also sources of greenhouse gases. Taking action for air quality often means good news for the climate.
Finally, vegetation also suffers from air pollution: too much ozone reduces the growth of agricultural crops and forests. A high supply of nitrogen from the air causes acidification and eutrophication of the soil and reduces biodiversity.
So you can safely say that good air quality is important for the health of people, nature and the environment.
Measurable pollutants
For these polluting substances, so-called pollutants, the VMM proposes measuring methods with which you can map the air quality yourself.
Fine dust
Particulate matter is a mixture of very small particles that float in the air. Scientists usually speak of PM 10 and PM 2.5 . These are the particles smaller than 10 micrometers or 0.01 mm, and the particles smaller than 2.5 micrometers.
Nature itself also produces fine dust, for example in the form of sea salt or ash from volcanic eruptions. Yet humans produce most of the particulate matter themselves. Wood burning in stoves and fireplaces is the most important Flemish source of particulate matter, followed by agriculture & horticulture and traffic. Particulate matter causes respiratory diseases such as bronchitis and in the worst case even lung cancer. Particulate matter also has many adverse effects on the heart and blood vessels.
Primary particulate matter is emitted directly into the air. In addition, there is also secondary particulate matter that is created after chemical and physical reactions of gases in the air.
The daily average PM10 concentration of 45 micrograms per cubic meter (µg/ m3 ) may be exceeded a maximum of three times a year according to the WHO , while this may be exceeded up to 35 times for the EU and we speak of a daily average concentration of 50 µg/m 3 .
Only the WHO imposes a recommended exposure limit of 5 µg/m 3 for PM 2.5 , which may be exceeded 25 times per year.
The most important sources of primary particulate matter with a size of PM 2.5 can be found in an infographic with data for 2019.
More information about particulate matter can be found on the website of the Flemish Environment Agency .
Nitrogen Dioxide
Nitrogen dioxide is a gas made up of nitrogen (N) and oxygen ( O2 ). It arises, among other things, when fossil fuels are burned. The main sources of nitrogen dioxide are traffic, industry and agriculture and horticulture. NO 2 plays an important role in the acidification and eutrophication of ecosystems and in the formation of smog or ozone. Nitrogen dioxide can irritate the airways, causing respiratory diseases such as asthma and making people more susceptible to infections.
Traffic causes about half of the total NO 2 emissions in Flanders. Diesel cars are especially responsible for this: this is because diesel works with an excess of oxygen, which promotes the formation of nitrogen oxides.
For the annual average, both the European Union (EU) and the World Health Organization (WHO) use the same limit value of 40 µg/m 3 . The WHO is stricter than the EU with regard to the peak values of NO 2 : an hourly average of NO 2 may never exceed 200 µg/m 3 for the WHO. The EU allows this standard to be exceeded 18 times a year.
More information about NO 2 can be found on the website of the Flemish Environment Agency .
Soot
Soot is also known as black carbon and has the scientific abbreviation BC ('black carbon'). It forms part of particulate matter (PM 10 and PM 2.5 ) and mainly consists of soot particles that are formed during incomplete combustion of fuels such as diesel, wood and coal.
By black carbon we mean more or less the same as elemental carbon. Scientists speak of black carbon when the measurements are made in an optical way, ie by measuring how 'black' a filter is. When they measure in a different way, they usually speak of elemental carbon.
More information can be found on the website of the Flemish Environment Agency .
Difficult to measure pollutants
As a citizen, you cannot measure all polluting substances yourself. You need special tools or analyzes in specialized labs. And yet these pollutants are also important when it comes to air quality.
Ammonia
Ammonia (NH 3 ) is a colorless gas that consists of hydrogen and nitrogen. It causes secondary particulate matter, acidifying and eutrophic deposits and causes nitrate and metals to end up in the groundwater. Fine dust is harmful to our health. Acidification and eutrophication affect ecosystems and have a negative impact on biodiversity.
Agriculture, especially intensive livestock farming, is the main source of ammonia.
More information about NH 3 can be found on the websites of the Flemish Environment Agency , the RIVM or Natura 2000 in Flanders.
Ozone Depleting Substances
The ozone layer is an important part of the atmosphere. It protects us from the most harmful part of the ultraviolet radiation in sunlight. Several substances, such as CFCs, HCFCs and halons , break down this important layer. As a result, a larger part of the harmful radiation reaches the earth's surface. This radiation affects the genetic material of life on Earth, which can lead to abnormalities and cancers.
Ozone-depleting substances are mainly found in insulation material or as a refrigerant in refrigeration, freezing and air conditioning installations. You can also find them in fire extinguishers and aerosols. More information can be found on the website of the Flemish Environment Agency .
Heavy metals
Heavy metals occur naturally in the environment. However, in high concentrations they are harmful. Usually they spread through dust particles in the air and fall to the ground under the influence of gravity. We inhale these heavy metals, or absorb the particles through drinking water or food grown in a garden where heavy metals are present in the soil.
By heavy metals we mean antimony, arsenic, cadmium, chromium, manganese, iron, mercury, nickel, copper, lead and zinc. The last 4 metals have the highest emissions, mainly from industry and to a lesser extent from traffic and the energy sector.
More information about heavy metals can be found on the website of the Flemish Environment Agency .
Zwaveldioxide
Bij de verbranding van fossiele brandstoffen die zwavel bevatten, zoals kolen en aardolie, kan het gas zwaveldioxide (SO2) ontstaan. Zwaveldioxide lost goed op in water en zorgt via zure regen mee voor de verzuring van ecosystemen. Het gas is op die manier niet alleen slecht voor planten, maar tast ook historische monumenten en stenen aan, en doet metalen roesten.
De industrie en raffinaderijen vormen de belangrijkste bron van zwaveldioxide. Daarnaast zorgen ook het verkeer, met de zeescheepvaart op kop, en de verwarming van gebouwen voor een groot deel van de uitstoot.
Meer informatie over SO2 vind je op de website van de Vlaamse Milieumaatschappij.
Ozonafbrekende stoffen
De ozonlaag is een belangrijk onderdeel van de atmosfeer. Het beschermt ons tegen het schadelijkste deel van de ultraviolette straling in zonlicht. Verschillende stoffen, zoals CFK’s, HCFK’s en halonen, breken deze belangrijke laag af. Hierdoor bereikt een groter deel van de schadelijke straling het aardoppervlak. Deze straling tast het genetisch materiaal van het leven op aarde aan, wat tot afwijkingen en kankers kan leiden.
Ozonafbrekende stoffen komen voornamelijk voor in isolatiemateriaal of als koudemiddel in koel-, vries- en airconditioningsinstallaties. Je vindt ze ook in brandblusapparaten en spuitbussen. Meer informatie vind je op de website van de Vlaamse Milieumaatschappij.
Zware metalen
Zware metalen komen van nature in het milieu voor. In hoge concentraties zijn ze echter schadelijk. Meestal verspreiden ze zich via stofdeeltjes in de lucht en vallen onder invloed van de zwaartekracht neer op de grond. We ademen deze zware metalen in, of nemen de deeltjes op via het drinkwater of voedsel gekweekt in een tuin waar zware metalen in de bodem zitten.
Onder zware metalen verstaan we antimoon, arseen, cadmium, chroom, mangaan, ijzer, kwik, nikkel, koper, lood en zink. De laatste 4 metalen kennen de hoogste uitstoot, vooral door de industrie en in mindere mate door het verkeer en de energiesector.
Meer informatie over zware metalen vind je op de website van de Vlaamse Milieumaatschappij.
Dioxins
Dioxins are created when organic material containing chlorine burns incompletely. This phenomenon can be found in nature, for example during volcanic eruptions or forest fires, and in human activities. The incineration of household waste or the heating of buildings are examples of this.
The substance ends up in our water and food through the air. Dioxins enter our body mainly through high-fat food, where they accumulate in our adipose tissue and only slowly break down.
Dioxins are harmful to the development of children.
More information about dioxins can be found on the website of the Flemish Environment Agency.
VOC
Volatile Organic Compounds (VOC) is a collective name for a group of gaseous substances. They mainly consist of carbon and hydrogen atoms. VOCs mainly arise from biological processes, although they are also created artificially in industries where petroleum, natural gas or coal are the main raw materials.
Evaporation, especially at gas stations and in traffic, is the main cause of VOC emissions. Furthermore, these gases also end up in the air during the use of solvents, in refineries, in chemical production, incineration and waste processing.
These substances are often bad for our health and the environment. Some VOCs, such as benzene, are carcinogenic or react under the influence of sunlight to form ozone. Others pose a threat to the ozone layer or increase the greenhouse effect, such as methane.
More information about VOS can be found on the website of the Flemish Environment Agency.
Carbon monoxide
Carbon monoxide (CO) is created by incomplete combustion where too little oxygen is available. It is a colorless, tasteless and odorless gas that is poisonous and very dangerous. The greatest risk of carbon monoxide poisoning is at home in poorly ventilated areas with old heating systems. The gas is also present in car exhaust and tobacco smoke.
More information about CO can be found on the website of the Flemish Environment Agency.
Sulphur dioxide
The combustion of fossil fuels containing sulphur, such as coal and petroleum, can produce the gas sulfur dioxide (SO2). Sulfur dioxide dissolves well in water and contributes to the acidification of ecosystems through acid rain. In this way, the gas is not only bad for plants, but also affects historical monuments and stones, and causes metals to rust.
Industry and refineries are the main source of sulfur dioxide. In addition, traffic, with maritime shipping in the lead, and the heating of buildings also account for a large part of the emissions.
More information about SO2 can be found on the website of the Flemish Environment Agency.
PAH
Polycyclic aromatic hydrocarbons (PAHs) damage human DNA and are therefore very carcinogenic.
PAHs are found in crude oil, coal and tar, among other things. They escape when fossil fuels or biomass are burned in, for example, wood stoves or stoves. There are also PAHs in cigarette smoke, burnt meat and smoked foods. In addition, traffic (especially diesel vehicles) is also an important source of certain types of PAHs.
More information about PAHs can be found on the website of the Flemish Environment Agency.
POP
Persistent organic pollutants (POPs) are often found in products such as pesticides or fire retardants. They are substances that break down very slowly or are converted by chemical, biological or other processes in nature. As a result, they remain present in our environment for a long time and they often travel over longer distances. They end up in the food chain via rainwater and our body absorbs them. POPs are particularly harmful to human health and the environment.
Dioxins, PAHs and PCBs are in fact POPs.
More information about POPs can be found on the website of the Flemish Environment Agency.
POP
Persistente organische polluenten (POP’s) zitten vaak in producten als pesticiden of brandvertragers. Het zijn stoffen die zeer traag afbreken of omgezet worden door chemische, biologische of andere processen in de natuur. Hierdoor blijven ze lange tijd aanwezig in ons leefmilieu en reizen ze ook vaak over langere afstanden. Via regenwater belanden ze in de voedselketen en neemt ons lichaam ze op. POP’s zijn bijzonder schadelijk voor de volksgezondheid en voor het milieu.
Dioxines, PAK’s en PCB’s zijn in feite POP’s.
PAK
Polycyclische aromatische koolwaterstoffen (PAK’s) beschadigen het menselijk DNA en zijn daardoor erg kankerverwekkend.
PAK’s komen onder andere voor in ruwe olie, kolen en teer. Ze ontsnappen bij het verbranden van fossiele brandstoffen of biomassa in bijvoorbeeld houtstoven of kachels. Ook in sigarettenrook, aangebrand vlees en bij gerookte etenswaren zitten PAK’s. Daarnaast vormt het verkeer (vooral dieselvoertuigen) ook een belangrijke bron voor bepaalde soorten PAK’s. De bekendste en meest kankerverwekkende PAK is benzo(a)pyreen, afgekort als BaP. De metingen en regelgeving leggen daarom ook vooral de nadruk op deze stof.
Meer informatie over PAK’s vind je op de website van de Vlaamse Milieumaatschappij.
Poly- en perfluoralkylstoffen (PFAS)
Poly- en perfluoralkylstoffen (PFAS) zijn water-, vuil-, en vetafstotend en bestand tegen hoge temperaturen. Daarom worden ze veel gebruikt in een brede waaier aan industriële toepassingen en consumentenproducten zoals antiaanbakpannen of smeermiddelen. PFAS komen vooral in het milieu terecht via productieprocessen en de verwerking van afvalstromen, en tot 2010 ook via de bestrijding van branden. Eens in het milieu breken PFAS erg traag af. Uiteindelijk belanden ze in de voedselketen en neemt ons lichaam ze op. Ook daar breken ze erg traag af en stapelen ze zich dus op. De gezondheidseffecten variëren naargelang de dosis en soort PFAS in het lichaam en zijn doorgaans van chronische aard. De voornaamste effecten zijn de verstoring van de immuniteit, hormoonbalans en leverfunctie, alsook de verhoging van het risico op kanker en obesitas. Vanwege de schadelijkheid, persistentie en overvloedig gebruik van PFAS is het meten daarvan van groots belang want op die manier kunnen er doelgerichte maatregelen genomen worden om emissies te beperken.
Meer informatie over PFAS vind je op de websites van de Vlaamse Milieumaatschappij en de Vlaamse Overheid.