Leaf litter incineration
//////////////////////////////////////////////////////////////////////////////////////
Misconceptions about leaf litter incineration and composting
"So now you can't heat with wood either? Can't I have a barbecue in my own garden? Does taking away green waste pollute the environment more than burning it? Isn't burning the walnut husk fly the only solution?" The Clean Air Action Group has received many similar questions, indicating that there are many misconceptions about the issue of burning green waste and composting as a solution.
Although the burning of green waste is banned nationally from 1 January 2021 (Act LIII of 1995 on the General Rules for the Protection of the Environment) - municipalities have been granted a concession to introduce the ban only during emergencies (Government Decree 549/2020 (2.XII.) of 2 December 2020). In addition, it is already common knowledge that burning garden and green waste releases a lot of harmful substances into the air, yet many people insist on burning and are reluctant to compost vegetable waste, often on the basis of misinformation and misconceptions. In this article, we have investigated some of the misconceptions on the internet and social media and the truth behind them.
Misconception: Burning green waste should not be so harmful, as it is allowed to heat with wood.
While wood-burning does release significant amounts of pollutants into the air, the air pollution caused by heating with dry firewood in a properly designed combustion system is a fraction of that released by burning green waste in the open air. Firstly, this is because leaf litter and other plant waste are wet, compacted, and materials that are difficult to burn: therefore they burn slowly and with a lack of oxygen. In addition, in the open air, in the absence of a firebox, it is difficult to achieve the high temperatures needed for perfect combustion - so combustion usually involves a lot of harmful emissions. Furthermore, all the emissions get directly to the height of people, children, and windows from ground level. In contrast, in the enclosed firebox of a stove or fireplace, a properly designed combustion device ensures oxygen supply, generates hundreds of degrees of heat, and thus produces fewer harmful emissions than outdoor green waste burning. The fumes from the combustor are discharged through a chimney several metres high. Of course, improper, outdated wood-burning practices can also cause significant air pollution, so we need to learn how to burn wood properly (video).
Misconception: Green waste disposal is even more harmful, as it is put out in plastic bags and taken away in diesel cars.
If composting on-site is not feasible, taking green waste away is still less harmful than incineration. Green waste bags are handled on the waste treatment site. The pollution from vehicles driving through the municipalities, although significant in itself, is still much less than from the incineration of green waste, which releases pollutants into the air for hours without any filtering.
Misconception: Composting is a fad for city dwellers, and fruit tree branches cut in a large garden cannot fit, not even in three composters.
Many farmers cultivate and care for areas of several hectares without incineration. The general scientific approach is that as much green waste as is generated in a garden can be composted there.
For larger branches, there are several solutions:
- When thoroughly dried, they can be burned in a combustion plant for heating.
- When green waste is removed, it is also taken away (e.g. in many places, it is not put in a bag, but a bag is hung on the outside to indicate that the transport fee has been paid by buying the bag).
- Many municipalities provide community shredders and grinders, and some even deliver them free of charge for shredding on-site (this allows for composting in a much smaller space and much faster, or the shredded material can even be turned into the soil). If there is none, it should be proposed to the municipality to purchase it.
Misconception: We don't have the money to install new composters, and they are plastic anyway thus harmful to the environment.
Composting is not a question of money, and it is not at all necessary to use plastic compost bins: you can make a compost bin out of wood, you can fence off an area for composting with a dense woven metal net, or you can even designate a simple compost pile for the purpose - in this case, the lower temperatures will take a little longer for the humus to form.
The composter will pay for itself! 20-50% of household waste is biodegradable organic matter, which can reduce the amount of municipal waste, and keeping smaller bins or fewer bins in condominiums can save money.
Compost heap surrounded by old stakes
Misconception: There's nothing wrong with burning, it should be done at night when no one is setting the table.
Burning grass is a significant air quality pollutant: burning 100 kg of grass releases enough hazardous substances into the air to pollute the entire airspace of a medium-sized town above a certain limit. Burning in the evening does nothing to improve this situation, and in calm weather the pollutants can remain trapped for hours in houses, easily persisting until morning, and of course, a considerable amount of smoke can enter the interior through the gaps in the windows. Not to mention the fact that many people would like to ventilate and go out in the evening. Because of the night-time inversion that is common in our climate, pollutants can remain close to the ground for much longer.
Misconception: We should also stop cooking in cauldrons and bacon on fire because they are just as harmful.
Banning outdoor cooking and barbeques is not the aim. Although these activities also pollute the air, they are much less polluting than burning piles of green waste that smoulder for long periods of time, provided that they are properly built and managed and that good quality fuel is used. Small amounts of dry wood or charcoal are generally used for outdoor cooking.
Misconception: On the same basis, smoking sausages, ham, and bacon could be banned.
Smoking meat and bacon is not a preserving process using wood shavings, but quality firewood (although unfortunately we also hear of cases of people burning plastic waste for smoking meat, contaminating the food with toxic substances), so the regulation of burning wood shavings and green waste has no effect on the smoking of food.
Misconception: Walnut and oak leaves are not compostable.
They indeed contain so-called allelopathic compounds that inhibit the growth of other plants, but they too are completely degradable in a few months. The leaves of walnut trees are also compostable, and in an average of six months to a year, they also make excellent hummus, which can be used to produce potting soil quality.
Misconception: Diseased, infected plant parts must be burned, there is no other solution for pests.
Decomposers, pathogens, are usually infectious in a particular life cycle of the plant, so they damage a living plant in a completely different way than the organisms that do the decomposing in the compost. Compost is good, and when available in sufficient quantities (a few cubic metres), it can generate considerable heat to kill even the most stubborn pests. For large gardens, it is worth composting the remains of vegetables and fruit trees separately: the "fruiting" humus can then be safely buried in the vegetable garden and vice versa.
Misconception: The walnut husk fly is a pest that requires all fallen nuts to be burnt.
The larvae of the walnut husk fly can quickly chew itself out the nuts, burrow into the soil and do the overwintering there. So, even if you burn the walnut and its leaves, this does not affect the fate of the walnut husk fly, which you have to take plant protection measures against (for example, by putting foil under the tree to prevent the larvae from getting into the ground). Moreover, the control is only effective if the neighbours and gardeners in the area also control the walnut husk fly. In any case, the spread of the walnut husk fly is mainly due to the changing climate, i.e. burning and air pollution are contributing to its spread.
Misconception: Smoking on frosty spring mornings protects orchards from frost.
Smoking to protect fruit trees from frost can only rarely be effective (in complete calm, with very careful procedures) - fumigation is completely unnecessary against frosty winds, for example. The best solution is prevention: growing native fruit trees that are well adapted to the local climate. A very small percentage of garden burning is for this purpose, and in the agricultural sector, burning for strictly plant protection purposes is subject to appropriate authorisation.
Misconception: Large amounts of leaf litter cannot be composted, I don't have the space to fit it.
It is not advisable to put the leaves on the compost heap immediately after they have fallen in autumn. Pile up the leaves in a corner of the garden or in a cylinder bent from metal mesh. In a month or two, the compaction and decomposition processes will reduce the dry volume to 10%, which can then be easily piled on top of the compost.
Misconception: Compost stinks
Various gaseous decomposition products are produced during the composting process, but compost that is properly moist and aerated never stinks. Unpleasant-smelling compost can be produced if the wrong materials are added. In such cases, aeration of the compost or an odour-eliminating preparation available in farmers' shops, which is actually an extract of decomposing bacteria that speeds up the decomposition process, can be a solution.
Misconception: Compost is full of pathogenic worms.
In the composter there is a whole range of organisms (bacteria, fungi, mites, ants, worms, earthworms, etc.), which in fact help the natural process of composting to take place, helping to break down, shred and transform organic matter. These organisms do not make us sick.
Misconception: Composting is only a hobby for people with big gardens. It's not feasible in a city apartment building, concrete block of flats, or a garden the size of your palm.
Composting can be done in a composting bin a metre long, even in an apartment. You can buy a wide range of these or make your own. There is considerable literature available, so anyone can choose the method that suits them best. And in a small garden, even a single square metre is enough to absorb all the compostable produce of a family.
What happens if someone sets fire to the garden "smoke factory"?
(Photo by Hajnalka Barsi)
Burning garden waste and wood waste is a widespread "national disease" in our country. Few people know how harmful this activity is to the environment and human health. The valuable organic matter produced during the incineration process is reduced to ash, which is only suitable for soil replenishment in limited quantities. In contrast, composting completely decomposes the plant parts and produces useful humus. An average garden fire, with a mixture of branches, grass cuttings, and twigs, causes enormous air pollution. The main causes of high pollution are poor air supply, low combustion temperatures, and high humidity. For example, the carbon in plant parts is oxidised, but only partially, and carbon monoxide is produced instead of carbon dioxide, which is toxic even in small quantities. But let's take a look at the substances produced by burning an average pile (100 kg) and their effects on our bodies:
Carbon monoxide: 5-7 kg (= 5-7 billion micrograms - μg)
Immediate effects: headache, dizziness, nausea, loss of vision, and hearing.
Lasting effects: reduces the circulation in the coronary arteries supplying the heart muscle, promotes coronary artery calcification, narrows the coronary arteries, increases the risk of myocardial infarction. Obstructs the ability of the blood to carry oxygen. Health limit 10000 μg/m3.
PM10 (airborne particles smaller than 10 micrometres): 1.7-4.9 kg (= 1.7-4.9 billion μg)
Immediate effects: asthma attacks, respiratory irritation, cardiovascular disorders.
Long-term effects: carcinogenic, immune system damage, heart attack, cerebral vasospasm, pneumonia. Health limit 50 μg/m3.
Hydrocarbons: 1.5-2 kg
Carcinogens, mutagens, damage the immune system. If they enter the body around birth, they can alter hormone production for life.
Nitrogen oxides: 20 g (= 20 million μg)
Irritates the eyes and respiratory system. Inhalation may cause watering of the lungs, may affect the blood, may cause methahemoglobin formation. Health limit 200 μg/m3.
Methyl ethyl ketone: 3,6 g
Causes irritation/annoyance to eyes and respiratory system may affect the central nervous system, may have toxic effects on human reproduction.
Photo by Gábor Bartha
Ethylbenzene: 3.3 g
Causes irritation/annoyance to eyes and respiratory system, possible effects on the central nervous system, possible effects on liver and kidneys, carcinogenic, possible effects on human reproduction.
Styrene: 6,8 g
Causes irritation/annoyance to eyes and respiratory system, inhalation may cause watery lungs, may affect the central nervous system, a possible human carcinogen, a possible human carcinogen, possible hearing impairment, possible effect on human reproduction.
Phenol: 3,3
This substance may have effects on the central nervous system, heart, kidneys, may cause convulsions, coma, cardiac dysfunction, respiratory failure, fainting.
Dibenzofuran: 0,45 g
The Seveso disaster was caused by dibenzo-dioxin, which has a very similar chemical structure. It is a carcinogen and can damage the endocrine system. Can cause birth and developmental defects, damage the immune system, accumulates in the body, do not break down.
Benz-a-pyrene: 0.06 g (=60 million nanograms)
BaP is one of the most dangerous compounds, according to the World Health Organisation (WHO) it is classified as category I, with a health limit of 1 nanogram/m3. It can cause permanent genetic damage to human germ cells. Animal studies suggest that this substance may have toxic effects on human reproduction.
The burning of the pile of straw in the example above releases enough PM10 particles to pollute about 90 million cubic metres of air above the health limit. That is the entire atmosphere of a medium-sized town on an autumn evening today.
What causes particulate pollution (PM10, PM2.5)?
Ultrafine particulate matter (PM2.5) is responsible for the premature deaths of around 11,970 people in our country every year, according to a 2017 report by the European Environment Agency. This translates into 129,400 years of life lost each year, so those who die prematurely because of this pollutant lose an average of 11 years of their life, according to a study by the European Commission. The damage caused by pollution in our country is as high as 19% of our gross national income (GDP) each year, according to the WHO. The most dangerous are the so-called ultrafine particles, which can get directly from the lungs into the bloodstream within 20 minutes, causing serious lesions and contributing to blood clot formation. This is why the Clean Air Action Group carries out such measurements, as the most dangerous pollutants are the ones to watch out for.
Measurement of air pollution from incineration in Göd
At the request of the "Clean Air Gödön" Facebook group, we measured the air pollution from the burning of wood in Gödön. The measurement showed that the burning of wood chips increases the number of ultrafine particles in the air by almost two and a half times. The results led to a winter ban on burning in the municipality.
Ultrafine particle pollution from incineration in Göd
05.11.2015 06.11.2015 (incineration of leaf litter)
Domestic regulation
Act LIII of 1995 on the Protection of the Environment gives local authorities the possibility to regulate the burning of waste.
Art. 48 (4) It is the competence of the body of representatives of the local government:
(b) to lay down by decree certain specific rules on air pollution caused by domestic activities and on the burning of refuse and garden waste
If a municipality has not adopted an ordinance on the burning of leaf litter, the activity is prohibited by default, and if it has adopted an ordinance, the provisions of the ordinance must be complied with.
Government Decree 306/2010 on-air protection contains further provisions on the control and fining of the burning of garden and yard waste. The competent authority is the authority department of the relevant district office and the fine for individuals can be up to HUF 100 000.
Interestingly, in the province of British Columbia of Canada, violators of the rules on the burning of grass may be fined up to $200,000, i.e. 42 million forints. When you look at the health effects detailed above, perhaps the strictness is not unjustified.
What are local authorities doing?
Since it is usually legal for anyone to pollute by burning leaf litter, the Clean Air Action Group has taken up the fight. It has already succeeded in getting a decree banning the burning of garden and yard waste in Budapest (69/2008 (XII. 10.). In other places, however, it is generally free and local regulations show a complete lack of professionalism. This was also noted by the Commissioner for Fundamental Rights and the Deputy Commissioner for the Protection of the Interests of Future Generations in his investigation.
A survey by KÖTHÁLÓ showed that other municipalities have also joined the ranks of those protecting public health. In Pest County, 17 municipalities (Budakalász, Budapest, Csömör, Galgahévíz, Gyál, Gyömrő, Ipolydamásd, Kóspallag, Nagybörzsöny, Nagykovácsi, Nagykőrös, Pilisszántó, Százhalombatta, Tárnok, Törökbálint, Vácszentlászló, Vecsés) while two municipalities apply extreme stringency, in Csővár four and in Tök three predetermined days are allowed to burn garden waste.
What are civilians doing?
The Clean Air Action Group has developed a comprehensive programme to reduce air pollution from residential sources, which has been submitted to the relevant state secretariat, the ministry's back office, and the members of the Parliament's Committee on Sustainable Development.
The Network of Environmental Consultancy Agencies has issued a publication on the incineration of waste.
Its member organisations have been helping the public to resolve complaints free of charge for 15 years and have processed the ordinances of 200 municipalities in the course of the project mentioned above. As a result of its proposals, 2 municipalities (Budakalász, Gyál) have joined the group of those imposing a total ban.
The solution - composting
All garden waste and garden waste residues can be composted. In the process, dead plant matter is broken down by micro-organisms and transformed into humus, an essential material for life on land. The humus stores the minerals needed for growth over a long period and supplies them to the plants in a form that is easily absorbed. But perhaps more importantly, it can bind and store water many times its mass. Composting avoids massive air pollution and provides valuable humus and plant manure. Everyone can compost. All you need is a few square metres of shady space and a little time in the garden. The basic rules of composting are to properly chop the material to be composted, mix the compost regularly, keep it moist and protect it from the hot sun. It is important that the compost is in direct contact with the soil, as the decomposing micro-organisms "move" into it from there. The composting process usually takes 1 year, but some plants and thicker branches may take longer. It is a common misconception that walnut and oak leaves cannot be composted. It is true that they contain so-called allelopathic compounds that inhibit the growth of other plants. However, these compounds are also completely degraded in a few months, as the University of Horticulture study has shown, and the nut leaf compost grew better than the control group. A pitchfork or spade fork is an essential tool for mixing the compost. A useful tool is a composting container, a shredder, and composting accelerators, starter cultures. In the absence of these, you can also compost in piles, or shred with pruning shears.
And the pests?
Indeed, many people are afraid that plant pests will not be destroyed by composting. But the situation is much better than we think. Decomposing pathogenic organisms are usually infectious and even hostile to each other during a particular life cycle of the plant. So quite different organisms damage a living plant from the organisms that do the decomposition in the compost. Good compost, if available in sufficient quantities (a few cubic metres), can produce a considerable amount of heat, which kills even the most stubborn pests.
And perfect compost produces as much as the plant did when it was alive. Only the crop is not tomatoes or apples, but eggs. The combination of compost and poultry yard is therefore ideal, with insect larvae and edible plant parts turning into eggs and barbecued chicken.
Further practical advice on composting can be found in the Environmental Advisory Offices' information booklet or by contacting the offices' advisers.
Péter Lenkei, Head of the Environmental Advisory Office of the Clean Air Action Group