Odorant emissions (aroma compounds, bad smelling gases) causing unpleasant andburdensome odours (olfactory sensations, malodors) at livestock farmsand in the adjacent area can become a significant inconvenience for theresidents of areas close to large-scale high-dense livestock operations.Odours are equally harmful for the agroecosystems. The sources ofodours are: farm animals (livestock buildings), secondary emissions fromnatural fertiliser storage sites, and landspreading. Animal breedingand rearing account for only 20% of all odour-related complaintsreported in Poland, including around 40% for poultry farms, and 35% forswine farms.
Odoursproduced by intensive livestock production can include as many as100-200 volatile odorants, of which at least 30 compounds areparticularly burdensome and harmful for health, such as hydrogensulphide, ammonia, methane, thiol, indole, skatole, phenol, aliphaticamines and sulphides, volatile fatty acids, mercaptans, organicsulphides, a variety of organic acids (including acetic acid, propionicacid, butyric acid, isobutyric acid), carbonyl compounds (aldehydes andketones), diacetyl, heterocyclic organic nitrogen and sulphur compounds,aliphatic alcohols, esters, and aromatic hydrocarbons (toluene,xylene).
Airpollution with bad smelling gases can be carried over large distances.Volatile odorants are easily carried in the air by wind, and are poorlymiscible with the air, which means they can be carried in highlyconcentrated streams. For example, a cattle farm of 140,000 animalsemits 25,7 tons of nitrogen compounds per day. 90% of these volumesevaporate within a week to the atmosphere in the form of pure ammonia. Aswine farm of 25,000 animals generates 240 kg of ammonia within 24hours, which increases air ammonia levels within the area of around 600km2. In the summer period, a swine farm of 100,000 animals produces around 7.6 kg of hydrogen sulphide per 1 hour.
Thesecompounds have been shown to cause a number of dangerous diseases,including migraines, cough, rhinorrhea, nasal congestion, chest pain,and other conditions of the respiratory system, inflammatory andallergic reactions, allergies, lacrimation, haemoglobin transformationto hematin, the resulting hypoxia, and emotional reactions (insomnia,stress, apathy and depression, irritation and unrestlessness).
Intensityand nuisance of odours can be difficult to quantify. Odorant levels at abroiler farm of 25000 birds are around 2.420 OU/m3 (OU ?odour unit, corresponding amount of odorant(s) in one cubic metre ofneutral gas and detected by 50% of a group representative for thepopulation), odorant emissions amount to 20.000 OU/s, i.e. 0,8OU/animal/s. Odour can be smelled within the radius of 250 m from thefarm. Similar odorant concentrations in the air are observed at minkfarms, i.e. 1.000-2.500 OU/m3, directly at cages. Estimatedodorant release from a breeding pavilion with 2.000 animals is 300 OU/s,i.e. 0.2 OU/s per animal. At a farm with 12.000 minks, the odour radiuscan extend over a distance of 200-300 m from the farm.
Despite the gravity of the problem, Poland currently has no legal regulations concerning odour emissions and no objective criteria to determine odoure missions.