Emissions of bioaerosols, mainly from intensive livestock housing and using manure and slurry, are an emerging concern for localised air quality and human health impacts. Bioaerosols are airborne particulates of biological origin, such as bacteria and fungal spores.
There are currently no regulations covering emissions of bioaerosols in England. There are only guideline levels aimed at protecting human health.
The agricultural sector is the largest source of ammonia emissions. In 2016, 88% of all ammonia emissions in the UK were from agriculture. Manure management on livestock farms (41%, of which almost three-quarters comes from cattle), manure applied to soils (24%) and nitrogen-based fertiliser application (22%) are the main contributors to the agricultural total.
Excessive fertiliser use also leads to the release of nitrous oxide (N2O), a highly potent greenhouse gas, which also contributes to stratospheric ozone depletion.
Driving down pollution requires everyone to act. From individuals, making choices about how to travel and heat homes (such as with wood burning fires), to governments, because transboundary pollution from international emissions contributes to poor air quality in some parts of the country.
Despite overall reductions in UK emissions, serious threats to health and the environment persist. Unacceptably high levels of nitrogen dioxide, ozone and particulate matter remain in many urban areas. Particulate matter can have impacts on health even below current legal thresholds. High concentrations around homes and schools are a serious public concern.
Nitrogen deposition is one of the main threats to worldwide biodiversity, alongside climate change and habitat destruction. Manure management on livestock farms, manure applied to soils, and nitrogen-based fertiliser application produce high emissions of ammonia. In some urban and industrial areas, NOx emissions from road transport and other combustion sources are high. These air pollutants are transported, react chemically in the atmosphere and are then introduced into habitats through deposition.
Increased levels of nutrients in watercourses encourage plant growth, leading to problems such as algal blooms which reduce light and oxygen levels. This process, known as eutrophication, affects ecosystems, killing fish and altering plant communities.
Increased nitrogen deposition to land can alter the composition and diversity of plant communities, for example by favouring certain plants such as grasses which then outcompete nitrogen sensitive species. In turn this affects the diversity of wildlife. This can be a serious threat to protected habitats and conservation areas. Nitrogen deposition also damages the growth of lichens, which are very sensitive to air pollution. They are recognised worldwide as useful indicators of air quality.
Looking ahead
We are all affected by air pollution, be it through the health, economic or environmental costs it brings about, and whether we live in cities or in the countryside. There have been significant reductions in levels of some pollutants in recent decades. However there is still much to be done, and a worsening picture for some substances, such as ammonia. These, and roadside pollutant levels from traffic must be urgently addressed. Our increasing scientific knowledge of what is in the air we all breathe means that we are uncovering new and emerging pollutants. Some of these come from familiar sources such as road transport, while the sources of others, such as microplastics, are less clear. With the right regulation in place it is not too optimistic to say that improvements made over past decades could continue, allowing people and the environment to look forward to a healthier future.
https://www.gov.uk/government/publications/state-of-the-environment
https://consult.environment-agency.gov.uk/psc/tr13-0az-richland-foods-limited-draft-decision/
https://www.facebook.com/groups/1696469517315302/
https://www.gofundme.com/stop-the-free-range-egg-farce