By Ann Link of TTL
You might not expect Lewes to have an air pollution problem except after Bonfire. But it does. There is an Air Quality Management Area covering part of the town centre, and a monitor for NO2 and PM10 particles in West Street. The county has an air alert scheme whereby anyone can sign up to be warned of air pollution. airAlert and the airAlert service for Sussex
This is intended for people with respiratory health problems, but anyone can access it.
The warnings are for PM10, PM 2.5, NO2 and ozone. Lewes monitoring point measures PM10 and NO2; Eastbourne also monitors ozone. A Wealden site monitors SO2. There is one in Isfield, two near Hastings, one in Horsham. I think they must interpolate so that, for example, I get ozone warnings in Lewes.
Since the start of the year I have had 23 alerts:
- 6 for ozone alone; 3 for ozone and moderate particles
- 10 for moderate particles
- 2 for high particles
- 1 for moderate unspecified.
What are the sources? One reason Lewes has a problem is that we get pollution from Europe as well as producing our own. Then still conditions trap it and make it worse.
Agriculture: The Guardian: Farming is ‘single biggest cause’ of worst air pollution in Europe
When ammonia in the atmosphere reaches areas of industry, the pollutants from combustion, which include nitrogen oxides produced by diesel vehicles, and sulphur compounds from power plants and some other industrial processes, the chemicals combine to create very small particles, about 2.5 micrometres across. i.e. PM 2.5
It’s ammonia reacting with NO2 mainly. Agricultural ammonia pollution is getting worse in the UK
The Guardian: Ammonia emissions rise in UK, as other air pollutant levels fall
Diesel vehicles are still a major source of nitrogen oxides and particulates:
Friends of the Earth: Diesel and air pollution: 10 facts about an invisible killer
Sahara dust does give particulates, but it is much less responsible than the hype suggests:
The Guardian: Sahara dust only ‘partly responsible’ for UK’s worst pollution event in 10 years
Bonfire definitely has an effect the next day. There’s a peak on the graphs that you can access through airAlert.
Ozone is not emitted directly into the air, but is formed by the reaction of volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the presence of heat and sunlight. VOCs are emitted by a variety of sources, including motor vehicles, chemical plants, refineries, and other factories.
Clean Air Trust: Health risks Of Ozone Pollution
NOx is emitted by motor vehicles, electric power plants, and other combustion sources. Ozone can be transported into an area from pollution sources found hundreds of miles upwind. It is often found in rural areas for this reason. It’s dense and stays near the ground.
Lewes District Council is working to reduce air pollution around schools: Air quality and health