Air survey results - what have we discovered so far?

With more than 2,000 air surveys submitted, lichen expert Pat Wolseley from the Natural History Museum takes a look at what your results have shown so far.

Pollution scores

What does the pollution score map tell us?

The green spots show that nitrogen-sensitive lichens are on their way back across much of the country, especially in areas that were formerly lichen deserts, such as London and Birmingham. This is most probably because of the decrease in sulphur dioxide pollution in recent years.

Blue spots are limited to the coasts and remote areas where the air is very clean. The blue spot in London is a clear error.

Red spots indicate poor air quality and are seen mainly in the country areas where ammonia levels are high due to intensive agriculture.

The yellow spots suggest that nitrogen-loving lichens are increasing everywhere, in both agricultural and urban areas. You can see that this corresponds to levels of ammonia and nitrogen dioxide shown in the air quality maps on the pollution score page.

Many of the surveys have been carried out in areas where the human population is high and where we would expect there to be nitrogen-loving lichens. So we need more surveys to see how the lichens are responding to air quality in protected and more remote locations.

Lichen distribution

What can the map tell us about lichen distribution?

Nitrogen-sensitive lichens have been recorded in rural areas in the north, south and west of the country but they are also appearing in our towns and cities, which is a good sign. However, in these places they are often found together with nitrogen-loving lichens so check the pollution score map to see how these areas rate for air quality.

Intermediate lichens are present in all the areas that have been surveyed. These lichens appear to be returning to towns and cities where they had been absent before, as well as to country areas. This indicates that they are tolerant of a wide range of conditions.

Nitrogen-loving lichens are increasingly widespread in country and urban areas where nitrogen levels are high due to ammonia from intensive farming or nitrogen oxides from heavy traffic.

Lichen diversity scores

What do the diversity scores show us?

The red and yellow spots (places with no or few lichens) are widely distributed in agricultural and urban areas, where nitrogen levels are high due to intensive farming or pollution from cars and industry.

The blue and green spots (places with high lichen diversity) show that lichens are returning to urban areas, such as London, where they were once absent due to high sulphur pollution.

The blue spots also show that diversity is highest in coastal and country areas.

 
Have you submitted your survey yet?

The more surveys we receive, the more valuable the results become, so we'd love you to take part. and submit your findings. Simply download the survey pack from this website to get started today.