How is pollen, pollution and climate change affecting our health?

The impact of air pollution, weather and climate change on the environment and human health is a vital concern globally. The health hazard it causes includes severe allergic reactions and several medical conditions, especially in conjunction with pollen grains.

Pollen grains are minute bodies in the form of fine to coarse dust from catkins of certain plant species. They contain pores through which their proteins can be distributed to human upper airways; which means we are inhaling pollen grains almost everywhere. Pollen from birch trees and ragweed are responsible for hay fever, also known as allergic rhinitis (the inflammation of the lining of the nose, characterised by nasal congestion, sneezing and itching) and other allergenic problems.

Birch pollen is actually one of the major causes of allergic reactions in the UK. These reactions, producing hay fever symptoms, have been increasing throughout the world especially within westernised urban areas.

Hay fever reaction is accompanied by frustrating symptoms that cause a loss of productivity in adults, making learning difficult for children, and can even spark the risk of a severe asthma attack, resulting in hospitalisation.

A century ago, the illness was almost unheard of, but now around one in four Britons are affected, compared with just one in eight in the early 1980s. There is evidence to suggest that the interaction between pollen grains, environmental pollution and weather change is increasing the allergenicity of the pollen grain affecting so many more hay fever sufferers. The interaction of pollen, weather changes and pollution can affect a number of things such as increasing the duration of the allergen season, the amount of allergenic pollen/spore (productivity) and the allergenicity per pollen. However, the exact reasons are still unclear.

Current research at the University of Birmingham is investigating the changes that occur on the pollen grain upon exposure to particular key primary air pollutants, such as nitrogen dioxide (NO2, which comes predominantly from car exhausts) and Ozone (O3) under a range of environmentally relevant conditions (temperature and relative humidity).

Samples were then probed using a proteomic approach (liquid chromatography coupled with an ultra high resolution spectrometer), which looks at the whole structure of a protein. Researchers found that NOx (Nitrogen oxide) mediated modification (nitration and nitrosylation) occurred on the protein responsible for triggering allergenic reaction in humans, which may suggest a possible reason for increased allergic reactions to such altered protein.

The findings demonstrated a link between the air pollutants and protein specific modification, which supports findings from other literature. Further investigations using a statistical approach will investigate if there is a clear signal of increased allergenic illnesses when both pollen and pollutant concentrations are high. In particular, ambulance real-time call-out data will be analysed looking at a variety of medical conditions.

At Birmingham, research has already established the basic relationship between temperature and some medical conditions. But now the effect of pollen and pollution on ambulance call-out rates will be investigated.

Unfortunately, half of all hay fever sufferers have not been diagnosed, as witnessed within many family and friends often saying: 'I have got recurrent cold.'

Furthermore, people are not mindful that westernised lifestyles, including rapid urbanisation and high vehicle emissions are epidemiologically correlated to increase in the frequency of pollen induced hay fever.

It is hoped the results of the research at Birmingham will create more awareness and better understanding of pollen allergenicity. It will also serve as an early warning tool for health surveillance systems, assisting suffers to know when to pack their tissues and have their antihistamine handy.

Marliyyah A Mahmood

Doctoral Researcher, School of Geography, Earth and Environmental Sciences, University of Birmingham