A high level of air pollution can cause an increase in hospital admissions and even contribute to the premature death of people who are seriously ill. People with respiratory conditions, severe lung diseases or heart conditions are especially sensitive to increases in air pollution.
The main pollutants of concern in Cambridge are particulate matter and nitrogen dioxide.
Particulate matter
Particulate matter (PM) affects more people than any other pollutant. The major components of PM are small particles of sulphate, nitrates, ammonia, sodium chloride, carbon, mineral dust and water.
The particles are identified according to their aerodynamic diameter: PM10 is particles smaller than 10µm, and PM2.5 is particles smaller than 2.5µm. The latter are more dangerous because they can travel further into the lungs.
Chronic exposure to particles contributes to the risk of developing cardiovascular and respiratory diseases, as well as of lung cancer.
The effects of particulate matter on health occur at levels currently being experienced by most urban and rural populations in both developed and developing countries. In the EU, average life expectancy is 8.6 months lower due to exposure to PM2.5 produced by human activities.
Particulate matter levels in parts of Cambridge are above the WHO guideline values, but below the UK National Air Quality Objectives.
Nitrogen dioxide
The major source of nitrogen dioxide (NO2) emissions is combustion processes used in heating, power generation, and engines.
Nitrogen dioxide can cause both short-term and long-term health impacts. In the short term, concentrations exceeding 200 micrograms per cubic metre it is a toxic gas, which causes significant inflammation of the airways.
Studies have shown that symptoms of bronchitis in asthmatic children increase in association with long-term exposure to nitrogen dioxide. Reduced lung function is also linked to exposure at concentrations currently observed in European and North American cities.
An Air Quality Management Area was declared in 2004 because nitrogen dioxide levels in parts of Cambridge city centre and around the inner ring road were above both the WHO guideline values and the National Air Quality Objectives. Since then we have seen a steady fall in measured levels of nitrogen dioxide; levels in Cambridge are now below the National Air Quality Objectives, but above the WHO guideline values.
Find out more
Defra’s daily air quality index tells you about levels of air pollution and provides recommended actions and health advice.
The index is numbered 1 to 10 and divided into four bands, low (1) to very high (10), to provide detail about air pollution levels in a simple way, similar to the sun index or pollen index.
If you (or your children) are likely to be at-risk from air pollution and are planning strenuous activity outdoors, check the air pollution forecast.
Defra also provides forecasts of air pollution concentrations for up to 24 hours ahead are updated daily. Forecasts are issued for sixteen urban areas and sixteen UK regions; these cover roadside, urban background and rural locations.
See also:
- Committee on the Medical Effects of Air Pollutants: Reports assessing the impacts of small particles, ozone and nitrogen dioxide on human health
- Public Health England: Report on the estimated local mortality burdens in local authority areas associated with particulate air pollution [PDF]
- Royal College of Physicians and the Royal College of Paediatrics and Child Health: Report on the impact of exposure to air pollution
- World Health Organisation: Air pollution and health
