Air pollution - State and impacts (United Kingdom)

Particulate matter (PM10)

The objective that by the end of 2004 the 24 hour mean should not exceed 50 µg/m³ more than 35 times a year was not met at six sites. The objective that by 2004 the annual mean should not exceed 40 µg/m³ was exceeded only at London Marylebone Road. 

PM₁₀ annual mean: Comparison with health objective for 2004: 1992-2008 Urban Sites

 PM₁₀ fixed 14 hour mean: Number of days exceeding 50µg/m³ compared with health objective for 2004: Urban sites 1992-2008

More information can be found in Defra’s particulate statistics

Annual mean background PM₁₀ concentration, 2008 (µg m^-3, gravimetric)

Map from EIONET Central Data Repository

Nitrogen dioxide (NO₂)

The figures below show trends in exceedences at urban sites of the objective levels for the 1-hour and health-based annual mean respectively. There were 6 sites where hourly concentrations reached 'moderate' levels in 2006. None of the sites exceeded the EC Alert Threshold on any one day.

Nitrogen Dioxide 1 hour mean: Number of periods exceeding 200µg/m³ compared with health objective for 2005: Urban Sites 1987-2008.

More information can be found in Defra’s nitrogen dioxide statistics.

Urban major urban roads, annual mean roadside NO₂ concentration, 2008, µg m^-3

Map from EIONET Central Data Repository

Tropospheric Ozone

There has been a marked increase in ozone concentrations in urban areas since the 1990s, due to the reduction in urban emissions of nitrogen oxides (NO_X), which destroy ozone close to their emission source. Rural ozone levels averaged 71 µg m^-3 in 2008 compared to 74 µg m^-3 in 2006 and 68 µg m^-3 in 1993. There is no clear long term trend.

From year to year there can be significant variations caused by the weather.

Annual levels of ozone 1987-2008: index shows annual mean of the daily maximum 8-hour running mean.

Further information can be found at particulate/ozone statistics.

Number of days with ozone concentration > 120 µg m^-3 in 2008

Map from EIONET Central Data Repository

Acidification and Eutrophication

Currently, 54 per cent of all habitat areas sensitive to acidification exceed the critical load for acidity, predominantly due to the deposition of nitrates.

Despite reductions in ammonia emissions, total N-deposition has changed little. Currently, 58 per cent of all habitat areas sensitive to eutrophication from N-deposition exceed the critical load for nutrient nitrogen.

Human Health impacts

Air pollution is currently estimated to reduce life expectancy by an average of 6 months with estimated equivalent health costs of up to £19 billion a year. There is currently an underestimation of the full range of possible health benefits that could be attained from policy measures to improve air quality, because it has not been possible to quantify all health outcomes. Work to review the evidence is ongoing and it is expected that this would lead to an increase in the number of health outcomes identified.