There are a wide range of terms and concepts in national and international initiatives, for example, standards, objectives, target values and limit values. An explanation of these terms is provided on Defra UK Air webpages. The two which feature within the UK’s Air Quality Strategy are standards and objectives. The strategy sets air pollution standards to protect people’s health and the environment.
The air quality objectives applicable to Local Air Quality Management (LAQM) in England are set out in the Air Quality (England) Regulations 2000 (SI 928), as amended by The Air Quality (England) (Amendment) Regulations 2002 (SI 3043).
The table below shows the objective pollutant concentrations in units of micrograms per cubic metre µg/m3 (milligrams per cubic metre, mg/m3 for carbon monoxide) with the number of exceedances in each year that are permitted (where applicable).
Local Authorities are expected to report on NO2, PM10 and SO2 as standard within their ASRs. The Government does not expect local authorities to report annually on benzene, 1,3-butadiene, carbon monoxide and lead as objectives for these pollutants have been met for several years.
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Pollutant
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Air Quality Objective
Concentration
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Air Quality Objective Measured as
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Nitrogen dioxide (NO2)
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200 µg/m3 not to be exceeded more than 18 times a year
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1-hour mean
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40 µg/m3
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Annual mean
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Fine and Coarse Particulate Matter (PM10) (gravimetric)
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50 µg/m3, not to be exceeded more than 35 times a year
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24-hour mean
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Fine and Coarse Particulate Matter (PM10) (gravimetric)
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40 µg/m3
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Annual mean
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Sulphur Dioxide (SO2)
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266 µg/m3, not to be exceeded more than 35 times a year
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15-minute mean
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350 µg/m3, not to be exceeded more than 24 times a year
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1 hour mean
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125 µg/m3, not to be exceeded more than 35 times a year
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24 hour mean
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Benzene
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16.25 µg/m3
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Running annual mean
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5.00 µg/m3
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Annual mean
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1,3-butadiene
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2.25 µg/m3
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Running annual mean
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Carbon Monoxide
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10.00 mg/m3
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Maximum daily running 8-hour mean
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Lead
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0.5 µg/m3
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Annual mean
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0.25 µg/m3
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Annual mean
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Under the Environment Act 2021, government introduced the Air Quality Strategy for England in 2023. The strategy, to which Local Authorities must have regard, sets out the need to maintain and improve local air quality so as to make air healthier to breathe, protect nature and boost the economy through clean growth and innovation, and reducing emissions from transport, homes, farming, and industry.
The strategy introduced 2 new legally binding long-term targets to reduce concentrations of fine particulate matter, PM2.5, by 2040. It also sets out interim targets for 2028 for each long-term target. The targets are shown below:
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Pollutant and Metric
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Target
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Target Year
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PM2.5 annual mean concentration
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Interim target: 12μg/m3
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2028
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PM2.5 annual mean concentration
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Legally binding target: 10μg/m3
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2040
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PM2.5 annual mean concentration
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Interim target: 22% reduction in exposure compared to 2018
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2028
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PM2.5 annual mean concentration
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Legally binding target: 35% reduction in exposure compared to 2018
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2040
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