Monitoring and improving air quality
Ozone precursors
NPL is the Central Calibration Laboratory (CCL) for non-methane hydrocarbons (NMHCs) within the World Meteorological Organisation Global Atmospheric Watch programme (WMO-GAW).
NPL provides a 30-component primary reference material (PRM) that contains all the ozone precursor hydrocarbon compounds listed in Annex X of the European Directive 2008/50/EC on Ambient Air Quality and Cleaner Air for Europe. These mixtures are typically prepared at amount fractions of 4 nmol/mol, but other amount fractions from 1 to 200 nmol/mol are also available.
| Ethane |
1,3-butadiene |
2,2,4-trimethylpentane |
| Ethene (ethylene) |
Pentane |
Benzene |
| Ethyne (acetylene) |
2-methylbutane |
Toluene |
| Propane |
1-pentene |
Ethylbenzene |
| Propene |
trans-2-pentene |
m-xylene |
| Butane |
2-methyl-1,3-butadiene (isoprene) |
p-xylene |
| 2-methylpropane (i-butane) |
Hexane |
o-xylene |
| 1-butene |
2-methylpentane |
1,2,3-trimethylbenzene |
| trans-2-butene |
Heptane |
1,2,4-trimethylbenzene |
| cis-2-butene |
Octane |
1,3,5-trimethylbenzene |
BTEX mixtures
NPL provides a range of BTEX PRMs containing benzene, toluene, ethylbenzene, m-xylene, p-xylene and o-xylene at amount fractions from 1 nmol/mol to 10 µmol/mol. Mixtures containing BTEX and 1,3-butadiene are also available.
Oxygenated VOCs (OVOCs)
NPL offers a range of OVOC PRMs at amount fractions of 1 to 10 μmol/mol. One typical multi-component mixture contains the components shown below. Mixtures containing other OVOCs (e.g., acetaldehyde, acetonitrile, methyl ethyl ketone) are available on request.
|
Methanol
|
Ethanol
|
Acetone
|
|
n-hexane
|
Propane
|
Benzene
|
Bespoke mixtures
NPL can provide, on request, bespoke PRMs containing C2 to C10 hydrocarbons, chlorinated hydrocarbons and fluorinated hydrocarbons at a range of amount fractions. For example, PRMs of perdeuterated toluene (d8-toluene) are available due to their use as an internal standard in GC-MS applications. We can provide these mixtures at a range of amount fractions but most commonly at 5 µmol/mol.
Download the User Guide for NPL VOC Standards
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