PM particles, in particular fine particulate matter of diameter 2.5 or less, nitrogen dioxide and tropospheric ozone are the most harmful air pollutants for human health in Europe.
It is also well known that the link between particulate pollution and health problems is well established, which is why the World Health Organisation has set new, much more ambitious control targets.
Given the urgency of the measures to be taken, it has been necessary to revise legislation at European level to bring it into line with WHO requirements.
New WHO Air Quality Guidelines
The new WHO global air quality guidelines, updated on 22 September 2021, include recommendations for guideline air quality levels and intermediate targets for 6 key air pollutants:
- Particulate matter (PM2.5 and PM10)
- Ozone (O3)
- Nitrogen dioxide (NO2)
- Sulphur dioxide (SO2)
- Carbon monoxide (CO)
Among the new features of this new version are the use of new methodologies for guideline development and test synthesis, and the inclusion of new values, such as O3 in periods of exceedance and NO2 and CO for 24 hours, among others.
It also provides guidance and good practice for dealing with certain types of particulate matter, such as black carbon/elemental carbon, ultrafine particles and particles from sand and dust storms.
Proposal for a new European Ambient Air Quality Directive
In line with the ambition of the Zero Pollution Action Plan, the European Commission is preparing the Proposal for a Directive of the European Parliament and of the Council on ambient air quality and cleaner air for Europe, which would enshrine in law a “Zero Air Pollution Target”.
According to this proposed Directive, air quality across the EU should progressively improve to levels that are no longer considered harmful to human health and natural ecosystems by 2050.
Following this strategy, it is proposed to merge the existing ambient air quality Directives 2008/50/EC and 2004/107/EC into a single Directive – COM(2022)0542 – and to revise them with the following objectives:
- Better alignment of EU ambient air quality standards with the latest WHO recommendations.
- Improve the legislative framework for air quality, including penalties and information to the public.
- More effectively support local authorities in achieving cleaner air by strengthening monitoring, modelling and air quality plans.
To move forward on this path, the proposed Directive sets air quality standards for 2030 that are more in line with the WHO Air Quality Guidelines.
The proposal also introduces a regular review mechanism to check whether the standards applicable in the EU are still adequate for the objectives of the Directive on the protection of health and the environment, and whether other air pollutants need to be included.
As mentioned above, the intention is that the revised EU standards should be guided by WHO interim objectives closer to the levels of air quality standards.
For example: the annual concentration limit for PM 2.5 is set at 10 µg/m3 which corresponds to the WHO interim objective 4.
| Pollutant | Averaging period | IT 1 | IT 2 | IT 3 | IT 4 | OMS 2021 | Revised EU 2030 | Current standard |
| PM 2.5 | Annual | 35 | 25 | 15 | 10 | 5 µg/m3 | 10 µg/m3 | 25 µg/m3 |
| 24h | 75 | 50 | 37,5 | 25 | 15 µg/m3 | 25 µg/m3 | – | |
| PM 10 | Annual | 70 | 50 | 30 | 20 | 15 µg/m3 | 20 µg/m3 | 40 µg/m3 |
| 24h | 150 | 100 | 75 | 50 | 45 µg/m3 | 45 µg/m3 | 50 µg/m3 | |
| O3 | Peak standard | 100 | 70 | – | – | 60 µg/m3 | 120 µg/m3 | 120 µg/m3 |
| 8h | 160 | 120 | – | – | 100 µg/m3 | 100 µg/m3 | 120 µg/m3 | |
| NO2 | Annual | 40 | 30 | 20 | – | 10 µg/m3 | 20 µg/m3 | 40 µg/m3 |
| 24h | 120 | 50 | – | – | 25 µg/m3 | 50 µg/m3 | – | |
| SO2 | 24h | 125 | 50 | – | – | 40 µg/m3 | 50 µg/m3 | 125 µg/m3 |
| CO | 24h | 7 | – | – | – | 4 µg/m3 | 10 mg/m3 | 10 mg/m3 |
Number and location of monitoring stations
Rules on the number and location of sampling points are also under review.
To ensure continuity of monitoring, the relocation of sampling points where exceedances of any limit value have been recorded in the previous three years will not be allowed, except in special circumstances.
In addition, the minimum number of stations per inhabitant will change, with the number of stations measuring PM2.5 being the same as for PM10, and the number of stations may be reduced if the air quality assessment is supplemented by indicative measurements (where appropriate).
Mandatory creation of supersites
The proposal includes the mandatory establishment by Member States of monitoring “Supersites” combining multiple sampling points to collect long-term data on the pollutants covered by the Directive, as well as on pollutants of emerging concern such as black carbon, ammonia, ultrafine particulate matter etc.
Supersites are monitoring stations located in an urban or rural environment that combine several sampling points to collect long-term data on several pollutants.
Member States would have to establish at least one Supersite as follows:
- At least 1 per 10 million inhabitants in an urban background site.
- At least 1 per 100,000 km2 in a rural background location.
And not only ultrafine particulate matter concentrations should be monitored at supersites: Member States should monitor ultrafine particulate matter where high concentrations are likely to occur (e.g. at airports, ports, roads, industrial areas or domestic heating) with at least one sampling point per 5 million inhabitants.
Dates and milestones
The proposal COM(2022)0542 is currently under discussion in the Council of the European Union, most recently on 26/04/2023.
The indicative date for the plenary session is 10 July 2023, when negotiations between the European Parliament, the European Council and the European Commission will start.
Ultrafine particles UFP: a key monitoring parameter in the proposed directive
Ultrafine particles (UFPs) are airborne particles with a diameter of less than 0.1 micron (PM 0.1).
UFPs are considered one of the most dangerous pollutants because their small size allows them to enter the lungs and bloodstream once inhaled.
Ultrafine particle sources
The main non-natural sources of ultrafine particles are:
- Vehicle emissions
- Natural gas and biofuel emissions
- Aircraft emissions
- Industrial and factory emissions
- Emissions from power plants
- Use of office equipment such as printers and photocopiers
- …
All of these sources can pose significant health risks because they emit new particles almost continuously over long periods of time, are mostly associated with traffic and industrial activity, and represent a significant threat to the millions of people living in cities today.
Conclusion: revision of European Directives in line with new WHO standards
The health effects of air pollutants (in particular PM 2.5 and ultrafine particles and NO2) have been scientifically proven over the years.
This means that the European Union should draw up a proposal to revise the European air quality directives in order to bring them into line with the objectives set by the World Health Organisation, with particular emphasis on the monitoring of particulate matter.
