Released by the Air Quality Expert Group on Thursday, June 16 Particulate Matter in the United Kingdom says that while airborne particulate matter levels have dropped over the past few decades background levels are still very high and more needs to be done to meet national targets.
Stricter targets set for 2010 are unlikely to be met.
Professor Roy Harrison, vice chairman of the group, said: : “The report is based on a substantial amount of data analysis and modelling work, conducted by members of the Air Quality Expert Group.
“It represents our best view of current and future ambient concentrations of particulate matter and their relationship to air quality objectives and limit values.”
The main conclusions of the report are:
- The 2005 annual average limit value of 40 Ug/m3 for particulate matter should be met nearly everywhere but that there will be some exceedences of the limit of 35 days with 24-hour averages over 50 Ug/m3, especially in London.
- Substantial exceedences of the 2010 provisional annual average objectives and indicative limit values for particulate matter are likely.
Given the substantial background levels of particulate matter and the extent of the exceedences, the additional reductions required by 2010 to meet targets cannot be met by the control of primary emissions alone.
- Action plans are being developed for areas in which the 2005 limit values have been exceeded to ensure they are driven down.
However, these measures will probably only make a marginal contribution to the wider reductions because of substantial background levels of particulate matter.
- Improvements in the monitoring network, including enhanced monitoring of the chemical components that make up the particulate matter, would improve the accuracy of these models.
- While road traffic is a major source of particulate matter near to roads, the regional background contributions, both rural and urban, is dominant. Reducing background levels of particulate matter must form a central component of mitigation strategies.
AQEG says it is concerned that too much local air quality management is aimed to combat exceedences of one air quality objective, which tend to focus on particular hotspots.
It argues that consideration should be given to additional forms of regulation to reduce average population exposure, complementing the existing concentration-based limit values.
The group noted links between different pollutants and feels that a more flexible and holistic approach to air quality management might deliver more effective control strategies.
By Sam Bond