薪焚きがウェスト・ミッドランズにおけるPM2.5大気汚染の大きな原因になっている(Woodburning creates major PM2.5 air pollution issue in West Midlands)

2024-12-10 バーミンガム大学

＜関連情報＞

• https://www.birmingham.ac.uk/news/2024/woodburning-creates-major-pm2.5-air-pollution-issue-in-west-midlands
• https://www.sciencedirect.com/science/article/pii/S1352231024006381?via%3Dihub

英国の都市部における微小粒子状物質（PM2.5）の発生源に関する比較受容体モデリング Comparative receptor modelling for the sources of fine particulate matter (PM2.5) at urban sites in the UK

Deepchandra Srivastava, Supattarachai Saksakulkrai, W. Joe F. Acton, Daniel J. Rooney, James Hall, Siqi Hou, Mark Wolstencroft, Suzanne Bartington, Roy M. Harrison, Zongbo Shi, William J. Bloss
Atmospheric Environment  Available online: 30 November 2024
DOI:https://doi.org/10.1016/j.atmosenv.2024.120963

Graphical abstract

Highlights

• Declining (NH₄)₂SO₄ contribution to PM_2.5 from 25% in 2007 to 15% in 2021/2022.
• Consistent NH₄NO₃ contribution to PM_2.5 (20–22%) despite air quality measures.
• Key sources: Biomass burning, resuspended dust and traffic-related, secondary aerosols.
• Biomass burning PM_2.5 in 2021/2022 is 7 times higher than in 2008–2010.

Abstract

The concentration of fine particulate matter (PM_2.5) in the UK has been decreasing in the last few decades but remains the leading environmental health risk. As a consequence of changing population, behaviour, activity factors, emissions and regulation, it is likely that the sources of PM_2.5 in the UK are changing but a quantitative source apportionment has not been reported for many years. This study analyses the characteristics and sources of PM_2.5 collected in 2021 and 2022 at two urban background sites: Birmingham Air Quality Supersite (BAQS) and Ladywood (LW) in Birmingham. Results indicate a notable decrease in the contribution (concentration) of (NH₄)₂SO₄ to PM_2.5 from 25% (2.9 μg m⁻³) in 2007 to 15% (1.5 μg m⁻³) in 2022. In contrast, the contribution of NH₄NO₃ (20–22%) to PM_2.5 remains consistent with that in 2007, despite various air quality actions implemented over the years. These shifts are attributed to changes in SO₂ and NO_x emissions, coupled with relatively stable NH₃ levels—key precursors for (NH₄)₂SO₄ and NH₄NO₃, which altered the formation dynamics of these compounds, ultimately affecting their contribution to PM_2.5 concentrations. Positive matrix factorization (PMF) analysis showed that biomass burning factors (25%), resuspended dust and traffic-related emissions (22%), and secondary aerosols (25%) are the major contributors to PM_2.5 mass. Furthermore, PMF and Aethalometer-model analyses consistently showed that biomass burning aerosol concentrations are approximately seven times higher (1.5 μg m⁻³) than those observed in studies from 2008 to 2010. These findings suggest that targeted measures to reduce wood burning and road traffic have the greatest potential to reduce PM_2.5-related health risks in the West Midland region.