PM10 source apportionment in a Swiss Alpine valley impacted by highway traffic

Area of Science:

• Environmental Science
• Air Quality
• Public Health

Background:

• Trans-Alpine highway traffic exhaust is a major air pollution source in Alpine valleys.
• Limited understanding exists regarding its contribution to residential exposure and respiratory health impacts.
• Particulate matter (PM10) exposure is a growing concern in sensitive environments like Alpine villages.

Purpose of the Study:

• To determine source-specific contributions to PM10 concentrations in an Alpine village.
• To analyze the spatio-temporal distribution of PM10 sources.
• To provide data for a pediatric asthma panel study.

Main Methods:

• Positive matrix factorization (PMF) was applied to daily PM10 filters.
• Chemical trace elements, elemental carbon, and organic carbon data were used.
• Samples were collected from seven village locations between November 2007 and June 2009.

Main Results:

• Nine PM10 sources were identified, with four directly related to road traffic (exhaust, dust, tire/brake wear, road salt).
• Traffic-related sources contributed 16% (exhaust), 8% (dust), 1% (tire/brake wear), and 2% (road salt) to annual PM10.
• Other significant sources included secondary particles (27%), biomass burning (18%), railway (11%), and mineral dust (13%).
• Traffic-related source contributions showed a clear distance dependence from the highway.

Conclusions:

• Road traffic is a significant contributor to PM10 in Alpine village environments.
• Source apportionment provides crucial data for understanding residential exposure and health impacts.
• Biomass burning and secondary particles are also major contributors, particularly in winter.