PM2.5 concentration from bus traffic in Helsinki in 2020
Scope
- Spatial limits: Helsinki metropolitan area
- Temporal limits: year 2020
- Type of pollutant: primary PM2.5
- Source of pollutant: bus traffic
Definition
Causality
List of parents:
Data
List of data files or sources:
- Database from EXPOLIS study (1996-1997) - individual measurements of total outdoor PM exposure
- Database from ULTRA study - fixed monitoring sites
Formula
Total PM2.5 exposure/concentration was used as the starting point for the calculations of PM2.5 due to bus traffic, subtracting the contributions from other sources.
Ebus = (Ec-Elrt)/ftr*fbus
fi = (Emi * wfi)/Sum(Emi*wfi)
Where: Ebus is average PM2.5 exposure to primary particles from local buses Ec is exposure to total exposure to combustion originating particles Elrt is the concentration of combustion-based long-range transport (average exposure to long-range transported PM2.5) ftr is the ratio of local road traffic exposure to local CoPM fbus is the ratio of local bus-derived primary CoPM to all local road-traffic-derived CoPM Emi is the CoPM emissions in the Helsinki area (tn/year) wfi is the relative weight factors to CoPM-emissions Index i denotes different CoPM sources in Helsinki wf is an estimate of the the impact of a unit emission on the average population exposure in the area
Unit
μg/m3
Result
Estimation of average bus-related primary PM2.5 in 2020 in Helsinki area