Chemistry Reference
In-Depth Information
Anthropogenic and Natural Constituents
in PM10 at Urban and Rural Sites in North-
Western Europe: Concentrations, Chemical
Composition and Sources
Ernie Weijers and Martijn Schaap
Abstract This study focuses on north-western region of Europe discussing
questions like the following: Which anthropogenic and natural constituents build
up the particulate matter? To what extent do they contribute to the total mass? And
where do these constituents originate? To answer, we elaborated data sets
containing chemical information of PM recently becoming available in the
Netherlands, Germany and Belgium.
The chemical composition of PM10 shows a considerable conformity in these
countries. Always, secondary inorganic aerosols (SIA) are the major constituent
(
25%). Contributions of sea
salt and mineral dust vary between 10% and 15% depending on presence and
distance of respective sources. The unidentified mass is some 15% indicating that
the composition of PM10 in this region is fairly well known.
PM10 concentrations and constituents appear systematically higher at urban sites.
Urban increments have been measured for most chemical constituents. Nearby
(anthropogenic) sources and reduced dispersion in the urbanised areas are the main
determining factors here. The observed increment for SIA is caused by more nitrate
and sulphate. It is explained by depletion of chloride stabilising part of the nitrate and
sulphate in the coarse mode. The question then arises how to assign the coarse mode
nitrate (and sulphate) in the mass closure exercise as they replace the chloride.
Important for the national and European air pollution policy is how much of the
measured particulate matter is of anthropogenic origin. A simple assessment
indicates that 20-25% of PM10 is of natural origin; hence, the majority of PM10
40%) followed by the carbonaceous compounds (
