Abstract. To gain insight into the spatial and chemical variation
in submicron aerosol, a nationwide characterization of wintertime
PM1 was performed using an aerosol chemical speciation monitor (ACSM)
and aethalometer at four representative sites across Ireland. Dublin, the
capital city of Ireland, was the most polluted area with an average PM1
concentration of 8.6 µg m−3, ranging from < 0.5 to 146.8 µg m−3 in December 2016. The PM1 in
Dublin was mainly composed of carbonaceous aerosol (organic aerosol (OA) + black carbon (BC)), which, on average, accounted for 80 % of total PM1 mass during the monitoring period. Birr, a small town in the midlands area of Ireland with a population < 1 % of that in Dublin, showed an average PM1 concentration (4.8 µg m−3, ranging from < 0.5 to 63.0 µg m−3 in December 2015) of around half that (56 %)
in Dublin. Similarly, the PM1 in Birr was also mainly composed of
carbonaceous aerosol, accounting for 77 % of total PM1 mass. OA
source apportionment results show that local emissions from residential
heating were the dominant contributors (65 %–74 % of the OA) at the two
sites, with solid fuel burning, on average, contributing 48 %–50 % of the
total OA. On the other hand, Carnsore Point and Mace Head, which are both
regional background coastal sites, showed lower average PM1
concentrations (2.2 µg m−3 for Carnsore Point in December 2016 and 0.7 µg m−3 for Mace Head in January 2013) due to the distance from
emission sources. Both sites were dominated by secondary aerosol comprising
oxygenated OA (OOA), nitrate, sulfate, and ammonium. This nationwide source
apportionment study highlights the large contribution of residential solid
fuel burning to urban air pollution and identifies specific sources that
should be targeted to improve air quality. On the other hand, this study
also shows that rural and coastal areas are dominated by secondary aerosol
from regional transport, which is more difficult to tackle. Detailed
characterization of the spatial and chemical variation in submicron aerosol
in this relatively less studied western European region has significant
implications for air quality policies and mitigation strategies, as well as
for regional-transport aerosol modeling.
Wintertime aerosol dominated by solid fuel burning emissions across Ireland: insight into the spatial and chemical variation of submicron aerosol