Wintertime PM10 and black smoke concentrations across Europe: results from the peace study

In the framework of the PEACE study, measurements of particles less than 10 μm (PM10) and black smoke (BS) in ambient air have been made at 28 sites in ten countries in Europe. For about two months in the winter of 1993/94 24-h average measurements were conducted. Each center studied both an urban and a more rural site. The difference of particle concentrations across countries appeared to be considerably larger than the difference between the urban and rural location within countries. The median PM10 concentration ranged from 11 μgm−3 at three rural Scandinavian sites to 92 μg m−3 in Athens, Greece. The median BS concentration ranged from 3 μg m−3 in Umea, Sweden to 99 μg m−3 in Athens, Greece. The most striking difference across countries was the low particle concentration found at the eight Scandinavian locations. PM10 and BS concentrations in the urban area were on average 22% and 43% higher than the corresponding rural area concentrations, respectively. The correlation between the particle concentration measured at the urban and the more rural site exceeded 0.70 at almost all sites. PM10 concentrations from all Western and Central European locations were significantly correlated. No or a low correlation was found between these locations and the South-European and Scandinavian locations. PM 10 and BS measured at the same site were highly correlated at most sites. However, the median PM 10/BS ratio ranged from 0.67 to 3.67 across sites. PM10/BS ratios were close to unity for Athens, the Central European sites and Oslo. There was a tendency of lower PM10/BS ratios in the urban area, consistent with the contribution of (diesel) motor vehicle emissions.