For the years 2008-2013, particles of diameter 〈 10 and 2.5 μm （PM10 and PM2.5, respectively）, NOx, SO2, and O3 concentrations at urban, suburban, rural, and traffic sites in the Paris metropolitan area were analy...For the years 2008-2013, particles of diameter 〈 10 and 2.5 μm （PM10 and PM2.5, respectively）, NOx, SO2, and O3 concentrations at urban, suburban, rural, and traffic sites in the Paris metropolitan area were analyzed. Strong spatial variability at traffic and rural sites and relatively uniform profiles at urban and suburban sites for PM10, PM2.5, and O3 were observed. The O3 weekend effect was induced by lower NOx emissions during the weekend, and favored volatile organic compounds （VOCs）-limited atmospheric conditions. In conJunction with low ambient temperature, these conditions could also favor increased formation of secondary particulate nitrates in winter. Winter air pollution events were associated with multiple pollutants, whereas those observed in spring were caused by high PM10 and PM2.5 levels. Back- ward trajectory analyses showed the contribution of sources in Western and Central Europe on days with high PM10, PM2.5, and O3, and a local/national comvonent for NOx and SO2.展开更多
文摘For the years 2008-2013, particles of diameter 〈 10 and 2.5 μm （PM10 and PM2.5, respectively）, NOx, SO2, and O3 concentrations at urban, suburban, rural, and traffic sites in the Paris metropolitan area were analyzed. Strong spatial variability at traffic and rural sites and relatively uniform profiles at urban and suburban sites for PM10, PM2.5, and O3 were observed. The O3 weekend effect was induced by lower NOx emissions during the weekend, and favored volatile organic compounds （VOCs）-limited atmospheric conditions. In conJunction with low ambient temperature, these conditions could also favor increased formation of secondary particulate nitrates in winter. Winter air pollution events were associated with multiple pollutants, whereas those observed in spring were caused by high PM10 and PM2.5 levels. Back- ward trajectory analyses showed the contribution of sources in Western and Central Europe on days with high PM10, PM2.5, and O3, and a local/national comvonent for NOx and SO2.
