Mobile Particle and NO_x Emission Characterization at Helsinki Downtown: Comparison of Different Traffic Flow Areas

10.4209/aaqr.2013.10.0311

Tero Lähde；Jarkko V. Niemi；Anu Kousa；Topi Rönkkö；Panu Karjalainen；Jorma Keskinen；Anna Frey；Risto Hillamo；Liisa Pirjola

Urban aerosols ； Mobile samplers ； Automotive exhaust ； Air pollution

Aerosol and Air Quality Research

14卷5期（2014 / 08 / 01）

1372 - 1382

英文

A two weeks measurement campaign by a mobile laboratory van was performed at downtown Helsinki, Finland, in winter 2010. The characteristics of air pollutants such as fine particles in the size ranges of 7-40 nm (N_(p40)) and 40-1000 nm (N_(p1000)), black carbon (BC), fine particle mass (PM_(2.5)), as well as gaseous compounds NO, NO_2, NO_x, CO and CO_2 were studied. The statistical analysis showed that the air pollution conditions strongly depended on the traffic flow area; therefore, the street sections were classified as high traffic flow areas (HTF1-HTF4), low traffic flow areas (LTF1-LTF5), and urban background areas (BG1-BG3). Large variation of particle emissions was observed, and the momentary peak particle concentrations were 8 × 10^5 cm^(-3). At the HTF areas exhaust emissions followed clearly daily average heavy duty vehicle counts rather than the average daily vehicle counts. Higher correlation coefficients were found between CO_2 and NO than between CO_2 and N_(tot). The dispersion studies indicated that the air pollution conditions strongly improved from high traffic flow areas to low traffic flow areas. Therefore, proper city planning and locating, for example, cycle tracks, schools and hospitals farther from busy city streets might significantly reduce exposure risk for humans.