European Commission-Joint Research Centre, Institute for Environment and Sustainability, TP-441, 21027-Ispra (VA), Italy.
Environ Pollut. 2010 Sep;158(9):2880-7. doi: 10.1016/j.envpol.2010.06.016. Epub 2010 Jul 14.
The ambient air in Northern Italy is characterised by relatively high PAH and PM10 concentrations in relation to calm wind and intensive temperature inversions, especially during cold periods. These stagnant conditions are occasionally interrupted by North-Föhn events, which cause a drop in relative humidity and an increase in O3 levels, indicating the mixing of local and free troposphere air flows. In this study the influence of the North-Föhn on concentrations of tracer organic compounds, including polycyclic aromatic hydrocarbons (PAHs), PM10, O3 and black carbon (BC) was studied during a North-Föhn event in November 2007. Large fluctuations in the concentration of these compounds, as well as changes in PM(10) composition due to daytime and night-time variations of local source emissions were observed. Although these events occur at low frequencies (6-10%) they can for short periods, strongly affect the regional air quality by quickly decreasing the concentrations of these tracer organic compounds.
意大利北部的环境空气中，多环芳烃和 PM10 的浓度相对较高，这与静风和强烈的逆温有关，尤其是在寒冷时期。这些静止的条件偶尔会被北风事件打断，北风事件会导致相对湿度下降和臭氧水平上升，表明局部和自由对流层空气的混合。在这项研究中，研究了 2007 年 11 月北风事件对示踪有机化合物（包括多环芳烃、PM10、臭氧和黑碳）浓度的影响。这些化合物的浓度出现了大幅波动，由于当地排放源的昼夜变化，PM(10)成分也发生了变化。尽管这些事件发生的频率较低（6-10%），但它们可能在短时间内通过快速降低这些示踪有机化合物的浓度，强烈影响区域空气质量。
