Receptor modeling of C2–C7 hydrocarbon sources at an urban background site in Zurich, Switzerland: changes between 1993–1994 and 2005–2006

[摘要] Hourly measurements of 13 volatile hydrocarbons (C₂–C₇)were performed at an urban background site in Zurich (Switzerland)in the years 1993–1994 and again in 2005–2006. For the separationof the volatile organic compounds by gas-chromatography (GC), anidentical chromatographic column was used in both campaigns. Changesin hydrocarbon profiles and source strengths were recovered bypositive matrix factorization (PMF). Eight and six factors could berelated to hydrocarbon sources in 1993–1994 and in 2005–2006,respectively. The modeled source profiles were verified byhydrocarbon profiles reported in the literature. The sourcestrengths were validated by independent measurements, such asinorganic trace gases (NO_x, CO, SO₂), methane(CH₄), oxidized hydrocarbons (OVOCs) and meteorological data(temperature, wind speed etc.). Our analysis suggests that thecontribution of most hydrocarbon sources (i.e. road traffic,solvents use and wood burning) decreased by a factor of about two tothree between the early 1990s and 2005–2006. On the other hand,hydrocarbon losses from natural gas leakage remained at relativelyconstant levels (−20%). The estimated emission trends are in linewith the results from different receptor-based approaches reportedfor other European cities. Their differences to national emissioninventories are discussed.

[学科分类] 大气科学