Long-term measurements of the chemistry and sources of submicron aerosols at SIRTA in Paris area, France
Résumé
Atmospheric submicron aerosol particles (PM1, aerodynamic diameter ≤ 1 μm) are of major concern for air quality. PM1 also have potential impacts upon global climate change and ecosystems. However, the impacts remain highly uncertain, mainly due to their complex chemical processes, various sources, and the interactions between meteorology and atmospheric aerosols. In the last decade, many studies have investigated the chemistry of atmospheric aerosols worldwide using online instrumentation. However, there is a lack of longterm ambient measurements (e.g. >5 years) for a better understanding on the sources and formation mechanisms of PM1. This is especially needed for policy makers to elaborate and evaluate efficient air pollution control strategies, and for modellers to validate and improve model simulations. We have been performing multi-year in-situ measurements with real-time on-line instruments, including an Aerosol Chemical Speciation Monitor (ACSM) (Ng et al., 2011), and a 7-wavelength Aethalometer (Drinovec et al., 2015) at SIRTA station since mid-2011. These measurements are part of the European ACTRIS and ACTRIS-2 research programs. SIRTA is located about 25 km South-West of Paris city centre. The PM1 non-refractory chemical components (NR-PM1), i.e., organic aerosol (OA), nitrate, sulphate, ammonium, and chloride, as well as black carbon (BC) were measured by the ACSM and Aethalometer, respectively. BC sources were identified using the Aethalometer model (Sandradewi et al. 2008). Positive matrix factorization (PMF) with the multi-linear engine (ME-2) was performed using the Source Finder (SoFi) (Canonaco et al., 2013) for OA source apportionment (e.g., Fig. 1). Finally, combining with the potential source contribution function (PSCF), we evaluated the possibility of geographical sources of PM1 at SIRTA. We investigate the annual, seasonal, monthly, weekly (e.g., Fig. 1 and 2), and diurnal variations of various sources contributing to PM1 mass loadings, including primary sources (e.g., traffic and wood burning emissions) and secondary formation (from anthropogenic and biogenic related sources).