Details

Autor(en) / Beteiligte

• Megaritis, A. G
• Fountoukis, C
• Charalampidis, P. E
• Denier van der Gon, H. A. C
• Pilinis, C
• Pandis, S. N

Titel

Linking climate and air quality over Europe: effects of meteorology on PM.sub.2.5 concentrations

Ist Teil von

• Atmospheric chemistry and physics, 2014-09, Vol.14 (18), p.10283

Ort / Verlag

Copernicus GmbH

Erscheinungsjahr

2014

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• The effects of various meteorological parameters such as temperature, wind speed, absolute humidity, precipitation and mixing height on PM.sub.2.5 concentrations over Europe were examined using a three-dimensional chemical transport model, PMCAMx-2008. Our simulations covered three periods, representative of different seasons (summer, winter, and fall). PM.sub.2.5 appears to be more sensitive to temperature changes compared to the other meteorological parameters in all seasons. PM.sub.2.5 generally decreases as temperature increases, although the predicted changes vary significantly in space and time, ranging from -700 ng m.sup.-3 K.sup.-1 (-8% K.sup.-1) to 300 ng m.sup.-3 K.sup.-1 (7% K.sup.-1). The predicted decreases of PM.sub.2.5 are mainly due to evaporation of ammonium nitrate, while the higher biogenic emissions and the accelerated gas-phase reaction rates increase the production of organic aerosol (OA) and sulfate, having the opposite effect on PM.sub.2.5 . The predicted responses of PM.sub.2.5 to absolute humidity are also quite variable, ranging from -130 ng m.sup.-3 %.sup.-1 (-1.6% %.sup.-1) to 160 ng m.sup.-3 %.sup.-1 (1.6% %.sup.-1) dominated mainly by changes in inorganic PM.sub.2.5 species. An increase in absolute humidity favors the partitioning of nitrate to the aerosol phase and increases the average PM.sub.2.5 during summer and fall. Decreases in sulfate and sea salt levels govern the average PM.sub.2.5 response to humidity during winter. A decrease of wind speed (keeping the emissions constant) increases all PM.sub.2.5 species (on average 40 ng m.sup.-3 %.sup.-1) due to changes in dispersion and dry deposition. The wind speed effects on sea salt emissions are significant for PM.sub.2.5 concentrations over water and in coastal areas. Increases in precipitation have a negative effect on PM.sub.2.5 (decreases up to 110 ng m.sup.-3 %.sup.-1) in all periods due to increases in wet deposition of PM.sub.2.5 species and their gas precursors. Changes in mixing height have the smallest effects (up to 35 ng m.sup.-3 %.sup.-1) on PM.sub.2.5 . Regarding the relative importance of each of the meteorological parameters in a changed future climate, the projected changes in precipitation are expected to have the largest impact on PM.sub.2.5 levels during all periods (changes up to 2 μg m.sup.-3 in the fall). The expected effects in future PM.sub.2.5 levels due to wind speed changes are similar in all seasons and quite close to those resulting from future precipitation changes (up to 1.4 μg m.sup.-3). The expected increases in absolute humidity in the future can lead to large changes in PM.sub.2.5 levels (increases up to 2 μg m.sup.-3) mainly in the fall due to changes in particulate nitrate levels. Despite the high sensitivity of PM.sub.2.5 levels to temperature, the small expected increases of temperature in the future will lead to modest PM.sub.2.5 changes and will not dominate the overall change.