雾霾天对青岛P M2.5中铁、磷浓度及溶解度的影响

大气气溶胶中铁(Fe)和磷(P)溶解度决定了其沉降入海后对海洋初级生产及固碳能力的影响.本文分析了2017—2018年冬季在青岛采集的PM2.5样品中总态、溶解态Fe(Total Fe,TFe;Soluble Fe,SFe)和总态、溶解态P(Total P,TP;Soluble P,SP)浓度,讨论了雾、雾霾、霾和晴天...

Concentrations and Solubility of Iron and Phosphorus in PM2.5 in Hazy and Foggy Air at the Coastal City Qingdao of China

The solubility of iron(Fe)and phosphorus(P)in atmospheric aerosols is an important factor to determine overall effects of atmospheric Fe and P deposited into surface seawater on marine primary productivity and oceanic carbon uptake.PM2.5 samples were collectedat the coastal city Qingdao of China from Nov.2017 to Jan.2018,in which the total Fe(TFe),soluble Fe(SFe),total P(TP)and soluble P(SP)were measured.The discrepancies of the concentrations and solubility of Fe and P in weather conditions of fog,fog-haze and haze with that inclear-weather condition were discussed.On average,the concentrations of TFe in fog and fog-haze aerosols were significantly lower than that in aerosols inclear days,while the concentration in haze aerosols was comparable to that in clear days.However,the concentrations of SFe in fog and fog-haze aerosols were significantly higher than in aerosols in clear days.Although the concentrations of SFe in haze aerosols was also higher than in aerosols in clear days,there was no significant difference between the two.The solubility of Fe was the highest in fog aerosols,with an average of 16.8%,followed by fog-haze aerosols with 8.9%,and the solubility in haze and aerosols was about 3.5%,basically equal with that in clear days.TP vs.TFe and SP vs.SFe had significant correlations,and thus they had a consistent change trends under different weather conditions,respectively,but the differences in P concentrations between different weather conditions were significantly smaller than those of Fe.The solubility of P was about 80%in fog and fog-haze aerosols,which wassignificantly higher than 27%in aerosols in clear days and 45%in haze aerosols.Fe and P in PM2.5were mainly derived from mineral dust sources.The initial solubility of Fe and P in aerosols without human interference was 1.5%~2%and 16%~18%,respectively.The synergistic effect of atmospheric acidification and relative humidity(RH)was the main mechanism for the differences in Fe and P solubility under different weather conditions.RH below 60%in haze episodes limits the effect of atmospheric acidification on solubility was the reason why the solubility of aerosol Fe and P was significantly lower than in fog-haze episodes.