Pratte Pascal, Rossi Michel J
Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Pollution Atmosphérique et Sol, Bât CH H5, Station 6, CH-1015 Lausanne, Switzerland.
Phys Chem Chem Phys. 2006 Sep 14;8(34):3988-4001. doi: 10.1039/b604321f. Epub 2006 Jul 20.
The HOBr and HOCl uptake coefficient gamma on H(2)SO(4)-acidified submicron salt aerosol of known size distribution was measured in an atmospheric pressure laminar flow reactor. The interaction time of the trace gas with the aerosol was in the range 15 to 90 s and led to gamma values in the range 10(-4) to 10(-2). The acidity of the aerosol is essential in order to enable heterogeneous reactions of HOBr on NaCl, recrystallized sea salt (RSS) and natural sea salt (NSS) aerosols. Specifically, HOCl only reacts on acidified NSS aerosol with a gamma ranging from 0.4 x 10(-3) to 1.8 x 10(-3) at a relative humidity (rh) at 40 and 85%, respectively. Uptake experiments of HOBr on aqueous H(2)SO(4) as well as on H(2)SO(4)-acidified NaCl, RSS or NSS aerosol were performed for rh ranging from 40 to 93%. The gamma value of HOBr on acidified NSS reaches a maximum gamma = 1.9 x 10(-2) at rh = 76 +/- 1% and significantly decreases with increasing rh in contrast to acidified NaCl and RSS aerosols whose gamma values remain high at gamma = (1.0 +/- 0.2) x 10(-2) at rh >/= 80%. An explanation based on the formation of an organic coating on NSS aerosol with increasing rh is proposed.
在常压层流反应器中，测量了HOBr和HOCl在已知粒径分布的H₂SO₄酸化亚微米盐气溶胶上的摄取系数γ。痕量气体与气溶胶的相互作用时间在15至90秒范围内，导致γ值在10⁻⁴至10⁻²范围内。气溶胶的酸度对于使HOBr在NaCl、重结晶海盐（RSS）和天然海盐（NSS）气溶胶上发生非均相反应至关重要。具体而言，HOCl仅在酸化的NSS气溶胶上反应，在相对湿度（rh）分别为40%和85%时，γ范围为0.4×10⁻³至1.8×10⁻³。对rh范围为40%至93%的情况进行了HOBr在H₂SO₄水溶液以及H₂SO₄酸化的NaCl、RSS或NSS气溶胶上的摄取实验。酸化NSS上HOBr的γ值在rh = 76±1%时达到最大值γ = 1.9×10⁻²，并且与酸化的NaCl和RSS气溶胶相比，随着rh增加而显著降低，酸化的NaCl和RSS气溶胶在rh≥80%时γ值保持在γ = (1.0±0.2)×10⁻²的较高水平。提出了一种基于随着rh增加在NSS气溶胶上形成有机涂层的解释。
