Index Geophysics

pH Control in Fog and Rain in East Asia: Temporal Advection of Clean Air Masses to Mt. Bamboo, Taiwan

Fog and rain was collected during an 18-day period in January 2011 at Mt. Bamboo, northern Taiwan. Almost 300 hourly fog samples and 16 daily rain samples were taken. One single fog sample (pH 3.17) was influenced by local volcanic activity, otherwise the pH ranged from 3.23 to 6.41 in fog and from 3.59 to 6.31 in rain. All the respective air masses arrived from the northeast, but exhibited two distinct groups: Group_1 had high concentrations of all ions (median interquartile range of total ion concentrations 3200–6200 µeq.·L−1) and low pHs (median 3.52), the respective air masses had travelled over densely populated and industrialized regions of mainland China. Group_2 was from air masses with long travel times over the ocean and relatively low total ion concentrations (80–570 µeq.·L−1) and higher pHs (median 4.80). The cleanest samples are among the cleanest reported in the literature of worldwide fog and rain. In both groups, the pH was governed by the balance of sulfate, nitrate, ammonium, and, in some cases, calcium. The variability of these ions was higher than the variability of 10−pH, which shows that the pH is a rather robust parameter in contrast to its drivers such as non-sea-salt sulfate.

Otto Klemm

Wei-Ti Tseng

Chia-Ching Lin

Kerstin I. Klemm

Neng-Huei (George) Lin

fog chemistry

acid rain

East Asia

air pollution

pH

Meteorology. Climatology

QC851-999

MDPI AG

2015-11-01T00:00:00Z

article

2073-4433

10.3390/atmos6111785

https://doaj.org/article/63b31a0650bc44e183d48426edcc6c26

Atmosphere, Vol 6, Iss 11, Pp 1785-1800 (2015)

EN

http://www.mdpi.com/2073-4433/6/11/1785

https://doaj.org/toc/2073-4433

Journal Licence: CC BY