TITLE:
High Contribution of Sea Salt Aerosols on Atmospheric Particles Measured at an Urban Tropical Location in Reunion Island
AUTHORS:
Chatrapatty Bhugwant, Miloud Bessafi, Olivier Favez, Laura Chiappini, Bruno Sieja, Eva Leoz-Garziandia
KEYWORDS:
PM10; Nitrogen Dioxide; Anthropogenic; Sea Salt Aerosols; Chemical Characterization; Regulatory Values; Human Health; Lung Cancer; Urban; Tropical
JOURNAL NAME:
Journal of Environmental Protection,
Vol.4 No.8,
August
5,
2013
ABSTRACT: PM10 was monitored during 2008-2011
period at LUT and BON, two urban tropical stations close to each other at
Saint-Pierre city, in Reunion Island (south-western Indian Ocean). During the
study period, notable PM10 concentrations are observed at BON close to the
coasts. At LUT, a more inland site, the daily PM10 concentration range between
13 and 70 μg/m3. Importantly, the limit value for the protection of
the human health is systematically exceeded at BON while it is never exceeded
at LUT. Also, the quality objective (QO: 30 μg/m3, on annual
average) and the limit value for the human health protection (LV: 40 μg/m3,
on annual average) are exceeded at BON each year during 2008-2011, while at LUT
no regulatory values are exceeded. Nitrogen dioxide, an atmospheric tracer of
anthropogenic activities was also monitored at LUT and BON. The mean diurnal NO2 variation is of the same level and order of magnitude and exhibits a similar
pattern at both stations suggesting that distinct sources influence the PM10 at
LUT and at BON. Chemical analysis was performed on daily filters sampled in
September-November 2011 at the two stations to determine the sea salt
contribution on PM10 across Saint-Pierre city. It showed that the sea salt
contribution to the PM10 is 55% at BON in September 2011. The sea salt
particles are therefore the main cause for the exceedances of the regulatory
values of PM10 recorded at BON. The results importantly suggest that the
notable PM10 concentrations measured at this urban marine site might have some
but minor impact on human health.