PM10 measurement differences between a coastal and inland tropical forest site of French Guiana during 2018 desert dust season: first results

Effects of desert particle with diameter less than 10 μm (PM10) on human health were now well established. Desert dust is the major pollutant affected the air quality of French Guiana region. On another hand, recently a study highlights the importance of desert dust on Amazon rain forest. To work on the behavior of desert dust plume during the crossing from the coast to inland rain forest, a measurement campaign have been implemented. Our main goal is the forecasting of dust concentration level for inland people based on PM10 level performed along the coast. The first results of comparison between TEOM PM10 measurements in a costal site of Awala -Yalimapo (AY)and TEOM PM10 at Apatou (AP), a small town located 80 km from the sea. Strong desert dust events data, performed during the dust season of 2018, have been analyzed. Time series let appears a difference of 6 to 8 hours between dust arrival at AY and at AP. Those delays seem to be not conform with the dust propagation in altitude. Probably the change of the boundary layer during the crossing ocean to rain forest can explain this behavior. On another hand, a very strong correlation had been found between AY and AP PM10. A decrease of the PM10 level during the transfer was observed between 10 μg m-3 to 50 μg m-3. The concentration difference can be linked for a part with the loss of marine aerosols along the pathway. The other part must be related to the dust deposition at the rain forest. In conclusion this first experiment results obtain in French Guiana rain forest open numerous questions on interaction between the rain forest and desert dust.