# First Lidar Campaign in the Industrial Sites of Volta Redonda-RJ and Lorena-SP, Brazil
## 5 Conclusions  
We have reported on the first aerosol profiling campaign carried out with a backscatter lidar system in Volta Redonda and Lorena, two industrial cities located in the Paraiba valley. This very important region connects two large metropolitan areas (Rio de Janeiro and Sao Paulo) and lacks remote sensing measurements. Additionally, we analyzed data from the air quality station over the Paraiba valley region and data measured by the CALIPSO satellite. While the air quality station analysis shows an increase in air pollutant episodes for Volta Redonda and Lorena during dry seasons, satellite data analysis shows that both cities present the same AOD annual pattern and similar lidar ratio values. These results highlight the atmosphere homogeneity of the Paraiba valley. In relation to the results obtained with the ground-based lidar campaigns, several peaks observed in the aerosol backscatter profile of Volta Redonda and Lorena indicate the presence of several aerosol layers detached from the aerosol boundary layer. HYSPLIT air-mass back trajectories indicate a possible detection of long-range aerosol transported from biomass burning areas of South America and also the influence of local pollution, with detection of aerosol layers up to 4000 and 5000 m altitude in Volta Redonda. In the particular case of Volta Redonda, it is speculated that the existence of aerosols at high altitudes could also come from the activities of industries in the region, such as CSN and others that supply its demand. It is very important to keep monitoring the region, an important axis connecting the cities of Rio de Janeiro and Sao Paulo, ideally by repeating  
Figure 11: Three-day backward trajectories ending at Volta Redonda site with different altitude levels, from 1000 to 6000 m a.g.l, on 5 December of 2018 at 06:00 UTC. Several fire focuses, represented by the red points, are detected by AQUA MODIS and retrieved from the biomass burning database from the National Institute for Space Research (INPE)—[[http://queimadas.dgi.inpe.br/queimadas/portal](http://queimadas.dgi.inpe.br/queimadas/portal)]([http://queimadas.dgi.inpe.br/queimadas/portal](http://queimadas.dgi.inpe.br/queimadas/portal)) (accessed on 17 September 2021). the measurements for more days and in different seasons. New measurement campaigns are being planned to monitor the Paraiba do Sul basin, and allow a better understanding of the origins of aerosols. Furthermore, Raman lidar measurements could be very useful to better characterise the atmosphere by avoiding the assumption of the lidar ratio and reducing the uncertainty in the aerosol backscatter coefficient. In the present research article the individual contributions was followed by: Conceptualization: F.J.G.S.L., C.J.T.P., C.R.M., F.J.R., S.A.C. and R.M.d.A. ; methodology: F.J.G.S.L. and R.M.d.A. ; software and data analysis: F.J.G.S.L., C.J.T.P., C.R.M., F.C., F.J.R., S.A.C. and R.M.d.A. ; formal analysis: F.J.d.S.L., C.J.T.P., C.R.M., F.C., F.J.R., S.A.C. and R.M.d.A. ; resources: E.L. and R.M.d.A. ; data curation: C.J.T.P., C.R.M., J.J.G., S.F.J.R., S.A.C., C.E.F. and R.M.d.A. ; writing--original draft preparation: F.J.d.S.L., C.J.T.P., C.R.M., F.C., F.J.R., S.A.C. and R.M.d.A. ; writing--review and editing, F.J.d.S.L., C.J.T.P., C.R.M., F.C., J.J.d.S., F.J.R., S.A.C., E.L., C.E.F. and R.M.d.A. ; project administration, E.L. and R.M.d.A. ; funding acquisition, E.L., J.J.d.S. and R.M.d.A. All authors have read and agreed to the published version of the manuscript. Part of this research was funded by Conselho Nacional de Desenvolvimento Cientifico e Tecnologico-CNPQ under grant numbers 404993/2016-8, 152156/2018-6, The Universal Project 432515/2018-6, and the project number 306106/2019-1. The research has also funding by Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro--FAPERJ under the grant number E-26/202.803/2019, and the IPEN Postgraduate program in Nuclear Technology under the CAPES-PROEX program 33002010050P7-Project 403/2021. Not applicable.