A blaze started at the Eco-X rubbish depot in Pomezia, a municipality in the Metropolitan City of Rome at about 26 km from Italian capital, on 5th of May at around 6 UTC, and was active for about two days. The cloud of smoke was visible from several tenths of kilometres away. Both the fire service and the local health authority of Pomezia, warned locals inside an area of 5 km of radius to keep windows closed in homes, schools, offices, and health and social care structures, keep animals inside, and to avoid all unnecessary travel.
Figure 1 - ECO-X fire/smoke images – Left: the fire at 6:30 UTC, the building on the right will burn and collapse during the 5th May. Right: the smoke plume from Rome close to Appia GRA exit at 7:00 UTC (Rome outskirts) looking South.
Serco SpA IDEAS+ team located in Frascati (near Rome), in collaboration with the CNR-ISAC institution (National Council of Research – Atmospheric and Climate Science Institute), La Sapienza University of Rome and instrument manufacturers, has carried out a specific study on this event, using a set of ground-based instrumentation managed as part of their current Remote Sensing contract.
Observations from ground based instruments operated under the IDEAS+ Contract, in which Serco leads the Scientific Calibration and Validation activities in the context of ESA – ESRIN
(European Space Agency) projects, revealed that the smoke plume injected in the atmosphere was transported over Rome on May 5th and 6th. In this study have been used the two sun photometer PANDORA (http://pandonia.net/):
- PANDORA#115 located at CNR-ISAC, in a semi-rural environment, at ~ 30 km from the centre of Rome,
- PANDORA #117operated at Physics Department of La Sapienza University, i.e. in an urban environment close to Rome centre.
The measurements showed statistically significant increases of nitrogen dioxide (NO2) and formaldehyde (HCOH), being the last considered as tumour inducer following chronic exposure. In Figure 2 we show the evolution of the nitrogen dioxide (NO2) tropospheric column for PANDORA #115 (upper plot, red dots) and #117 (lower plot, blue dots), for the 5th and 6th of May. In each panel, the black line represents the average of the considered parameters evaluated from data taken on May 4th and 7th, considered as “clean days reference”.
Figure 2 - Nitrogen dioxide (NO2) tropospheric columnar content from PANDONIA. Upper row: PANDORA #115 (CNR-ISAC); lower row: PANDORA #117 (Sapienza). In each panel, the black line represents the “clean day reference”
Figure 3 Evolution of formaldehyde (HCOH) tropospheric column for May 5th 2017. Upper row: HCOH for PANDORA#115 (left, red line) and PANDORA#117 (right, blue line); lower left: excess of HCOH with respect to “clean days” for #115 (red) and #117 (blue); lower right: map showing the position of the fire (ECO-X) and of the two PANDORAs, the related line of sights and the position and altitude of the smoke plume at 10:30 UTC as evaluated from WRF model data analysis
In Figure 3 we show the formaldehyde (HCOH) tropospheric column parameters evolution for the 5th May for both the sites: in red the PANDORA #115 and in blue the PANDORA #117.
From both figures it can be clearly seen that the tropospheric amounts of NO2 and HCOH are significantly higher with respect to the reference values. Air parcel trajectories, estimated from atmospheric model simulations using the Weather Research Forecasting model (WRF), confirmed that the smoke plume was reaching the two PANDORAs at the time when the increase in concentration is observed. In Figure 3 (lower right panel) the colours of the filled circles indicate the approximate altitude of the polluted air parcels. It should be noted that the particles at lower level was transported in the Tiber Valley towards the city of Rome (North-East direction), while the upper altitude smoke was transported eastward.
The PANDORA #115 and #117 instruments are part of a suite of atmospheric remote sensing instruments operated in synergy, called Boundary layer Air Quality-analysis Using Networks of INstruments (BAQUNIN). BAQUNIN is funded by ESA within its Atmospheric Composition Cal/Val framework and is one of the IDEAS+ activities, its instrumental suite comprises, among others, elastic and Raman LIDARs, sun photometers (e.g. AERONET, SKYNET, PANDONIA), and SODARs.
From space, the smoke plume was detected by the PROBA-V mission, as shown in Figure 4 where a tile of the PROBA V product is displayed in form of RGB image. This image was acquired on May 5th at 10:04 UTC, i.e. few hours after the start of the fire; the spatial resolution is 100m. The smoke plume is clearly visible and the mostly optically thick (black) area was about 4x4 km2 wide. As discussed before the higher part of the smoke plume, visible from satellite, is heading eastwards from the industry location.
Figure 4 PROBA-V RGB image of May 5th 2017, 10:04 UTC. The white arrow indicates the ECO-X position.
The effects of ECO -X industrial fire was detected by our team from both ground based and satellite instruments. Our team detected the presence of pollutants complementing the analysis done by the central authority, in terms of types and distribution in the atmosphere.
It was a very good example of merging Ground-based instrumentation with Data modeling techniques and Satellite information to get a homogeneous view over time of a pollution spreading event.
This capability will be fully exploited in synergy with the next to fly SENTINEL-5P European mission, which will produce atmospheric chemistry products at relatively high spatial resolution.
S. Casadio (1), A.M. Iannarelli (1), F. Niro (1), E. Cadau (1), S. Pinori(1), M. Cardaci(1), M. Cacciani(2), M. Campanelli (3), PANDONIA TEAM (4)
(1) SERCO SpA, (2) Physics Department, University of Rome “Sapienza”, (3) CNR-ISAC, (4) LuftBlick