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The relationship between meteorological conditions and air quality in Naples, Italy Vincenzo Capozzi Ph.D Student in Marine, Earth and Climate Sciences.

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Presentation on theme: "The relationship between meteorological conditions and air quality in Naples, Italy Vincenzo Capozzi Ph.D Student in Marine, Earth and Climate Sciences."— Presentation transcript:

1 The relationship between meteorological conditions and air quality in Naples, Italy Vincenzo Capozzi Ph.D Student in Marine, Earth and Climate Sciences Università degli studi di Napoli “Parthenope”

2 Goals/outline of the work This work try to examine some relationship between meteorological conditions and pollutants concentrations in Naples. Motivation in the choise of this topic: the state of the atmosphere is one of main factors that controls the final concentration of pollutants in a site (Oke, 1987). The study is focused on three main aspects: 1.Relationship between wind (speed and direction) and PM10 concentration ( period); 2.Synoptic scale control of PM10 levels ( period); 3.Relationship between Ozone (O3) concentration and solar radiation ( period).

3 Relationship between wind conditions and pollutants concentration in Naples (1) PM10 daily data were retrieved from BRACE database (http://www.brace.sinanet.apat.it) and cover the period, unfortunately with many gaps. The air quality monitoring stations used are: 1)Napoli Ente Ferrovie (40°51’13’’N 14°16’18’’E, 13 m asl), which is part of A.R.P.A.C. monitoring newtork; 2)Napoli Scuola Vanvitelli (40°50’40’’N 14°13’41’’E, 190 m asl), which is part of A.R.P.A.C. monitoring network. Wind daily data (speed and direction) cover the period and were recovered from two weather station: 1)Napoli Capodichino (40°51’45’’N 14°17’08’’E, 88 m asl), which is part of Italian Meteorological Service Network (www.meteoam.it); 2)Napoli Via Acton (40°50’14’’N 14°15’12’’E, 10 m asl), which is part of the DiST (Dipartimento di Scienze e Tecnologie – Università di Napoli “Parthenope”) meteorological network.

4 Relationship between wind and pollutants concentration in Naples (2) y = 61.57*exp( x) R 2 = 0.14 y = 53.94*exp( x) R 2 = 0.13

5 Relationship between wind and pollutants concentration in Naples (3) Wind direction class (degree) Mean PM10 (μg/m 3 ) at Napoli Ente Ferrovie Number of events in period (based on available PM10 data) Mean PM10 (μg/m 3 ) at Napoli Scuola Vanvitelli Number of events in period (based on available PM10 data) Wind direction data were divided into 8 classes. For each class, PM10 concentration mean value for both air quality monitoring stations was computed.

6 Synoptic scale control of PM10 levels (1) Good air quality events occur when a trough is formed over the Ionio Sea. In this situation winds from first and fourth quadrant prevail in the Campania Region and in Naples Gulf. The map below was obtained from NCEP/NCAR Reanalysis (http://www.esrl.noaa.gov/psd/data/composites/day/) and shows the mean sea level pressure observed at synoptic scale in days characterized by a PM10 value in Naples (Ente Ferrovie station) below the 10th percentile.http://www.esrl.noaa.gov/psd/data/composites/day/ The map below was obtained from NCEP/NCAR Reanalysis (http://www.esrl.noaa.gov/psd/data/composites/day/) and shows the sea level pressure anomaly observed at synoptic scale in days characterized by a PM10 value in Naples (Ente Ferrovie station) below the 10th percentile.http://www.esrl.noaa.gov/psd/data/composites/day/

7 Synoptic scale control of PM10 levels (2) The map below was obtained from NCEP/NCAR Reanalysis (http://www.esrl.noaa.gov/psd/data/composites/day/) and shows the the sea level pressure anomaly observed at synoptic scale in days characterized by a PM10 value in Naples (Ente Ferrovie station) above the 10th percentile.http://www.esrl.noaa.gov/psd/data/composites/day/ The map below was obtained from NCEP/NCAR Reanalysis (http://www.esrl.noaa.gov/psd/data/composites/day/) and shows the mean Sea level pressure observed at synoptic scale in days characterized by a PM10 value in Naples (Ente Ferrovie station) above the 90th percentile.http://www.esrl.noaa.gov/psd/data/composites/day/ Poor air quality events occur when a ridge is formed over central-western Mediterranean basin. This situation results in weak pressure gradient and consequentely in low wind speed.

8 Relationship between Ozone concentration and solar radiation (1) Ozone daily time series was reconstructed means of BRACE database (http://www.brace.sinanet.apat.it). In order to have a dataset as complete as possible, two air quality monitoring station were used:http://www.brace.sinanet.apat.it 1)Napoli Osservatorio Astronomico (40°51’46’’N 14°15’16’’E, 145 m a.s.l.), which is a suburban station part of A.R.P.A.C. monitoring network. 2)Napoli Ospedale Santobono (40°51’00’ N 14°13’ 51’’E, 173 m a.s.l.), which is a urban station part of A.R.P.A.C. monitoring newtork. Daily Solar radiation data for the period were retrieved from Ischia weather Station (40°43’N 13°52’E, 104 m a.s.l.), which is part of the DiST (Dipartimento di Scienze e Tecnologie – Università di Napoli “Parthenope”) meteorological network.

9 Relationship between Ozone concentration and solar radiation (2) Daily Ozone concentration often exceed the 80 μg/m 3 when the level of solar radiation topped 250 W/m 2. y = x R 2 = 0.19 ρ = 0.43

10 Summary Wind speed explains ≈ 15% of PM10 variance in Naples, according to the data recorded in period; daily PM10 concentration and wind speed show and inverse correlation (ρ ≈ -0.35). Both sites chosen for the analysis show the highest and the lowest daily PM10 value at the lowest wind speed (< 1 m/s); mean daily concentration of PM10 is lower in both sites when the wind comes from the fourth quadrant ( °); good air quality events in Naples occurr when a ciclonic circulation is present over the Ionio Sea, while poor air quality events occurr when a ridge is formed over central- western Mediterranean basin; daily ozone concentration and solar radiation show a direct relationship (ρ = 0.43). Critical level of O3 concentration are often exceeded when solar radiation is above 250 W/m 2.

11 References Bercowicz, R., Palmgren, F., Hertel, O., Vignati, E. (1996), Using measurements of air pollution in streets for evaluation of urban air quality – meteorological analysis and model calculations, The Science of Total Environment, vol. 189/190, pp Katsoulis, B.D. (1996), The relationship between synoptic, mesoscale and microscale meteorological parameters during poor air quality events in Athens, Greece, The Science of the Total Environment, vol. 181, pp Oke, T.R. (1987), Boundary layer climates, 2 nd edn. Methuen, London. Silva Junior, R. S. da, Oliveira, M. G. L. de, Andrade, M. de F. (2009), Weekend/weekday differences in concentrations of ozone, nox, and non-methane hydrocarbon in the metropolitan area of São Paulo. Rev. bras. Meteorol, vol.24, n.1, pp


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