Variability of Atmospheric Aerosol and Ozone Concentrations at Marine, Urban, and High-Altitude Monitoring Stations in Southern Italy during the 2007 Summer Saharan Dust Outbreaks and Wildfire Episodes

Figures & data

Figure 1. Monitoring site locations: suburban background (SB), urban background (UB), and rural background (RB) sites.

Table 1. Coordinates and monitoring station classification for each sampling site

Site	Town	Altitude (m a.s.l.)	Latitude	Longitude	Monitoring Station Classification*
SB	San Lucido	49	39° 19′ 22″	16° 02′ 44″	Suburban background
UB	Rende	250	39° 20′ 0″	16° 11′ 0″	Urban background
RB	Longobucco	1379	39° 23′ 39″	16° 36′ 49″	Rural background
Note: *According to Decision 2001/752/CE.

Figure 2. Time evolution of PM₁₀ levels recorded at (a) SB, (b) UB, and (c) RB sites.

Table 2. Descriptive statistics for ozone levels

	O3 (ppb)
	Max 24 hr	Mean 24 hr	SD 24 hr	Max 1 hr	Max 8 hr
SB	—	—	—	—	—
UB	57.5	43.8	6.8	82.3	71.2
RB	63.6	50.9	6.2	82.9	80.4

Figure 3. Trajectory and mixed layer altitudes along the path followed by backward trajectory before their arrival at (a) SB, (b) UB, and (c) RB sites, respectively, on 30 August.

Figure 4. Time series of PM₁₀ (µg m⁻³) and O₃ (ppb) levels (left panels) and of T (°C) and RH (%) values (right panels) for (a, b) SB, (c, d) UB, and (e, f) RB sites, respectively. Grey bars highlight the identified SDO periods.

Table 3. Comparison of PM₁₀, O₃, T, and RH explorative statistic values recorded during days with and without SDO

	During SDO			Without SDO
	Min	Max	Mean	Min	Max	Mean	Δ%
PM10 (μg m^−3)
SB	29.0	134.0	69.8	11.8	64.6	29.6	135.5%
UB	42.9	99.3	66.9	1.1	45.6	25.0	167.4%
RB	29.6	86.4	55.1	8.6	86.4	27.0	103.6%
Firmo	28.6	57.6	41.8	6.3	35.5	16.7	151.1%
Saracena	14.1	33.4	25.6	1.5	21.6	9.5	170.1%
O3 (ppb)
SB	—	—	—	—'	—	—	—
UB	23.0	51.5	36.9	37.0	57.5	44.8	−17.7%
RB	37.9	54.4	44.4	35.1	63.6	51.5	−13.9%
Firmo	33.4	51.3	42.0	37.5	58.3	45.8	−7.5%
Saracena	38.7	55.2	46.0	37.9	62.7	97.8	−5.9%
T (°C)
SB	26.0	31.3	28.5	23.0	26.4	24.8	14.9%
UB	29.0	33.8	30.8	21.9	30.7	25.9	19.0%
RB	19.8	22.9	21.6	11.9	23.0	16.7	28.9%
RH (%)
SB	32.5	72.9	51.9	36.5	70.2	60.3	−13.9%
UB	20.7	44.6	32.9	30.9	59.8	47.2	−30.3%
RB	32.4	40.2	36.1	38.4	77.1	57.1	−36.8%
Note: Percent variation (Δ%) between mean values calculated over days with and without SDO is also reported.

Figure 5. Time series of PM₁₀ and O₃ levels recorded at (a) Firmo and (b) Saracena rural sites.

Figure 6. Daily total hotspot fires (HSFs) over Cosenza province (Calabria region), from the MODIS Rapid Response System-Web Fire Mapper (http://maps.geog.umd.edu). Dots represent the number of hotspot fires singularly affecting our sampling sites.

Figure 7. Cluster analysis based on the prevailing air mass trajectories and paths. Average values for PM₁₀, O₃, T, and RH over each kind of influence (left panels) and occurrence frequencies of the identified air mass classes (right panels) are reported for (a, b) SB, (c, d) UB, and (e, f) RB sites, respectively.

Figure 8. Quantification of the net African dust load at (a) SB, (b) UB, and (c) RB sites. Left panels report time series of PM₁₀ concentrations, with the black bars indicating the absolute dust load calculated for days with SDO influence. Absolute and percent values of number of exceedances are showed on the right panels with and without Saharan dust contribution.