Atmospheric Environment (v.36, #25)

The presence of polybrominated diphenyl ether (PBDE) flame retardants in total deposition (wet+dry) was assessed with the simultaneous use of three bulk samplers during a 2 week period. The particle associated and the ‘dissolved’ phase were separated during sampling. Volume weighted mean (VWM) concentrations of ∑PBDE (9 congeners) in rain were 209 pg l−1. Total deposition rates were 2±1 ng ∑PBDE m−2  day−1. The total PBDE deposition was dominated by decaBDE(209) and thereafter 2,2′4,4′-tetraBDE(47) and 2,2′4,4′,5-pentaBDE(99). Concentrations of particle associated and ‘dissolved’ PBDEs in total deposition were used to calculate filter/adsorbent ratios (F/A). We found that 65±18% of the total PBDEs were particle associated. Low F/A ratios for higher brominated congeners (Br>5) were observed. This is contradictory with predictions based on the PBDEs’ physico-chemical properties and was attributed to sampling artefacts, such as particle size distribution, and/or non-equilibrium processes. There was a negative relationship between the particulate ∑PBDE concentration and rain volume suggesting a dilution effect and the importance of particle scavenging for wet deposition of PBDEs.
Keywords: PBDE; Deposition bulk; Deposition rates; Partitioning; Model;

Gas–particle concentrations and distribution of aliphatic hydrocarbons, PAHs, PCBs and PCDD/Fs in the atmosphere of Athens (Greece) by Manolis Mandalakis; Manolis Tsapakis; Athanasia Tsoga; Euripides G Stephanou (4023-4035).
Air samples were collected at the urban center, a background site, and the adjacent coastal area of the metropolitan area of Athens during July 2000. Gas and particle phase concentrations of aliphatic hydrocarbons, α,β-hopanes, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were identified and measured. Total concentrations of aliphatic hydrocarbons, ranged between 943.0 ng m−3 (urban site) and 947.1 ng m−3 (coastal area) in the gas and from 141.8 ng m−3 (coastal site) up to 469.0 ng m−3 (urban center) in the particulate phase. The total concentration of α,β-hopanes (12 homologues) in the urban area was ca. 0.2 ng m−3 in the gas and 1.0 ng m−3 in the particulate phase. Total PAH concentrations (∑PAHs of 20 members) ranged from 3.5 ng m−3 (background site) to 26.0 ng m−3 (urban center) in the gas and from 1.3 ng m−3 (coastal area) up to 5.0 ng m−3 (urban center) in the particulate phase. The total concentration of PCBs (∑PCBs of 38 congeners) in the gas plus the particulate phase of the atmosphere ranged from 80.5 pg m−3 (background site) up to 348.6 pg m−3 (urban center) and the corresponding concentration of PCDD/Fs ranged from 166.6 fg m−3 (background site) up to 701.5 fg m−3 (urban center), respectively. Gas–particle partition coefficients K p of n-alkanes, PAHs, PCBs and PCDD/Fs were well correlated (R 2=0.50–0.99) with the sub-cooled liquid vapor pressure P L o . The average slopes m r of log  K p versus log P L o for n-alkanes (−0.46) and PCBs (−0.44) were low compared to other urban areas. The corresponding m r values for PAHs (−0.57), PCDDs (−0.78) and PCDFs (−0.75) are comparable to those obtained in other urban areas.
Keywords: Ambient concentrations; Gas–particle partitioning; Aliphatic hydrocarbons; α,β-hopanes; PAHs; PCBs; PCDDs; PCDFs;

Mid-nineteenth century smoke concentrations near London by R.G Harrison; K.L Aplin (4037-4043).
Measurements of atmospheric electricity began at Kew Observatory, London (51°28′N, 0°19′W) in 1843, with recording apparatus installed by Lord Kelvin in 1861. The measured electric potential gradient (PG) at Kew has always been influenced by smoke pollution, causing a December PG maximum and July minimum. Theory links PG variations with aerosol concentrations, and the 20th century smoke measurements made at Kew permit smoke concentrations to be retrieved from 19th century PG data. Absolute calibration of the 1862–1864 PG is achieved by considering changes in the global electric circuit, for which the geomagnetic aa-index is used as a proxy. The mean annual PG in 1863 is estimated as 363±29 V m−1, and the mean smoke concentration found is 0.17±0.05 mg m−3. Diurnal variations in smoke pollution differ between the seasons, and change in their character after the advent of motor traffic.
Keywords: Aerosol pollution; Atmospheric electricity; Historical measurements; Solar variability;

The regional distribution of ozone across the British Isles and its response to control strategies by S.E Metcalfe; J.D Whyatt; R.G Derwent; M O’Donoghue (4045-4055).
The spatial pattern of summertime ozone concentrations across the British Isles has been revealed using a simple long-range transport model (ELMO). The model describes the chemical development of air parcels reaching an array of 3064 arrival points after 4 days of travel across Europe during typical summertime photochemical episodic conditions. Model results have been compared against observations and the model responses to VOC and NO x controls against established indicator ratios. The model has been used to assess the likely impacts of policy commitments under the Gothenburg Protocol to the United Nations Convention on Long-Range Transboundary Air Pollution and other policy instruments.
Keywords: Ozone pollution climate; VOC control; NO x control; Long-range transport model;

Measurements and modelling of PM2.5 concentrations near a major road in Kuopio, Finland by Petri Tiitta; Taisto Raunemaa; Jarkko Tissari; Tarja Yli-Tuomi; Ari Leskinen; Jaakko Kukkonen; Jari Härkönen; Ari Karppinen (4057-4068).
A particle measurement campaign was conducted in a suburban environment near a major road in Kuopio, Central Finland from 3 August to 9 September 1999. The mass concentrations of fine particles (PM2.5) were measured simultaneously at distances of 12, 25, 52 and 87 m from the centre of a major road at a height of 1.8 m, using identical samplers. The concentration measurements were conducted during 16 daytime hours (from 6.00 a.m. to 10.00 p.m.) for 27 days. Traffic flows and relevant meteorological parameters were measured on-site; meteorological measurements from a nearby synoptic weather station were also utilised. We also suggest a preliminary model for predicting the concentrations of PM2.5 and apply this model in order to analyse the measured data. The regionally and long-range transported contribution was evaluated on the basis of a semi-empirical mathematical model utilising as input values the daily sulphate, nitrate and ammonium measurements at the EMEP stations (Co-operative programme for monitoring and evaluation of the long-range transmission of air pollutants in Europe). The influence of primary vehicular emissions from the nearest roads was evaluated using a roadside emission and dispersion model, CAR-FMI, in combination with a meteorological pre-processing model, MPP-FMI. The contribution of non-exhaust particulate matter emissions (including resuspension of particulate matter from road surfaces) was estimated simply to be directly proportional to the concentrations originating from primary vehicular emissions. Comparison of the predicted results and measurements yields information on the relative importance of various source categories of the measured concentrations of PM2.5. The regionally and long-range transported contribution, the primary and non-exhaust vehicular emissions, and other sources were estimated to contribute on average 41±6%, 33±6% and 26±7% of the observed PM2.5 concentrations, respectively. The model presented could also be applied in other European cities for analysing the source contributions to measured fine particulate matter concentrations.
Keywords: Fine particulate matter; Vehicular pollution; Dispersion model; Measurement campaign; Roadside;

Use of moss (Tortula muralis Hedw.) for monitoring organic and inorganic air pollution in urban and rural sites in Northern Italy by Renato Gerdol; Luca Bragazza; Roberta Marchesini; Alessandro Medici; Paola Pedrini; Stefano Benedetti; Alessandro Bovolenta; Simona Coppi (4069-4075).
Concentrations of polycyclic aromatic hydrocarbons (PAHs) and trace metals, as well as stable nitrogen (N) isotope composition, were determined in moss tissues from an urban area and from rural sites in northern Italy. The total PAH contents were higher in the urban area. The percentage fraction of low molecular weight volatile PAHs on total PAHs was greater in rural sites. The mean concentration ratio (urban:rural) was, overall, much lower for trace metals than for PAHs. Among metals, only Pb levels were highest in the city center, and were, in turn, associated with a more positive δ15N signature in moss tissue. This indicates that exposure to slow-moving traffic in the city center resulted both in higher Pb deposition and a greater contribution of NO x , compared with NH x , in atmospheric N pollution. Most metals (namely Cd, Cr, Fe, Ni, V and Zn) were moderately enriched in moss tissues from the urban area, especially in the sectors downwind from the main emission sources. In contrast, Co and Cu contents in the urban area did not differ from those in rural sites. We concluded that organic (PAH) and inorganic (metal) pollution showed varying patterns which reflected differences as regards both emission sources and atmospheric transport pathways. Atmospheric deposition of PAHs peaked in close vicinity to urban emission sources. Conversely, the atmospheric deposition of metals, except Pb, was more diffuse over the territory.
Keywords: Atmospheric deposition; Biomonitoring; Metals; 15N; Nitrogen isotopes; PAH;

Spatial variability of fine particle concentrations in three European areas by Gerard Hoek; Kees Meliefste; Josef Cyrys; Marie Lewné; Tom Bellander; Mike Brauer; Paul Fischer; Ulrike Gehring; Joachim Heinrich; Patricia van Vliet; Bert Brunekreef (4077-4088).
Epidemiological studies of long-term air pollution effects have been hampered by difficulties in characterizing the spatial variation in air pollution. We conducted a study to assess the risk of long-term exposure to traffic-related air pollution for the development of inhalant allergy and asthma in children in Stockholm county, Munich and the Netherlands. Exposure to traffic-related air pollution was assessed through a 1-year monitoring program and regression modeling using exposure indicators. This paper documents the performance of the exposure monitoring strategy and the spatial variation of ambient particle concentrations.We measured the ambient concentration of PM2.5 and the reflectance of PM2.5 filters (‘soot’) at 40–42 sites representative of different exposure conditions of the three study populations. Each site was measured during four 14-day average sampling periods spread over one year (spring 1999 to summer 2000). In each study area, a continuous measurement site was operated to remove potential bias due to temporal variation.The selected approach was an efficient method to characterize spatial differences in annual average concentration between a large number of sites in each study area. Adjustment with data from the continuous measurement site improved the precision of the calculated annual averages, especially for PM2.5. Annual average PM2.5 concentrations ranged from 11 to 20 μg/m3 in Munich, from 8 to 16 μg/m3 in Stockholm and from 14 to 26 μg/m3 in the Netherlands. Larger spatial contrasts were found for the absorption coefficient of PM2.5. PM2.5 concentrations were on average 17–18% higher at traffic sites than at urban background sites, but PM2.5 absorption coefficients at traffic sites were between 31% and 55% increased above background. This suggests that spatial variation of traffic-related air pollution may be underestimated if PM2.5 only is measured.
Keywords: PM2.5; Diesel; Soot; Traffic; Exposure;

Statistically significant downward trends in measured UK annual mean PM10 concentrations have been observed at eight out of the nine urban background monitoring sites between the start of monitoring in 1992 or 1993 and 2000.Site-specific projections of the individual components of measured PM10 concentrations have been derived for the period 1992–2000 at three monitoring sites from receptor modelling results for 1999 monitoring data. Measured annual average PM10 concentrations declined to between 71% and 66% of the 1992 values during this period at the sites studied. The largest contributions to the decline in total PM10 are from secondary particles at London Bloomsbury (40%, 3.4 μg m−3, tapered element oscillating microbalance (TEOM)), stationary sources at Belfast Centre (53%, 4.6 μg m−3, TEOM) and roadside traffic emissions at Bury Roadside (49%, 5.0 μg m−3, TEOM). The good agreement between the projected total PM10 concentrations and measured values for the years 1992–2000 indicate that the combination of the receptor model and the site-specific projections provide a suitably robust method for predicting future PM10 concentrations and the quantification of the impact of possible future policy measures to reduce PM10 concentrations. The good agreement between the projections and measured concentration also provides a useful verification of the trends in emissions inventory estimates for the 1990s.Projections of estimated PM10 concentrations have also been calculated for the London Bloomsbury site for the period from 1970 to 1991. Annual mean concentrations are predicted to have been in the range from 30 to 35 μg m−3, TEOM from 1977 to 1991 but much higher at values between 39 and 46 μg m−3, TEOM in the early 1970s.
Keywords: PM10; Trends; Source apportionment; National air emission inventory;

Characterisation of particulate matter in the Royal Museum of Fine Arts, Antwerp, Belgium by Kristin Gysels; Felix Deutsch; René Van Grieken (4103-4113).
Aerosol samples were collected during two campaigns in February and July 1999 both inside and outside the Koninklijk Museum voor Schone Kunsten (KMSK, Royal Museum of Fine Arts) in Antwerp. Bulk aerosol concentrations, as well as the composition of the individual particles, were determined. The influence of the outdoor aerosol was clearly visible. In winter, restoration and construction works constituted an additional indoor source of Ca-rich and Ca–Si particles. Along with sea salt, these were the main particle types identified in this season. In summer, S-rich particles were most frequent. The summer abundances of Ca-rich particles remained low, even though the museum is situated in a limestone building. Moreover, dry deposition samples were collected in order to determine what amount of particles could actually be deposited onto the works of art.
Keywords: Aerosol particles; Conservation; Indoor air quality; Museum;

Roadside measurements of fine and ultrafine particles at a major road north of Gothenburg by Peter Molnár; Sara Janhäll; Mattias Hallquist (4115-4123).
Particle measurements were conducted at a road site 15 km north of the city of Gothenburg for 3 weeks in June 2000. The size distribution between 10 and 368 nm was measured continuously by using a differential mobility particle sizer (DMPS) system. PM2.5 was sampled on a daily basis with subsequent elemental analysis using EDXRF-spectroscopy. The road is a straight four-lane road with a speed limit of 90 kph. The road passing the site is flat with no elevations where the vehicles run on a steady workload and with constant speed. The traffic intensity is about 20,000 cars per workday and 13,000 vehicles per day during weekends. The diesel fuel used in Sweden is low in sulphur content (<10 ppm) and therefore the diesel vehicles passing the site contribute less to particle emissions in comparison with other studies. A correlation between PM2.5 and accumulation mode particles (100–368 nm) was observed. However, no significant correlation was found between number concentrations of ultrafine particles (10–100 nm) and PM2.5 or the accumulation mode number concentration. The particle distribution between 10 and 368 nm showed great dependency on wind speed and wind direction, where the wind speed was the dominant factor for ultrafine (10–100 nm) particle concentrations. The difference in traffic intensity between workday and weekend together with wind data made it possible to single out the traffic contribution to particle emissions and measure the size distribution. The results presented in combination with previous studies show that both PM2.5 and the mass of accumulation mode particles are bad estimates for ultrafine particles.
Keywords: Traffic emissions; Ultrafine particles; Sulphur; PM2.5; Size distribution; DMPS;

In the present work, a box model is applied to estimate the direct climate forcing of aerosol particles for rural air in Central Europe during summertime. In the model, the input parameters reflect regional character: data from satellite observations and other surface measurements are used referring to the selected area, Hungary. In the calculation of direct climate forcing of aerosol particles satellite observations serve as the source of incoming solar radiation intensity data and cloudiness, while different aerosol parameters of the model (mass extinction coefficient, chemical composition, scale height, hygroscopic growth factor, etc.) are based on local measurements. Finally, surface albedo of the area studied was determined on the basis of vegetation cover and precipitation amount. As the summary of our calculations, in Central Europe direct climate forcing of ammonium sulfate is equal to –2.4 W m−2. The climate forcing of total carbon is composed of two terms. The forcings due to scattering and absorption are –1.0 and +0.2 W m−2, respectively. In spite of the fact that the mass concentrations of ammonium sulfate and total carbon are similar, their contribution to the aerosol direct forcing is different. We conclude that ammonium sulfate plays the major role in this process and organics have an additional impact.
Keywords: Box model; Regional direct climate forcing; Central Europe; Ammonium sulfate and carbonaceous particles;

Estonia is an example of a country with economy in transition whose atmospheric air pollution has been remarkably influenced by economic changes. During the period of 1994–1999 GDP increased by one-fourth, while agricultural production, electricity and heat production dropped by one-sixths during the studied period. These processes are reflected in the quantity of emissions and structure of air pollution.The study is based on the measurements of concentrations of pollutants at six Estonian Euroairnet monitoring stations—at three sites in the capital city and at three sites in remote areas. The pollutants concerned are the first-priority pollutants in the European Union legislation—nitrogen oxides, SO2, O3, particulate matter, and additionally CO.The study reveals that concentrations of gaseous pollutants in Estonia remain within the EU limit values except for ozone in remote areas. The main trend during the studied period was a significant, up to several times, decrease in concentrations of SO2 and CO while the decrease of nitrogen oxides was less remarkable. The paper propose ratio of NO x /SO2 as an index describing increasing transport loads and drop in use of sulphur-rich fuels—thus of structure of economy. The annual variation of pollutants is explained by seasonal variations of anthropogenic activity in conditions where local fuels are widely used for heating during winter.Air pollution in Estonian rural stations mostly originated from transboundary fluxes. The 1–3 day delay of the weekly minimum of pollutant concentrations and the wind roses allow to conclude that essential part of pollutants is imported from West Europe.
Keywords: Air pollution; Air quality; Monitoring; Estonia; Economic change;

Trends of Hungarian air pollution levels on a long time-scale by Ágnes Havasi; Zahari Zlatev (4145-4156).
Hungarian air pollution levels are studied by using the Danish Eulerian Model. The air pollution levels under consideration include (i) concentrations of SO2, NO2, NH3 and O3 and (ii) four quantities related to critical ozone levels (accumulated exposure over threshold of 40  ppb values for crops and forests, the number of days when 8-h rolling averages of ozone concentrations exceed 60  ppb , and averaged over a given period daily maxima of the ozone concentrations). Setting all the Hungarian emissions to zero, we estimate the contributions from the SO2, NO x , VOC and NH3 emissions in the other European countries to the Hungarian pollution levels. An attempt to evaluate the Hungarian pollution levels for year 2010 is made under the assumption that the European emissions will, in general, be reduced considerably before year 2010.
Keywords: Air pollution; Large-scale models; Danish Eulerian Model; Emission reductions; Prediction of future pollution levels;

Erratum to “Development and application of a mechanistic model to estimate emission of nitrous oxide from UK agriculture” by L Brown; B Syed; S.C Jarvis; R.W Sneath; V.R Phillips; K.W.T Goulding; C Li (4157).