Papers
Roadside measurements of fine and ultrafine particles at a major road north of Gothenburg
Atmospheric Environment, Vol 36, Issue 25, Pages 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.
LikeVertical distribution of air pollutants at the Gustavii Cathedral in Göteborg, Sweden
Atmospheric Environment, Vol 37, Issue 2, Pages 209-217
Atmospheric trace gases and particles were measured at two heights at the Gustavii Cathedral in Göteborg, Sweden, during 7 weeks in September and October 1999. The Gustavii Cathedral is situated in the city centre of Göteborg, which is near the harbour area and encircled by heavy traffic some hundred metres away. The main body of the church is as high as the surrounding buildings, while the tower extends well above. The sampling points were placed on the west wall of the tower at 10 and 32 m height, i.e. well below and above the roof top level of surrounding buildings, respectively.
Sulphur dioxide and nitric acid were sampled using the denuder technique and analysed by Ion Chromatography, IC. Total suspended particulates (TSP) were sampled using filter cups and subsequently analysed by energy dispersive X-ray fluorescence spectroscopy (EDXRF). In addition to the diurnal sampling of species, nitrogen oxides were measured using chemiluminescence detectors. Additional data from the Environmental Office in Göteborg was used in the analysis.
Differences between the concentrations measured at the upper and lower levels were calculated and their variation and dependence on meteorological factors were evaluated. On the average larger concentrations were found at the lower level for soil derived elements and TSP, while nitric acid and nitric oxide showed larger concentrations at the upper level. Sulphur dioxide and nitrogen dioxide, as well as many of the elements in the TSP, showed equal concentrations at the two levels. However, depending on wind direction the measured differences of nitrogen oxides could be both positive and negative.
Size resolved traffic emission factors of submicrometer particles
Atmospheric Environment, Vol 38, Issue 26, Pages 4331-4340
Size resolved emission factors for submicrometer particles related to trace gases have been obtained from measurement data at a suburban road side, with a traffic intensity of 18,000 vehicles per day. Number of particles with diameter 10–368 nm, trace gases (NO, NOx,O3 and SO2), traffic and meteorology parameters were measured outside of Göteborg, Sweden. Size distributions of small particles at the site are presented and their relation to meteorological and traffic related variables was evaluated. Wind speed correlated negatively with 10–368 nm particles and temperature correlated negatively with the smaller particles (10–60 nm). Nitric oxide was shown to be a better tracer for traffic related ultrafine particles, than traffic intensity itself.
The calculated emission factor, with errors at 95% confidence level, for particles in the range 10–368 nm is presented in relation to nitrogen oxides. The emission factors were 268±60 and 176±37 particles cm−3 per ppb NO and NOx, respectively. The particle emission factors for 10–100, 10–50, 50–170 and 170–368 nm were 260±70, 228±52, 41±11 and <1 particle cm−3 per ppb NO, respectively. The size distribution of the emissions is given by number of particles normalised by the width of the size bin, i.e. in units of dNd log Dp−1 ppb−1. The maximum normalised emission factor was 450 cm−3 per ppb NO for 20 nm particles. The shape of the size distribution of emissions revealed one sharp peak at 20 nm, with a small shoulder at 70 nm.
Domestic wood burning and PM2.5 trace elements: Personal exposures, indoor and outdoor levels
Atmospheric Environment, Vol 39, Issue 14, Pages 2643-2653
Personal exposures as well as indoor and outdoor levels of PM2.5 were measured with cyclones and impactors simultaneously in the winter of 2003 in a residential area where wood burning for domestic space heating is common. Twenty-four-hour samples from both wood-burning households (“wood burners”) and a reference group were analysed for mass and elemental concentration using energy dispersive X-ray fluorescence (EDXRF) and for black smoke (BS) concentration using an EEL 43 reflectometer. Wood-smoke particles made statistically significant contributions of K, Ca, and Zn for both personal exposure and indoor concentration, the median levels of these elements being 66–80% higher for the wood-burning group. In addition, Cl, Mn, Cu, Rb, and Pb were found to be possible markers of wood smoke, though levels of these were only significantly higher among the wood-burning group for either personal exposure or indoor concentrations. PM2.5 mass and S levels were not significantly elevated in wood burners, probably due to large variations in outdoor concentrations from long-distance transported air pollution. Personal exposure and indoor levels showed high correlations for all species, and the personal exposure levels were usually higher than or equal to the indoor levels. The associations between personal exposure and outdoor levels were generally weak except for outdoor S and PM2.5 levels that were both highly correlated with personal S exposure levels (rs>0.8).
Personal exposures and indoor, residential outdoor, and urban background levels of fine particle trace elements in the general population
J. Environmental Monitoring, 2006, Vol 8, Issue 5, 543 - 551
Personal exposures and indoor, residential outdoor, and urban background levels of PM2.5 and PM1 were measured simultaneously in Göteborg, Sweden. A total of 270 24 hour samples from 30 subjects were analyzed for elemental concentrations using X-ray fluorescence (XRF) spectroscopy. Personal exposures to PM2.5 were significantly higher for Cl, Ca, Ti, and Fe compared with the other locations. For most elements, residential outdoor levels were significantly higher than urban background levels. Correlations between personal exposure and stationary measurements were moderate to high for Zn, Br, and Pb (rs= 0.47–0.81), while Ca and Cu showed low correlations. The penetration indoors from outdoors was 0.7, as calculated from S and Pb ratios. For the pairs of parallel PM1 and PM2.5 measurements, only Ca and Fe levels were significantly lower for PM1 at all sites. Significant correlations were found between urban background mass concentrations and personal exposure levels for elements attributed to combustion processes (S, V, and Pb) and resuspended dust (Ti, Fe, and Zn), indicating that both sources could be relevant to health effects related to urban background mass. Air mass origin strongly affected the measured urban background concentrations of some elements (S, Cl, V, Ni, Br, and Pb). These findings were also seen for personal exposure (S, Cl, V, and Pb) and indoor levels (S, Cl, V, Ni, and Pb). No differences were seen for crustal elements. Air mass origin should be taken into account in the description and interpretation of time series studies of air pollution and health.
Experimental wood smoke exposure in humans
Inhalation Toxicology 2006, Vol. 18, No. 11, Pages 855-864
Experimental studies are used to evaluate effects of human exposure to diesel exhaust and concentrated ambient particles. This article describes a system for studying exposure of humans to wood smoke. Wood smoke was generated using a wood stove placed outside an exposure chamber that can hold at least 10 subjects. A partial flow of the generated wood smoke from the stove was mixed with filtered indoor air. Personal and stationary measurements were performed of PM2.5 and PM1 mass concentrations and various volatile organic compounds (VOCs): 1,3-butadiene, benzene, and aldehydes. In addition, particulate matter ( PM) mass, number concentrations, and size distributions of particles (0.007 - 6.7 mu m), as well as nitrous oxides, CO2, and CO, were measured online. Filters were analyzed for trace elements and black smoke. Polycyclic aromatic compounds, toluene, and xylenes were determined in stationary samples. Results of the first experiment showed no differences between personal and stationary measurements for particles or VOCs. Consequently, stationary measurements can be used to predict personal exposure. All PM mass ( about 250 mu g/m(3)) was in the PM1 fraction. Subjective symptoms were generally weak, while clear objective signs were found, for example, in biomarkers of inflammation. With careful control of the combustion process, relatively constant mass and number concentrations were obtained over each exposure session. By varying the combustion and dilution of the wood smoke, different exposure scenarios can be achieved and thus, knowledge about which of the properties of particles and gaseous compounds are crucial for the effects.
Indoor and outdoor concentrations of PM2.5 trace elements at homes, preschools and schools in Stockholm, Sweden
J. Environmental Monitoring, 2007, Vol 9, Issue 4, 348 - 357
Fine particles (PM2.5) were sampled indoors and outdoors at 40 sampling sites; in ten classrooms in five schools, at ten preschools and 20 non-smoking homes, in three communities in Stockholm, Sweden, during nine 2-week periods. Each sampling site was sampled twice, once during winter and once during spring. The samples were analysed for elemental concentrations using X-ray fluorescence (XRF) spectroscopy. In all locations significantly higher outdoor concentrations were found for elements that are related to long-range transported air masses (S, Ni, Br and Pb), while only Ti was higher indoors in all locations. Similar differences for S, Br and Pb were found in both seasons for homes and schools. In preschools different seasonal patterns were seen for the long-range transported elements S, Br and Pb and the crustal elements Ti, Mn and Fe. The indoor/outdoor ratios for S and Pb suggest an outdoor PM2.5 particle net infiltration of about 0.6 in these buildings. The community located 25 km from the city centre had significantly lower outdoor concentrations of elements of crustal or traffic origin compared with the two central communities, but had similar levels of long-range transported elements. Significant correlations were found between PM2.5 and most elements outdoors (rs = 0.45–0.90). Copper levels were found to correlate well (rs = 0.64–0.91) to the traffic marker NO2 during both winter and spring in all locations. Copper may be a suitable elemental marker for traffic-related aerosols in health studies in areas without other significant outdoor Cu sources.
Exposure to fine particles (PM2.5 and PM1) and black smoke in the general population: personal, indoor, and outdoor levels
Journal of Exposure Science and Environmental Epidemiology, Vol, 17 Issue 7, Page 613 -624
Personal exposure to PM2.5 and PM1, together with indoor and residential outdoor levels, was measured in the general adult population (30 subjects, 23-51 years of age) of Gothenburg, Sweden. Simultaneously, urban background concentrations of PM2.5 were monitored with an EPA WINS impactor. The 24-h samples were gravimetrically analyzed for mass concentration and black smoke (BS) using a smokestain reflectometer. Median levels of PM2.5 were 8.4 mu g/m(3) (personal), 8.6 mu g/m(3) (indoor), 6.4 mu g/m(3) (residential outdoor), and 5.6 mu g/m(3) (urban background). Personal exposure to PM1 was 5.4 mu g/m(3), while PM1 indoor and outdoor levels were 6.2 and 5.2 mu g/m(3), respectively. In non-smokers, personal exposure to PM2.5 was significantly higher than were residential outdoor levels. BS absorption coefficients were fairly similar for all microenvironments (0.4-0.5 10(-5) m(-1)). Personal exposure to particulate matter ( PM) and BS was well correlated with indoor levels, and there was an acceptable agreement between personal exposure and urban background concentrations for PM2.5 and BS2.5 (r(s) = 0.61 and 0.65, respectively). PM1 made up a considerable amount (70-80%) of PM2.5 in all microenvironments. Levels of BS were higher outdoors than indoors and higher during the fall compared with spring. The correlations between particle mass and BS for both PM2.5 vs. BS2.5 and PM1 versus BS1 were weak for all microenvironments including personal exposure. The urban background station provided a good estimate of residential outdoor levels of PM2.5 and BS2.5 within the city (r(s) = 0.90 and 0.77, respectively). Outdoor levels were considerably affected by long-range transported air pollution, which was not found for personal exposure or indoor levels. The within-individual ( day-today) variability dominated for personal exposure to both PM2.5 and BS2.5 in non-smokers.
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