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Ken Donaldson - One of the best experts on this subject based on the ideXlab platform.
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increased inflammation and altered macrophage chemotactic responses caused by two Ultrafine Particle types
Occupational and Environmental Medicine, 2004Co-Authors: L C Renwick, David M Brown, Anna Clouter, Ken DonaldsonAbstract:Background: Ultrafine Particles have been hypothesised to be an important contributing factor in the toxicity and adverse health effects of particulate air pollution (PM10) and nanoParticles are used increasingly in industrial processes. Aims: To compare the ability of Ultrafine and fine Particles of titanium dioxide and carbon black to induce inflammation, cause epithelial injury, and affect the alveolar macrophage clearance functions of phagocytosis and chemotaxis in vivo. Methods: Rats were instilled with fine and Ultrafine carbon black and titanium dioxide. Inflammation was quantified by bronchoalveolar lavage; the ability of the macrophages to phagoytose indictor fluorescent beads and to migrate towards aC5a were determined. Results: Ultrafine Particles induced more PMN recruitment, epithelial damage, and cytotoxicity than their fine counterparts, exposed at equal mass. Both Ultrafine and fine Particles significantly impaired the phagocytic ability of alveolar macrophages. Only Ultrafine Particle treatment significantly enhanced the sensitivity of alveolar macrophages to chemotact towards C5a. Conclusions: Ultrafine Particles of two very different materials induced inflammation and epithelial damage to a greater extent than their fine counterparts. In general, the effect of Ultrafine carbon black was greater than Ultrafine titanium dioxide, suggesting that there are differences in the likely harmfulness of different types of Ultrafine Particle. Epithelial injury and toxicity were associated with the development of inflammation after exposure to Ultrafines. Increased sensitivity to a C5a chemotactic gradient could make the Ultrafine exposed macrophages more likely to be retained in the lungs, so allowing dose to accumulate.
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the role of free radicals in the toxic and inflammatory effects of four different Ultrafine Particle types
Inhalation Toxicology, 2003Co-Authors: Colin A J Dick, David M Brown, Ken Donaldson, Vicki StoneAbstract:PM10 contains an Ultrafine component, which is generally derived from combustion processes. This Ultrafine fraction may be a factor in the increases in exacerbations of respiratory disease and deaths from cardiorespiratory causes associated with transient increases in levels of PM10. By using four different Ultrafine Particles (carbon black, cobalt, nickel, and titanium dioxide), we set out to determine the attributes of the Ultrafine Particle (surface area, chemical composition, Particle number, or surface reactivity) that contribute most to its toxicity and proinflammatory effects both in vivo and in vitro. Instillation of 125 micro g Ultrafine carbon black (UFCB) and Ultrafine cobalt (UFCo) Particles induced a significant influx of neutrophils at both 4 and 18 h postinstillation. Accompanying the influx of neutrophils was an increase in macrophage inflammatory protein-2 (MIP-2) (at 4 h) and an increase in gamma-glutamyl transpeptidase (at 18 h) in bronchoalveolar lavage fluid (BAL). Ultrafine nickel (UFNi) did not induce a significant increase in neutrophil influx until 18 h postinstillation. The increase in neutrophils induced by UFNi at this timepoint was comparable to that induced by UFCo and UFCB. UFTi did not induce a significant increase in neutrophils following instillation into the rat lung. The levels of MIP-2 observed at 4 h and neutrophil influx at 18 h induced by the Particle samples were consistent with the pattern of surface free radical generation (as measured by the plasmid scission assay) whereby UFCo, UFCB, and UFNi all cause significant increases in inflammatory markers, as well as inducing a significant depletion of supercoiled plasmid DNA, indicative of hydroxyl radical generation. A role for free radicals and reactive oxygen species (ROS) in mediating Ultrafine inflammation is further strengthened by the ability of the antioxidants N-acetylcysteine (NAC) and glutathione monoethyl ester (GSHme) to block the Particle induced release of tumour necrosis factor-alpha (TNF-alpha) from alveolar macrophages in vitro. The Ultrafine Particles in PM10 may cause adverse effects via oxidative stress, and this could have implications for susceptible individuals. Susceptible individuals, such as those with COPD or asthma, already exhibit preexisting oxidative stress and hence are in a primed state for further oxidative stress induced by occupational or environmental Particles.
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increased inflammation and intracellular calcium caused by Ultrafine carbon black is independent of transition metals or other soluble components
Occupational and Environmental Medicine, 2000Co-Authors: David M Brown, V Stone, P Findlay, William Macnee, Ken DonaldsonAbstract:OBJECTIVES—Particulate air pollution has been shown to cause adverse health effects, and the Ultrafine Particle component has been implicated. The aim of the present study was to investigate whether an Ultrafine Particle exerted its effects through transition metals or other soluble factors released from the surface of the Particles. METHODS—Both in vitro and in vivo models were used to test the imflammogenicity of carbon black (CB) and Ultrafine carbon black (UfCB) and the role of transition metals was investigated by treating the Particles with desferrioxamine mesylate (desferal), a transition metal chelator. Rats were instilled with Particles and the cell population assessed by bronchoalveolar lavage (BAL). Calcium homeostasis in macrophages was assessed with a fluorimetric technique. RESULTS—UfCB was inflammogenic compared with CB when instilled into Wistar rat lungs, an effect which could not be ameliorated by desferal treatment of the Particles. Particle leachates produced no significant inflammation in vivo. In vitro experiments showed that the cytosolic calcium ion concentration in Mono Mac 6 cells was increased significantly after UfCB treatment and treatment of Particles with desferal did not alter these effects. Particle leachates had no effect on cytosolic calcium ion concentration. Iron was not detected in leachates of the Particles with the desferal assay, however, ng/mg of Particles were detectable in citrate leachates with inductively coupled plasma-mass spectrometry (ICP-MS). CONCLUSIONS—The increased inflammogenicity of UfCB compared with CB cannot be explained by soluble transition metals released from or by accumulation of iron at the Particle surface. Differences may be accounted for by increased surface area or Particle number. Keywords: Ultrafine; calcium; transition metals
David M Brown - One of the best experts on this subject based on the ideXlab platform.
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increased inflammation and altered macrophage chemotactic responses caused by two Ultrafine Particle types
Occupational and Environmental Medicine, 2004Co-Authors: L C Renwick, David M Brown, Anna Clouter, Ken DonaldsonAbstract:Background: Ultrafine Particles have been hypothesised to be an important contributing factor in the toxicity and adverse health effects of particulate air pollution (PM10) and nanoParticles are used increasingly in industrial processes. Aims: To compare the ability of Ultrafine and fine Particles of titanium dioxide and carbon black to induce inflammation, cause epithelial injury, and affect the alveolar macrophage clearance functions of phagocytosis and chemotaxis in vivo. Methods: Rats were instilled with fine and Ultrafine carbon black and titanium dioxide. Inflammation was quantified by bronchoalveolar lavage; the ability of the macrophages to phagoytose indictor fluorescent beads and to migrate towards aC5a were determined. Results: Ultrafine Particles induced more PMN recruitment, epithelial damage, and cytotoxicity than their fine counterparts, exposed at equal mass. Both Ultrafine and fine Particles significantly impaired the phagocytic ability of alveolar macrophages. Only Ultrafine Particle treatment significantly enhanced the sensitivity of alveolar macrophages to chemotact towards C5a. Conclusions: Ultrafine Particles of two very different materials induced inflammation and epithelial damage to a greater extent than their fine counterparts. In general, the effect of Ultrafine carbon black was greater than Ultrafine titanium dioxide, suggesting that there are differences in the likely harmfulness of different types of Ultrafine Particle. Epithelial injury and toxicity were associated with the development of inflammation after exposure to Ultrafines. Increased sensitivity to a C5a chemotactic gradient could make the Ultrafine exposed macrophages more likely to be retained in the lungs, so allowing dose to accumulate.
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the role of free radicals in the toxic and inflammatory effects of four different Ultrafine Particle types
Inhalation Toxicology, 2003Co-Authors: Colin A J Dick, David M Brown, Ken Donaldson, Vicki StoneAbstract:PM10 contains an Ultrafine component, which is generally derived from combustion processes. This Ultrafine fraction may be a factor in the increases in exacerbations of respiratory disease and deaths from cardiorespiratory causes associated with transient increases in levels of PM10. By using four different Ultrafine Particles (carbon black, cobalt, nickel, and titanium dioxide), we set out to determine the attributes of the Ultrafine Particle (surface area, chemical composition, Particle number, or surface reactivity) that contribute most to its toxicity and proinflammatory effects both in vivo and in vitro. Instillation of 125 micro g Ultrafine carbon black (UFCB) and Ultrafine cobalt (UFCo) Particles induced a significant influx of neutrophils at both 4 and 18 h postinstillation. Accompanying the influx of neutrophils was an increase in macrophage inflammatory protein-2 (MIP-2) (at 4 h) and an increase in gamma-glutamyl transpeptidase (at 18 h) in bronchoalveolar lavage fluid (BAL). Ultrafine nickel (UFNi) did not induce a significant increase in neutrophil influx until 18 h postinstillation. The increase in neutrophils induced by UFNi at this timepoint was comparable to that induced by UFCo and UFCB. UFTi did not induce a significant increase in neutrophils following instillation into the rat lung. The levels of MIP-2 observed at 4 h and neutrophil influx at 18 h induced by the Particle samples were consistent with the pattern of surface free radical generation (as measured by the plasmid scission assay) whereby UFCo, UFCB, and UFNi all cause significant increases in inflammatory markers, as well as inducing a significant depletion of supercoiled plasmid DNA, indicative of hydroxyl radical generation. A role for free radicals and reactive oxygen species (ROS) in mediating Ultrafine inflammation is further strengthened by the ability of the antioxidants N-acetylcysteine (NAC) and glutathione monoethyl ester (GSHme) to block the Particle induced release of tumour necrosis factor-alpha (TNF-alpha) from alveolar macrophages in vitro. The Ultrafine Particles in PM10 may cause adverse effects via oxidative stress, and this could have implications for susceptible individuals. Susceptible individuals, such as those with COPD or asthma, already exhibit preexisting oxidative stress and hence are in a primed state for further oxidative stress induced by occupational or environmental Particles.
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increased inflammation and intracellular calcium caused by Ultrafine carbon black is independent of transition metals or other soluble components
Occupational and Environmental Medicine, 2000Co-Authors: David M Brown, V Stone, P Findlay, William Macnee, Ken DonaldsonAbstract:OBJECTIVES—Particulate air pollution has been shown to cause adverse health effects, and the Ultrafine Particle component has been implicated. The aim of the present study was to investigate whether an Ultrafine Particle exerted its effects through transition metals or other soluble factors released from the surface of the Particles. METHODS—Both in vitro and in vivo models were used to test the imflammogenicity of carbon black (CB) and Ultrafine carbon black (UfCB) and the role of transition metals was investigated by treating the Particles with desferrioxamine mesylate (desferal), a transition metal chelator. Rats were instilled with Particles and the cell population assessed by bronchoalveolar lavage (BAL). Calcium homeostasis in macrophages was assessed with a fluorimetric technique. RESULTS—UfCB was inflammogenic compared with CB when instilled into Wistar rat lungs, an effect which could not be ameliorated by desferal treatment of the Particles. Particle leachates produced no significant inflammation in vivo. In vitro experiments showed that the cytosolic calcium ion concentration in Mono Mac 6 cells was increased significantly after UfCB treatment and treatment of Particles with desferal did not alter these effects. Particle leachates had no effect on cytosolic calcium ion concentration. Iron was not detected in leachates of the Particles with the desferal assay, however, ng/mg of Particles were detectable in citrate leachates with inductively coupled plasma-mass spectrometry (ICP-MS). CONCLUSIONS—The increased inflammogenicity of UfCB compared with CB cannot be explained by soluble transition metals released from or by accumulation of iron at the Particle surface. Differences may be accounted for by increased surface area or Particle number. Keywords: Ultrafine; calcium; transition metals
F L Eisele - One of the best experts on this subject based on the ideXlab platform.
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thermal desorption chemical ionization mass spectrometer for Ultrafine Particle chemical composition
Aerosol Science and Technology, 2003Co-Authors: Didier Voisin, F L Eisele, James N Smith, Hiromu Sakurai, Peter H McmurryAbstract:A thermal desorption chemical ionization mass spectrometer has been developed for real time, quantitative chemical analysis of Ultrafine Particles. The technique combines recently developed nanoParticle separation and collection techniques with highly sensitive chemical analysis provided by selected ion chemical ionization mass spectrometry. Sensitivity tests using laboratory-generated ammonium sulfate Particles in the diameter range 10-16 nm show that sulfate and ammonium can be quantified with as little as 1 pg of collected aerosol mass. Such sensitivity makes this instrument suitable for real time measurements of the chemical composition of sub-10 nm Particles reported recently from nucleation events.
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measurements of new Particle formation and Ultrafine Particle growth rates at a clean continental site
Journal of Geophysical Research, 1997Co-Authors: F L Eisele, Peter H Mcmurry, Rodney J Weber, James Marti, D J Tanner, A JeffersonAbstract:Simultaneous measurements of aerosol Particles and their expected gas phase precursors were made at Idaho Hill, Colorado, a remote continental site. This study used apparatus and techniques similar to those employed in an earlier study at the Mauna Loa Observatory, Hawaii [Weber et al., 1995]. New Particle formation, identified by the presence of Ultrafine Particles (nominally 3 to 4 nm diameter), was commonly observed in downslope (westerly) air and was correlated with high sulfuric acid (H2SO4) concentrations, low relative humidity and low Particle surface area concentrations. The data point to H2SO4 as a principle nucleation precursor species with typical daytime concentrations between 106 and 107 molecules cm−3. Particle production was observed at H2SO4 concentrations that are well below predicted values for binary nucleation of H2O and H2SO4, suggesting that another species participated. Particle growth rates were estimated from the data with two independent approaches and in both cases were ∼5 to 10 times higher than can be explained by condensation of H2SO4 and its associated water. This suggests that species in addition to H2S04 were also making large contributions to Ultrafine Particle growth. Finally, calculated steady-state H2SO4 concentrations were found to be in good agreement with measured values if the mass accommodation coefficient for H2SO4 on aerosol surfaces was assumed equal to ∼1.
Mark J Nieuwenhuijsen - One of the best experts on this subject based on the ideXlab platform.
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determinants of personal exposure to pm2 5 Ultrafine Particle counts and co in a transport microenvironment
Environmental Science & Technology, 2009Co-Authors: S Kaur, Mark J NieuwenhuijsenAbstract:Short-term human exposure concentrations to PM2.5, Ultrafine Particle counts (Particle range: 0.02−1 μm), and carbon monoxide (CO) were investigated at and around a street canyon intersection in Central London, UK. During a four week field campaign, groups of four volunteers collected samples at three timings (morning, lunch, and afternoon), along two different routes (a heavily trafficked route and a backstreet route) via five modes of transport (walking, cycling, bus, car, and taxi). This was followed by an investigation into the determinants of exposure using a regression technique which incorporated the site-specific traffic counts, meteorological variables (wind speed and temperature) and the mode of transport used. The analyses explained 9, 62, and 43% of the variability observed in the exposure concentrations to PM2.5, Ultrafine Particle counts, and CO in this study, respectively. The mode of transport was a statistically significant determinant of personal exposure to PM2.5, Ultrafine Particle cou...
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exposure visualisation of Ultrafine Particle counts in a transport microenvironment
Atmospheric Environment, 2006Co-Authors: S Kaur, R D R Clark, P Walsh, S J Arnold, R N Colvile, Mark J NieuwenhuijsenAbstract:Abstract An increasing number of studies indicate that short-term peak exposures, such as those seen in the transport microenvironment, pose particular health threats. Short-term exposure can only be sufficiently characterised using portable, fast-response monitoring instrumentation with detailed summaries of individual activity. In this paper, we present an exposure visualisation system that addresses this issue—it allows the simultaneous presentation of mobile video imagery synchronised with measured real-time Ultrafine Particle count exposure of an individual. The combined data can be examined in detail for the contribution of the surrounding environment and the individual's activities to their peak and overall exposure. The exposure visualisation system is demonstrated and evaluated around the DAPPLE study site in Central London using different modes of transport (walking, cycling, bus, car and taxi). The video images, synchronised with the exposure profile, highlight the extent to which Ultrafine Particle exposure is associated with traffic density and proximity to pollutant source. The extremely rapid decline in concentration with increasing distance away from the pollutant source, such as from the main street to the backstreets, is clearly evident. The visualisation technique allows these data to be presented to both technical audiences and laypersons thus making it an effective environmental risk communication tool. Some exposure peaks however are not obviously associated with any event recorded on video—in these cases it will be necessary to use advanced dispersion modelling techniques to investigate meteorological conditions and other variables influencing in-street conditions to identify their possible causes.
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personal exposure of street canyon intersection users to pm2 5 Ultrafine Particle counts and carbon monoxide in central london uk
Atmospheric Environment, 2005Co-Authors: S Kaur, Mark J Nieuwenhuijsen, R ColvileAbstract:Abstract Short-term human exposure to PM 2.5, Ultrafine Particle counts (Particle range: 0.02–1 μm) and carbon monoxide (CO) was investigated at and around a street canyon intersection in Central London, UK. During a four-week field campaign, groups of four volunteers collected samples at three timings (morning, lunch and afternoon), along two different routes (a heavily trafficked route and a backstreet route) via five modes of transport (walking, cycling, bus, car and taxi). PM 2.5 was sampled using high-flow gravimetric personal samplers, Ultrafine Particle counts were measured using TSI P-TRAKs and Langans were used to measure CO exposure. Three hundred and ninety-four samples were collected—197 PM 2.5 , 86 Ultrafine Particle count and 111 CO. Arithmetic means of PM 2.5 personal exposure were 27.5, 33.5, 34.5, 38.0 and 41.5 μg m −3 , Ultrafine Particle counts were 67 773, 93 968, 101 364, 99 736 and 87 545 pt cm −3 and CO levels were 0.9, 1.1, 0.8, 1.3 and 1.1 ppm for walking, cycling, bus, car and taxi respectively. On the heavily trafficked route, personal exposure was 35.3 μg m −3 , 101142 pt cm −3 and 1.3 ppm, and on the backstreet route it was 31.8 μg m −3 , 71628 pt cm −3 and 0.6 ppm for PM 2.5 , Ultrafine Particle counts and CO, respectively. Personal exposure levels were high during the morning measurements for all three pollutants (34.6 μg m −3 , 106 270 pt cm −3 and 1.5 ppm for PM 2.5 , Ultrafine Particle counts and CO, respectively).There was a moderately strong correlation between personal exposure of Ultrafine Particle counts and CO ( r = 0.7 , N = 67 ) but a weaker correlation between PM 2.5 and Ultrafine Particle counts ( r = 0.5 , N = 83 ) and a low correlation between PM 2.5 and CO exposure ( r = 0.2 , N = 105 ). The exposure assessment also revealed that the background and kerbside monitoring stations were not representative of the personal exposure of individuals to PM 2.5 and CO at and around a street canyon intersection.
S Kaur - One of the best experts on this subject based on the ideXlab platform.
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determinants of personal exposure to pm2 5 Ultrafine Particle counts and co in a transport microenvironment
Environmental Science & Technology, 2009Co-Authors: S Kaur, Mark J NieuwenhuijsenAbstract:Short-term human exposure concentrations to PM2.5, Ultrafine Particle counts (Particle range: 0.02−1 μm), and carbon monoxide (CO) were investigated at and around a street canyon intersection in Central London, UK. During a four week field campaign, groups of four volunteers collected samples at three timings (morning, lunch, and afternoon), along two different routes (a heavily trafficked route and a backstreet route) via five modes of transport (walking, cycling, bus, car, and taxi). This was followed by an investigation into the determinants of exposure using a regression technique which incorporated the site-specific traffic counts, meteorological variables (wind speed and temperature) and the mode of transport used. The analyses explained 9, 62, and 43% of the variability observed in the exposure concentrations to PM2.5, Ultrafine Particle counts, and CO in this study, respectively. The mode of transport was a statistically significant determinant of personal exposure to PM2.5, Ultrafine Particle cou...
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exposure visualisation of Ultrafine Particle counts in a transport microenvironment
Atmospheric Environment, 2006Co-Authors: S Kaur, R D R Clark, P Walsh, S J Arnold, R N Colvile, Mark J NieuwenhuijsenAbstract:Abstract An increasing number of studies indicate that short-term peak exposures, such as those seen in the transport microenvironment, pose particular health threats. Short-term exposure can only be sufficiently characterised using portable, fast-response monitoring instrumentation with detailed summaries of individual activity. In this paper, we present an exposure visualisation system that addresses this issue—it allows the simultaneous presentation of mobile video imagery synchronised with measured real-time Ultrafine Particle count exposure of an individual. The combined data can be examined in detail for the contribution of the surrounding environment and the individual's activities to their peak and overall exposure. The exposure visualisation system is demonstrated and evaluated around the DAPPLE study site in Central London using different modes of transport (walking, cycling, bus, car and taxi). The video images, synchronised with the exposure profile, highlight the extent to which Ultrafine Particle exposure is associated with traffic density and proximity to pollutant source. The extremely rapid decline in concentration with increasing distance away from the pollutant source, such as from the main street to the backstreets, is clearly evident. The visualisation technique allows these data to be presented to both technical audiences and laypersons thus making it an effective environmental risk communication tool. Some exposure peaks however are not obviously associated with any event recorded on video—in these cases it will be necessary to use advanced dispersion modelling techniques to investigate meteorological conditions and other variables influencing in-street conditions to identify their possible causes.
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personal exposure of street canyon intersection users to pm2 5 Ultrafine Particle counts and carbon monoxide in central london uk
Atmospheric Environment, 2005Co-Authors: S Kaur, Mark J Nieuwenhuijsen, R ColvileAbstract:Abstract Short-term human exposure to PM 2.5, Ultrafine Particle counts (Particle range: 0.02–1 μm) and carbon monoxide (CO) was investigated at and around a street canyon intersection in Central London, UK. During a four-week field campaign, groups of four volunteers collected samples at three timings (morning, lunch and afternoon), along two different routes (a heavily trafficked route and a backstreet route) via five modes of transport (walking, cycling, bus, car and taxi). PM 2.5 was sampled using high-flow gravimetric personal samplers, Ultrafine Particle counts were measured using TSI P-TRAKs and Langans were used to measure CO exposure. Three hundred and ninety-four samples were collected—197 PM 2.5 , 86 Ultrafine Particle count and 111 CO. Arithmetic means of PM 2.5 personal exposure were 27.5, 33.5, 34.5, 38.0 and 41.5 μg m −3 , Ultrafine Particle counts were 67 773, 93 968, 101 364, 99 736 and 87 545 pt cm −3 and CO levels were 0.9, 1.1, 0.8, 1.3 and 1.1 ppm for walking, cycling, bus, car and taxi respectively. On the heavily trafficked route, personal exposure was 35.3 μg m −3 , 101142 pt cm −3 and 1.3 ppm, and on the backstreet route it was 31.8 μg m −3 , 71628 pt cm −3 and 0.6 ppm for PM 2.5 , Ultrafine Particle counts and CO, respectively. Personal exposure levels were high during the morning measurements for all three pollutants (34.6 μg m −3 , 106 270 pt cm −3 and 1.5 ppm for PM 2.5 , Ultrafine Particle counts and CO, respectively).There was a moderately strong correlation between personal exposure of Ultrafine Particle counts and CO ( r = 0.7 , N = 67 ) but a weaker correlation between PM 2.5 and Ultrafine Particle counts ( r = 0.5 , N = 83 ) and a low correlation between PM 2.5 and CO exposure ( r = 0.2 , N = 105 ). The exposure assessment also revealed that the background and kerbside monitoring stations were not representative of the personal exposure of individuals to PM 2.5 and CO at and around a street canyon intersection.
