Inflammation and tissue damage in mouse lung by single and repeated dosing of urban air coarse and fine particles collected from six European cities.

The authors have previously demonstrated heterogeneities in the inflammatory activities of urban air fine (PM(2.5-0.2)) and coarse (PM(10-2.5)) particulate samples collected from six European cities with contrasting air pollution situations. The same samples (10 mg/kg) were intratracheally instilled to healthy C57BL/6J mice either once or repeatedly on days 1, 3, and 6 of the study week. The lungs were lavaged 24 h after the single dose or after the last repeated dosing. In both size ranges, repeated dosing of particles increased the total cell number in bronchoalveolar lavage fluid (BALF) more than the respective single dose, whereas cytokine concentrations were lower after repeated dosing. The lactate dehydrogenase (LDH) responses increased up to 2-fold after repeated dosing of PM(2.5-0.2) samples and up to 6-fold after repeated dosing of PM(10-2.5) samples. PM(10-2.5) samples evoked a more extensive interstitial inflammation in the mouse lungs. The constituents with major contributions to the inflammatory responses were oxidized organic compounds and transition metals in PM(2.5-0.2) samples, Cu and soil minerals in PM(10-2.5) samples, and Zn in both size ranges. In contrast, poor biomass and coal combustion were associated with elevated levels of polycyclic aromatic hydrocarbons (PAHs) and a consistent inhibitory effect on the inflammatory activity of PM(2.5-0.2) samples. In conclusion, repeated intratracheal instillation of both fine and coarse particulate samples evoked enhanced pulmonary inflammation and cytotoxicity compared to single-dose administration. The sources and constituents of urban air particles responsible for these effects appear to be similar to those encountered in the authors' previous single-dose study.

Seasonal variation in chemical composition of size-segregated urban air particles and the inflammatory activity in the mouse lung.

We investigated the seasonal variations in the chemical composition and in vivo inflammatory activity of urban air particulate samples in four size ranges (PM(10-2.5), PM(2.5-1), PM(1-0.2), and PM(0.2)). The samples were collected in Helsinki using a high-volume cascade impactor (HVCI). Healthy C57BL/6J mice were intratracheally instilled with a single dose (10 mg/kg) of the particulate samples. The lungs were lavaged and the bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation and tissue damage: cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6, and keratinocyte-derived chemokine [KC]) at 4 h, and total cell number and total protein concentration at 12 h. The PM(10-2.5) and PM(2.5-1) samples had much higher inflammatory potency than the PM(1-0.2) and PM(0.2) samples. The relative inflammatory activities of the autumn samples were the highest on an equal mass basis, but when estimated for the particulate mass per cubic meter of air, the springtime samples had the highest inflammatory potential. Resuspended soil material and other non-exhaust particulate material from traffic were associated with a high inflammatory activity of the PM(10-2.5) and PM(2.5-1) samples. Secondary inorganic ions in the PM(1-0.2) and PM(0.2) samples had inconsistent negative or positive correlations with the inflammatory activity. There were no systematic seasonal variations in the tracers of incomplete combustion and atmospherically oxidized organics in the PM(1-0.2) and PM(0.2) samples, which probably explains their low correlations with the inflammatory activity. In conclusion, in a relatively clean Nordic city, the resuspension of road dust and other non-exhaust particulate material from traffic were the major sources of inflammatory activity of urban air inhalable particles.

Dose and time dependency of inflammatory responses in the mouse lung to urban air coarse, fine, and ultrafine particles from six European cities.

We investigated the dose and time dependency of inflammatory and cytotoxic responses to size-segregated urban air particulate samples in the mouse lung. Coarse (PM10-2.5), fine (PM2.5-0.2), and ultrafine (PM0.2) particles were collected in six European cities (Duisburg, Prague, Amsterdam, Helsinki, Barcelona, Athens) in selected seasons using a modified Harvard high-volume cascade impactor. Healthy C57Bl/6J mice were intratracheally exposed to the particulate samples in a 24-h dose-response study (1, 3, and 10 mg/kg) and in 4-, 12-, and 24-h time course studies (10 mg/kg). After the exposures, the lungs were lavaged and the bronchoalveolar lavage fluid (BALF) was assayed for indicators of inflammation and tissue damage: total cell number, cell differential, total protein, and lactate dehydrogenase (LDH) and cytokine (tumor necrosis alpha [TNF-alpha], interleukin-6 [IL-6], and keratinocyte-derived chemokine [KC]) concentrations. In general, PM10-2.5 samples had higher inflammatory activity than PM2.5-0.2 samples. PM0.2 samples showed negligible inflammatory activity. PM10-2.5 and PM2.5-0.2 samples caused large increases in BALF cytokine concentrations at 4 h, but not at 12 or 24 h, after exposure. The BALF total cell number and total protein concentrations increased significantly at 12 h for both the PM10-2.5 and PM2.5-0.2 samples, but only PM10-2.5 samples produced consistent, significant increases at 24 h after exposure. There was more heterogeneity in BALF cytokine and neutrophil cell number responses to PM2.5-0.2 samples than to PM10-2.5 samples between the sampling campaigns. Thus, particle size, sources, and atmospheric transformation processes affect the inflammatory activity and response duration of urban air particulate matter in the mouse lung.

Performance of a high-volume cascade impactor in six European urban environments: mass measurement and chemical characterization of size-segregated particulate samples.

The performance of a modified Harvard high-volume cascade impactor (HVCI) was evaluated in six field campaigns with size-segregated particulate samplings for chemical and toxicological characterization. The 7-week sampling campaigns in 2002-2003 in Duisburg (autumn), Prague (winter), Amsterdam (winter), Helsinki (spring), Barcelona (spring), and Athens (summer) were selected to represent contrasting urban environments and seasons of public health interest due to high particulate concentrations or previous findings in epidemiological studies. Particulate samples were collected in parallel with the HVCI (PM(10-2.5), PM(2.5-1), PM(1-0.2), PM(0.2)), a virtual impactor (VI; PM(10-2.5), PM(2.5)), and a Berner low-pressure impactor (BLPI; 10 stages between 0.035 and 10 mum in particle diameter) using a 3- or 4-day sampling duration. The campaigns exhibited different profiles with regard to particulate mass concentration, size distribution, chemical composition and meteorological conditions, thus providing a demanding setup for an overall field comparison of the HVCI with the VI and BLPI reference samplers. Size-segregated particulate mass concentration could be reasonably well measured with the present HVCI configuration. The coarse (PM(10-2.5)) and fine (PM(2.5)) particulate mass agreed within 10% with the low-volume reference samplers, and the four-stage size distribution of the HVCI followed the modal pattern of urban aerosol. The concentrations of chemical constituents measured and integrated especially for the HVCI-PM(2.5) differed to some extent from those measured from the corresponding VI-PM(2.5) samples. This implies that when investigating the association of toxicological responses with the chemical constituents of particulate matter, it is necessary to use the chemical composition data of the same samples as used in toxicological experiments.

Characterization of respiratory exposure to and effects of cold-air hyperventilation in guinea pigs.

The purpose of this study was to characterize the respiratory effects of single and repeated controlled exposures to clean warm humid and cold dry air in a new model of anesthetized, mechanically ventilated guinea pigs, and to compare findings with known effects in humans. Intratracheal air (T(tr)) and retrotracheal tissue (T(oe)) temperatures and peak expiratory airflow (PEF), tidal volume (V(T)), heart rate, and blood pressure of hyperventilating animals were measured continuously. Four consecutive 10-min exposures to warm humid air (n = 7) produced slight airway warming and minimal lung function changes during the exposure. In a single 10-min exposure to cold dry air (n = 39), T(tr) decreased from (means +/- SEM) 36.1 +/- 0.3 degrees C to 26.3 +/- 0.3 degrees C (Delta = -9.8 +/- 0.4 degrees C) and T(oe) from 36.4 +/- 0.2 degrees C to 35.5 +/- 0.2 degrees C (Delta = -0.9 +/- 0.1 degrees C). PEF and V(T) decreased in response to airway cooling with maximal decrements within the first 2-4 min from the beginning of the exposure period. The maximal decrease in PEF was from 21.7 +/- 0.3 ml s(-1) to 15.9 +/- 0.5 ml s(-1) (Delta = -26.7%) and that in V(T) from 5.2 +/- 0.1 ml to 4.2 +/- 0.1 ml (Delta = -19.2%) (p <.05 for both changes). The decreases in lung functions attenuated significantly during the course of the 10-min exposure to cold dry air, indicating adaptation. Consequently, the decrements in PEF and V(T) at 5, 7.5, and 10 min were significantly smaller than those at 3 min. In four consecutive 10-min exposures to cold dry air (n = 15), there were no statistically significant differences in T(tr) or T(oe) decreases between the exposure periods. The largest decreases in the lung function parameters were during the first exposure period, whereas there were significantly smaller responses during the second and third exposure periods (p <.05). Thus, a highly reproducible airway cooling and an immediate bronchoconstriction were produced in response to cold dry air hyperventilation in guinea pigs. During the course of cold-air exposure and in repeated exposures, there was a significant attenuation of the bronchial response, which resembled the refractoriness of the asthmatic airways to repeated hyperventilation of cold or warm dry air. The present guinea pig model seems to be well suited for production of complementary animal data on the pathophysiological effects of cold dry air on the tracheobronchial airways.

Combined respiratory effects of cold air with SO(2) or NO(2) in repeated 10-minute exposures of hyperventilating guinea pigs.

Previous studies in asthmatic subjects and guinea pigs have demonstrated attenuation of bronchoconstriction in repeated exposures to clean cold dry air. In the present animal study, we have simulated short-lasting human exposures to subfreezing urban air containing sulfur dioxide (SO(2)) and nitrogen dioxide (NO(2)). The anesthetized, paralyzed, and mechanically ventilated guinea pigs had 4 consecutive 10-min exposures either to clean cold dry air or to cold air with graded concentrations of SO(2) (0-5 ppm) or NO(2) (0-4 ppm). Peak expiratory flow (PEF) and tidal volume (V(T)) were continuously measured both during and after highly controlled exposures. Bronchoalveolar lavage fluid (BALF) and histological samples were obtained after finishing the consecutive exposures. Cold air + SO(2) at 1 and 2.5 ppm (n = 12) produced immediate concentration-dependent increases in the lung function responses compared to the preceding single exposure to clean cold dry air in the same animals (DeltaPEF = -32.7 +/- 6.1% and -35.6 +/- 6.5% vs. -27.0 +/- 3.1%; DeltaV(T) = -22.4 +/- 4.4% and -28.3 +/- 4.7% vs. -18.1 +/- 2.9%). In a multivariate analysis, these responses were significantly larger than the attenuated lung function responses to the corresponding second and third clean cold dry air exposures (p <. 05). The fourth exposure to cold air + SO(2) at 5 ppm produced a smaller response (DeltaPEF = -25.3 +/- 4.8% and DeltaV(T) = -17.8 +/- 3.7%) than cold air with the lower SO(2) concentrations. Cold air + NO(2) at 1 and 2.5 ppm (n = 12) produced roughly similar lung function responses to the preceding single exposure to clean cold dry air in the same animals, and there was no significant attenuation of bronchoconstriction as with the consecutive exposures to clean cold dry air. The largest decreases in lung functions (DeltaPEF = -33.8 +/- 6.7% and DeltaV(T) = -26.2 +/- 6.8%) were recorded during the fourth exposure, which was to cold air + NO(2) at 4 ppm. In the cold air + SO(2) group, there was a significantly lower proportion of macrophages in the differential count of BALF white cells compared to the clean cold dry air group. In addition, there was eosinophilic infiltration within and below the tracheal epithelium in all guinea pigs exposed to either clean cold dry air, cold air + SO(2), or cold air + NO(2). In conclusion, the addition of moderate concentrations of SO(2) or NO(2) to clean cold dry air counteracted the attenuation of bronchoconstriction induced by repeated cold dry air exposures in guinea pigs. Cold air + SO(2) also decreased the proportion of macrophages in BALF white cells.

Combined respiratory effects of cold air with SO(2) or NO(2) in single 1-hour exposures of hyperventilating guinea pigs.

The present study is a continuation of our previous experiments on repeated 10-min exposures of anesthetized, mechanically ventilated guinea pigs to clean cold dry air (Hälinen et al., 2000a), and to cold air plus gaseous air pollutants (Hälinen et al., 2000b). This time we made continuous 60-min exposures to clean cold dry air, cold air + SO(2) at 1 ppm, cold air + NO(2) at 1 ppm, and warm humid air + NO(2) at 1 ppm, and focused on responses at 10-60 min. Clean cold dry air and cold air + pollutants (n = 8-9 in each group) produced similar cooling in the guinea pig lower respiratory tract. The decreases in intratracheal temperature (T(tr)) reached a plateau at 20 min with mean maximal decreases of 9.7-11.3 degrees C from the pre-exposure control values of 36.0-37.3 degrees C. In contrast, there were progressive decreases in esophageal temperature (T(oe)) during the exposures, indicating constant conductive and evaporative heat losses from the tracheobronchial tissues. The mean maximal decreases in T(oe) were 1.2-1.4 degrees C from the preexposure control values of 37.8-38.0 degrees C. Clean cold dry air induced 4. 5-10.8% mean decreases in peak expiratory flow (PEF) at 10-60 min of exposure, which were statistically nonsignificant due to a relatively large variation between animals. Cold air + SO(2) at 1 ppm induced a mean decrease of 11.4% in PEF at 10 min (p <.05), which was spontaneously abolished during the next 10 min of exposure. Cold air + NO(2) at 1 ppm caused no decrease, but in fact small, nonsignificant increases in PEF at 30-60 min of exposure. Cold air + NO(2) at 1 ppm, and to some extent also cold air + SO(2) at 1 ppm, attenuated significantly the mechanical ventilation induced gradual decrease in tidal volume (V(T)), when compared to clean cold dry air exposure. Cold air + NO(2) at 1 ppm, but not warm humid air + NO(2) at 1 ppm, increased significantly the proportion of macrophages in the differential count of bronchoalveolar lavage fluid (BALF) white cells when compared to both clean warm humid air and cold dry air. None of the exposure conditions caused morphological or inflammatory changes in the respiratory tissues. In conclusion, continuous 60-min exposures to clean cold dry air, cold air + SO(2), and cold air + NO(2) produced weaker functional effects on the lower respiratory tract of guinea pigs than our previous consecutive 10-min exposures to these air conditions. After the first 10 min, there was a strong attenuation of the bronchoconstrictor responses, especially to cold air + NO(2) at 1 ppm. The small airway effects of prolonged mechanical ventilation were significantly modified by NO(2) at 1 ppm in both cold dry and warm humid breathing air. Finally, cold air + NO(2) at 1 ppm increased the proportion of macrophages in BALF white cells.

A Chemical and Toxicological Comparison of Urban Air PM10 Collected During Winter and Spring in Finland.

We have used a new high-volume, low-cutoff inertial impactor (HVLI) in a pilot study on chemical characterization and toxicity testing of ambient air PM10 in Helsinki, Finland. Ambient air PM10 was collected at 1100 L/min in 2- to 4-day periods. Two different PM10 samples were selected to represent wintertime combustion type and springtime resuspension type particulate matter (PM) pollution. The most abundant water-soluble ions and elements were analyzed by ion chromatography and inductively coupled plasma mass spectrometry, respectively. The proinflammatory activation ¡NO and interleukin 6 (IL-6) production] and viability of cultured murine RAW 264.7 macrophages were tested in 24-h incubations with increasing mass doses (30-2000 µg per 10(6) cells) from the collected PM10 samples. The winter sample had a higher assessed PM2.5 fraction and sulfate content, and lower chloride, sodium, calcium, aluminum, copper, manganese, and especially iron contents than the spring sample. Both PMjo samples induced dose-dependent NO production in murine macrophages, and the springtime PM10 produced also a strong, dose-dependent IL-6 production. In conclusion, the HVLI proved to be a suitable technique for short-term collection of relatively large ambient air PM masses, enabling extensive chemical characterization and toxicity testing from the same samples.

A new guinea-pig model for acute inhalation studies on combined effects of cold air and pollutants.

We have developed a new small animal model for acute inhalation studies on combined effects of cold air and gaseous urban air pollutants. The anaesthetised, tracheostomised and paralysed guinea-pig was placed inside a small, sealed whole-body-box, in which it was ventilated mechanically by using cyclic negative pressure (Pbox) for active expansion of the chest. During a 2-h normal ventilation with warm humid air (n=6), there was a need for increasing Pbox with time to maintain the fixed tidal volume (VT) of 11 ml/kg. No such need was seen in the experiments with 15-min periods of isocapnic hyperventilation at 80 and 120 breaths/min (n=13). During the 2-h normal ventilation and in experiments with hyperventilation, there was a gradual increase in heart rate and small gradual decreases in PaCO2 and pH with time. Cold air + SO2 2.5 ppm produced a significantly stronger bronchoconstriction (deltaVT=-30.3+/-7.2%, n=6, P < 0.05) than clean cold dry air (deltaVT=-10.6+/-1.3%, n=6) and cold air + NO2 2.5 ppm (deltaVT=-13.2+/-3.3%, n=6), although these three exposure conditions produced similar decreases in tracheal air and retrotracheal tissue temperatures. With the present guinea-pig model, the combined respiratory effects of cold air and gaseous urban air pollutants can be investigated in a highly controlled manner.

Characterization of air quality problems in five Finnish indoor ice arenas.

The air quality in five Finnish ice arenas with different volumes, ventilation systems, and resurfacer power sources (propane, gasoline, electric) was monitored during a usual training evening and a standardized, simulated ice hockey game. The measurements included continuous recording of carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO2) concentrations, and sampling and analysis of volatile organic compounds (VOCs). Emissions from the ice resurfacers with combustion engines caused indoor air quality problems in all ice arenas. The highest 1-hour average CO and NO2 concentrations ranged from 20 to 33 mg/m3 (17 to 29 ppm) and 270 to 7440 micrograms/m3 (0.14 to 3.96 ppm), respectively. The 3-hour total VOC concentrations ranged from 150 to 1200 micrograms/m3. The highest CO and VOC levels were measured in the arena in which a gasoline-fueled resurfacer was used. The highest NO2 levels were measured in small ice arenas with propane-fueled ice resurfacers and insufficient ventilation. In these arenas, the indoor NO2 levels were about 100 times the levels measured in ambient outdoor air, and the highest 1-hour concentrations were about 20 times the national and World Health Organization (WHO) health-based air quality guidelines. The air quality was fully acceptable only in the arena with an electric resurfacer. The present study showed that the air quality problems of indoor ice arenas may vary with the fuel type of resurfacer and the volume and ventilation of arena building. It also confirmed that there are severe air quality problems in Finnish ice arenas similar to those previously described in North America.

Nitrogen dioxide in indoor ice skating facilities: an international survey.

An international survey of nitrogen dioxide (NO2) levels inside indoor ice skating facilities was conducted. One-week average NO2 concentrations were measured inside and outside of 332 ice rinks located in nine countries. Each rink manager also completed a questionnaire describing the building, the resurfacing machines, and their use patterns. The (arithmetic) mean NO2 level for all rinks in the study was 228 ppb, with a range of 1-2,680 ppb, based on a sample collected at breathing height and adjacent to the ice surface. The mean of the second indoor sample (collected at a spectator's area) was 221 ppb, with a range of 1-3,175 ppb. The ratio of the indoor to outdoor NO2 concentrations was above 1 for 95% of the rinks sampled, indicating the presence of an indoor NO2 source (mean indoor:outdoor ratio = 20). Estimates of short-term NO2 concentrations indicated that as many as 40% of the sampled rinks would have exceeded the World Health Organization 1-hour guideline value of 213 ppb NO2 for indoor air. Statistically significant associations were observed between NO2 levels and the type of fuel used to power the resurfacer, the absence of a catalytic converter on a resurfacer, and the use of an ice edger. There were also indications that decreased use of mechanical ventilation, increased number of resurfacing operations per day, and smaller rink volumes were associated with increased NO2 levels. In rinks where the main resurfacer was powered by propane, the NO2 concentrations were higher than in those with gasoline-powered resurfacers, while the latter had NO2 concentrations higher than in those using diesel. Rinks where the main resurfacer was electric had the lowest indoor NO2 concentrations, similar to the levels measured outdoors.

The effects of atipamezole, an alpha-2 antagonist, on the performance of young and aged rats in the delayed nonmatching to position task.

The present experiments were undertaken to study whether pharmacological activation of the noradrenergic system would improve age-related deficits in short-term memory. Thus, we investigated the effects the single dose administration (0.1, 0.3, 0.9 and 2.7 mg/kg, subcutaneously) or atipamezole, a specific alpha-2 adrenoceptor antagonist, had on the performance of young and aged rats in a delayed nonmatching to position task. After substantial training, aged rats made more errors at longer delays (4-30 seconds) than did young rats, although the percent correct responses at short delays (0-2 seconds) did not differ between young and aged rats. Atipamezole (0.1-0.9 mg/kg) did not improve the performance of young and aged rats in this task. Moreover, the highest dose (2.7 mg/kg) used increased the number of omissions and increased the latency to collect food pellets, indicating disruption of the performance of rats in this task. According to the present results, alpha-2 antagonist (administered peripherally at a single dose), which increases the release of noradrenaline, did not improve age-related deficit in short-term memory in rats.