Effect of industrial point-source air pollutants on fractional exhaled nitric oxide in healthy volunteers.

BACKGROUND: Few studies have examined the effects of industrial, fixed-site sources of air pollution on lung inflammation in nearby residents. We investigated the effects of short-term exposure to ambient air near a steel plant on the fractional exhaled concentration of nitric oxide (FeNO), a measure of airway inflammation, in healthy volunteers. METHODS: A cross-over study design was used. Fifty-nine non-smoking participants (mean age 24 years) were randomly assigned to each of two 5-day exposure scenarios: breathing ambient air adjacent to a steel plant or 5 km away at a college campus site. FeNO and on-site air pollutants were measured daily. Mixed effects linear regression models were used for data analysis, adjusting for sex, temperature, humidity and day of week. RESULTS: Compared with the college site, PM 2.5, ultrafine PM, SO2, NO2 and CO levels were significantly greater near the steel plant. FeNO was 15.3% (95% CI, 6.6%, 24.8%) higher near the plant compared to the college site. CONCLUSIONS: Exposure to ambient air near a steel plant was associated with increased airway inflammation as measured by exhaled nitric oxide.

Cardiovascular and inflammatory mechanisms in healthy humans exposed to air pollution in the vicinity of a steel mill.

BACKGROUND: There is a paucity of mechanistic information that is central to the understanding of the adverse health effects of source emission exposures. To identify source emission-related effects, blood and saliva samples from healthy volunteers who spent five days near a steel plant (Bayview site, with and without a mask that filtered many criteria pollutants) and at a well-removed College site were tested for oxidative stress, inflammation and endothelial dysfunction markers. METHODS: Biomarker analyses were done using multiplexed protein-array, HPLC-Fluorescence, EIA and ELISA methods. Mixed effects models were used to test for associations between exposure, biological markers and physiological outcomes. Heat map with hierarchical clustering and Ingenuity Pathway Analysis (IPA) were used for mechanistic analyses. RESULTS: Mean CO, SO2 and ultrafine particles (UFP) levels on the day of biological sampling were higher at the Bayview site compared to College site. Bayview site exposures "without" mask were associated with increased (p < 0.05) pro-inflammatory cytokines (e.g IL-4, IL-6) and endothelins (ETs) compared to College site. Plasma IL-1ß, IL-2 were increased (p < 0.05) after Bayview site "without" compared to "with" mask exposures. Interquartile range (IQR) increases in CO, UFP and SO2 were associated with increased (p < 0.05) plasma pro-inflammatory cytokines (e.g. IL-6, IL-8) and ET-1(1-21) levels. Plasma/saliva BET-1 levels were positively associated (p < 0.05) with increased systolic BP. C-reactive protein (CRP) was positively associated (p < 0.05) with increased heart rate. Protein network analyses exhibited activation of distinct inflammatory mechanisms after "with" and "without" mask exposures at the Bayview site relative to College site exposures. CONCLUSIONS: These findings suggest that air pollutants in the proximity of steel mill site can influence inflammatory and vascular mechanisms. Use of mask and multiple biomarker data can be valuable in gaining insight into source emission-related health impacts.

Exposure to air pollution near a steel plant is associated with reduced heart rate variability: a randomised crossover study.

BACKGROUND: Epidemiological studies have shown that as ambient air pollution (AP) increases the risk of cardiovascular mortality also increases. The mechanisms of this effect may be linked to alterations in autonomic nervous system function. We wished to examine the effects of industrial AP on heart rate variability (HRV), a measure of subtle changes in heart rate and rhythm representing autonomic input to the heart. METHODS: Sixty healthy adults were randomized to spend five consecutive 8-h days outdoors in one of two locations: (1) adjacent to a steel plant in the Bayview neighbourhood in Sault Ste Marie Ontario or (2) at a College campus, several kilometers from the plant. Following a 9-16 day washout period, participants spent five consecutive days at the other site. Ambient AP levels and ambulatory electrocardiogram recordings were collected daily. HRV analysis was undertaken on a segment of the ambulatory ECG recording during a 15 min rest period, near the end of the 8-h on-site day. Standard HRV parameters from both time and frequency domains were measured. Ambient AP was measured with fixed site monitors at both sites. Statistical analysis was completed using mixed-effects models. RESULTS: Compared to the College site, HRV was statistically significantly reduced at the Bayview site by 13% (95%CI 3.6,19.2) for the standard deviation of normal to normal, 8% (95%CI 0.1, 4.9) for the percent normal to normal intervals differing by more than 50 ms, and 15% (95%CI 74.9, 571.2) for low frequency power. Levels of carbon monoxide, sulphur dioxide, nitrogen dioxide, and fine and ultrafine particulates were slightly, but statistically significantly, elevated at Bayview when compared to College. Interquartile range changes in individual air pollutants were significantly associated with reductions in HRV measured on the same day. The patterns of effect showed a high degree of consistency, with nearly all pollutants significantly inversely associated with at least one measure of HRV. CONCLUSIONS: The significant associations between AP and changes in HRV suggest that ambient AP near a steel plant may impact autonomic nervous system control of the heart.

Associations between urinary biomarkers of oxidative stress and air pollutants observed in a randomized crossover exposure to steel mill emissions.

The effects of industrial air pollution on human health have not been as thoroughly investigated as those of urban air pollution which originates mostly from automotive transport. To better assess the health impacts of point sources of industrial air pollution, a randomized crossover exposure study was conducted. Sixty one young and healthy volunteers were randomly assigned to spend five consecutive eight-hour days near a steel mill or at a location five kilometres away. After a nine or sixteen-day washout period, volunteers spent another five consecutive days at the second site. Meteorological conditions and air pollutants were monitored at both exposure sites. On each exposure day, the first morning urine was collected along with a second urine sample obtained immediately before leaving the exposure site at the end of the day. Urinary levels of biomarkers of oxidative stress 8-hydroxy-2'-deoxyguanosine (8-OHdG, a biomarker of oxidative DNA damage), malondialdehyde (MDA, a biomarker of lipid peroxidation), 8-isoprostane (8-IsoP, a bioactive metabolite resulting from the peroxidation of arachidonic acid) and Vascular Endothelial Growth Factor (VEGF, involved in response to oxidative stress) were measured. According to mixed-effects linear regression models, intra-individual variations in 8-OHdG urinary levels were significantly associated with exposure site, but surprisingly, lower levels were observed at the steel mill site. Delayed, temporally-defined associations with specific air pollutants were observed for 8-OHdG, 8-IsoP and VEGF. However, these associations were subtle, presented complex patterns and their biological consequences remain unclear.

Metal composition of fine particulate air pollution and acute changes in cardiorespiratory physiology.

BACKGROUND: Studying the physiologic effects of components of fine particulate mass (PM2.5) could contribute to a better understanding of the nature of toxicity of air pollution. OBJECTIVES: We examined the relation between acute changes in cardiovascular and respiratory function, and PM2.5-associated-metals. METHODS: Using generalized linear mixed models, daily changes in ambient PM2.5-associated metals were compared to daily changes in physiologic measures in 59 healthy subjects who spent 5-days near a steel plant and 5-days on a college campus. RESULTS: Interquartile increases in calcium, cadmium, lead, strontium, tin, vanadium and zinc were associated with statistically significant increases in heart rate of 1-3 beats per minute, increases of 1-3 mmHg in blood pressure and/or lung function decreases of up to 4% for total lung capacity. CONCLUSION: Metals contained in PM2.5 were found to be associated with acute changes in cardiovascular and respiratory physiology.

Exposure to air pollution near a steel plant and effects on cardiovascular physiology: a randomized crossover study.

BACKGROUND: Iron and steel industry is an important source of air pollution emissions. Few studies have investigated cardiovascular effects of air pollutants emitted from steel plants. OBJECTIVE: We examined the influence of outdoor air pollution in the vicinity of a steel plant on cardiovascular physiology in Sault Ste. Marie, Canada. METHODS: Sixty-one healthy, non-smoking subjects (females/males=33/28, median age 22 years) spent 5 consecutive 8-hour days outdoors in a residential area neighbouring a steel plant, or on a college campus approximately 5 kilometres away from the plant, and then crossed over to the other site with a 9-day washout. Mid day, subjects underwent daily 30-minute moderate intensity exercise. Blood pressure (BP) and pulse rate were determined daily and post exercise at both sites. Flow-mediated vasodilation (FMD) was determined at the site near the plant. Air pollution was monitored at both sites. Mixed-effects regressions were run for statistical associations, adjusting for weather variables. RESULTS: Concentrations of ultrafine particles, sulphur dioxide (SO2), nitrogen dioxide (NO2) and carbon monoxide (CO) were 50-100% higher at the site near the plant than at the college site, with minor differences in temperature, humidity, and concentrations of particulate matter ≤2.5 µm in size (PM2.5) and ozone (O3). Resting pulse rate [mean (95% confidence interval)] was moderately higher near the steel plant [+1.53 bpm (0.31, 2.78)] than at the college site, male subjects having the highest pulse rate elevation [+2.77 bpm (0.78, 4.76)]. Resting systolic and diastolic BP and pulse pressure, and post-exercise BP and pulse rate were not significantly different between two sites. Interquartile range concentrations of SO2 (2.9 ppb), NO2 (5.0 ppb) and CO (0.2 ppm) were associated with increased pulse rate [0.19 bpm (-0.00, 0.38), 0.86 bpm (0.03, 1.68), and 0.11 bpm (0.00, 0.22), respectively], ultrafine particles (10,256 count/cm(3)) associated with increased pulse pressure [0.85 mmHg (0.23, 1.48)], and NO2 and CO inversely associated with FMD [-0.14% (-0.31, 0.02), -0.02% (-0.03, -0.00), respectively]. SO2 during exercise was associated with increased pulse rate [0.26 bpm (0.01, 0.51)]. CONCLUSION: Air quality in residential areas near steel plants may influence cardiovascular physiology.

Acute changes in lung function associated with proximity to a steel plant: a randomized study.

BACKGROUND: Steel production is a major industry worldwide yet there is relatively little information on the pulmonary effects of air quality near steel manufacturing plants. OBJECTIVES: The aim of this study was to examine how lung function changes acutely when healthy subjects are situated near a steel plant which is adjacent to a residential area. METHODS: Sixty-one subjects were randomly assigned to spend 5 consecutive, 8-hour days in a residential neighborhood approximately 0.9km from a steel plant, or approximately 4.5km away at a college campus. Subjects crossed-over between sites after a nine-day washout period. Lung function was measured daily at both sites along with air pollutants including SO2, NO2, O3, PM2.5, and ultrafine particles. Diffusion capacity and pulse oximetry were also examined. RESULTS: Compared with the college site, the forced expiratory volume in 1-second/forced vital capacity, forced expiratory flow between 25% and 75% of the FVC, total lung capacity, functional residual capacity, and residual volume were lower near the steel plant by 0.67% (95% CI: 0.28, 1.06),1.62% (95% CI: 0.50, 2.75), 1.54% (95% CI: 0.68, 2.39), 3.54% (95% CI: 1.95, 5.13) and 11.3% (95% CI: 4.92, 17.75), respectively. Diffusion capacity, forced expiratory volume in 1s, and pulse oximetry were also lower near the plant but these effects were not statistically significant. Sulfur dioxide, ultrafine particulates, and oxides of nitrogen were greater near the steel plant site compared to the college site. CONCLUSIONS: Spending short periods of time near a steel plant is associated with a decrease in lung function.

The influence of neighborhood traffic density on the respiratory health of elementary schoolchildren.

BACKGROUND: Several studies have found that living near major roadways is associated with an increase in respiratory illness but few studies have measured the volume and type of traffic. OBJECTIVE: We investigated the relation between traffic volume and respiratory health of 2328 children 9 to 11 years old in the city of Windsor, Canada. METHODS: We identified the roadways within a 200 meter radius of the child's neighborhood using the latitude and longitude of the residential postal code. Traffic exposure was defined as the sum of the annual volume of vehicles on all of these roadways. Volume was calculated using sensors to detect passing vehicles (simple traffic counts), and by counts and direction of traffic at intersections (turning movement counts). Ventilatory lung function was measured by spirometry and airway inflammation by exhaled nitric oxide (eNO). RESULTS: The odds ratio between an interquartile increase in truck turning movement counts and chest congestion was 1.20 (1.06-1.35). The percentage of predicted FVC declined 0.68%, (95% CI 1.32, 0.03) for an interquartile increase in simple traffic counts (33,787 vehicles daily). Among those with self-reported asthma, effect sizes were larger. Percentage predicted FEV(1) declined 1.84% (95% CI 0.07, 3.61) associated with an interquartile range increase in turning movement counts. No statistically significant change was detected between traffic measures and exhaled nitric oxide. CONCLUSIONS: Our findings provide further support for the hypothesis that neighborhood exposure to traffic-related air pollution increases respiratory symptoms and reduces ventilatory function in children, especially those with self-reported asthma.

The influence of neighborhood roadways on respiratory symptoms among elementary schoolchildren.

OBJECTIVE: To investigate the respiratory health effects of living near roadways. METHODS: We administered a questionnaire to Windsor school children. Exposure to roadways was defined as the total length of roadways within a 200 meter radius around the postal code of each household calculated using geographic information systems. RESULTS: The adjusted odds ratios comparing the highest to the lowest exposure (roadway density) quintiles, were statistically significant for wheeze 1.23 (95% CI: 1.07 to 1.41) (P = 0.0041) and wheeze with dyspnea 1.27 (95% CI: 1.05 to 1.52) (P = 0.0125). Expressed as a continuous variable roadway density was associated with asthma, odds ratio 1.08 (95% CI: 1.012 to 1.149) equivalent to an 8% relative increase in the odds of asthma for an interquartile increase (0.6 km) in roadway density. CONCLUSIONS: Residential traffic appears to adversely influence respiratory health.

The influence of living near roadways on spirometry and exhaled nitric oxide in elementary schoolchildren.

BACKGROUND: Living near major roadways has been associated with an increase in respiratory symptoms, but little is known about how this relates to airway inflammation. OBJECTIVE: We assessed the effects of living near local residential roadways based on objective indicators of ventilatory function and airway inflammation. METHODS: We estimated ambient air pollution, resolved to the level of the child's neighborhood, using a land-use regression model for children 9-11 years of age. We also summed the length of roadways found within a 200-m radius of each child's neighborhood. We had measurements of both air pollution exposure and spirometry for 2,328 children, and also had measurements of exhaled nitric oxide (eNO) for 1,613 of these children. RESULTS: Each kilometer of local roadway within a 200-m radius of the home was associated with a 6.8% increase in eNO (p = 0.045). Each kilometer of any type of roadway (local, major, highway) was also associated with an increase in eNO of 10.1% (p = 0.002). Each microgram per cubic meter increase in PM2.5 was associated with a 3.9% increase in eNO (p = 0.058) and 0.70% decrease in forced vital capacity (FVC) expressed as a percentage of predicted (p = 0.39). Associations between roadway density and both forced expired volume in 1 sec and FVC were negative but not statistically significant at p < 0.05. CONCLUSION: Traffic from local neighborhood roadways may cause airway inflammation as indicated by eNO. This may be a more sensitive indicator of adverse air pollution effects than traditional measures of ventilatory function.

Percutaneous nephrolithotomy in children before school age: experience of a Pakistani centre.

OBJECTIVE: To review our experience of percutaneous nephrolithotomy (PCNL) in children before school age, and determine its efficacy and safety in this age group. PATIENTS AND METHODS: The records of children aged < or = 5 years undergoing PCNL were reviewed. Variables assessed included stone number, size, location and type. The PCNL puncture site and number were also recorded. We reviewed stone clearance with PCNL, ancillary procedures used, complication rates and follow-up status of the children. RESULTS: There were 30 renal units in 29 children (median age 3.8 years, range 1.4-5). Because of poor growth the mean (SD) body weight of the children was only 12.2 (2.8) kg, which is near the 50th percentile for children of mean age 3.5 years. The median (range) stone burden was 2.35 (1.3-6) cm; 60% of the patients had single stones while 28% had more than five. There were five staghorn stones. All PCNL was primary and with one puncture, using a 17 F angled nephroscope; stones were fragmented using a pneumatic lithoclast. After PCNL stones were completely cleared in 60% of the renal units, which increased to 100% after combining it with extracorporeal shockwave lithotripsy. The median (range) follow-up was 24.9 (4-51) months; the overall complication rate was 6%. In the long follow-up hypertension was not detected in any child and isotopic renograms in 17 kidneys detected no new scarring or loss of renal function. CONCLUSION: PCNL is a safe and effective for treating renal stones in very young children.