Hongyu You

Effects of indoor, outdoor, and personal exposure to particulate air pollution on cardiovascular physiology and systemic mediators in seniors.

Objective: To investigate the associations between exposure to particulate air pollution and changes in cardiovascular function and plasma mediators in seniors. Methods: We monitored daily indoor and outdoor black carbon and particulate matter ≤2.5 &mgr;m (pm2.5) and personal pm2.5 repeatedly for 28 nonsmoking seniors. We then measured their blood pressure, heart rate, and brachial artery function, and determined plasma mediators of inflammation, vascular function, and oxidative stress. We tested associations using mixed-effects models. Results: Increases in black carbon and pm2.5 were associated with increases in blood pressure, heart rate, endothelin-1, vascular endothelial growth factor, and oxidative stress marker thiobarbituric acid reactive substances, and a decrease in brachial artery diameter (P < 0.05). Conclusion: Daily exposure to particulate pollution, likely traffic-related, may result in adverse effects on cardiovascular function and blood mediators that modulate vascular system in seniors.

Validation of continuous particle monitors for personal, indoor, and outdoor exposures

Continuous monitors can be used to supplement traditional filter-based methods of determining personal exposure to air pollutants. They have the advantages of being able to identify nearby sources and detect temporal changes on a time scale of a few minutes. The Windsor Ontario Exposure Assessment Study (WOEAS) adopted an approach of using multiple continuous monitors to measure indoor, outdoor (near-residential) and personal exposures to PM2.5, ultrafine particles and black carbon. About 48 adults and households were sampled for five consecutive 24-h periods in summer and winter 2005, and another 48 asthmatic children for five consecutive 24-h periods in summer and winter 2006. This article addresses the laboratory and field validation of these continuous monitors. A companion article (Wheeler et al., 2010) provides similar analyses for the 24-h integrated methods, as well as providing an overview of the objectives and study design. The four continuous monitors were the DustTrak (Model 8520, TSI, St. Paul, MN, USA) and personal DataRAM (pDR) (ThermoScientific, Waltham, MA, USA) for PM2.5; the P-Trak (Model 8525, TSI) for ultrafine particles; and the Aethalometer (AE-42, Magee Scientific, Berkeley, CA, USA) for black carbon (BC). All monitors were tested in multiple co-location studies involving as many as 16 monitors of a given type to determine their limits of detection as well as bias and precision. The effect of concentration and electronic drift on bias and precision were determined from both the collocated studies and the full field study. The effect of rapid changes in environmental conditions on switching an instrument from indoor to outdoor sampling was also studied. The use of multiple instruments for outdoor sampling was valuable in identifying occasional poor performance by one instrument and in better determining local contributions to the spatial variation of particulate pollution. Both the DustTrak and pDR were shown to be in reasonable agreement (R2 of 90 and 70%, respectively) with the gravimetric PM2.5 method. Both instruments had limits of detection of about 5 μg/m3. The DustTrak and pDR had multiplicative biases of about 2.5 and 1.6, respectively, compared with the gravimetric samplers. However, their average bias-corrected precisions were <10%, indicating that a proper correction for bias would bring them into very good agreement with standard methods. Although no standard methods exist to establish the bias of the Aethalometer and P-Trak, the precision was within 20% for the Aethalometer and within 10% for the P-Trak. These findings suggest that all four instruments can supply useful information in environmental studies.

Personal, Indoor, and Outdoor Concentrations of Fine and Ultrafine Particles Using Continuous Monitors in Multiple Residences

Concentrations of airborne continuous fine particulate matter or (PM2.5), black carbon (BC), and ultrafine particles (UFP) were continuously measured over 5 days in winter and summer both indoors and outdoors at residences for forty-eight adults in 2005 and forty-seven asthmatic children in 2006. During 2006, personal concentrations of PM2.5 were also measured continuously. All 4 continuous instruments employed performed well both in laboratory and field conditions. Mean outdoor concentrations of PM2.5, BC, and UFP were significantly higher than either indoor or personal concentrations. Air exchange rates were low (median value only 0.2/h), there was widespread use of central forced air and high-quality furnace filters. Outdoor concentrations of all particle-related pollutants showed overnight decreases followed by increases during the morning rush hours. Afternoon concentrations increased for UFP and decreased for BC, with PM2.5 staying about the same. Between 5:00 pm and 7:00 pm, indoor UFP and PM2.5 concentrations exceeded their mean daily values by 160% and 60%, respectively, suggesting that cooking is an extremely important source for these two pollutants. However, BC values did not increase at these hours. The highest indoor–outdoor ratios were observed for UFP suggesting that indoor sources were relatively more important for UFP than for other particle components. BC measurements in Windsor agreed moderately well (R2 = 41%) with an independent measure of elemental carbon (EC) in Detroit. This large residential air pollution study has provided data making it possible to identify short-term variations and possible sources that can influence the relationships between pollutants and environments.

Windsor, Ontario Exposure Assessment Study: Design and Methods Validation of Personal, Indoor, and Outdoor Air Pollution Monitoring

ABSTRACT The Windsor, Ontario Exposure Assessment Study evaluated the contribution of ambient air pollutants to personal and indoor exposures of adults and asthmatic children living in Windsor, Ontario, Canada. In addition, the role of personal, indoor, and outdoor air pollution exposures upon asthmatic childrens respiratory health was assessed. Several active and passive sampling methods were applied, or adapted, for personal, indoor, and outdoor residential monitoring of nitrogen dioxide, volatile organic compounds, particulate matter (PM; PM ≤ 2.5 μm [PM2.5] and ≤ 10 μm [PM10] in aerodynamic diameter),elemental carbon, ultrafine particles, ozone, air exchange rates, allergens in settled dust, and particulate-associated metals. Participants completed five consecutive days of monitoring during the winter and summer of 2005 and 2006. During 2006, in addition to undertaking the air pollution measurements, asthmatic children completed respiratory health measurements (including peak flow meter tests and exhaled breath condensate) and tracked respiratory symptoms in a diary. Extensive quality assurance and quality control steps were implemented, including the collocation of instruments at the National Air Pollution Surveillance site operated by Environment Canada and at the Michigan Department of Environmental Quality site in Allen Park, Detroit, MI. During field sampling, duplicate and blank samples were also completed and these data are reported. In total, 50 adults and 51 asthmatic children were recruited to participate, resulting in 922 participant days of data. When comparing the methods used in the study with standard reference methods, field blanks were low and bias was acceptable, with most methods being within 20% of reference methods. Duplicates were typically within less than 10% of each other, indicating that study results can be used with confidence. This paper covers study design, recruitment, methodology, time activity diary, surveys, and quality assurance and control results for the different methods used. IMPLICATIONS It is important to obtain data to identify any factors that can influence the relationships among personal, indoor, and outdoor concentrations for a range of air pollutants. Ensuring that the methods used are valid and comparable to reference methods used in typical air pollution, monitoring is crucial for data to be of use to regulators. These exposure data can then be used to develop risk management policies that reduce personal and indoor exposures to air pollutants.

A randomized double‐blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community

UNLABELLED Few studies have examined indoor air quality in First Nations communities and its impact on cardiorespiratory health. To address this need, we conducted a crossover study on a First Nations reserve in Manitoba, Canada, including 37 residents in 20 homes. Each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week. Indoor air pollutants were monitored throughout the study period. Indoor PM2.5 decreased substantially during air filter weeks relative to placebo (mean difference: 37 μg/m(3) , 95% CI: 10, 64) but remained approximately five times greater than outdoor concentrations owing to a high prevalence of indoor smoking. On average, air filter use was associated with a 217-ml (95% CI: 23, 410) increase in forced expiratory volume in 1 s, a 7.9-mm Hg (95% CI: -17, 0.82) decrease in systolic blood pressure, and a 4.5-mm Hg (95% CI: -11, 2.4) decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM2.5 and lung function. In general, our findings suggest that reducing indoor PM2.5 may contribute to improved lung function in First Nations communities. PRACTICAL IMPLICATIONS Indoor air quality is known to contribute to adverse cardiorespiratory health, but few studies have examined indoor air quality in First Nations communities. Our findings suggest that indoor PM2.5 may contribute to reduced lung function and that portable air filters may help to alleviate these effects by effectively reducing indoor levels of particulate matter.

Impact of microenvironments and personal activities on personal PM2.5 exposures among asthmatic children

Personal activity patterns have often been suggested as a source of unexplained variability when comparing personal particulate matter (PM2.5) exposure to modeled data using central site or microenvironmental data. To characterize the effect of personal activity patterns on asthmatic children’s personal PM2.5 exposure, data from the Windsor, Ontario Exposure Assessment Study were analyzed. The children spent on an average 67.1±12.7% (winter) and 72.3±22.6% (summer) of their time indoors at home where they received 51.7±14.8% and 66.3±19.0% of their PM2.5 exposure, respectively. In winter, 17.7±5.9% of their time was spent at school where they received 38.6±11.7% of their PM2.5 exposure. In summer, they spent 10.3±11.8% ‘indoors away from home’, which represented 23.4±18.3% of their PM2.5 exposure. Personal activity codes adapted from those of the National Human Activity Pattern Survey and the Canadian Human Activity Pattern Survey were assigned to the children’s activities. Of the over 100 available activity codes, 19 activities collectively encompassed nearly 95% of their time. Generalized estimating equation (GEE) models found that, while indoors at home, relative to daytime periods when sedentary activities were conducted, several personal activities were associated with significantly elevated personal PM2.5 exposures. Indoor playing represented a mean increase in PM2.5 of 10.1 μg/m3 (95% CI 6.3–13.8) and 11.6 μg/m3 (95% CI 8.1–15.1) in winter and summer, respectively, as estimated by a personal nephelometer.

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.

The impact of a landfill fire on ambient air quality in the north: A case study in Iqaluit, Canada

A large landfill fire occurred in Iqaluit, Canada in spring/summer 2014. Air quality data were collected to characterize emissions as well as potential threats to public health. Criteria pollutants were monitored (PM2.5, O3, NO2) along with dioxins/furans, polycyclic aromatic hydrocarbons, and volatile organic compounds. Median daily dioxin/furan concentrations were 66-times higher during active burning (0.2 pg/m(3) Toxic Equivalency Quotient (TEQ)) compared to after the fire was extinguished (0.003 pg/m(3) TEQ). Other pollutants changed less dramatically. Our findings suggest that airborne concentrations of potentially harmful substances may be elevated during landfill fires even when criteria air pollutants remain largely unchanged.

Effect of venting range hood flow rate on size-resolved ultrafine particle concentrations from gas stove cooking

Abstract Cooking is the main source of ultrafine particles (UFP) in homes. This study investigated the effect of venting range hood flow rate on size-resolved UFP concentrations from gas stove cooking. The same cooking protocol was conducted 60 times using three venting range hoods operated at six flow rates in twin research houses. Size-resolved particle (10–420 nm) concentrations were monitored using a NanoScan scanning mobility particle sizer (SMPS) from 15 min before cooking to 3 h after the cooking had stopped. Cooking increased the background total UFP number concentrations to 1.3 × 103 particles/cm3 on average, with a mean exposure-relevant source strength of 1.8 × 1012 particles/min. Total particle peak reductions ranged from 25% at the lowest fan flow rate of 36 L/s to 98% at the highest rate of 146 L/s. During the operation of a venting range hood, particle removal by deposition was less significant compared to the increasing air exchange rate driven by exhaust ventilation. Exposure to total particles due to cooking varied from 0.9 to 5.8 × 104 particles/cm3·h, 3 h after cooking ended. Compared to the 36 L/s range hood, higher flow rates of 120 and 146 L/s reduced the first-hour post-cooking exposure by 76% and 85%, respectively.

Assessing the Value of Including Global Position System in Personal Exposure Monitoring Studies

Assessing the Value of Including Global Position System in Personal Exposure Monitoring Studies Gary Mallach, Andrew Davidson, Diego Ripley, Elizabeth Nethery, Keith van Ryswyk, Hongyu You, Mandy Fisher, Warren Foster, Elaine Moore, Tye Arbuckle, and Amanda Wheeler Air Health Science Division, Health Canada, Ottawa, Ontario, Canada; University of Waterloo, Waterloo, Ontario, Canada; Population Studies Division, Health Canada, Ottawa, Ontario, Canada; and McMaster University, Hamilton, Ontario, Canada.