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This study investigates temporal variations and long-term (1996–2015) trends of ground-level O3 (ozone) and its precursors, NOx (nitrogen oxides), and volatile organic compounds in Windsor, Ontario, Canada. During the 20-year study period, NOx , non-methane hydrocarbon concentrations, and ozone formation potential decreased significantly by 58 %, 61 %, and 73 %, respectively, while O3 concentrations increased by 33 % (20.3 ppb in 1996 vs. 27 ppb in 2015). Our analysis revealed that the increased annual O3 concentrations in Windsor were due to (1) decreased O3 titration (by 50 % between 1996 and 2015) owing to declining nitric oxide concentrations, which is suggested by a slightly decreasing trend of annual mean total O3 concentrations after the titration effect is removed, (2) reduced local photochemical production of O3 because of dwindling precursor emissions, and (3) an increased background O3 level that has a greater impact on the low-to-median concentrations. The net effect of those factors is decreasing peak O3 levels during the smog season from May to September but an overall increasing trend of annual means. These results indicate that the emission control measures are effective in reducing peak ozone concentrations. However, challenges in lowering annual O3 levels call for long-term collaborative efforts in the region and around the globe. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Annoyance produced by air pollution has been suggested as a useful proxy for determining ambient air pollution exposure. However, most of the studies, to date, have focused on nitrogen dioxide and sulphur dioxide, with no work done on volatile organic compounds (VOC). This study is aimed at examining the associations between odour annoyance and VOC in 'Chemical Valley', Sarnia, Ontario, Canada. Annoyance scores were extracted from a community health survey ( N = 774), and exposures to VOC were estimated from respondents' six-digit alphanumeric postal codes using land use regression models. Univariate analyses were used to explore the relationships between odour annoyance and modelled pollutants, whilst multivariate ordinal logistic regression was utilized to examine the determinants of odour annoyance. The results indicate that odour annoyance is significantly associated with modelled benzene, toluene, ethylbenzene, o-xylene and ( m + p) xylene (BTEX) pollutants. The findings also show that the determinants of odour annoyance in the context of VOC include gender, number of relatives in the community, perception of air pollution, community satisfaction, medical checkups, ability to cope with daily life demands and general symptoms. When compared, the analysis indicates that Sarnia residents respond to considerably lower BTEX concentrations than the allowable 'safe' levels in the province of Ontario. In general, the results exhibit a dose-response gradient with annoyance score increasing with rising modelled pollutant concentrations. The observed relationships suggest that odour annoyance might be a function of true exposure and may serve as a proxy for air quality and ambient air pollution monitoring. However, questionnaire-based odour annoyance scores need to be longitudinally validated across different geographical scales and pollutants if they are to be adopted at the national level. [ABSTRACT FROM AUTHOR]

Abstract: An air quality monitoring study focusing on spatial patterns was carried out in the urban industrial city of Windsor, Ontario, Canada (42.267°N, 82.95°W). This study took place over a three-year period (2004–2006), during all four seasons for a total of 12 two-week sampling periods (each with approximately 50 sites) at 162 sites across the city. Benzene, toluene, ethylbenzene, (m + p)-xylene, and o-xylene (BTEX) were measured using 3M #3500 Organic Vapor Samples (Guillevan, Montreal). Results from this investigation indicate that significant variability is present temporally (seasonally and annually) and spatially. The three-year mean concentrations in μg m−3 were: benzene (0.76), toluene (2.75), ethylbenzene (0.45), o-xylene (0.47), (m + p)-xylene (1.36), and total BTEX (5.64), with greater variability within each year compared with variability between the three years. Concentrations were highly correlated between most BTEX species, consistent with previous studies in urban areas. Toluene to benzene ratios were consistent between years, with the highest observed ratios occurring in summer, the lowest in winter, and fall and spring values falling in between. The range of ratios suggests that the majority of these two compounds originate from mobile emissions. (m + p)-Xylene to ethylbenzene ratios, used as indicators of photochemical age, showed a three-year mean of 3.0 with little spatial and temporal variability suggesting that relatively fresh and homogenous sources of these species are present in this area. The seasonal trends across the spatial network were representative of the seasonal patterns obtained at a long term monitoring station, with both methods indicating that fall and spring concentrations were preferred proxies of annual means. However, significant spatial variability of concentrations was observed. The upper range of concentrations compared with the values obtained at the central monitoring station differed by up to a factor of six, highlighting the importance of multiple sampling sites to reduce exposure misclassification. Significant correlations between seasons were observed in all three years, revealing a consistent rank order of high to low concentrations among the monitoring sites within a given year. Consideration of all analyses suggests that when resources are limited to a single sampling season, fall and spring mean values for concentrations and ratios seem to best represent the annual average in this city. Other study design consideration suggestions are also provided for future air quality research. [Copyright &y& Elsevier]

Land use regression (LUR) models have been widely used to characterize the spatial distribution of urban air pollution and estimate exposure in epidemiologic studies. However, spatial patterns of air pollution vary greatly between cities due to local source type and distribution. London, Ontario, Canada, is a medium-sized city with relatively few and isolated industrial point sources, which allowed the study to focus on the contribution of different transportation sectors to urban air pollution. This study used LUR models to estimate the spatial distribution of nitrogen dioxide (NO2) and to identify local sources influencing NO2concentrations in London, ON. Passive air sampling was conducted at 50 locations throughout London over a 2-week period in May–June 2010. NO2concentrations at the monitored locations ranged from 2.8 to 8.9 ppb, with a median of 5.2 ppb. Industrial land use, dwelling density, distance to highway, traffic density, and length of railways were significant predictors of NO2concentrations in the final LUR model, which explained 78% of NO2variability in London. Traffic and dwelling density explained most of the variation in NO2concentrations, which is consistent with LUR models developed in other Canadian cities. We also observed the importance of local characteristics. Specifically, 17% of the variation was explained by distance to highways, which included the impacts of heavily traveled corridors transecting the southern periphery of the city. Two large railway yards and railway lines throughout central areas of the city explained 9% of NO2variability. These results confirm the importance of traditional LUR variables and highlight the importance of including a broader array of local sources in LUR modeling. Finally, future analyses will use the model developed in this study to investigate the association between ambient air pollution and cardiovascular disease outcomes, including plaque burden, cholesterol, and hypertension. [ABSTRACT FROM AUTHOR]

This study analyzes the crashes that occur at midblock called “midblock crashes” in an urban arterial road. The association of midblock crashes with various factors was examined using the 7-year (2000–2006) crash data on a section of a divided arterial road in Windsor, Ontario, Canada. To account for difference in traffic volume and road geometric factors between two directions of travel in a divided road, the data were collected for two directions separately. The results of log-linear models using these bidirectional data show that midblock crashes are more likely to occur on the road sections with access points and high percentage of trucks (>20%). The results of logistic regression models show that median opening, driver age/gender, lighting, time of day, and day of week are associated with different types of crashes classified by the vehicles involved in crashes. The study shows the importance of analyzing midblock crashes using the bidirectional data by vehicle type in urban divided arterial roads with high truck volume. [ABSTRACT FROM AUTHOR]

Abstract: Windsor (Ontario) is located on the Canada-US border. Some believe that the heavy industrial facilities such as power generation and automobile production in the neighbouring regions of US greatly affect Windsor''s air quality. This study investigates the frequency of air mass exchange between Windsor and the neighbouring US states. Two-day (48-hr) and one-day (24-hr) back trajectories were run using the Hybrid Single-Particle Langrangian Integrated Trajectory (HYSPLIT) model. Windsor Airport (42.27o N, 82.96o W) was the starting point. The model resolution was three days a week. Two calendar years, 2008 and 2009, were modeled thus seasonal and inter-annual variations could be observed. It was found that the fraction of air mass parallel to the border is small. When considering the 48-hr trajectories on an annual basis, 53-55% of air masses arriving Windsor were from the US, whereas the 24-hr trajectories showed a much higher percentage (81-82%). The inter-annual variability between 2008 and 2009 was small. In both years, winter had higher frequency of US to Canada transport than Canada to US. In the other three seasons (spring, summer and fall), one year had more frequent US to Canada transport while the other year had less. It was concluded that overall the US-Canada transport had a higher frequency. However, this alone is inadequate to support the claim of air masses coming from US greatly affect Windsor air quality. Further analyses using state and province wide emission densities and ambient concentrations were conducted for a two-week period during each year to quantitatively assess the trans-boundary movement of air pollutants. Statistical analyses showed no consistent, significant correlations between the travel path of the air mass prior to arrival and the measured NO2 or PM2.5 concentrations at the receptor. [Copyright &y& Elsevier]

There are acknowledged difficulties in epidemiological studies to accurately assign exposure to air pollution for large populations, and large, long-term cohort studies have typically relied upon data from central monitoring stations. This approach has generally been adequate when populations span large areas or diverse cities. However, when the effects of intra-urban differences in exposure are being studied, the use of these existing central sites are likely to be inadequate for representing spatial variability that exists within an urban area. As part of the Border Air Quality Strategy (BAQS), an international agreement between the governments of Canada and the United States, a number of air health effects studies are being undertaken by Health Canada and the US EPA. Health Canada''s research largely focuses on the chronic exposure of elementary school children to air pollution. The exposure characterization for this population to a variety of air pollutants has been assessed using land-use regression (LUR) models. This approach has been applied in several cities to nitrogen dioxide (NO2), as an assumed traffic exposure marker. However, the models have largely been developed from limited periods of saturation monitoring data and often only represent one or two seasons. Two key questions from these previous efforts, which are examined in this paper, are: If NO2 is a traffic marker, what other pollutants, potentially traffic related, might it actually represent? How well is the within city spatial variability of NO2, and other traffic-related pollutants, characterized by a single saturation monitoring campaign. Input data for the models developed in this paper were obtained across a network of 54 monitoring sites situated across Windsor, Ontario. The pollutants studied were NO2, sulfur dioxide (SO2) and volatile organic compounds, which were measured in all four seasons by deploying passive samplers for 2-week periods. Correlations among these pollutants were calculated to assess what other pollutants NO2 might represent, and correlations across seasons for a given pollutant were determined to assess how much the within-city spatial pattern varies with time. LUR models were then developed for NO2, SO2, benzene, and toluene. A multiple regression model including proximity to the Ambassador Bridge (the main Canada—US border crossing point), and proximity to highways and major roads, predicted NO2 concentrations with an R 2=0.77. The SO2 model predictors included distance to the Ambassador Bridge, dwelling density within 1500m, and Detroit-based SO2 emitters within 3000m resulting in a model with an R 2=0.69. Benzene and toluene LUR models included traffic predictors as well as point source emitters resulting in R 2=0.73 and 0.46, respectively. Between season pollutant correlations were all significant although actual concentrations for each site varied by season. This suggests that if one season were to be selected to represent the annual concentrations for a specific site this may lead to a potential under or overestimation in exposure, which could be significant for health research. All pollutants had strong inter-pollutant correlations suggesting that NO2 could represent SO2, benzene, and toluene. [Copyright &y& Elsevier]

As part of a multi-year personal exposure monitoring campaign, we collected personal, indoor, and outdoor levels of 188 volatile organic compounds (VOCs). In 2005, data were obtained for 48 non-smoking adults from Windsor, Ontario in order to assess their exposure to VOCs based on their daily routines and characteristics of their homes. During the 8-week winter and summer sampling sessions, five repeated 24-h measurements were obtained for each home. This paper focuses on the analysis of 18 VOCs: 11 have been declared toxic as defined under the Canadian Environmental Protection Act, [1999. Statutes of Canada. Act assented to September 14, 1999. Ottawa: Queen''s Printer. Available at Canada Gazette (Part III) 22(3): (Chapter 33). http://canadagazette.gc.ca/partIII/1999/g3-02203.pdf], and seven are commonly found in household and personal care products. Results of mixed effects models indicate that personal exposure to these VOCs can be largely predicted by indoor concentrations, with models including indoor concentrations found to have an r 2 value for the fixed effects ranging from 58.4% to 87.2% for the CEPA toxic VOCs and from 41.7% to 90.1% for the commonly found VOCs. Given that people spend the majority of their time inside their home, characteristics of the home such as air exchange rates, type of garage, and type of stove have a greater potential to impact personal exposures. [Copyright &y& Elsevier]

Photovoltaic (PV) system is widely recognized as one of the cleanest technologies for electricity production, which transforms solar energy into electrical energy. However, there are considerable amounts of emissions during its life cycle. In this study, life cycle assessment (LCA) was used to evaluate the environmental and human health impacts of PV electricity production in Canada. The PV potential varies considerably among the provinces, with higher values in Manitoba (MB), Saskatchewan (SK), Alberta (AB), and southern Ontario (ON). A grid-connected slanted-roof mono-crystalline silicon (mono-Si) PV system with a capacity of 3 kWp (the peak power of the system in kilowatts) in Toronto, Ontario, was considered as the case study system. Ten impact categories were considered including (1) acidification, (2) carcinogenic, (3) ecotoxicity, (4) eutrophication, (5) fossil fuel depletion, (6) global warming, (7) non-carcinogenic, (8) ozone depletion, (9) respiratory effects, and (10) smog. Among the four components of the PV system, i.e., mono-Si panel, mounting system, inverter, and electric installation, the mono-Si panel production was the highest contributor in seven out of ten impact categories, including acidification (68%), eutrophication (60%), fossil fuel depletion (81%), global warming (77%), ozone depletion (88%), respiratory effects (74%), and smog (70%). For the other three processes, the electric installation contributed most to ecotoxicity at 58%, followed by the mounting system in the carcinogenic category (29%), and the inverter in the non-carcinogenic category (31%). By normalizing the impacts based on the reference scores in Canada, it was found that the ecotoxicity and carcinogenic categories had dominant contributions to the overall impact by 53% and 42%, respectively. The global warming potential impact was estimated as 79 gr CO 2 eq /kWh, which is close to the mean value of 79.5 gr CO 2 eq /kWh, reported in the literature. The sensitivity analysis indicated that a 10% increase in the panel and mounting system area will increase the ozone depletion and carcinogenic categories by 8.1% and 2.8%, respectively., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The aim of this study was to assess how children's personal exposure to fine particulate matter (PM 2.5 ) during the school commute is influenced by mode of travel and neighborhood environment in a mid-sized Canadian city. A total of 101 commutes to and from school were tracked using a GPS, and personal exposure to PM 2.5 along commute routes was assessed by spatially-referencing the monitored exposure levels with time-synchronized GPS data. Students who walked to and from school were exposed to lower PM 2.5 concentrations than those in cars or riding the school bus. There was also a significant difference in mean PM 2.5 concentrations by the built environment, with children who walked to school in suburban neighborhoods experiencing higher personal concentrations than children in urban neighborhoods. To reduce children's daily exposure to air pollutants, neighborhoods should be designed to maximize the number of children who are able to walk between home and school., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The Geospatial Determinants of Health Outcomes Consortium (GeoDHOC) study investigated ambient air quality across the international border between Detroit, Michigan, USA and Windsor, Ontario, Canada and its association with acute asthma events in 5- to 89-year-old residents of these cities. NO2, SO2, and volatile organic compounds (VOCs) were measured at 100 sites, and particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) at 50 sites during two 2-week sampling periods in 2008 and 2009. Acute asthma event rates across neighborhoods in each city were calculated using emergency room visits and hospitalizations and standardized to the overall age and gender distribution of the population in the two cities combined. Results demonstrate that intra-urban air quality variations are related to adverse respiratory events in both cities. Annual 2008 asthma rates exhibited statistically significant positive correlations with total VOCs and total benzene, toluene, ethylbenzene and xylene (BTEX) at 5-digit zip code scale spatial resolution in Detroit. In Windsor, NO2, VOCs, and PM10 concentrations correlated positively with 2008 asthma rates at a similar 3-digit postal forward sortation area scale. The study is limited by its coarse temporal resolution (comparing relatively short term air quality measurements to annual asthma health data) and interpretation of findings is complicated by contrasts in population demographics and health-care delivery systems in Detroit and Windsor.

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/m(3) (95% CI 6.3-13.8) and 11.6 μg/m(3) (95% CI 8.1-15.1) in winter and summer, respectively, as estimated by a personal nephelometer.

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 children's 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 pm [PM2.5] and < or =10 microm [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.

As part of a community health study, an air quality investigation was carried out in Sarnia, Ontario, Canada, which is located within a government-designated "Area of Concern". The Sarnia area, also known as Chemical Valley, has been known to have an abundance of air quality problems that are frequently attributed to the large number of chemical companies located in the area, which are among the largest industrial sources of criteria air pollutants in Canada. Ambient volatile organic compounds (VOC) were monitored during a 2-wk period in October 2005 at 37 sites across the city of Sarnia, using 3M organic vapor monitors. The spatial variability was investigated using ranking and mapping techniques to identify spatial patterns of the VOC across the city. The results show a large spatial variability of most of the VOC investigated. Furthermore, most of the VOC were highly correlated, suggesting common sources in Sarnia. The results also indicate that the industrial and chemical facilities strongly influence the concentrations of VOC in Sarnia, with higher outdoor VOC levels found closer to industrial facilities. The measured VOC and those obtained from a long-term government monitoring station were compared. It was determined that the exposure gradients observed during the study period are relatively representative of the long-term pattern. The results of this study will be used for the community health study.