2013 Research Highlights

Air pollution and health

Air quality is a critical issue because even small amounts of air pollutants can cause significant adverse health effects. Road traffic is a major contributor to air pollution both through aerosols from exhaust emissions (EE) and non-exhaust emissions (NEE). The latter result from mechanical abrasion of brakes and tires, erosion of road surfaces and resuspension of road dust into the atmosphere by passing traffic. EE have been extensively characterized and have declined over time due to mitigation measures. By contrast, NEE have been less studied, are not tightly regulated and there are limited data on their toxicity. Thus, NEE relative part has become prevalent, potentially making of these emissions a major human health concern. The aim of this systematic review was to provide an overview of the current state of knowledge on the biological effects of NEE. We paid particular attention to the toxicological effects of Tire and Road Wear Particles (TRWP) induced in vitro and in vivo in mammalian models. To this end, we performed a bibliographic search in two databases (PubMed and Web of Science). Of the 400 papers, 22 were found to be relevant and included in our analysis, confirming that the assessment of the TRWP toxicity in mammalian models is still limited. This review also reports that oxidative stress and inflammation are the main mechanisms underlying the toxicity of TRWP.

Traditionally, vehicle emissions measurements rely on reference-grade instruments whose high cost and complexity have limited their deployment in real-world environments. New simple-to-operate, low-cost sensing technologies are a potential solution to this problem. To assess their suitability, we deployed six Sensit Real-time, Affordable, Multi-Pollutant (RAMP) monitors measuring PM_2.5, NO, NO₂, CO₂, O₃ and CO in three parking garages on the UBC Vancouver campus from April–August 2019. UBC Parking Services provided real-time vehicle counts to help validate our method. After sensor calibration, integrated pollutant and CO₂ signals were converted to fuel-based emission factors (EFs). Our calculated EFs fell within the range of previous studies. Evening EFs when vehicles were cold were 10–50% higher than in the morning. We also observed a disproportional contribution of high emitters; the top 25% of plumes contributed 45–65% of total emissions. Our findings indicate that low-cost sensors are a promising technology for real-world vehicle emissions measurement.

Particulate matter (PM) in the air is one of the several challenges that densely built urban areas are facing today, and the severe health risks that PM poses to a city's inhabitants are well known. While the sources of increase in PM levels could arise from a combination of several factors, it is imperative to take the necessary measures to maintain a ‘healthy’ city. One such measure is to install air treatment systems that filter out PM from the surrounding air. The effectiveness of such air treatment units in an urban setting is investigated using Computational Fluid Dynamics (CFD). For the configuration used in this study, the mean performance of filters in reducing the uniform background PM levels is found to be approximately 11.4%. If PM sources due to traffic is also included, then the mean performance of filters in reducing the increased ambient PM levels is 7.6%. This study shows that introduction of such air treatment systems are generally effective in reducing outdoor PM levels and can be considered as one of the mitigation measures to improve the air quality.

Air pollution is a major environmental concern. Children are highly exposed to air pollution because they spend much time outdoors and have a high breathing rate. Detrimental cardiovascular and respiratory effects of air pollution are well documented. Recently, the neurobehavioral effects in children have received a considerable amount of attention. A number of epidemiological studies have observed a negative association of long-term air pollution exposure with intelligence and cognitive skills such as memory and attention. Additionally, some preliminary human data suggest that air pollution exposure is associated with an increased risk of neurodevelopmental conditions such as autism and attention-deficit/hyperactivity disorder. The causality of the association between air pollution exposure and negative neurobehavioral outcomes during childhood has been supported by experimental animal studies, although only some of them used environmentally relevant exposure levels.