Assessing the Impact of Vehicle Speed Limits and Fleet Composition on Air Quality Near a School

Abstract

Traffic is a major source of urban air pollution that affects health, especially among children. As lower speed limits are commonly applied near schools in many cities, and different governments have different policies on vehicle fleet composition, this research estimated how different speed limits and fleet emissions affect air quality near a primary school. Based on data of traffic, weather, and background air quality records in Dublin from 2013, traffic, emission, and dispersion models were developed to assess the impact of different speed limits and fleet composition changes against current conditions. Outside the school, hypothetical speed limit changes from 30 km/h to 50 km/h could reduce the concentration of NO2 and PM10 by 3% and 2%; shifts in the fleet from diesel to petrol vehicles could reduce these pollutants by 4% and 3% but would increase the traffic-induced concentrations of CO and Benzene by 63% and 35%. These changes had significantly larger impacts on air quality on streets with higher pollutant concentrations. Findings suggest that both road safety and air quality should be considered when determining speed limits. Furthermore, fleet composition has different impacts on different pollutants and there are no clear benefits associated with incentivising either diesel or petrol engine vehicles.

The effect of the ventilation retrofit in a school on CO2, airborne particles, and energy consumptions

“…Different recent studies paid close attention to airborne particles including both indoor-generated super-micron particles (PM 2.5 , PM 10 ) and outdoor-generated traffic-related sub-micron particles [21,[36][37][38][39][40]. Several papers recognized that high exposure to particles can be measured in schools placed in urban areas and/or close to main roads [37,[41][42][43][44]. Such high exposure lead to not negligible contribution of the school-time to the daily dose of particle received by children and, then, to health risks and effects higher than the acceptable levels [25,37,45,46].…”

Análisis espacial de PM10 en el aire y su composición de metales con relación a factores ambientales alrededor de centros de educación preescolar en Cuenca

“…El Pb está relacionado con el uso de frenos y neumáticos para mantener las bajas velocidades promedio de circulación en calles (50 km/h) en comparación con las avenidas (90 km/h). Además de que las bajas velocidades de circulación generan una mayor cantidad de contaminantes, especialmente en áreas de alto tráfico vehicular (Tang, McNabola, Misstear, Pilla, & Alam, 2019). Finalmente, el PM10 y Zn fueron los únicos contaminantes que presentaron una correlación positiva con el número de líneas de transporte público alrededor de los puntos de monitoreo.…”

Australian childcare centres are too close to car parks exposing children with developing lungs to high levels of traffic pollution

“…[2][3][4] The slow speeds of vehicles, stop-start nature of movement and high degrees of braking also generate higher levels of emissions, with cars generally being most efficient when at a constant/cruising speed. 5 There is currently no evidence that a safe level of exposure to traffic-related air pollution (TRAP) exists -any level of exposure may have adverse effects. 6 The link between exposure to vehicle pollutants and respiratory disease in both children and adults is strongly supported.…”

“…Car parks present additional issues as they attract increased traffic and high levels of pollutants generated by idling cars and cold starts of engines 2–4 . The slow speeds of vehicles, stop‐start nature of movement and high degrees of braking also generate higher levels of emissions, with cars generally being most efficient when at a constant/cruising speed 5 . There is currently no evidence that a safe level of exposure to traffic‐related air pollution (TRAP) exists – any level of exposure may have adverse effects 6…”