Quantifying decade-long effects of fuel and traffic regulations on urban ambient PM 2.5 pollution in a mid-size South American city

Most of urban air quality studies focus on the megacities of North America, Europe and, recently, Asia. Meanwhile, the most polluted urban areas in the world are rapidly growing large, mid-size and small cities of Asia, Middle East, Africa and South America. This raises a question: why relatively smaller cities are more polluted than the megacities? This study presents the first comprehensive decade-long analysis of the effects of fuel and transport regulations on PM2.5 (particulate matter of aerodynamic diameter <2.5 μm) pollution in Quito, a medium-size city of South America. The effectiveness of a number of regulations is quantified through the elaboration of a high accuracy (98%) regression model. The model estimated that the PM2.5 concentrations were reduced by 67.6 μg/m3, combating the effect of city growth and intense motorization, reducing the annual PM2.5 concentrations to 17.4 μg/m3. This study is recommended as a guideline for thousands of other cities worldwide looking for optimal urban particulate pollution management. © 2017 Turkish National Committee for Air Pollution Research and Contro

Assessment of indoor and outdoor PM species at schools and residences in a high-altitude Ecuadorian urban center

An air monitoring campaign to assess children’s environmental exposures in schools and residences, both indoors and outdoors, was conducted in 2010 in three low-income neighborhoods in Z1(north), Z2(central), and Z3(southeast) zones of Quito, Ecuador - a major urban center of 2.2 million inhabitants situated 2850 meters above sea level in a narrow mountainous basin. Z1 zone, located in northern Quito, historically experienced emissions from quarries and moderate traffic. Z2 zone was influenced by heavy traffic in contrast to Z3 zone which experienced low traffic densities. Weekly averages of PM samples were collected at schools (one in each zone) and residences (Z1=47, Z2=45, and Z3=41) every month, over a twelve-month period at the three zones. Indoor PM(2.5) concentrations ranged from 10.6±4.9 μg/m(3) (Z1 school) to 29.0±30.5 μg/m(3) (Z1 residences) and outdoor PM(2.5) concentrations varied from 10.9±3.2 μg/m(3) (Z1 school) to 14.3±10.1 μg/m(3) (Z2 residences), across the three zones. The lowest values for PM(10–2.5) for indoor and outdoor microenvironments were recorded at Z2 school, 5.7±2.8 μg/m(3) and 7.9±2.2 μg/m(3), respectively. Outdoor school PM concentrations exhibited stronger associations with corresponding indoor values making them robust proxies for indoor exposures in naturally ventilated Quito public schools. Correlation analysis between the school and residential PM size fractions and the various pollutant and meteorological parameters from central ambient monitoring (CAM) sites suggested varying degrees of temporal relationship. Strong positive correlation was observed for outdoor PM(2.5) at Z2 school and its corresponding CAM site (r=0.77) suggesting common traffic related emissions. Spatial heterogeneity in PM(2.5) concentrations between CAM network and sampled sites was assessed using Coefficient of Divergence (COD) analysis. COD values were lower when CAM sites were paired with outdoor measurements (< 0.2) and higher when CAM and indoor values were compared (> 0.2), suggesting that CAM network in Quito may not represent actual indoor exposures