P. Cascão

Wildland Smoke Exposure Values and Exhaled Breath Indicators in Firefighters

Smoke from forest fires contains significant amounts of gaseous and particulate pollutants. Firefighters exposed to wildland fire smoke can suffer from several acute and chronic adverse health effects. Consequently, exposure data are of vital importance for the establishment of cause/effect relationships between exposure to smoke and firefighter health effects. The aims of this study were to (1) characterize the relationship between wildland smoke exposure and medical parameters and (2) identify health effects pertinent to wildland forest fire smoke exposure. In this study, firefighter exposure levels of carbon monoxide (CO), nitrogen dioxide (NO2), and volatile organic compounds (VOC) were measured in wildfires during three fire seasons in Portugal. Personal monitoring devices were used to measure exposure. Firefighters were also tested for exhaled nitric oxide (eNO) and CO before and after their firefighting activities. Data indicated that exposure levels during firefighting activities were beyond limits recommended by the Occupational Exposure Standard (OES) values. Medical tests conducted on the firefighters also indicated a considerable effect on measured medical parameters, with a significant increase in CO and decrease in NO in exhaled air of majority of the firefighters.

Pedestrian Exposure to Air Pollution in Cities: Modeling the Effect of Roadside Trees

The exposure of students to traffic-emitted carbon monoxide (CO) in their daily walk to school is evaluated, with a particular emphasis on the effect of trees and route choice. The study is focused on the city centre of Aveiro, in central Portugal. Time evolution of the georeferenced location of an individual is tracked with a GPS for different alternative walking routes to a school. Spatial distribution of CO concentration is simulated with a computational fluid dynamics (CFD) model. An exposure model is developed that associates the georeferenced location of the student with the computed air quality levels (at an average breathing height) for that specific grid cell. For each individual, the model calculates the instantaneous exposure at each time frame and the mean value for a given period. Results show a general benefit induced by the trees over the mean exposure of the student in each route. However, in the case of instantaneous exposure values, this is not consistent along the entire period. Also, the variability of the estimated exposure values indicates the potential error that can be committed when using a single value of air quality as a surrogate of air pollution exposure.

Impact of urban planning alternatives on air quality: URBAIR model application

In the last decades, the study of the urban structure impacts on the quality of life and on the environment became a key issue for urban sustainability. Nowadays the relevance of urban planning for the improvement of the interactions between different land uses and economic activities, and also towards a more sustainable urban metabolism, is consensually accepted. A major interest relies on understanding the role of planning on induced mobility patterns and thereafter on air quality, particularly related with the increasing use of private cars. This is one of the main objectives of BRIDGE, a research project funding by the European Commission under the 7 th Framework Programme and focused on “SustainaBle uRban plannIng Decision support accountinG for urban mEtabolism”. In this scope, and to evaluate the impact on air quality due to different city planning alternatives (PA), the urban scale air quality modelling system URBAIR was applied to selected areas in Helsinki (Finland), Athens (Greece) and Gliwice (Poland), to estimate traffic related emissions and induced pollutant concentration of different air pollutants, in a hourly basis for the entire year of 2008. For the Helsinki study case the results suggest that urban traffic and building placement considered on the different PA have an influence on local air quality despite no significant concentration levels. In the Athens case study some PA induce a decrease on traffic flows with an improvement of the air quality over the domain. On the contrary, other leads to an increase of PM10 in selected hotspots. The simulations for the Gliwice study case show minor changes between the baseline and the PA, since the proposed interventions do not imply major changes in traffic flows.

Modelling the Effects of Urban Morphology, Traffic and Pedestrian Dynamics on Students’ Exposure to Air Pollution

The United Nations Environment Programme stated that the human exposure to air pollutants primarily emitted by road traffic is associated to nearly 0.8 million premature deaths annually, especially in sensitive groups such as children. This paper evaluates the individual exposure of students in a Portuguese town accounting for their walk to school and the time spent in the classroom. The analysis was carried out for 8 hypothetical walking routes that were tracked and profiled with a GPS. Ambient air pollutant concentrations of CO and PM10 were simulated with a Computational Fluid Dynamics (CFD) model, while indoor air pollutant levels were estimated for different classrooms using the simulated outdoor concentrations and a mass transfer approach. Results show that the individual exposure of pedestrians in a city is extremely spatially dependent, as a consequence of air pollutant dispersion patterns, leading to significant disparities between the children’s exposure. A tendency between the orientation of classroom’s facade and resulting exposure was not found, but in the case of the outdoor exposure the children coming from N and NE have the highest values. The variability of the estimated exposure values shows the magnitude of the error that can be committed when using a single value of air quality as a surrogate of air pollution exposure. This problem can be overcome by using building-resolving CFD models that provide an accurate and detailed understanding of how human behaviour and habits can affect the exposure of urban citizens and ultimately their health.

Characterization of Exhaust Emissions from A EURO 5 Light Passenger Vehicle Using Biodiesel Blends

The authors have performed experiments using a EURO 5 light passenger vehicle, operated over the New European Driving Cycle (NEDC). Fuel blends containing 7% (B7) and 20% (B20) of biodiesel (84% soyabean/16% palm) in petroleum-based diesel were tested and compared with a diesel fuel (B0). The exhaust gases emissions were assessed for NO, NO₂, SO₂ and volatile organic compounds (VOC), including a speciation analysis of VOC. The experiment reveals that biodiesel blends improve the combustion efficiency, NO and SO₂ emissions, and increasing NO₂ and total VOC emissions. The VOC speciation analysis suggests that the type and fraction of VOC existent in exhausted gases is fuel dependent, changing their presence and concentrations according to the fuel used. Additionally, the concentration of the three main VOC species in exhaust gases from B0 (benzene, toluene and octane) decrease 60-80% if a B20 blend is used. This experimental study contributes to a better characterization of the emission factors of EURO 5 light passenger vehicles using diesel/biodiesel blends and to a better understanding of the impact of the use of biodiesel blends on pollutant emissions.

Modelling of tree-induced effects on pedestrian exposure to road traffic pollution

According to the United Nations Environment Programme (UNEP) information in 2009, at least 1 billion people are exposed to outdoor air pollution that exceeds the air quality standards of the World Health Organization (WHO). Poor air quality in urban areas, mainly associated with the transportation sector, has been directly linked to almost 0.8 million premature deaths annually, especially in sensitive groups such as children. In this context, the role of trees on improving urban air quality has been discussed. However, there is still a scarce understanding on the ultimate impact of trees over the exposure of pedestrians. This paper evaluates the exposure of students in their daily walk to/from school, and how it relates with the effect of trees over the local concentrations of road traffic-emitted air pollutants. The study is focused on an area of 0.380.22 km 2 centred at a high school of the city of Aveiro, in central Portugal, which is located close to a road with significant traffic. A period of one day was chosen, based on data availability. Time evolution of georeferenced location of an individual was tracked with a GPS for different alternative walking routes to the school. Air quality and meteorological data were measured in the school yard. Simulations of carbon monoxide (CO) concentrations in the study domain were performed with the Computational Fluid Dynamics (CFD) model VADIS, with and without considering the influence of trees over the dispersion. Traffic emissions were estimated with the TREM model, using traffic counts (with vehicles categories discretization) data. Simulated wind speed and CO concentrations were compared with measured values showing a very good agreement (normalized mean square error, NMSE, equals 0.29 and 0.04, respectively). An exposure model was developed that associates the georeferenced location of the student with the computed air quality

Monitoring fire-fighters' smoke exposure and related health effects during Gestosa experimental fires

The main objective of this study is to contribute to the scientific knowledge regarding fire-fighters’ exposure to smoke and its related health effects. Forest fire experiments were developed with an extensive number of measurements of individual exposure to smoke pollutants and of medical parameters for a group of fire-fighters. For the smoke exposure monitoring, ten fire-fighters from four different fire brigades were selected. The fire-fighters’ individual exposure to toxic gases and particulate matter was monitored with portable devices, and their location in time was registered with GPS equipment. For all the monitored fire-fighters, air pollutant concentration values acquired during the fire experiments were beyond the limits recommended by the World Health Organization (WHO), namely for PM2.5, CO and NO2. Daily averages of PM2.5 concentration values as high as 738 µg.m -3 were obtained, well above the recommended limit of 25 µg.m -3 . In terms of CO, hourly averaged values higher than 73,000 µg.m -3 were monitored, clearly above the 30,000 µg.m -3