Extreme concentrations of fine particulate matter and black carbon during commute

<p>Commuters are vulnerable to traffic air pollutants, especially to fine particulate matter (PM<sub>2.5</sub>) and black carbon (BC) because of their proximity to on-road vehicles. Both pollutants have been extensively associated to adverse health effects (i.e., stroke, diabetes, cardiovascular and respiratory diseases, and cancer). Therefore, this work aims to investigate the extreme concentrations of PM<sub>2.5</sub> and BC occurrence in commuters in the megacity of São Paulo, Brazil. We carried out a field campaign measuring the commuter exposure to PM<sub>2.5</sub> and BC concentrations inside buses, cars and undergrounds in São Paulo during morning and evening peak-hours. We fitted an Extreme Value Distribution to the collected data to investigate the behavior of the extreme values in the different transport modes and periods of the day. The results suggest that higher concentrations of PM<sub>2.5</sub> and BC occur more frequently inside buses, followed by cars and undergrounds. Extreme concentrations for both pollutants are more likely to happen during morning peak-hours when compared to evening peak-hours. Our findings add further evidence that the transport mode and period of the day affect substantially the PM<sub>2.5</sub> and BC exposure in commuters. Furthermore, the results are quite useful for supporting urban policies that consider the improvement of the efficiency of air filtering systems inside public transport and private cars.</p>

Commuter Exposure to Black Carbon, Fine Particulate Matter and Particle Number Concentration in Ferry and at the Pier in Istanbul

This paper presents measurements and analyses of the concentrations of black carbon (BC), particle number concentration (PNC), and PM2.5 (≤2.5 μm) while commuting by ferries in Istanbul. In this context, exposures to the mentioned pollutants were estimated for car ferry, fast ferry, and at the piers, and for two travel routes, for a total of 89 trips. BC, PNC, and PM2.5 measurements were simultaneously performed in a ferry and at the piers, and the correlation between pollutant concentrations, meteorological parameters, and environmental factors were analyzed. The mean concentrations for all pollutants in car ferry were lower than the average concentrations in fast ferry. The concentration ratios of fast ferry to car ferry for BC, PNC, and PM2.5 were 6.4, 1.2, and 1.3, respectively. High variability in the concentrations was observed at the piers and in ferry during berthing. The highest mean concentrations (±standard deviation) of BC (14.3 ± 10.1 µg m−3) and PNC (42,005 ± 30,899 pt cm−3) were measured at Yalova pier. The highest mean concentration (±standard deviation) of PM2.5 (26.1 ± 11.5) was measured at Bostancı pier. It was observed that the main external sources of BC, PNC, and PM2.5 at the piers were road transport, residential heating, and shipping activity. There were no significant correlations between BC, PNC, and PM2.5 in fast ferry, while BC was positively correlated with PNC (r = 0.61, p < 0.01) and PM2.5 (r = 0.76, p < 0.01) in car ferry. At the piers, significant relations between pollutants and meteorological variables were observed. It was noticed that there was no significant difference between summer and winter in ferry and at the pier concentrations of BC, PNC, and PM2.5 except for Yenikapı pier and Bakırköy pier. The highest total exposure to PNC and PM2.5 was in car ferry mode, while the highest total exposure to BC was in fast ferry mode.