HOW MUCH CARBON MONOXIDE DO WE INHALE WHILE RIDING A BICYCLE IN A MODERN CITY?

BERTRAND, LIDWINA; DAWKINS, LAURA; JAYARATNE, ROHAN; MORAWSKA, LIDIA

San Luis

Congreso; VII Congreso Argentino de la Sociedad de Toxicología y Química Ambiental; 2018

SETAC

According to the World Health Organization the air pollution in urban areas is responsible for a million deaths per year, mainly associated with inhalation of gaseous pollutants and particulate matter. Carbon monoxide (CO) from the incomplete combustion of fuels, is able to bind with haemoglobin, decreasing the blood oxygen-delivery and inducing tissues hypoxia; being more pronounced under conditions of stress like physical activity. The aim of the present study was to evaluate the atmospheric levels of CO in a growing Australian city (Brisbane) as well as the inhaled rate by a cyclist riding along bike paths. Different daytime periods were studied, during the week and weekend, through real-time monitoring of CO levels using an Alphasense CO-B4 sensor. According to the traffic, green space and the most used bike paths, the route (8 km) was designed including 3 city zones: the Central Business District (CBD), South Bank (SB) and Botanical Gardens (BG). A total of 48 route laps were completed. The CO inhaled rates (IR) were calculated for each zone and period considering ventilation (L/min) associated with different intensity of physical activity. The results showed CO levels lower than international guidelines. Nevertheless, concentrations were significantly higher in the CBD compared to BG and SB; with increased levels during the evening and early in the morning. Considering meteorological data, atmospheric CO was significantly affected by wind speed (negative relationship) whereas the wind direction, temperature and relative humidity did not show a significant association. With respect to IR, the worst scenario occurred during CBD evenings when the IR reached 278 ± 79 CO µg km-1 for a high-intensity physical activity. Besides, results showed that people cycling during the week in the CBD inhaled CO levels from 4 to 6 times higher than while riding in the BG. On the contrary, ratios derived for weekend days showed IR in the CBD 3 times higher than in the BG. In all cases, levels of inhaled CO were similar in SB when compared with the BG.