Particulate matter exposure of bicycle path users in a high-altitude city

It is necessary to evaluate cyclists' exposure to particulate matter and if they are at a higher risk due to their increased breathing rate and their exposure to freshly emitted pollutants. The aim of this pilot study was to determine cyclists' exposure to PM10 in a highly-polluted, high-altitude city such as Bogota, and comment on the appropriateness of building bicycle paths alongside roads with heavy traffic in third world cities. A total of 29 particulate matter (PM10) measurements, taken at two sampling sites using Harvard impactors, were used for estimating the exposure of users of the 80th street bicycle path to this pollutant. PM10 dose could be considered as being high, especially due to high concentrations and cyclists' increased inhalation rates. A random survey was conducted over 73 bicycle path users to determine cyclists' time, distance and speed on the bicycle path on a daily and weekly basis, their level of effort when cycling and general characteristics, such as this population's gender and age. Based on this information, the PM10 average daily dose (ADD(c)) for different bicycle path users and the ratio between ADD(c) and a reference ADD for people at rest exposed to an indoor concentration of 25 mu g m(-3) were estimated. The average increase in ADD was 6%-9% when riding with light effort and by 12%-18% when riding with moderate effort. The most enthusiastic bicycle path users showed ADD(c)/ADD(r), ratios as high as 1.30 when riding with light effort and 1.64 when riding with moderate effort, thereby significantly increasing their PM10 exposure-associated health risks. (C) 2011 Elsevier Ltd. All rights reserved.