demiological characteristics of cyclists on both routes were similar. Exposure to fine and middle-size particulate matter (PM 2.5 and PM 10 , respectively) was not dierent between routes, but the NO 2 environmental concen- tration was higher in Route 1 and the noise level was higher in Route 2. NO 2 is produced from vehicle emissions, petroleum refineries, and fuel combustion (WHO Regional Oce for Europe, 2021). Exposure to NO 2 is converted to ozone (in the presence of sunlight) and promotes respira- tory and cardiovascular morbidity as well as mortality; these adverse eects have been well documented in epidemiological and real-world evidence in Europe, Asia, and the U.S. (Burnett et al., 2018; Costa et al., 2017; Hvidtfeldt et al., 2019; Janssen et al., 2017; Linares et al., 2018; Liu et al., 2019; Zúñiga et al., 2016). For our study, measurements of NO 2 con- centrations were done in the morning dur- ing the rush hour when many people are traveling to schools and worksites. Due to the characteristics of Route 1, it is possible that a higher NO 2 concentration was facili- tated by higher production in the busy time of the day (more trac) and by the narrow corridors of streets surrounded by build- ings (i.e., urban canyons). Potential inhaled doses were also higher in Route 1 for PM 10 and NO 2 . Furthermore, Route 2 showed higher noise levels. This route has more trac (per- haps because it has more schools and health centers along the route), and the route also has a high rate of use by trucks and buses, which are slower vehicles. These two fac- tors could explain the high sound pressure levels. This finding coincides with the high percentage of time exceedances of noise >70 dBA along the route. Even though there is more trac, NO 2 and PM 2.5 can better dissi- pate in an environment of broad streets, but the exceedance time remains high for PM 2.5 (Li et al., 2019). Air quality cut-points for 24 hr suggested in the Air Quality Guidelines are 15 μg/m 3 for PM 2.5 and 45 μg/m 3 for PM 10 (WHO, 2022). For Route 2, all mean values were above the recommendations. These findings suggest that the population might be exposed to higher health risks related to air pollutants along Route 2. The mean values for NO 2 , however, were below the recommended lim- its of 200 μg/m 3 for 1 hr for both routes.
TABLE 2
Parameters Measured During Cycling Trips on Each Route
Parameter
Route 1 M ( SD ) 24.9 (4.3) 16.7 (2.6) 56.4 (17.5) 38.2 (10.5)
Route 2 M ( SD ) 26.0 (7.4) 17.6 (2.8) 43.0 (13.4) 50.5 (33.6) 26.5 (26.3)
Mann–Whitney p -Value
Trip duration (min) Cyclist speed (km/h)
.767 .168 .003 .475 .151
Cyclist ventilation rate (L/min) PM 10 concentration ( μ g/m 3 ) PM 2.5 concentration ( μ g/m 3 ) NO 2 concentration ( μ g/m 3 ) PM 10 potential inhaled dose ( μ g) PM 2.5 potential inhaled dose ( μ g) NO 2 potential inhaled dose ( μ g)
15.1 (7.2)
42.5 (10.1) 45.0 (17.9) 18.2 (11.5) 47.4 (16.3) 14.0 (10.0)
32.6 (8.1)
<.001
41.7 (33.7) 21.9 (26.2) 28.2 (13.4) 51.4 (91.0)
.044 .169
<.001 <.001
Noise pollution dose (%)
Note. NO 2 = nitrogen dioxide; PM = particulate matter. Source: D’Angelo et al., 2023.
TABLE 3
Percentage of Exceedance Time Over the Threshold for Measured Environmental Pollutants
Pollutant
Route
M and SD (%) 70.8 ± 10.7 81.2 ± 8.4 14.7 ± 17.8 34.3 ± 33.2 81.7 ± 30.4 83.3 ± 30.2
p -Value
Noise
1 2 1 2 1 2
.0003
PM 2.5
.0005
.8301
PM 10
Note. PM = particulate matter.
combinations of variables, including age; sex; smoking status; sedentary lifestyle; BMI; pre- vious pathologies; the regular use of bicycles; and the proportion of time exposed to high levels of PM 2.5 , PM 10 , and noise. No significant associations were found in any setting with CO-oximetry measurements. Discussion This study is the first to report on the short-term impact of trac-related atmo- spheric pollutants (PM 2.5 , PM 10 , CO, NO 2 , and noise) at the street level among healthy cyclists in Uruguay.
Unfortunately, there is no estimation of the number of cyclists in the city of Montevideo; however, in 2016, the Origin-Destiny Survey was administered in Montevideo (https:// montevideo.gub.uy/observatorio-de-movili- dad). This survey explored the mobility pat- terns of a subset of people living in Montevi- deo. The resulting data showed that among adults using bicycles, the mean age was 47.9 years ± 18.1 ( SD ) and 54% of the sample self- reported their sex as female. In our study, the mean age was 36.5 ± 10.2 years, and 40% of participants self-reported their sex as female. Demographic and epi-
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July/August 2024 • our:-l o2 :A5ro:me:?-l e-l?4
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