atmosphere Article Modelling Cyclists’ Multi-Exposure to Air and Noise Pollution with Low-Cost Sensors—The Case of Paris Jérémy Gelb and Philippe Apparicio * Institut National de la Recherche Scientifique, Centre Urbanisation Culture Société, Montréal, QC H2X 1E3, Canada; [email protected] * Correspondence: [email protected] Received: 5 March 2020; Accepted: 19 April 2020; Published: 22 April 2020 Abstract: Cyclists are particularly exposed to air and noise pollution because of their higher ventilation rate and their proximity to traffic. However, few studies have investigated their multi-exposure and have taken into account its real complexity in building statistical models (nonlinearity, pseudo replication, autocorrelation, etc.). We propose here to model cyclists’ exposure to air and noise pollution simultaneously in Paris (France). Specifically, the purpose of this study is to develop a methodology based on an extensive mobile data collection using low-cost sensors to determine which factors of the urban micro-scale environment contribute to cyclists’ multi-exposure and to what extent. To this end, we developed a conceptual framework to define cyclists’ multi-exposure and applied it to a multivariate generalized additive model with mixed effects and temporal autocorrelation. The results show that it is possible to reduce cyclists’ multi-exposure by adapting the planning and development practices of cycling infrastructure, and that this reduction can be substantial for noise exposure. Keywords: cyclist; exposure; multi-exposure; noise; air pollution; NO2; Bayesian modelling; spatial analysis; Paris 1. Introduction Environmental noise and air pollution are two growing issues in cities. Their impacts on health and population well-being are now widely acknowledged. In its latest report on environmental noise in Europe, the World Health Organization (WHO) recognized it as one of the main environmental risks in cities. Two types of health impacts are distinguished: the auditory effects (hearing loss and tinnitus) and non-auditory effects linked to annoyance and stress generated by exposure to noise (physiological distress, disturbance of the organism’s homeostasis, increasing allostatic load, sleep loss, concentration difficulties, etc.) [1–5]. The latter are important if the exposure is chronic and prolonged. For example, the WHO guideline development group identified two priority health outcome lines of evidence for the road traffic noise. The first threshold value of 53.3 Lden corresponds to an absolute risk of 10% for the prevalence of a highly annoyed population. The second one of 59.3 dB Lden corresponds to an increase of 5% of the relative risk for the incidence of ischemic heart disease [3]. The case of air pollution is more complex because air pollutants are numerous. Research distinguishes gaseous pollutants and vapors (e.g., NO2,O3, CO2, CO, COVs, etc.) from particulate matter (fine: PM2.5 and coarse: PM10). The health impacts of these pollutants are numerous: nausea, breathing difficulties, skin and respiratory tract irritations, development of certain types of cancer, birth defects, delayed development in children, reduced immune system activity, etc. [6]. The WHO identifies nitrogen dioxide (NO2), particulate matter (fine: PM2.5 and coarse: PM10), ozone (O3), and sulphur dioxide (SO2) as the pollutants with the strongest impact on health. For NO2 (measured in Atmosphere 2020, 11, 422; doi:10.3390/atmos11040422 www.mdpi.com/journal/atmosphere Atmosphere 2020, 11, 422 2 of 21 Atmosphere 2020, 11, x FOR PEER REVIEW 2 of 22 this study), the WHO advises not exceeding a mean value of 200 µg/m3 in an hour, as exposure above not exceeding a mean value of 200 µg/m3 in an hour, as exposure above this level causes significant inflammationthis level causes of airways significant [7]. inflammation of airways [7]. 1.1. Cyclists’ Exposure and Transport Justice 1.1. Cyclists’ Exposure and Transport Justice Cyclists are particularly exposed to these pollutions. Indeed, they do not have a cabin or an Cyclists are particularly exposed to these pollutions. Indeed, they do not have a cabin or an air air conditioning system to protect them. A considerable body of literature has compared the levels conditioning system to protect them. A considerable body of literature has compared the levels of of exposure to air pollution according to the mode of transportation. Studies have concluded that exposure to air pollution according to the mode of transportation. Studies have concluded that the differencesthe differences in terms in terms of exposure of exposure are inconsistent are inconsistent [8]. However, [8]. However, when the when ventilation the ventilation rate is taken rate into is account,taken into it is account, clear that it iscyclists clear inhale that cyclists more air inhale pollutants more airthan pollutants other road than user others. In a road recent users. literature In a review,recent literatureCepeda et review,al. [9] have Cepeda found et that al. [car9] haveusers foundinhaled that an average car users of inhaledonly 16% an of averagethe total ofdose only inhaled 16% byof thecyclists total for dose similar inhaled trips. by Less cyclists information for similar is avai trips.lable Less for informationexposure to noise, is available but Okokon for exposure et al. [10] to havenoise, foundbut Okokon that, on etaverage, al. [10] cyclishavets found are exposed that, on to average, 6 more cyclistsdB(A) than are exposedcar usersto in6 Helsinki more dB(A) (Finland), than andcar users4.0 in inThessaloniki Helsinki (Finland), (Greece), andon average 4.0 in Thessaloniki for similar trips, (Greece), and Apparicio on average et foral. similar[11] have trips, found and a differenceApparicio of et 1.92 al. [ 11(LAeq,1min] have) foundin Montreal a diff erence(Canada). of 1.92 (LAeq,1min) in Montreal (Canada). TheThe second second main main cause cause of of cyclists’ cyclists’ overexposure overexposure is their is their direct direct proximity proximity to a to major a major source source of air of and air noiseand noise pollution, pollution, i.e., road i.e., roadtraffic. tra Thisffic. Thisproximity proximity is reinforced is reinforced by planning by planning policies policies encouraging encouraging road sharing.road sharing. In Paris, In this Paris, is thisstriking is striking when one when observes one observes the development the development of the bicycle of the network bicycle network [12]. In 2001, [12]. theIn 2001,city permitted the city permitted cyclists to cyclists use bu tos lanes use busand lanes in 2010, and many in 2010, one-way many streets one-way were streets opened were to opened cyclists toin bothcyclists directions in both (Figure directions 1). These (Figure two1). breaks These represent two breaks major represent increases major in available increases cycling in available infrastructures, cycling butinfrastructures, this raises the but question this raises of the the quality question of ofthese the qualityinfrastructures of these and infrastructures the closeness and to thetraffic closeness that they to entail.traffic that they entail. FigureFigure 1. 1.The The developmentdevelopment ofof a cycling network in Paris Paris between between 1995 1995 and and 2017. 2017. Cyclists’Cyclists’ overexposure overexposure supports supports the the statements statements of Göss of Gösslingling [13] on [13 transportation] on transportation justice. justice. The bicycle The isbicycle a durable is a durable mode modeof transport of transport and helps and helps to redu to reducece congestion, congestion, environmental environmental noise, noise, emission emission of greenhouseof greenhouse gas, gas, and andhealth health costs. costs. 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