Mapping Nairobi’s environmental noise using a custom crowdsourcing smartphone app for evidence-based urban noise regulation and policy

Key Points

• This study aims to determine if citizen-science smartphone measurements can effectively map road-traffic noise in Nairobi for policy-making.
• Volunteers collected road-traffic noise data using the Urban Ear app in various sub-counties.
• Analysis focused on identifying noise hotspots and comparing averages to WHO thresholds.
• Significant noise hotspots were found, with sub-county averages exceeding WHO thresholds by 10–35 dB(A).
• Citizen-science mapping identified priority corridors for potential policy decisions.