High-resolution spatiotemporal measurement of air and environmental noise pollution in Sub-Saharan African cities: Pathways to Equitable Health Cities Study protocol for Accra, Ghana

Abstract

IntroductionAir and noise pollution are emerging environmental health hazards in African cities, with potentially complex spatial and temporal patterns. Limited local data are a barrier to the formulation and evaluation of policies to reduce air and noise pollution.Methods and analysisWe designed a year-long measurement campaign to characterise air and noise pollution and their sources at high-resolution within the Greater Accra Metropolitan Area (GAMA), Ghana. Our design uses a combination of fixed (year-long, n=10) and rotating (week-long, n =~130) sites, selected to represent a range of land uses and source influences (eg, background, road traffic, commercial, industrial and residential areas, and various neighbourhood socioeconomic classes). We will collect data on fine particulate matter (PM2.5), nitrogen oxides (NOx), weather variables, sound (noise level and audio) along with street-level time-lapse images. We deploy low-cost, low-power, lightweight monitoring devices that are robust, socially unobtrusive, and able to function in Sub-Saharan African (SSA) climate. We will use state-of-the-art methods, including spatial statistics, deep/machine learning, and processed-based emissions modelling, to capture highly resolved temporal and spatial variations in pollution levels across the GAMA and to identify their potential sources. This protocol can serve as a prototype for other SSA cities.Ethics and disseminationThis environmental study was deemed exempt from full ethics review at Imperial College London and the University of Massachusetts Amherst; it was approved by the University of Ghana Ethics Committee (ECH 149/18-19). This protocol is designed to be implementable in SSA cities to map environmental pollution to inform urban planning decisions to reduce health harming exposures to air and noise pollution. It will be disseminated through local stakeholder engagement (public and private sectors), peer-reviewed publications, contribution to policy documents, media, and conference presentations.

Spatial-temporal patterns of ambient fine particulate matter (PM2.5) and black carbon (BC) pollution in Accra

“…The GAMA is in a tropical climate zone with high average monthly temperatures and relative humidity (RH) ranging between 25 °C and 33 °C (77–90 °F) and 77%–85%, respectively [ 25 ]. The GAMA has two major seasons: the rainy (May–October) period, and the dry period comprising the Harmattan (November–February) characterized by north-easterly trade winds from the Sahara Desert [ 27 ].…”

“…As previously described [ 27 ], we designed a year-long campaign to examine the spatial (land-use features) and temporal (daily, weekly, monthly and seasonal) variations in ambient PM 2.5 and BC by sampling at a combination of fixed (∼1 year, n = 10 sites) and rotating (7 d, n = 136) sites. This design allowed for detailed assessment of both the temporal (using fixed site data) and spatial (using rotating site data) variability of PM 2.5 and BC over the study area.…”

“…Further, this design allowed us to optimally use a finite number of monitoring equipment to capture data across the entire geographical extent of the study area. We used a structured form to collect information on land-use features at each monitoring site [ 27 ]. The sites were subsequently grouped into four land-use classes: commercial, business, industrial (CBI); high-density residential; medium/low-density residential; or peri-urban (see supplementary text S1 for additional details).…”

“Our Home Is a Muddy Structure”: Perceptions of Housing and Health Risks Among Older Adults in Contrasting Neighborhoods in Ghana

“…Excessive noise pollution was a general issue of public concern in the city (55). For older adults, this upheaval was intolerable, as it presented a common environmental press affecting their health and well-being.…”

Commentary: Opportunities for the application of low-cost sensors in epidemiological studies to advance evidence of air pollution impacts on human health

“…Sensors set up by universities, schools, and local media organizations are also being used to upskill civil society to better understand the quality of the air they breathe and to lobby for cleaner air when necessary (Desouza et al, 2017). Studies using low-cost sensors in Ghana and Nigeria have assessed relationships between air pollution exposure and adverse health outcomes, indicating the potential of such sensors for health research (Quinn et al, 2017;Alexander et al, 2018;Clark et al, 2020).…”