Background: The GEOHealth Hub for Eastern Africa is tackling growing challenges from environmental and occupational health hazards through research on air pollution in Ethiopia, Uganda, Rwanda and Kenya. Ambient air pollution in Addis Ababa is understood to be in the increasing side due to household fossil burning and vehicular emissions. The road structure, topography, socio-economic status and temperature inversion are believed to be some factors that contribute to the rising air pollution levels. Even though there exist some data on air pollution levels in Addis Ababa using short duration averaging times, the GEOHealth Hub has established one of the first continuous monitoring stations that could fill critical data gaps by providing the time series profile of PM_2.5 for Addis Ababa.

Methods: We used a Beta Attenuator Monitor (BAM) to measure the hourly PM_2.5 level since April 2017 by mounting on roof slab surface, at height of 12m, in the premises of Tikur Anbessa Hospital. BAM is an accredited instrument by the Environmental Protection Agency (EPA/USA), which is a standard method next to gravimetric counterparts, and is guaranteed high quality and accurate information on air quality. The hourly averages were aggregated to provide 24-hour daily averages in order to characterize the temporal profile of pollution using different scales of temporality. Standard operative procedures were developed for data downloading, cleaning and analysis. Descriptive statistics and time series smoothening plots were analyzed examine the temporal pattern in the data.

Results: We present findings from the just completed one year PM_2.5 profile (April, 2017-March, 2018. Over 5000 data points were used for the daily mean estimation. The annual mean (SD) was 43.4 (7.9) µg/m³. There exists variations by day of week, month, and season. Increasing level of PM_2.5 was observed on Monday's; and Tuesday's for the week days, while low levels were observed on weekends including Friday's. Wet months, including July, August, and September had increased level of PM, while the lowest was on April and May. There existed visible differences in the amount of PM by season, wet season showing the high level. Short-term maximum concentration was observed as high as 131.1 µg/m³ on September.

Conclusions: The increased level of PM above the proposed WHO guideline is a concern of policy debate. The time series PM data linking with a daily cause of hospital admission and acute deaths will be an opportunity for researchers. Similar studies in Hub partner countries in East Africa will provide comparisons in the trend of air pollution and health.