Validating PM2.5 Concentrations measured by PATS+Relative to UPAS device in households in Addis Abeba.
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Date
2019-10
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Addis Ababa University
Abstract
Background; - PM2.5 is an indicator of household air pollutants to measure the risk of air pollution.
UPAS and PATS+ PM measuring instruments are portable monitors that were used to measure
particulate matters in the households of Addis Ababa in a GEO Health for Eastern Africa. The
validity of the measurements using these two instruments is a concern for exposure assessment as
they use different principles of measuring PM2.5.
Objective: This study aims to validating PM2.5 concentrations measured by PATS+ relative to
UPAS device in households in Addis Ababa and explore factors affecting the level of UPAS PM2.5
concentration.
Methods: The study was cross-sectional, involving 150 households. The study used two
instruments with different technologies: the light scattering method in PATS+ and the gravimetric
in UPAS. Fifteen households were randomly selected from each sub-city from the source
population that it used GEO Health project for Children’s Health Study. Different statistical tools
were used to explore the consistency and validity of the measured PM2.5 by the two tools used to
monitor for 24 hours for each household: paired t-test, and Bland-Altman scatter plot analysis were
performed to evaluate the extent of agreement. P-Value <0.05 and 95% CI of parameters were
used for statistical significance.
Results: There wasno agreement and had a proportional bias between PATS+ and UPAS measured
PM2.5 concentrations. Child room located in the kitchen and household had highpollution
levelwere affected UPAS PM2.5concentration. We recommend the need of a correction factor for
PM2.5concentration measured by PATS+.
Conclusion and Recommendations
There is difference in PATS+ and UPAS measured PM2.5 concentration and has no agreement. The
location of child room and the pollution category of the household had an effect on the
measurments of PM2.5concentration. Generating a correction factor for PATS+ monitor using
UPAS as a gold standard is suggested.
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Keywords
Indoor PM2.5 concentration, PATS+, UPAS, light scattering PM sensor, validation