Kitchen fine particulate matter (PM2.5) concentrations from biomass fuel use in rural households of Northwest Ethiopia

Abstract

Background: Combustion of solid biomass fuels using traditional stoves which is the daily routine for 3 billion people emits various air pollutants including fine particulate matter which is one of the widely recognized risk factors for various cardiorespiratory and other health problems. But, there is only limited evidences of kitchen PM_2.5 concentrations in rural Ethiopia.

Objective: This study is aimed to estimate the 24-h average kitchen area concentrations of PM_2.5 and to identify associated factors in rural households of northwest Ethiopia.

Method: The average kitchen area PM_2.5 concentrations were measured using a low-cost light-scattering Particle and Temperature Sensor Plus (PATS+) for a 24-h sampling period. Data from the PATS+ was downloaded in electronic form for further analysis. Other characteristics were collected using face-to-face interviews. Independent sample t-test and one-way analysis of variance were used to test differences in PM_2.5 concentrations between and among various characteristics, respectively.

Result: Mixed fuels were the most common cooking biomass fuel. The 24-h average kitchen PM_2.5 concentrations was estimated to be 405 μg/m³, ranging from 52 to 965 μg/m³. The average concentrations were 639 vs. 336 μg/m³ (p < 0.001) in the thatched and corrugated iron sheet roof kitchens, respectively. The average concentration was also higher among mixed fuel users at 493 vs. 347 μg/m³ (p = 0.042) compared with firewood users and 493 vs. 233 μg/m³ (p = 0.007) as compared with crop residue fuel users. Statistically significant differences were also observed across starter fuel types 613 vs. 343 μg/m³ (p = 0.016) for kerosene vs. dried leaves and Injera baking events 523 vs. 343 μg/m³ (p < 0.001) for baked vs. not baked events.

Conclusion: The average kitchen PM_2.5 concentrations in the study area exceeded the world health organization indoor air quality guideline value of 15 μg/m³ which can put pregnant women at greater risk and contribute to poor pregnancy outcomes. Thatched roof kitchen, mixed cooking fuel, kerosene fire starter, and Injera baking events were positively associated with high-level average kitchen PM_2.5. concentration_. Simple cost-effective interventions like the use of chimney-fitted improved stoves and sensitizing women about factors that aggravate kitchen PM_2.5 concentrations could reduce kitchen PM _2.5 levels in the future.

Keywords: Ethiopia; biomass fuel; cooking; fine particle; kitchen concentration.

Figure 1

Small thatched roof kitchen near the main house.

Figure 2

Small corrugated iron sheet roof kitchen near the main house.

Figure 3

Placement position of particulate matter monitoring devices in the kitchen area.

Figure 4

The distribution of kitchen area hourly average concentrations of PM_2.5 (μg/m³) by the time of day.

Figure 5

Box and whisker plots of 24- h kitchen PM_2.5 concentrations by kitchen roof type. The ends of the box are at quartiles, so that the length of the box is the interquartile range (IQR). The median is marked by a line within the box. The two whiskers outside the box extend to the smallest and largest observations.

Figure 6

Box and whisker plots of 24- h kitchen PM_2.5 concentrations by types of cooking fuel used during sampling period. The whole boxes represent the interquartile range; numbers on the horizontal line inside the box indicate median. The top and bottom whiskers are minimum and maximum values, respectively.

Figure 7

Box plot presenting the 24-h Kitchen area PM_2.5 concentrations using different fuel types to start the fire in the kitchen. The whole boxes represent the interquartile range; numbers on the horizontal line inside the box indicate median. The top and bottom whiskers are minimum and maximum values, respectively.