. 2022 May 12;130(5):057007. doi: 10.1289/EHP10054

Table 5.

Pollutant concentration differences across follow-up visits for the intervention group in comparison with baseline using a daily mean metric and maximum hourly means in rural Peru ( $lowercase italic n equals 180$ participants).

Visit^b	Differences in daily means^a		Differences in maximum hourly means
Visit^b	Kitchen area percent differences (95% CI)	Personal exposure percent differences (95% CI)	Kitchen area percent differences (95% CI)	Personal exposure percent differences (95% CI)
$particulate matter begin subscript 2.5 end subscript$
3	$negative 92$ ( $negative 94$ , $negative 90$ )	$negative 69$ ( $negative 75$ , $negative 62$ )	$negative 93$ ( $negative 95$ , $negative 90$ )	$negative 88$ ( $negative 91$ , $negative 84$ )
6	$negative 95$ ( $negative 96$ , $negative 93$ )	$negative 70$ ( $negative 76$ , $negative 62$ )	$negative 95$ ( $negative 96$ , $negative 93$ )	$negative 90$ ( $negative 92$ , $negative 86$ )
12	$negative 97$ ( $negative 98$ , $negative 96$ )	$negative 78$ ( $negative 82$ , $negative 71$ )	$negative 96$ ( $negative 98$ , $negative 95$ )	$negative 91$ ( $negative 94$ , $negative 88$ )
18	$negative 81$ ( $negative 87$ , $negative 72$ )	$negative 66$ ( $negative 73$ , $negative 57$ )	$negative 83$ ( $negative 89$ , $negative 74$ )	$negative 79$ ( $negative 85$ , $negative 71$ )
24	$negative 82$ ( $negative 88$ , $negative 74$ )	$negative 67$ ( $negative 75$ , $negative 58$ )	$negative 81$ ( $negative 87$ , $negative 73$ )	$negative 79$ ( $negative 85$ , $negative 70$ )
CO
3	$negative 92$ ( $negative 94$ , $negative 89$ )	$negative 61$ ( $negative 70$ , $negative 50$ )	$negative 93$ ( $negative 95$ , $negative 90$ )	$negative 79$ ( $negative 85$ , $negative 70$ )
6	$negative 90$ ( $negative 93$ , $negative 87$ )	$negative 71$ ( $negative 78$ , $negative 62$ )	$negative 88$ ( $negative 92$ , $negative 84$ )	$negative 85$ ( $negative 89$ , $negative 79$ )
12	$negative 87$ ( $negative 91$ , $negative 83$ )	$negative 62$ ( $negative 71$ , $negative 51$ )	$negative 85$ ( $negative 90$ , $negative 79$	$negative 79$ ( $negative 86$ , $negative 70$ )
18	$negative 74$ ( $negative 82$ , $negative 62$ )	$negative 48$ ( $negative 61$ , $negative 32$ )	$negative 69$ ( $negative 79$ , $negative 54$ )	$negative 70$ ( $negative 80$ , $negative 56$ )
24	$negative 69$ ( $negative 78$ , $negative 55$ )	$negative 50$ ( $negative 62$ , $negative 33$ )	$negative 64$ ( $negative 76$ , $negative 47$ )	$negative 66$ ( $negative 78$ , $negative 49$ )
BC
3	$negative 96$ ( $negative 97$ , $negative 94$ )	$negative 85$ ( $negative 88$ , $negative 81$ )	—	—
6	$negative 97$ ( $negative 98$ , $negative 96$ )	$negative 86$ ( $negative 89$ , $negative 83$ )	—	—
12	$negative 99$ ( $negative 99$ , $negative 98$ )	$negative 89$ ( $negative 91$ , $negative 86$ )	—	—
18	$negative 78$ ( $negative 86$ , $negative 66$ )	$negative 65$ ( $negative 73$ , $negative 54$ )	—	—
24	$negative 83$ ( $negative 89$ , $negative 74$ )	$negative 71$ ( $negative 78$ , $negative 61$ )	—	—

Note: BC, black carbon; CI, confidence interval; CO, carbon monoxide; LOD, limit of detection; LPG, liquefied petroleum gas; $particulate matter begin subscript 2.5 end subscript$ , fine particulate matter with aerodynamic diameter of $equal to or less than 2.5 micrometers$ .

^{^a}

Daily mean metric used is defined as the mean of the two consecutive 24-h average concentrations, where available. All coefficients: $p$ $less than 0.001$ .

^{^b}

Follow-up visits: 3-, 6-, 12-, 18-, and 24-months. BC consisted of time weighted integrated samples therefore hourly maximums were not evaluated for this pollutant. Samples $< LOD$ were replaced by $LOD / \sqrt{2}$ : 7 and $1 microgram$ for $particulate matter begin subscript 2.5 end subscript$ and BC gravimetric integrated samples, respectively; and $0.7 part per million$ for direct reading CO measurements. Generalized estimating equation models using the log transformed pollutant concentrations were used. During the second year (follow-up visits:18- and 24 months) the intervention participants stopped receiving free fuel but kept the LPG stove.