Is remaining indoors an effective way of reducing exposure to fine particulate matter during biomass burning events?

Figures & data

Table 1. Characteristics of the houses monitored when biomass burning (BB) events were captured.

Characteristic	H10	H11	H12	H16	H7/H8	H21
Location relative to smoke event	10–20 km (see Figure 1c)	10–20 km (see Figure 1c)	Garden waste burn (few meters)	Neighbor’s burn (few meters)	Local wood smoke
Number of rooms	9	9	NA^1	7	NA	10
Age of house	~98 yr	8 yr	28 yr	~30 yr	NA	~23 yr
Building material	Timber	Colorbond	Timber or weatherboard	Timber or weatherboard	NA	Double brick
Number of windows	8	16	4 (sampling area)	8	NA	14
Number of doors to outside	4	4	2	3	NA	4
Heating system Primary Secondary	Electric Enclosed WH	Enclosed WH	Electric	Electric Enclosed WH	NA	Enclosed WH Electric
Wood heater	Yes	Yes	NA	Yes	NA	Yes
Type of stove	Electric	Electric	Gas	Electric	NA	Gas/electric
Air conditioner	Yes^a	Yes^a	Yes^a	Yes^a	NA	Yes^a

Notes. NA = data not available; WH = wood heater.

^aAir conditioner present but not used.

Figure 1. Hourly ambient PM_2.5 concentrations during smoke plume events.

Figure 2. Frequency distributions of the 24-hr indoor PM_2.5 concentrations (left) and hourly indoor PM_2.5 concentrations (right) measured at the 21 residences. Outdoor sources are shown in blue, and indoor sources are shown in gray.

Table 2. Summary of outdoor and indoor PM_2.5 measurements during smoke plume events.

		Total PM2.5 (μg m^−3 hr)		Hourly max PM2.5 (μg m^−3)
Residence	Duration (hr)^a	Outdoor	Indoor	Outdoor	Indoor	Reduction in hourly max indoor PM2.5 (%)	Finf^b	Ventilation status
Residence 10	11	2083	1792	335.8	295.6	12.0	0.83	Window/door open
Residence 11	15	2337	1282	386.5	167.3	56.7	0.39	Windows open
Residence 12	2	69.2	53.1	56.1	34.5	38.5	0.61	Windows/door open
Residence 16	6	157.5	110.9	56.0	28.8	48.5	0.49	Closed
Residence 7	11	99.3	63.9	17.1	7.9	53.8	0.32	Not available
Residence 7	14	194.8	83.7	38.5	9.3	75.9	0.17	Not available
Residence 8	10.5	183.3	106.4	25.1	15.5	38.4	0.58	Not available
Residence 8	10.5	236.9	87.0	48.7	16.9	65.4	0.32	Not available
Residence 21	4.5	159.5	94.8	118.5	38.5	67.5	0.26	4–6 windows open (1 hr)
Residence 21	14.5	355.1	203.9	70.4	21.3	69.7	0.24	1 window open (7 hr)
Residence 21	8	136.4	50.0	41.1	10.0	75.7	0.18	1 window open (5 hr)
Residence 21	5	97.9	34.6	35.0	9.6	72.7	0.19	1 window open (1 hr)

Notes. ^aThis represents the time that a residence was impacted by smoke due to a smoke plume event or a wood smoke event.

^bFinf – I/O ratios observed during hourly peak PM_2.5concentrations.

Figure 3. Hourly outdoor and indoor PM_2.5 concentrations and ventilation conditions during smoke plume events.

Figure 4. Time-series plots of 5-min PM_2.5 concentrations measured indoors and outdoors at residence H10 (top) and residence H11 (bottom) during a smoke plume event in 2015.

Figure 5. Measured and modeled PM_2.5 concentrations during smoke plume events.