Airborne contamination during post-fire investigations: Hot, warm and cold scenes

Figures & data

Figure 1. Study design and sample collection strategy.

Figure 2. Structure layout and sampling locations selected for the bedroom and common room (kitchen and living room) fire experiments.

Figure 3. Photographs of typical furnishings in the bedroom fires (top) and common room fires including kitchen (middle) and living room (bottom).

Table 1. Area air sampling collection and analysis methods.

Compound	Sampling media	Flow rate (L/min)^A	Analytical method
Aldehydes	Supelco LpDNPH S-10 cartridge	0.7–0.96	ASTM D5197
Fibers	Zefon 25 mm cassette 0.8 µm MCE	1.5–13.5^B	NIOSH 7400
Hydrogen Cyanide	Soda lime tube	0.15–0.53	NIOSH 6017
Hydrogen Sulfide	Charcoal tube	0.2	NIOSH 6013M
Mercury	Anasorb C300 tube	0.16–0.25	NIOSH 6009
Metals	Zefon 37 mm 0.8 µm MCE	1.5–3.3	NIOSH 7300M
Volatile Organic Compounds	Charcoal tube	0.25–0.60	EPA TO-17; ASTM 6196
Particulate	DustTrak DRX − 1 sample/sec (PM1, PM2.5, Respirable, PM10, Total)
Asphyxiant gases	MultiRAE Lite − 1 sample/sec (HCN, H2S, Carbon Monoxide (CO))

^A Flow rates were increased for sampling during the shorter Hot Scene A measurement

^B Flow rates for fiber sampling were reduced after initial samples were overloaded with soot in an attempt to collect viable measurements.

Table 2. Average particulate concentration (µg/m³) for submicron (PM1), less than 2.5 µm (PM2.5), respirable, less than 10 µm (PM10), and total fractions for all eighteen experiments as well as bedroom and common room fire experiments over a 60-min data collection period. Data are presented as median (range).

	Total (N = 18)		Bedroom (N = 9)		Common Room (N = 9)
	Pre	Hot Scene B	Pre	Hot Scene B	Pre	Hot Scene B
PM1^B,^C	20 (1–91)	96.5^A (15–490)	29 (13–91)	27 (15–311)	14 (1–29)	186^A (63–490)
PM2.5^B,^C	21 (1–98)	103.5^A (16–498)	32 (14–98)	28 (16–317)	15 (1–29)	191^A (64–498)
Respirable^B,^C	24.5 (1–117)	114.5^A (17–509)	40 (17–117)	30 (17–322)	19 (1–29)	196^A (66–509)
PM10^B	32.5 (1–202)	121^A (18–556)	67 (24–202)	35 (18–423)	25 (1–44)	208^A (68–556)
Total^+	36 (1–292)	127^A (19–823)	82 (25–292)	40 (19–823)	27 (1–85)	221^A (69–596)

^A p < 0.05 relative to pre-fire concentrations

^B p < 0.05 pre-fire concentrations in bedroom are different from common room

^C p < 0.05 Hot Scene B concentrations in bedroom are different from common room

Table 3. Peak particulate concentration (µg/m³) for submicron (PM1), less than 2.5 µm (PM2.5), respirable, less than 10 µm (PM10), and total fractions for all 18 experiments as well as bedroom and common room fire experiments. Data are presented as median (range).

	Total (N = 18)		Bedroom (N = 9)		Common Room (N = 9)
	Pre	Hot Scene B	Pre	Hot Scene B	Pre	Hot Scene B
PM1	118 (6–295)	1,045^A (197–23,500)	117 (61–236)	459^A (197–11,300)	119 (6–295)	1,290^A (275–23,500)
PM2.5	119.5 (6–301)	1,090^A (200–23,700)	119 (62–244)	474^A (200–11,500)	120 (6–301)	1,300^A (279–23,700)
Respirable	134 (8–314)	1,180^A (205–23,800)	152 (65–292)	497^A (205–12,000)	122 (8–314)	1,310^A (280–23,800)
PM10	212.5 (12–516)	1,385^A (279–23,800)	238 (70–516)	675^A (279–16,000)	167 (12–418)	1,660^A (287–23,800)
Total	281.5 (37–981)	1,625^A (393–34,700)	418 (89–981)	1,170^A (429–34,700)	270 (37–775)	1,990^A (393–23,800)

^A p < 0.05 relative to pre-fire concentrations

Figure 4. Respirable (left) and total (right) 60-min average (top) and peak (bottom) particulate concentrations (µg/m³) for 4 experiments including Hot Scene B (immediately post-fire sample at time = 0 hr), Warm Scene (1-day and 3-day post-fire samples at approximately 24 and 72 hr) and Cold Scene (5-day post fire samples at approximately 120 hr).

Table 4. Airborne concentration of VOCs (µg/m³) as 60-min time-weighted averages for pre-fire and Hot Scene B and averaged over 30–41 min in Hot Scene A. Data are presented as median (range).

		Pre N = 18	Hot Scene A N = 8	Hot Scene B N = 18
Benzene	Median (Range)	ND (ND–15.9)	121 (34.8–302)^A	30.6 (2.9–89.4)^A
	% Detect	50%	100%	100%
Toluene	Median (Range)	6.6 (ND–117)	56.6 (19.4–113)^A	8.8 (ND–29.8)
	% Detect	89%	100%	83%
Ethyl Benzene	Median (Range)	ND (ND–4.5)	26.4 (ND–66.4)^A	3.7 (ND–12.0)^A
	% Detect	22%	63%	61%
Xylene	Median (Range)	2.5 (ND–60.7)	48.5 (19.5–350)^A	2.7 (ND–33.5)
	% Detect	56%	100%	61%
Styrene	Median (Range)	3.5 (ND–18.8)	82.3 (ND–204)^A	35.2 (ND–76.3)^A
	% Detect	78%	88%	83%
Naphthalene	Median (Range)	10.5 (ND–73.7)	118 (64.0–213)^A	9.9 (ND–58.3)
	% Detect	78%	100%	94%
Total VOCs	Median (Range)	616 (35–1,770)	3,830 (1,460–10,700)^A	199 (14–1,360)^A
	% Detect	100%	100%	100%

ND indicates below quantifiable level (< 2 µg/m³)

^A p < 0.05 relative to pre-fire concentrations

Table 5. Airborne concentration of aldehydes (µg/m³) as 60-min time weighted averages for pre-fire and Hot Scene B and averaged over 30–41 min in Hot Scene A. Data are presented as median (range).

		Pre	Hot Scene A	Hot Scene B
		N = 18	N = 8	N = 18
Acetaldehyde	Median (Range)	16.5 (7.5–75.6)	1,380 (205–3,360)^A	171 (ND–416)^A
	% Detect	100%	100%	94%
Benzaldehyde	Median (Range)	5.0 (ND-17.0)	69.0 (25.6–176)^A	9.0 (5.0–16.4)^A
	% Detect	94%	100%	100%
Formaldehyde	Median (Range)	30.0 (14.8–167.0)	356 (140–775)^A	36.1 (16.5–82.5)
	% Detect	100%	100%	100%
Hexanal	Median (Range)	43.8 (8.7–104)	49.8 (14.7–122)	11.5 (2.4–28.6)^A
	% Detect	100%	100%	100%
Pentanal	Median (Range)	15.1 (3.6–50.8)	20.8 (ND–56.7)	5.7 (ND-13.3)^A
	% Detect	100%	75%	67%
Propanal	Median (Range)	8.4 (ND–95.0)	318 (ND–1,070)^A	36.3 (6.0–94.0)^A
	% Detect	83%	88%	100%

2-dimethyl benzaldehyde, 2,5-dimethyl benzaldehyde, 3- and/or 4-dimethyl benzaldehyde, butanal, 3-methyl butanal and 2-butenal were detected in less than 50% of all samples.

ND indicates below quantifiable level (< 2 µg/m³)

^A p < 0.05 relative to pre-fire concentrations

Figure 5. Benzene (top) and naphthalene (bottom) 60-min time-weighted average concentrations (µg/m³) for four experiments including Hot Scene B (immediately post-fire sample at time = 0 hr), Warm Scene (1-day and 3-day post-fire samples at approximately 24 and 72 hr) and Cold Scene (5-day post-fire samples at approximately 120 hr).

Figure 6. Acetaldehyde (top) and formaldehyde (bottom) 60-min time-weighted average concentrations (µg/m³) for 4 experiments including Hot Scene B (immediately post-fire sample at time = 0 hr), Warm Scene (1-day and 3-day post-fire samples at approximately 24 and 72 hr) and Cold Scene (5-day post-fire samples at approximately 120 hr).