Assessment of airborne exposures and health in flooded homes undergoing renovation

Our plain-English summary of Assessment of airborne exposures and health in flooded homes undergoing renovation, by K.A. Hoppe, N. Metwali, S.S. Perry, et al (Indoor Air, 2012).

The study

• Authors: K.A. Hoppe, N. Metwali, S.S. Perry, T. Hart, P.A. Kostle, P.S. Thorne
• Journal: Indoor Air
• Published: 2012;22(6):446-56
• Cited by: 30 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Unlabelled: In June 2008, the Cedar River crested flooding more than 5000 Cedar Rapids homes. Residents whose homes were flooded were invited to participate in this study. Household assessments and resident interviews were conducted between November 2008 and April 2009. We characterized exposures and symptoms experienced by individuals inhabiting 73 flood-damaged homes. Active air sampling and passive electrostatic dust collectors were used to assess exposures to culturable mold, culturable bacteria, fungal spores, inhalable particulate matter (iPM), endotoxin, glucans, allergens, lead, asbestos, radon, carbon dioxide, and carbon monoxide. Wall moisture levels and relative humidity were also measured. Exposures and questionnaire-based health assessments were compared at two levels of remediation, in-progress and completed. Homes with remediation in-progress (N = 24), as compared to the completed homes (N = 49), had significantly higher airborne concentrations of mold, bacteria, iPM, endotoxin, and glucan. Residents of in-progress homes had a significantly higher prevalence of doctor-diagnosed allergies (adjusted OR = 3.08; 95% CI: 1.05, 9.02) and all residents had elevated prevalence of self-reported wheeze (adjusted OR = 3.77; 95% CI: 2.06, 6.92) and prescription medication use for breathing problems (adjusted OR = 1.38; 95% CI: 1.01, 1.88) after the flood as compared to before. Proper post-flood remediation led to improved air quality and lower exposures among residents living in flooded homes.

Practical Implications: The number and severity of floods is on the rise, and health departments need evidence-based information to advise homeowners on recovery after such disasters. Our study suggests that proper remediation of flood-damaged homes can reduce bioaerosols to acceptable levels but exposures are significantly increased while remediation is in-progress leading to an increased burden of allergy and allergic rhinitis.

© 2012 John Wiley & Sons A/S.

In plain English

This study measured indoor air in 73 homes damaged by the June 2008 Cedar River flood around Cedar Rapids, Iowa, and surveyed residents' health. Homes were sampled from November 29, 2008, to May 1, 2009. In 24 homes repairs were still in progress, and in 49 they were completed. Air was tested for mold, bacteria, dust, endotoxin, fungal glucans, allergens, lead, radon and asbestos (fiber type not named). Asbestos averaged 0.02 fibers/cc in in-progress homes and 0.03 fibers/cc in completed homes. All asbestos readings were below the 0.1 fibers/cc workplace limit; lead was below the quantitation limit. Homes still being repaired had higher levels of several biological contaminants, including fivefold higher airborne endotoxin. Residents of in-progress homes had higher odds of doctor-diagnosed allergies (adjusted odds ratio 3.08; 95% CI 1.05 to 9.02). Among all participants, 38% reported wheeze in the past 6 months versus 15.5% for 12 months earlier (adjusted odds ratio 3.77; 95% CI 2.06 to 6.92). The authors concluded that remediation reduced biocontaminants. They noted that their study was modest, relied on questionnaires, and may have participation and recall bias.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Cross-sectional exposure assessment (home inspections, air sampling) combined with resident health questionnaires, comparing homes at two stages of post-flood remediation
• Who was studied: 73 flood-damaged homes in the Cedar Rapids, Iowa area (24 with remediation in progress, 49 with remediation completed), enrolled on a first-response basis and sampled from November 29, 2008, to May 1, 2009. Health data came from 23 in-progress and 48 completed household residents.
• Exposure: Indoor air during and after renovation of flood-damaged homes. Asbestos and lead were collected with closed-face cassettes, and asbestos was analyzed by NIOSH Method 7400; no fiber type is named. Bioaerosols (culturable mold and bacteria, fungal spores, endotoxin, glucans, allergens), inhalable particulate matter, radon, CO and CO2 were also measured.
• Main results:
  • Airborne asbestos in the family room: in-progress homes had an arithmetic mean of 0.02 fibers/cc (s.d. 0.01; range 0.01 to 0.06), detected in 13 of 21 samples. Completed homes had 0.03 fibers/cc (s.d. 0.02; range 0.01 to 0.08), detected in 27 of 47 samples.
  • All asbestos concentrations were below the workplace permissible exposure limit of 0.1 fibers/cc.
  • Lead was below the quantitation limit in all homes (0 of 24 in-progress, 0 of 49 completed).
  • Radon was measured in 51 homes; 13 had levels above 4.0 pCi/l.
  • Airborne endotoxin in in-progress homes had a geometric mean of 1.55 EU/m3, fivefold higher than the 0.30 EU/m3 in completed homes (P less than 0.0001).
  • In-progress homes had 1.6-fold higher culturable bacteria (P = 0.026), 2.6-fold higher culturable mold (P = 0.002), and 2.3-fold higher inhalable particulate matter (P = 0.012) than completed homes.
  • Doctor-diagnosed allergies were reported by 56.5% of in-progress residents and 29.2% of completed-home residents, giving an adjusted odds ratio of 3.08 (95% CI 1.05 to 9.02).
  • Across all participants combined, the proportion reporting any wheeze was 38% for the past 6 months versus 15.5% for 12 months earlier (adjusted OR 3.77; 95% CI 2.06 to 6.92; P less than 0.0001).
  • Across all participants combined, prescription use for breathing problems was 29.5% in the past 6 months versus 23.9% for 12 months earlier (adjusted OR 1.38; 95% CI 1.01 to 1.88).
• The authors' conclusion: The authors concluded that remediation of flood-damaged homes decreases biocontaminants inside the home. They also concluded that the health differences observed indicate exposures from the flood-damaged homes may have adversely affected residents' health.
• Limitations the authors state:
  • The study was relatively modest, and health outcomes were assessed only by questionnaire.
  • Participation bias may be present, because subjects were drawn from people who had contacted the county health department.
  • Recall bias and self-reporting bias are possible.
  • Health outcomes were assessed at the same time as air quality, so exposures before the health outcomes developed are unknown.
  • More severe water damage in in-progress homes could confound their bioaerosol levels.
  • Exposures immediately after the flood and during initial mucking and gutting were not measured.
  • Some in-progress participants slept elsewhere, which could bias health results toward the null.

Topics

Medical terms in this study, explained in our Lexicon: Air Sampling.

Related studies

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• Airborne asbestos in buildings — R.J. Lee, D.R. Van Orden (2008)
• Occupational exposure to airborne asbestos from coatings, mastics, and adhesives — D.J. Paustenbach, A. Sage, et al. (2004)
• Airborne asbestos levels in school buildings in Italy — A. Campopiano, S. Casciardi, et al. (2004)
• Airborne exposure during asbestos abatement of floor tile, wall plaster, and pipe insulation — J.H. Lange (2005)

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