Toxicological evidence obtained in vivo and in vitro supports these findings showing the occurrence of diverse inflammatory and toxic responses after exposure to microorganism including their spores, metabolites and components isolated from damp buildings

Mold and Bacteria in Today's Buildings

In today’s buildings microorganisms present a distinct challenge for those who manage and occupy them and are key components of bio-aero-pollution in today’s buildings. Studies have shown that the growth of microorganisms such as bacteria and fungi in and around a building serves as a source of indoor bio-pollutant. World Health Organization (WHO Guidelines for Indoor Air Quality, 2009) concluded that the most important effect is increased prevalence of respiratory symptoms, allergies and asthma, as well as perturbation of the immunological systems. According to the report building dampness (supporting factor for microbial growth in buildings) varies widely from country to country and climatic zone. Dampness is estimated to affect 10-50% of all indoor environments in North America, Australia, Europe, India, and Japan.

It is often difficult to ascertain the exact dose/affect relationship by which the indoor air microbes may cause adverse health effects. However, irritation/toxic reactions, allergy or hypersensitivity, beside systemic infections are common upon the exposure of indoor microorganisms.

Toxicological evidence obtained in vivo and in vitro supports these findings showing the occurrence of diverse inflammatory and toxic responses after exposure to microorganism including their spores, metabolites and components isolated from damp buildings.

Dr. Janvier Gasana, MD, professor at Florida International University (FIU), Robert Stempel College of Public Health, Environmental and Occupational Health and Chair of Florida Children’s Environmental Health stated “medically there is a direct association between poor indoor air quality in both homes and buildings and an increase in prevalence of asthma, emergency room visits and allergy-type symptoms.”

These organisms include but are not limited to: Aspergillus, Alternaria, Blastomyces, Candida, Cladosporium, Cryptococcus, Emmonsia, Ganoderma, Histoplasma, Microsporum, Mucor,Penicillium, Rhizopous, Stachybotris and Trichophyton etc. are example of some common molds reported from indoor environments that cause a number of health and hygiene problems.

Common indoor environmental bacteria such as Acetobacter, Actinomyces, Alcaligenes, Bacillus, Brucella,Citrobacter, Clostridum, Coliform, Escherichia, Entrobacter group, Francisella,Klebsiella, Pseudomonas, Salmonella, Staphylococcus, Sterptococcus, Mycobacterium, Legionella, Listeria, Yersinia etc. are all capable of adversely effecting health and hygiene. Relatively little is known about the viruses in indoor air; however, viruses like influenza may also spread in the indoor environment through ventilation system.

Microorganisms naturally occur and play an important position in the earth’s ecological system. Therefore, it is not possible to eliminate these metabolites in their entirety. The most important aspect is to facilitate the nature and extent of these organisms in order to maintain good indoor air quality (IAQ). To understand the complexity involved (as mentioned above), it is essential to identify the causal factors such as physical, chemical, biological, and environmental. Some important physical factors are light, heat, dampness, chemical factors includes nutrition such as availability of organic or in-organic materials, biological factors includes naturally occurring microorganisms and their growth potential etc., and environmental factor such as moisture, relative humidity, and temperature are noticed as significant. The adverse effects given by these microorganisms can be managed and prevented depending on the results of the aforesaid information.

It is not practical to design a universal guideline fit for all in terms of exposure and health because immunity varies greatly from individual to individual. EDLab at Pure Air Control Services performed a 10 year study analyzing more than 7,000 buildings and over 25,000 environmental samples that were collected across the United States and abroad. The building type included both commercial and residential. The majority of samples analyzed were tested positive for bacteria and fungi.

In this study the average (normal baseline) concentration of air-borne cultureable (viable) bacteria was 175 CFU (Colony Forming Unit)/m3, and the fungal concentration in ambient air was recorded at 350 CFU/m3. The average concentration of non viable air-borne mold/fungal elements was estimated at approximately 1,000 cts (counts)/ m3. These baseline numbers are used as a reliable indicator for an expected average disseminated microbial (bacteria/fungi only) concentrations in today’s modern buildings.

The Environmental Diagnostics Laboratory (EDLab) at Pure Air Control Services analyzes a wide array of environmental microorganisms (bacteria and fungi) including organisms such as Staphylococcus aureus and Legionella pneumophila. EDLab scientists identify microorganisms by using various lab techniques. Some common analysis performed by EDLab to identify microbial conditions include Bio-Scan and Spore Trap analysis, mycological culturable analysis of air/bulk/surface/swab/liquid environmental samples among many others. The type of sampling and analysis performed is determined by project specifications project requirements or individual needs.

For additional information you can contact Dr. Rajiv Sahay, Director, EDLab, Pure Air Control Services 1-800-422-7873 ext 304.

To discuss a more comprehensive environmental assessment of your building or home call the credentialed professional indoor environmental consultants at Pure Air Control Services-Building Sciences team at 800-422-7873, ext. 802.