Indoor Air Quality

Background

Poor indoor air quality typically results from inadequate ventilation resulting in the presence of contaminants in the indoor air.  However, in some cases, the contaminants may be generated within the building space at a rate that exceeds their elimination by standard ventilation rates. These contaminant sources include fungal/mold growth stemming from the presence of moisture and volatile organic compound (VOC) generation from furnishings, construction materials, cleaning products, personal care products, and activities such as printing and photocopying..

The term 'fungi' includes organisms such as yeasts, molds, and mildews.  Molds are known to cause a variety of health effects via ingestion, inhalation, and skin contact. These can include asthma, runny nose, hypersensitivity pneumonitis, organic dust toxic syndrome, irritation of the eyes, skin, nose, throat, and lungs.  Some molds produce toxic substances known as mycotoxins which may cause mucous membrane irritation, skin rash, nausea, immune suppression, liver damage, central nervous system damage, and cancer.  Fungi can also produce volatile organic compounds (VOCs) thought to be the source of odors.  Inhalation of the VOCs can cause symptoms such as headaches, nasal irritation, dizziness, fatigue, and nausea.

EHC Associates provides extensive Indoor Air Quality Services to its Residential, Commercial, Educational, Public, and Industrial Clients, including:

• Complaint Investigations

• Screening Inspections

• Air Quality Measurements

• Mold Sampling

• VOC Sampling

• Comprehensive Building Evaluations

• Preventive Maintenance Programs

• Remediation Consulting

Services range from simple mold testing to comprehensive investigation and remediation services as described below.  As most indoor air quality problems stem from inadequate ventilation and/or moisture infiltration, our architectural expertise facilitates solutions to these problems.

Survey

Generally an indoor quality survey is the first phase of an air quality investigation and consists of the following four components.  However, on numerous occasions, these components are performed individually as requested by our Clients.

• provision and evaluation of questionnaires completed by building occupants

• air quality testing of the survey area including temperature, relative humidity, carbon dioxide (ventilation), and Volatile Organic Compounds (VOCs).  

• air and surface testing for microbial (fungi, mold, and bacterial) contamination

• inspection and evaluation of the building HVAC system operation, construction, and custodial and maintenance activities

Questionnaire

An indoor air quality questionnaire, based on the National Institute of Occupational Safety and Health (NIOSH) model, is provided to the Client for approval and distribution to building occupants.  The returned questionnaires are evaluated to help determine the type and extent of any perceived air quality problem.

Overview Inspection 

An inspection of the affected building areas is conducted to determine any visual contaminant sources or HVAC system problems and to establish environmental measurement locations.  As EHC Associates is both an architectural and environmental firm, we have extensive knowledge of the operation of HVAC systems and the problems that can impact indoor air quality.

Environmental Measurements

The following measurements related to indoor air quality are taken as part of the survey:

• carbon dioxide levels as a screening technique to evaluate the adequacy of ventilation;

• temperature to determine compliance with ASHRAE Indoor Air Quality Guidelines;

• humidity to determine compliance with ASHRAE Indoor Air Quality Guidelines; 

• volatile organic compounds; and

• rate of air exchange in affected areas.

A Metrosonics electronic air quality monitor is utilized to automatically take measurements at one-minute intervals over a minimum 24-hour period in designated building areas to determine the effect of time of day, HVAC systems operation, and occupancy load on the air quality of the area. Data from the monitor is then transferred into our computer network, which will provide a detailed report including graphs of the air quality conditions over a 24-hour period in each of the areas.

The following standards are recommended for indoor air quality by the National Institute for Occupational Safety and Health (NIOSH) and/or the American Society of Heating, Refrigerating and Air Conditioning Engineers, Inc. (ASHRAE):

• Temperature:               Summer  73º - 79^o F

                                          Winter     68º - 74^o F

•  Relative Humidity:       30 - 60%

•  Carbon Dioxide:          Less than 600 PPM above
                                    outside background level*  

*Note:   At levels greater than 1,000 PPM (parts per million) above the outside background level, symptoms including headaches, fatigue, and eye and throat irritation will be prevalent.

Airborne Microbial Sampling

When deemed appropriate by the conditions observed during the facility inspection or determined during the air quality testing, air sampling is performed for microbial (fungi, mold,  and bacteria) contamination.

Viable Sampling

Viable sampling determines the presence of only those fungal spores and bacteria capable of reproduction. The viable microbiological collection procedure utilizes a multiple plate, N-6 impactor method sample collection procedure.   Samples are collected onto laboratory- prepared petri dishes at a 28.5-liters/minute-airflow rate for a 2-minute duration. After refrigeration, the exposed petri dishes are forwarded via overnight courier to an accredited laboratory for incubation and microscopic analysis.

Non-Viable Sampling

Non-Viable sampling determines the presence of a wide range of airborne particulates that include mycelial fragments and fungal spores.   Samples are collected in Air-O-Cell Spore Trap Cassettes at a minimum 15 liters/ minute airflow rate for a 5-minute duration.  The exposed cassettes are forwarded via overnight courier to an accredited laboratory for direct light microscopic analysis.

There are no current regulatory requirements or standards for acceptable levels of microorganisms in indoor air.  However, the following levels are generally acceptable in industry practice.  (cfu/cu.m) stands for colony forming units per cubic meter of air)

Additional guidelines include the following:

Bulk and Surface Microbial Sampling

Viable Sampling

Viable sampling determines the presence of only those fungal spores and bacteria capable of reproduction.  

When deemed appropriate by the conditions observed during the facility inspection bulk and/or surface sampling is performed for microbial (fungi, mold and bacteria) contamination.

Small bulk samples of building materials such as insulation, wallboard, textiles, and carpeting and placed in sterile zip-lock bags.

Surface samples are collected with individually packaged, sterile, hospital-grade swabs which are utilized to wipe a delineated suspect area and placed in sterile sealed containers.  

Non-Viable Sampling

Non-Viable sampling determines the presence of a wide range of particulates that include mycelial fragments and fungal spores.  

When deemed appropriate by the conditions observed during the facility inspection bulk and/or surface sampling is performed for microbial (fungi, mold and bacteria) contamination.

Small bulk samples of building materials such as insulation, wallboard, textiles, and carpeting and placed in sterile zip-lock bags.  Surface samples are collected with clear adhesive tape and placed in sterile zip-lock bags.  

After collection samples are shipped by overnight courier to an accredited laboratory for direct light microscopic analysis.

There are no current regulatory requirements or industry standards for acceptable levels of microorganisms on surfaces.  Acceptable levels are generally determined by the Consultant based on experience and the overall project testing results.

Report Preparation

A report of the indoor air quality survey containing a summary of the investigation and testing, summary of indoor air quality questionnaire data, the findings, and recommendations for corrections or further investigation and/or testing based on the initial findings is prepared.

Additional Testing

Based on the findings of the initial survey, additional testing including the following, along with chemicals and nuisance dust may be performed:

• Allergens

• Bacteria

• Endotoxins

• Fecal Coliforms

• Fungi

• Herbicides

• Inorganics

• Legionella pneumophila

• Mycotoxins

• Pesticides

• Pollens

• PCBs

• PAHs

• VOCs

• mVOCs

Detailed Investigation

Also based on the findings of the initial survey, a detailed follow-up inspection of specific areas or operations including the following, may be recommended:

• HVAC system components, control, and operation; 

• building construction and renovation drawings and documents;

• facility operations;

• maintenance and custodial procedures;

• behind-wall, below floor, and above-ceiling construction (moisture, contaminants); and

• site utilization and off-site activities and operations.

Building and Systems Upgrade

Most indoor air quality investigations determine that inadequate ventilation is the primary cause of poor indoor air quality.  As an architectural firm, EHC Associates can provide its clients with complete design services for upgrade of ventilation systems and heating and cooling systems as required to provide a comfortable environment for building occupants.  Another primary cause of poor indoor air quality is microorganism contamination (fungi and bacteria) facilitated by moisture. The firm's architectural capabilities facilitate location of the cause and correction of building envelope moisture infiltration and system moisture creation problems.

Management Program 

The facility owner/manager should initiate an operations and maintenance program containing responses,  procedures, and controls to maintain good air quality and minimize discomfort and health risk of building occupants.

Each management program must be designed to suit the individual facility construction, conditions, and operations. EHC Associates, in conjunction with the facility owner/manager, can develop a concise and detailed written plan which includes the following:

• purpose and approach

• initial decontamination and remediation 

• building envelope inspection and maintenance

• building envelope upgrade plan

• cleaning procedures

• operational procedures

• HVAC systems inspection

• HVAC systems operation monitoring

• HVAC systems upgrade plan

• maintenance procedures including timely air filter replacements

• record keeping

Remediation Design

When the presence of biological or chemical contaminants is confirmed, a remediation plan must be developed to remove, dilute, isolate and/or neutralize the contaminants.

Bidding Phase

The bidding phase includes the reproduction of bidding documents for distribution to bidders and assisting the Client in qualifying prospective bidders, obtaining and evaluating bids, and awarding abatement contracts. Administration of the bidding, including issuance of addenda, attendance at a pre-bid conference, and preparation and issuance of minutes are part of this phase.

Remediation Administration 

Remediation Phase  

This phase involves the administration of the remediation contract and generally includes:

• attendance at a pre-abatement conference, and preparation and issuance of minutes are part of this phase;

• review and approval of the contractor's cost breakdown, proposed subcontractors, proposed remediation and safety procedures, progress schedule, material samples, shop drawings, bonds, and other required submissions;

• inspection trips to the site to review the progress of the work and its quality in order to determine if the work is proceeding in accordance with the contract documents.  Formal job conferences will be held as required and will be followed by the issuance of job meeting minutes;  

• review of the contractor's applications for payment, determination and verification of the amounts owed to the contractor and issuance of certificates of payment for such amounts;  

• preparation of all supplemental drawings and sketches that may be required for the remediation sequence and issuance of any supplemental instructions or change orders covering authorized revisions in the work.  The Client is informed of, and his approval obtained, for any changes in the work;  

• complete documentation of the remediation work, including daily logs, monitoring/testing results, narrative description, disposal documents, photographs, etc., is forwarded to the Client upon completion of the contract work.  Copies of all contract related correspondence are forwarded to the Client upon initiation.  

Close-Out Report

A project close-out report including notifications, technician's daily reports and inspection reports, air monitoring records, and disposal documents will be prepared and submitted to the Client upon completion of the project. 

Wipe Sample and Air Monitoring  

The purpose of remediation wipe sample and air monitoring is to document and ensure that complete decontamination of the work area is achieved below the specified clearance levels.  Air monitoring also documents and ensures that areas of the facility beyond the remediation work area are not contaminated by airborne contamination released by any of the remediation contract work procedures.

These services include furnishing all labor, supervision, transportation, materials, services, tools, and equipment necessary for complete remediation wipe sampling and air monitoring and testing as specified and as otherwise required by all applicable regulations.  Incubation and analysis of wipe and air samples is performed at an independent laboratory.

Remediation Monitoring

Monitoring is performed to ensure that remediation is performed in a manner that:

• conforms to the intent of all health and safety laws and regulations; 

• recognizes and takes all reasonable precautions against the biological dangers of airborne contaminants; 

• causes no contamination to other parts of the building; 

• provides adequate protection for the workers performing this task; 

• creates no short- or long-term threat to the health of other persons in or around the premises now or in the future; and 

• leaves the building documentably safe for occupancy.

Inspections of the work area preparation and containment are performed prior to the actual start of remediation work, and periodically thereafter, to look for any breaches in the containment or conditions that do not meet regulations or the requirements of the remediation contract documents.  In addition to the wipe sample and air testing hereinbefore described, visual inspections of all surfaces during and after work area cleaning operations are conducted. 

A narrative log is maintained on a work shift basis, that documents all notable events that occur each day and provides a comprehensive picture of conditions, problems, and progress in and around the job site during the course of the remediation work.  Sample logs that record all wipe sample and air monitoring tests performed, are maintained on a daily basis.