When Should You Retest Your Indoor Air Quality?

Indoor air quality is important for employee health and comfort. Poor air quality can lead to several negative health effects, including irritation, coughing, and fatigue. More serious health hazards such as occupational asthma, specific organ toxicity, or cancer can also occur, depending on the chemicals being handled on site. Because of this, the Occupational Safety and Health Administration (OSHA) has developed permissible exposure limits (PELs) for several dusts, fumes, and vapors from various chemicals. These PELs, found in 29 CFR 1910.1000 Table Z-1, identify the maximum concentrations of different chemicals and materials an employee can be exposed over the course of an 8-hour work shift. Employees exposed to airborne concentrations of a material above a PEL may be at risk for serious health hazards.

In order to determine if an employee is at risk for serious health hazards related to airborne particles or chemicals, facilities shall conduct indoor air quality monitoring in order to determine the airborne concentration of materials present. To conduct this monitoring, you must first review applicable Safety Data Sheets (SDS) for materials used in each working area. Section 3 of the SDS identifies the ingredients and concentration of the material, and Section 8 of the SDS identifies any applicable exposure limits, engineering controls, or personal protective measures that can be used to minimize worker exposure to hazardous chemicals. These two sections can be used to identify what chemicals should be sampled for when conducting indoor air quality monitoring.

Once you have determined what chemicals should be monitored for throughout your facility, it is time to conduct the monitoring. This is typically done by an industrial hygienist, or someone with industrial hygiene experience. Monitoring is generally conducted by fitting personal sampling air pumps that pass air collected from the breathing zone of the employee through collection media. The pumps are run for a length of time as the monitored employee conducts his or her routine activities. Once monitoring is complete, the samples are analyzed by a laboratory to determine the airborne concentration of chemicals measured from each employee. These results can be compared to the OSHA PEL to determine if the employee is exposed to a hazardous airborne concentration of chemicals.

If it is determined that employees are above an OSHA PEL during their work shift, engineering or administrative controls shall be implemented or personal protective equipment (PPE) may need to be worn by all affected employees. However, in accordance with OSHA’s Heirarchy of Controls PPE should only be considered if administrative and engineering controls are infeasible or do not lower the exposure concentration to a safe level. Engineering controls are designed solutions that are implemented to reduce concentrations of airborne contaminants, such as installing new equipment to contain fugitive emissions into the work area or increasing ventilation using dedicated fume hoods, dust/fume collection systems, or fans. Administrative controls are work practices or procedures that are developed to change the way people work to minimize their exposure to the applicable hazards, such as implanting a schedule to reduce an employee’s time working in areas with high concentrations of airborne contaminants or limiting the amount of hazardous materials used during one shift. If these controls are not sufficient, then appropriate PPE such as dust mask or respirators should be worn by all affected employees. If respiratory protection is required, the facility must implement a Respiratory Protection Program, as defined in 29 CFR 1910.134. You will need to ensure that respirators with proper Assigned Protection Factors (APFs) are selected. All employees required to wear a respiratory will need to be medically evaluated to ensure they can safely wear a respirator, shall be fit tested for the respirators selected for them, and will need to be properly trained on their use.

So, say you have conducted indoor air quality monitoring. You have identified which employees are exposed to hazardous concentrations of airborne contaminants and where no additional controls are needed. When, if at all, should you conduct follow-up indoor air quality monitoring? The respiratory protection standard (29 CFR 1910.134) simply states that “the employer shall identify and evaluate the respiratory hazard(s) in the workplace” and does not specify how often sampling should be conducted. However, you shouldn’t assume that once you’ve conducted indoor air quality monitoring, no additional sampling is needed. Follow-up indoor air quality monitoring should be reconducted whenever there is a change at your facility that could potentially affect the airborne concentration of a hazardous chemical in a work area. This includes, but is not limited to, installing new equipment in the area, relocating a workstation to a different area in the facility, changing the amount or type of hazardous chemicals being handled, modifying ventilation, etc. Follow-up monitoring should also be conducted to validate the effectiveness of any engineering or administrative controls implemented in a work area. Airborne concentration of hazardous chemicals can also change over time simply because of changes in production rates or degradation of equipment. Because of this, many companies opt to conduct routine air quality monitoring every 2 or 3 years to ensure that their employees are safe in an ever-changing workplace.

When was the last time that indoor air quality monitoring was conducted at your facility? It’s very important to keep accurate, up-to-date records of airborne concentrations of hazardous chemicals in order to keep your employees safe. Even if no major changes have been made, it is possible for small modifications or changes in production to affect the amount of hazardous contaminants in the air. Because of this, it is a good idea to conduct periodic follow-up indoor air quality monitoring throughout your facility in order to ensure that your employees are being adequately protected.

If you would like help with conducting keeping your employees safe from potential respiratory hazards, CTI is prepared to help. Our staff of engineers can conduct indoor air quality monitoring throughout your facility and can help develop and implement engineering or administrative controls. If respiratory protection is deemed necessary, CTI can assist you in selecting appropriate respirators and can help develop an OSHA-compliant Respiratory Protection Program. If you would like assistance, please contact CTI at (770) 263-6330, or by email at cti@conversiontechnology.com.

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