Protecting Worker Exposure to Airborne Hazards

By: Tim Turney, Contributor

Air sampling is used to understand exposure levels; control of those levels is key to protecting employee health, using the hierarchy of controls. (photo courtesy Casella)

The effects of inhaled substances, such as dusts gases and vapors, has long been known to be a cause of occupational lung disease as a result of exposure in the workplace.

The effects of exposure can develop quickly or take years to develop, leaving workers vulnerable to asthmatic and allergic reactions and longer-term illnesses, such as cancer and cardiovascular, respiratory and nervous system disorders. While the cost to human health can be devastating, the financial costs to businesses through reduced productivity, employee absences, recruitment and compensation claims can be substantial.

The Occupational Safety and Health Administration (OSHA) issues citations and penalties if businesses violate permissible exposure limits (PEL). PELs are legal limits designed to control employee exposure to hazardous substances in an 8-hour period to prevent health risks. However, employers are also advised to monitor recommendations from industrial hygiene experts and manufacturers, because it is estimated that 90% of OSHA’s PELs have not been updated since the 1960s.[1]

Consequently, OSHA may issue citations under the general duty clause of the Occupational Safety and Health Act (OSH Act) if exposure limits exceed industry-wide standards and pose a threat to employee health. Any kind of dust is hazardous to health when present at a concentration in air, limits are in place or 10mg/m³ for inhalable general dust or 5mg/m³ of respirable general dust, as measured over the equivalent of an 8-hour day.

These concentration limits for different types of inhalable and respirable dusts can vary dramatically, depending on the health risks associated with the substance. For example, silica dust which is known to cause serious respiratory health conditions has a PEL of 0.05mg/m3 so it is important to check OSHA regulations and industrial hygiene experts’ recommendations, dependent on the dusts present in your working environment, to ensure compliance and the safety of employees. No matter exposure limits, the levels in the workplace should be kept as low as is practicable to protect worker health.

Industrial hygiene methods are geared towards measuring personal exposure using personal air sampling pumps, because the tried-and-tested method can quantify personal exposure and ensure compliance with regulatory limits. They also can measure risk to ensure control measures are working.

Using Air Sampling Pumps

IH methods are geared towards measuring personal exposure using personal air sampling pumps, because the tried-and-tested method can quantify personal exposure and ensure compliance with regulatory limits. (photo courtesy Casella)

Safety: Many pumps are intrinsically safe (IS) rated as standard, but it is worth checking that your pump’s IS rating is still appropriate for your facility to avoid any safety issues.

Design: Size, weight and accessibility are critical design elements. Pumps should allow freedom of movement and be unobtrusive, robust and not prone to leakage. Selecting a smaller, lightweight, low-flow pump (0.05-1L) for sampling vapors and gases, over a medium flow pump (1-5L) equipped with a low flow adaptor, is more user-friendly for workers.

When using a sorbent tube, managers need to check that the smaller (backup) section is nearer to the pump.

Calibration: All pumps should be calibrated with representative sampling media before use. It is also necessary to calibrate the pump before use; check again at the end of the day to make sure flow has not deviated by more than 5%. Of course, be certain you are calibrating the whole sample train, not just the pumps, to ensure accurate measurement.

Standards: It is vital to check that your pump meets the latest international standard for air sampling pumps. Compliance to ISO 13137 ensures accurate flow performance amongst other performance criteria—ensuring accurate sampling—and meaning you won’t have to repeat measurements.

Pulsation: If you are using a cyclone, do not assume that your pump has sufficiently low pulsation. The ISO standard states that this should not exceed 10% of the flow rate. A large pulsation value means that the size cut performance of cyclones used can be affected because their performance is flow rate-dependent. Consequently, pumps that generate significant pulsation will collect smaller samples, meaning less data to analyze. Updates in some of the latest electronic flowmeters mean pulsation can be measured.

Pump usage: Don’t leave your pump unused and uncared-for. If you don’t use your pump regularly, charge or cycle the battery, so when you do need it, the battery will last. Pump care is critical, so after sampling, check for damage and get your pump serviced at the prescribed interval.

The latest generation of Bluetooth®-enabled pumps and flow calibrators can automate the calibration process and save valuable time, thus increasing confidence in the calibration results, which can be saved and/or emailed for reporting.

Pulsation, once tested in a laboratory, can now be checked in the field at the same time as a normal flow rate calibration, through an airflow calibrator equipped with Bluetooth. As advances in technology continue to develop, remote methods can avoid disturbing workers and improve the validity and reliability of sample data. These advances also allow for real-time detection, giving workers peace of mind knowing that, should the air quality around them deteriorate, they can act instantaneously to protect themselves.

Critical Protection When it Counts

Skill and knowledge of air sampling can take years to build, so the information above can only be considered a foundational introduction. If certain aspects of air sampling are outside of an individual’s competencies, then external consultancies, training and support can be sought to bridge knowledge gaps and ensure employees get the critical protection they need. Air sampling is used to understand exposure levels; control of exposure levels is key to protecting employee health by using the hierarchy of controls.

About the Author:

Tim Turney is Global Marketing Manager at Casella and graduated as an engineer from Queen Mary and Westfield in London. Since starting at Casella in 1998, Tim has been involved in the acoustics and air sampling industry, specializing in measurement and instrumentation technologies. Casella is owned by TSI Instruments Ltd, a UK subsidiary of TSI Incorporated, and is supported by a network of distributors providing local service and support to those searching out solutions for risk reductions. www.casellasolutions.com

[1] https://www.osha.gov/annotated-pels