Exposure to suspended particulate matter in the air can have serious health consequences, especially in occupational environments where workers are continuously exposed.
Measuring air quality and monitoring airborne dust levels is essential to prevent diseases related to inhalation of particulate matter, the origins and background of which are detailed below.
Airborne particles definition
Dust can be defined as a suspension of solid particles in the air generated by mechanical processes. These solid particles that may mix with liquid particles and are suspended in the ambient air are also known by the term “aerosol”.
The health effects associated with exposure to aerosols are related to a number of factors, such as the physical characteristics of the aerosol itself, its chemical characteristics (water solubility and reactivity), its ambient concentration and its particle size.
Aerosol particle size
In general, when talking about particulate matter or just dust, reference is usually made to water-insoluble solid particles. These are discriminated by particle size, with smaller particles being deposited along the respiratory tract and reaching the alveolar zone.
Among the different sizes of suspended particles, those with the most relevance in terms of health are considered coarse particles – those with a diameter between 2.5 and 10 micrometres (PM10) – and fine particles, with a diameter of less than 2.5 micrometres (PM2.5).
There is also a further classification according to particle size and the European standard EN 481:
- Inhalable fraction: the mass fraction of total aerosol that is inhaled through the nose and mouth.
- Thoracic fraction: the mass fraction of inhalable particles that penetrate beyond the larynx.
- Respirable fraction: the mass fraction of inhaled particles that penetrate the non-ciliated airways.
Particles that enter the bronchial tubes can be eliminated by the body over time, but the respiratory system is unable to eliminate those that accumulate at the alveolar level and prolonged exposure over time can interact with the tissues where oxygen exchange with the blood takes place.
Airborne particles health effects
Exposure of workers to dust can occur in any workplace where dust is generated from materials of various contents and remains in suspension long enough.
The response at the individual level will depend not only on the nature of the particle and the duration, frequency and intensity of exposure, but also on the habits and physiological characteristics of each person.
The most common respiratory diseases associated with occupational dust exposure are as follows:
- Occupational and work-related asthma: chronic respiratory disease characterised by inflammation of the airways. Occupational asthma involves obstruction of the airways by a toxic product and no exposure outside of work. If there is pre-existing asthma due to other triggers and the person is exposed to toxic and irritant products, asthma aggravated by work occurs. Other associated conditions are rhinitis, with sneezing and runny nose due to inflammation and conjunctivitis.
- Chronic obstructive pulmonary disease: Inflammation of the bronchial walls that is usually not reversible. In the occupational setting, it is associated with contact with inorganic dust and repeated exposure to toxic substances. The advanced form may result in chronic bronchitis or emphysema (irreversibly damaged bronchi or alveoli).
- Pneumoconiosis: Diseases caused by the inhalation of different minerals that produce permanent damage to lung tissue as a result of the accumulation of dust in the alveoli, which causes fibrosis or permanent deterioration of the alveoli. Depending on the specific substance inhaled, it is called by different names, such as silicosis when the substance is crystalline silica, asbestosis and talcosis if exposed to asbestos and talc, lung disease due to hard metals or siderosis, which is lung disease due to iron, generally associated with welding work.
- Cancer, neoplasm, mesothelioma: Exposure to airborne particles containing carcinogenic substances, such as asbestos, arsenic and polycyclic aromatic hydrocarbons, increases the risk of developing lung cancer. It is especially relevant for those working in mining, construction and the chemical industry.
Exposure to particulate matter
Exposure to particulate matter is a common problem in a variety of work environments, such as construction sites, factories, mining, agriculture and activities involving the handling of solid materials.
Royal Decree 374/2001 of 6 April 2001, on the protection of the health and safety of workers against risks related to chemical agents at work, indicates as an obligation of the employer, among others, the need to consider in the risk assessment if there are hazardous chemical agents, to comply with the environmental limit values included in the document on Occupational Exposure Limits for Chemical Agents in Spain, prepared by the National Institute for Safety and Health at Work (INSST).
The limit values of chemical agents are expressed as “Environmental Limit Values (ELV)” which are reference values for the inhalable or respirable fractions of chemical agents in air and the following categories are considered:
- Ambient Limit Value – Daily Exposure (ELV-ED)
- Environmental Limit Value – Short Term Exposure (ELV-EC)
- Biological Limit Value – Daily Exposure (BLV)
Prevention of Occupational Risks and suspended particle matter
Occupational risk prevention is essential when it comes to exposure to airborne particles in the work environment.
In addition to personal protective equipment against airborne particles and industrial controls to minimise particulate generation and reduce worker exposure, it is important to carry out regular air quality measurements to assess airborne dust levels and to verify the effectiveness of control measures in place.
The ability to monitor the environment with an aerosol particle size analyzer can help identify non-compliance with established exposure limits and allow appropriate corrective action to be taken.
