The human health risk

Air Pollution: A Danger to Human Health

We know with certainty that the air we breathe has a massive impact on our health. Humans should breath as much unpolluted air as possible. In the modern age, it is almost impossible to breath clean, fresh air regularly and consistently. Air pollution has been a growing problem for a long time in developed and under developed countries alike, and it confronts each of us in our jobs, homes, cities and towns every day.

Every year, air pollution causes the premature death for 5.5 to 7 million people worldwide. Often underestimated, air pollution kills more people than HIV, automobile accidents and diabetes combined. In Europe, air pollution reduces the average life expectancy by almost  a year. Worldwide, more than 80% of people living in urban areas breathes air that exceeds the pollution limits recommended by the World Health Organization (WHO)

Particulate matter in the air is the main risk factor for human health. According to WHO, particulates cause roughly 800,000 premature deaths worldwide each year, ranking in as the 13th leading cause of death globally.

The International Agency for Research on Cancer has long established with sufficient evidence that the carcinogenicity of atmospheric particulate matter in polluted air can cause lung cancer.

The situation in Italy today remains a substantial risk. The VIIAS Project (Integrated Assessment of the Impact of Air Pollution on the Environment and Health), funded by the Health Control Center (CCM) of the Ministry of Health, and coordinated by the Department of Epidemiology of the Regional Health Service of Lazio with collaboration of Universities and research centers have shown that atmospheric pollution of fine particulate matter (PM 2.5) is responsible for 30,000 deaths or 7% of all deaths annually.

In Italy, the Po Valley represents the highest levels of air pollution due to its natural conformation and concentration of large cities, however the phenomenon impacts the whole peninsula, even areas traditionally considered “healthy.”

pericolo reale inquinamento
Fonte Immagine OMS.

The comparison between Outdoor Pollution and Indoor Pollution

It is generally believed that air pollution is a phenomenon linked to the outdoor environment whereas quality is substantially better inside buildings. Scientific data collected over the last thirty years challenges this belief.

In the mid-1980s, the US Environmental Protection Agency (EPA) was the first government agency to consider the relationship between External Pollution (Outdoor) and Internal Pollution (Indoor).

In 1985 the "Total Exposure Methodology Assessment Study" (TEAM, Volumes I-IV) surveyed levels of about a dozen common organic pollutants. The results showed that levels of pollutants were 2 to 5 times higher inside a home than in the outside environment. This is regardless of whether the houses were located in rural or highly industrial areas. The TEAM study indicated that while people used products containing organic chemicals, they could still expose themselves to very high levels of pollutants and in addition, high concentrations of these pollutants could persist in the air for a long time.

In 1998, through IEMB (Indoor Environment Management Branch), the EPA again systematically compared the level of concentration / exposure to numerous air pollutants recorded in the indoor environment with the level recorded in the outdoor environment. The analysis of the data confirmed that the indoor concentrations observed were generally 1 to 5 times higher than the outdoor ones and that the indoor exposure was 10 to 50 times higher than the outdoor exposure.

In a subsequent 2003 study that observed  175 homes in six different urban areas of the United States, the EPA concluded the following, summarized below.

tabella sostanza chimiche
Fonte Immagine EPA.

In Europe, the  OfficAir Project is a vast research project aimed at reducing health effects from exposure to more than 30 indoor air pollutants. The study has examined roughly 200 modern office buildings, approximately 20 from each of the eight Countries involved (Italy, France, Finland, Holland, Hungary, Greece, Spain and Portugal).  In Italy, the research  was entrusted to the CNR (National Research Center).

Countries representative of various European geographical and meteorological conditions were selected. Highly uniform standardized environments were chosen, with equal  environmental characteristics (air conditioning systems to mechanical ventilation of the air and artificial lighting ).

The results of the research showed that the levels of "indoor" pollutants were always higher than levels measured outdoors. In particular, in most of the buildings examined, levels of pollution from formaldehyde, benzene and terpenes were found in quantities far above threshold levels.

In developed countries, much of the population spends a significant part of their time (more than 75%) inside buildings or in other confined places. That said, it is clear why the phenomenon of indoor pollution has become of primary importance to public health.

Furthermore, it should also be noted  that people exposed to indoor air pollutants for longer periods of time are often also those most sensitive to the effects of such pollution. These groups include children, the elderly and the chronically ill, particularly those who suffer from respiratory or cardiovascular diseases.


Indoor pollution and air treatment plants

Air treatment plants can be one of the main causes of indoor air pollution. Due to their very structure and function these systems can become contaminated or malfunction overtime from lack of maintenance or lack of continuous monitoring.

Air system malfunctions often derive from a technical default  which blocks the system from being able to operate correctly as designed and can cause harm to human health. Malfunctions to air systems typically include:

-Damage to the filtering sections;

  •                 Incorrect regulation of temperature and relative humidity;
  •                 Bad air recirculation ratio, with excessive CO2 levels.
  •                 Aeraulic unbalance, with excessive or insufficient air flows.


Whatever the cause, the consequence of the plant malfunction often always results in a worsening of environmental factors (physical, chemical and microbiological).

tabella sostanza chimiche

Contamination is the most common cause of plant malfunction. For many office personnel, it is not always clear when levels of contamination in an air system become dangerous to human health.

Contamination in an air system takes two forms: chemical and microbiological.

Chemical contamination is normally due to the accumulation of pollutants from the outside environment through the external air intake, and from inside the building (through recirculation).

Microbiological contamination is more complex with various types of pathogens, various levels of danger and resistance to disinfection, all of which can lead to lethal health problems.

Microbiological contamination occurs through the proliferation of microorganisms such as bacteria, viruses, molds and yeasts inside HVAC systems.

The main microbiological agents often detected in HVAC systems are:

Bacteria: Staphylococcus Aureus, Pseudomonas Aeruginosa, Legionella Pneumophila, Legionella Gormani.

Viruses: Rhinoviruses, Influenza A and B viruses, Parainfluenza viruses, Coronaviruses, Adenoviruses.

Mycetes: Aspergillus, Cladosporium, Penicillium, Paecylomyces, Cephalosporium, Fusarium, Streptomyces, Tricoderma.

The World Health Organization (WHO) has affirmed through series of studies carried out over twenty years that chemical and biological contaminations deriving from failed or incorrect hygienic management of air treatment plants represents a driving force behind various types of pathologies and illnesses including:

Sick Building Syndrome (SBS - Unhealthy Building Syndrome), a condition affecting office workers, typically marked by headaches , respiratory problems, chest tightness, skin irritation, burning and redness of eyes, widespread malaise, attributed to unhealthy or stressful factors in the working environment such as poor ventilation.

This symptomatology is manifested in a high percentage of the exposed subjects and is shown to be chronologically associated with the work environment. Often times, symptoms are resolved with the removal from the unhealthy environment.

Building Related Illness (BRI - Building Related Diseases) or those diseases caused by bacteria, fungi, viruses and those arising from dust and chemical contaminants. These pathologies, much more serious than SBS, present a generally uniform clinical picture, a well-identified etiology, defined clinical and laboratory signs, prolonged recovery despite removal from the building and the need to remove the contaminating agent in order for patient recovery. These pathologies occur with a low prevalence among the occupants of the building. For example, this group of diseases can be traced back to:

Infectious Diseases:  "Legionnaire's Disease" (or Legionellosis), "Pontiac Fever", Influenza, Tuberculosis.

Severe Allergic Reactions : Extrinsic Allergic Alveolitis, Bronchial Asthma, Dermatitis, Rhinitis, Contact Urticaria;

Immunological Disorders: Hypersensitivity pneumonitis, "Humidifier fever".

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