The Dust We Breathe

Our experience in operating air quality networks leads us to think that there is still little knowledge of what we breathe in our daily lives. A lack of knowledge that extends to all the statutes of our society, often including the political class or even environmental technicians.

And it's not that the topic doesn't worry, but that there is no real awareness beyond the social alarm that is created when an episode of pollution persists over a large city or when there is some apocalyptic news that numbers the number of estimated deaths.

This same lack of awareness and real information may be behind a lack of logical judgment when treating some pollutants such as particles, which are relegated to less attention and regulatory pressure, as well as to a less strict treatment of their levels of intake.

However, particles are more than just suspended dust, and behind them a very dangerous pollutant is discovered that requires a radical change in approach.

A matter of size and composition:

Although particles can be considered pollutants as such, if only because of their dirtying effect when deposited, the tendency has been to classify them according to their size, since the most harmful to the respiratory system of living beings are those found in aerodynamic diameters of less than 10 µm.

From this diameter onwards, the particles we breathe can be almost any size, with coarser particles (those between 2.5 and 10 µm) and fine particles (which are between 1 and 2.5 µm), the most common in the literature.

Although below these you can still find ultrafine particles (which are between 0.02 and 1 µm), or even talk about nanoparticles, when we find diameters smaller than 100 nm (0.1 µm).

Obviously, the smaller the size, the greater the penetrating capacity.

From the point of view of control, what we measure in air quality are not exactly particles of a certain “thickness”, but rather a range of particles that goes from the diameter of particles that the so-called cutting head allows through to that which is capable of retaining the measurement support, which in the case of gravimetric sampling is usually between 0.4 µm and 0.7 µm.

Although the reference method for measuring particles is gravimetry, continuous monitoring is usually performed using automatic equipment based on beta radiation or oscillating microbalance, which allows hourly measurements to be obtained.

However, these devices require an intercomparison with the reference method to correct their measurements, a necessary requirement to know what they measure, which, however, is not performed correctly every time or for all equipment.

In networks, PM10 is usually measured, and although it is true that they give us a total volume of particles encompassing all diameters smaller than 10 µm, this parameter does not allow us to know how many of them are the ones that can really have a greater impact on our health.

But besides the diameter, another factor to consider in particles is their composition, information that is rarely handled in control networks, except for specific studies.

The composition of the particle itself is decisive for its reactivity within our body and, therefore, for its capacity to cause us more or less serious damage, which is why the study of the composition of particulate matter is so important, even if in the reality of our control networks it is not carried out on a regular basis.

Health effects of particulate matter.

Breathing is the only action that human beings do continuously, throughout the day, and that is also not possible to postpone until environmental conditions are healthier. This high frequency of use makes air the most vital resource, requiring between 7,000 and 9,000 liters per day to survive.

If you look at it, the rest of the actions that relate us to the environment and make us dependent on its environmental conditions (such as eating or drinking) are nowhere near as intimate, “necessary” or as immediate, and human beings can choose the time of their consumption or the actions necessary to perform before it.

This is precisely what makes air pollution so dangerous, and that its degree of affection to living beings refers to such low concentration values, based on micrograms and nanograms per cubic meter, several degrees of magnitude lower than pollution on other media such as water.

In fact, the poor quality of the air we breathe is the fundamental basis of many of the diseases that humanity currently experiences, and causes the mortality of nearly 3.7 million people a year worldwide, as indicated by the World Health Organization for the year 2012, most of these deaths from heart attacks, ischemic heart disease or obstructive pulmonary diseases directly related to air pollution.

And one of the main “killers” is precisely suspended particulate matter, a reviled and semi-forgotten pollutant that, however, has been revealed as one of the most dangerous in the environment for a couple of decades.

Particles are a pollutant that affects health in the medium/long term and has become a more than relevant factor for the development of diseases of various kinds, and especially in the increase in mortality and morbidity due to vascular accidents, increased cholesterol, contributing to the development of atherosclerotic plaques, the hypersensitization of the immune system and the production of coronary events and strokes of varying severity.

Particles are therefore discovered today as a vital factor for human health.

The limit values that we have today have proved to be highly insufficient and ineffective in controlling the condition to our health. Coherent regulation and adequate control and monitoring of them should be the main objectives to be pursued by our legislators and supervisory bodies.

We therefore need new ways of considering the control of air pollution, giving real relevance to those pollutants that are most harmful to health and the environment, and always looking for the source of the pollution to act on it.

If you want to know more about the topic: http://ferfollos.blogspot.com.es/2015/06/respirando-polvo.html