By now, the damage caused by air pollution to human health is obvious, in particular when it comes to lung or circulatory system diseases
The growth of air pollution
In recent years, air pollution has increased beyond recognition, and with it the risks to human health. Since 2011, the World Health Organization has been filling in a database every two or three years on air quality data. This is in order to calculate the population’s exposure to pollution.
«The data on particulate matter compiled in this database are directly used as inputs to model the Sustainable Development Goal 11.6.2 indicator – air quality in cities», declares the Organization. The data collected refers to ground-based measurements of annual average concentrations of particulate matter, PM10 o PM2,5, and nitrogen dioxide.
They used measurements covering a more limited part of the year in cases where averaging was impossible. Air quality results refer to areas where it is possible to calculate human exposure. This includes urban background, residential, commercial, and mixed zones.
Limits and their importance in maintaining the air quality
The limits set by WHO come from studies with leading experts in the field of pollution. They are the standards that ensure human health protection.
«After surviving a pandemic, it is unacceptable to still have seven million preventable deaths and countless preventable lost years of good health due to air pollution. That’s what we’re saying when we look at the mountain of air pollution data, evidence, and solutions available. Yet too many investments are still being sunk into a polluted environment rather than in clean, healthy air», declared Dr Maria Neira.
She is the WHO Director, in the Department of Environment, Climate Change and Health. The doctor explains that these are only an initial stage in being able to act on the data of diseases and mortality caused by air pollution. The WHO site reports the latest guidelines drafted in 2021.
It recommends the following concentration limits: for PM2.5 annual average 5 µg/m3; 24-hour average 15 µg/m3, for PM10 annual average 15 µg/m3. Then 24-hour average 45 µg/m3, for NO2 annual average 10 µg/m3; and 24-hour average 25 µg/m3.
Spread differences between the most and least developed countries
The tracking of the Air quality occurs in 117 countries and 6,000 cities. The organization noted from the data collected that: «In higher income countries, particulate pollution is lower, but most cities have problems with nitrogen dioxide».
Seventeen percent of the cities, which are part of high-income countries, have air quality lower than that tracked by WHO. This is due to PM2.5 or PM10 pollutants. Less than one percent of cities in low or middle income countries comply with the recommended limits.
At the global level less developed countries are more exposed to high levels of PM compared to the average. In contrast, NO2 prevalence does not see major differences between high and low income countries. Data collected of 4,000 cities on NO2 at ground level. Of those, a mere twenty-three percent of residents breathe acceptable concentrations of it according to updated guidelines.
The means of measurement
There are three different methods of measuring air quality, Dr. Neira explains. The first is ground monitoring. This gauges the levels of pollutants in the air in a certain environment and at a certain place. They are not available everywhere.
Then, there is the addition of mathematical models to study how particulate matters move through the air. It can estimate rates from the collected data considering chemical and aerodynamical aspects. Then, also data from satellites. Space agencies such as the European one or NASA, provide their own records of pollution levels.
These are useful for those places where it is difficult to do estimations. These three parameters provide a broad view of the global situation, the doctor points out. It is clear that in more developed countries the possibility of air quality measurement is widespread.
Low and middle income countries have fewer means at their disposal. In any case, people living in these areas are the most exposed to air pollution. What WHO emphasizes is that there is the need to improve air monitoring. Europe and parts of North America remain the regions with the most complete data.
PM2.5 measurements are critical in low-lying countries. There have been improvements in the latest database tracking that see the addition of 1,500 human settlements to the monitoring.
The sources of pollution
The above measurements make it possible to determine which pollutant sources affect the air the most. As Dr. Neira specifies, the causes vary by area. In most of developed countries, they are related to the use of energy resources given the dependence on fossil fuels.
Mobility, transportation, and travel habits also contribute along industrial processes and agricultural production to pollution in these regions. In countries such as Africa, however, the causes are related to the incineration of agriculture fields or waste. There are also industrial processes within cities.
The proportions in which certain actions affect air quality are relative to each individual area examined. The airborne particles considered most impactful, the doctor continues, are: PM2.5 one of the smallest size, PM10 and NO2 which are the most harmful to health as well.
WHO warning to maintain a certain air quality
After fifteen years since the global update was published in 2005, WHO has revised air quality guidelines as of 2016. Since that time, there is evidence that air pollution has increasing adverse health effects. This is due in part to advances in air pollution measurement and exposure assessment.
The overall goal, WHO points out, is to offer hard data and recommendations for air quality management. This can be done by expressing long-term or short-term concentrations for a number of key air pollutants. The guidelines are also required to allow governments to take note and act to reduce levels of air pollutants.
This is in order to decrease health burdens, although they are not legally binding. Among the pollutants considered in drafting these guidelines are PM2.5, PM10, ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide, chosen because of their global prominence.
Developed guidelines for government action
In addition to outlining reduction targets for countries that exceed the limits in a meaningful way, other guidance is provided. This is in order to manage certain types of PM. They include black carbon or elemental carbon (BC/EC)3, ultrafine particles (UFPs)4 and particles originating from sand and dust storms (SDS).
The required implementations are on a global scale. They involve the different areas that must work on reduction. The involvement of the health sector is relevant. It must be able to warn the population about serious threats to public health.
This act is comparable now to tobacco smoking or unbalanced diets. Although there are uncertainties, WHO clarifies that: «Future research will further strengthen the scientific basis for making clean air policy decisions around the world».
Danger for human health conditions
«For many years, air pollution and the exposure to toxic substances has been much linked to respiratory diseases representing one of the main causes», Dr. Neira explains. Among the main diseases related to bad air conditions are cancer and even chronic respiratory diseases such as asthma.
This is exacerbated by the pollution situation, such as with acute infections like pneumonia. Researchers proved that these particles by entering the body through the respiratory system can reach the bloodstream. In this way, those particles enter the vascular system causing ischemic heart diseas.
The doctor goes on to clarify that a high percentage of these illnesses are due to air quality. Traces of these substances have even been found in the placenta. Therefore, this condition can be harmful to babies even before birth. The data also reveals that poor air quality influenced the spread of Covid19.
It favors its action on the lungs and citizens of the most polluted areas have been more vulnerable. Those organs already exposed to this hostile and polluted environment are predisposed to the development of respiratory diseases.
«In addition to that, people who live in cities that are very polluted, they develop diseases that will create a kind of precondition for being more sensible by another infection like Covid-19», she concludes.
Ways governments can improve air quality
Government action remains an essential element in order to be able to implement the guidelines provided by the organization. It also ensures that they a baseline from which to improve air quality. WHO encourages revising national standards by keeping air quality monitored and identifying sources of air pollution.
Other actions to implement include transitioning to exclusive use of clean household energy for cooking; heating and lighting; increasing public transportation; pedestrian and bicycle-friendly networks; managing waste and vehicle efficiency standards.
In addition, a further key step according to WHO is to include the study of air pollution in the health sector and involve it in this battle in a direct way. «First it is necessary to create awareness and warn about this situation, second it is required to reduce dependence on fossil fuels and use clean energy resources, third it is needed to create a healthy urban plan to live risk-free in the most polluted areas. We need a healthy air it, is a human right», Dr. Neira concludes.
World Health Organization
Established in 1948, is a specialized agency of the United Nations that deals with public health at the international level. Its Constitution states that its goal is ‘the attainment by all peoples of the highest possible level of health’.