Guide about urban pollution: environmental impact, public health and solutions

Urban pollution, particularly air pollution, is a problem affecting almost every city.

It is a direct result of the industrial activities that drive our economy, and urban expansion. In short, a consequence of our daily life, with negative connotations on the environment and our health.

That is why we decided to put together this guide on urban pollution.

We believe that the best way to deal with a problem is to learn about it in depth, find out what is causing it and, lastly, consider what solutions can be applied to either solve it or minimise its impact.

What is urban pollution?

Urban pollution is a term used to describe the presence of substances or forms of energy (such as noiseImagine waking up every morning at 5:00 a.m. to the relentless roar of a motorway just metres from your window. Experiencing such high-intensity noise is n...
Read more) that can generate risks or problems for materials or living beings.

Soil, water and the air we breathe can all be affected by these pollutants. And the quality of air in urban areas can condition their viability to meet human needs.

However, the focus of this particular article is on urban air pollution, a problem that, according to the WHO (World Health Organization) affects 9 out of 10 people on the planet.

Environmental impact of urban pollution

Pollutants that impact air qualityAir quality refers to the state of the air we breathe and its composition in terms of pollutants present in the atmosphere. It is considered good when poll...
Read more in urban areas can also harm natural ecosystems.

Aside from the direct discharge into the natural environment, it has been found that gases like tropospheric ozoneTropospheric ozone (O3) or ground-level ozone is a gas found in the lowest layer of the Earth's atmosphere, the troposphere, which extends up to 10 kilomet...
Read more or “bad ozone” can reduce plant growth. A direct consequence of this effect could be, for example, a decrease in crop yields.

In addition, other substances, such as nitrogen oxides (NO_x) or ammonia (NH₃), are deposited on the soil. This mechanism can, for example, alter the normal functioning of natural ecosystems by changing the chemical composition of the soil. In the case of water resources, an increase in nitrogen concentration can lead to an increased risk of eutrophication.

Public health consequences of urban pollution

99% of the world’s population lives in places where the WHO recommended limits are exceeded. The most tragic consequence is the number of premature deaths. The combination of indoor and outdoor pollution causes more than 6 million people per year.

But in what ways does urban pollution directly impact human health? In the most basic terms, there are two broad categories of urban pollution:

• Noise pollution. As well as potential hearing loss, prolonged exposure to high noise levels can cause problems with sleep, and performance at work or school and can even lead to cardiovascular problems.
• Gas and particulate air pollution. Unlike noise pollution, this particular type of pollution has received great attention, and there have been dozens of clinical trials and studies carried out demonstrating multiple effects on the respiratory and cardiovascular systems.

Causes of pollution in large cities

There are multiple sources of urban air pollution, mostly caused by humans. Here are some of the main ones.

Emissions caused by road traffic

The vehicles that drive through cities each day are one of the main causes of urban pollution.

In Europe, road traffic is estimated to generate almost 40% of nitrogen oxide emissions.

Traffic is also a significant source of PM₁₀ and PM_2.5 particles and lead emissions.

Energy consumption

The energy consumed by residential, commercial and government buildings generates a large volume of suspended particulate matter, rising to almost 60% in the case of PM_2.5 particles.

Residential, commercial and institutional buildings are also a major source of carbon monoxide (CO)The carbon monoxide (CO) is an invisible gas (colorless and odorless) that, at the same time, is a silent killer because in just a few minutes it exhibits ...
Read more and black carbon emissions.

Industrial areas

Most cities are surrounded by industrial areas occupied by polluting businesses that also contribute to the deterioration of air quality in urban areas.

In addition to the gases generated by burning fossil fuels, industry is responsible for releasing heavy metals, such as nickel and arsenic.

Types of pollutants in cities

So far in this article, we have mentioned a number of the most significant pollutants, but it is also worth taking a moment to look at what they actually are.

Particulate Matter (PM₁₀ and PM_2.5)

PM₁₀ and PM_2.5 particulate matter are so-called because of their size. They have a diameter of less than 10 and 2.5 µm respectively.

The small size of these particulates allows them to penetrate deep into the respiratory system, and they can even enter the bloodstream.

PM has been linked to significant health problems such as respiratory diseases, cardiovascular problems and lung cancer.

Ozone (O₃)

As mentioned earlier, tropospheric ozone can cause serious damage to plant life. But it is also harmful to human health.

Ozone is a secondary pollutant. This means that it is formed as a result of a photochemical reaction between nitrogen oxides (NO_x) and volatile organic compounds (VOCs), which is triggered by sunlight. In other words, pollutants from cars or industry are released into the atmosphere and, as they circulate through the air, they are transformed into other substances, such as ozone. Ozone causes smogSmog, beyond that dense fog Smog is a mixture of air pollutantsAir pollution caused by atmospheric contaminants is one of the most critical and complex environmental problems we face today, both because of its global r...
Read more that accumulate in the atmosphere, especially in urban areas. This phenomenon is character...
Read more and can cause breathing difficulties.

Sulphur oxides (SO_x)

Sulphur oxides are mainly generated by the burning of fossil fuels containing sulphur. Until recent maritime emissions regulations were introduced, ships were one of the forms of transport that generated the greatest volume of SO_x emissions.

In addition to their harmful impact on the respiratory system, when combined with water, they turn into sulphuric acid, one of the gases responsible for acid rain.

Nitrogen oxides (NO_x)

Nitrogen is one of the elements contained in fossil fuels. Therefore, their presence in the atmosphere is directly related to the burning of fossil fuels, such as in road vehicles.

Prolonged exposure to high concentrations of NO_x can lead to lung problems and inflammation of the airways.

Furthermore, NO_x also contributes to the formation of tropospheric ozone.

Carbon monoxide (CO)

Carbon monoxide is a notoriously toxic pollutant. The incomplete combustion of fossil fuels such as petrol, natural gas, oil, coal or wood causes this colourless, odourless and tasteless gas.

Volatile Organic Compounds (VOC)Volatile Organic Compounds (VOCs) are chemical substances primarily composed of carbon and hydrogen, but they can also contain other elements such as oxyge...
Read more

VOCs are another pollutant that is released when fossil fuels are burned. However, two of the main sources of VOCs are solvents and paints, and the companies that manufacture these products are significant contributors to this form of pollution.

For people, they can cause a range of problems from breathing difficulties to dizziness or a lack of concentration.

Like NO_x, they contribute to the formation of bad ozone.

Solutions to air pollution in cities

Urban air pollution cannot be solved or minimised by tackling a single issue in isolation.

A problem of this magnitude requires a range of policies and strategies that need to be implemented in parallel, such as:

• Restricting the movement of the most polluting vehicles; creating low emission zones (LEZ);
• Improving public transport services;
• Creating more green areas to help clean up the atmosphere;
• Increasing the amount of energy generated from clean sources, such as solar and wind energy;
• Improving building insulation to reduce energy consumption, or
• Promoting remote working to reduce the number of daily commuters.

However, one thing that all these measures have in common is the need to monitor air quality continuously and in real time. It is only possible to successfully implement these measures if you know what the starting point is and can monitor how the situation evolves over time.

Success stories

Kunak is proud to have been offering the very best air quality monitoringControlling air quality is an essential task in order to enjoy optimal environmental conditions for healthy human development and to keep the environment i...
Read more solutions for more than 10 years.

Our disruptive technology and the professionalism of our team have earned us international recognition and led to the successful implementation of several projects, including:

• The Air and Noise Monitoring scheme in Albacete (Spain).
• The Urban Air Quality Network in Rivas – Vaciamadrid (Spain).
• The Hybrid Environmental Monitoring Network in urban areas around Calais (France).
• The Measurement of Environmental Pollutants in Cartagena de Indias (Colombia)