What is the harm of polluted air to health?

Air pollution is a major concern worldwide. The World Health Organization (WHO) states that exposure to air pollutants can lead to higher incidences of respiratory issues, cardiovascular diseases, and certain forms of cancer. This has resulted in 6.7 million deaths per year.

Although it can be challenging to avoid polluted air, monitoring the air quality through international online platforms and limiting outdoor activities during times of high pollution can help reduce the health risks.

Polluted Air: A Threat to Human Health

The air is considered polluted when it contains pollutants in the form of dust, smoke, or gas at levels that can harm human health. Pollutants are divided into two main categories: natural, such as dust from hurricanes, smoke from forest fires, and gases from volcanic eruptions; and anthropogenic, which result from human activities like industrial and domestic activities.

Historically, the primary anthropogenic air pollutants were produced from the combustion of sulfur-containing fuels such as coal. However, today, vehicle emissions with gasoline and diesel engines are the main source of air pollution. These emissions release harmful substances such as carbon monoxide, nitrogen oxides, volatile organic compounds, and particulate matter.

Furthermore, nitrogen oxides and volatile organic compounds undergo photochemical reactions in the presence of sunlight and form ozone, leading to the formation of smog over cities. Anthropogenic pollutants significantly impact air quality and are more prevalent in cities with high vehicle density than in rural areas.

However, wind can easily carry both fog and pollutants, making air pollution a problem in rural areas as well. For example, researchers have found that the concentration of particulate matter in the air in rural areas in Washington state is comparable to that in Seattle, the largest city in the northwest US.

WHO research shows that 99% of the world’s population breathes air with higher levels of pollutants than established norms, with residents of low and middle-income countries suffering the most.

At what times does air pollution present a risk to health?

Breathing in polluted air can have different effects based on four important factors. The duration of inhalation of contaminated air is the first factor, which can be divided into short-term exposure, lasting a few hours to a day, and long-term exposure, which can persist for years or even a lifetime.

For healthy adults, short-term exposure to pollutants is usually not severe. For example, inhaling smoke for a few hours may cause symptoms like headaches, coughing, eye, nose, and mouth irritation, but once the person is away from the contaminated area, their symptoms will subside and their health will return to normal.

However, for those with heart and lung conditions, short-term exposure can trigger the worsening of their chronic illness.

The type of pollutant in the air is another factor, as different pollutants have different effects on health:

• large solid particles can accumulate in the lungs and hinder their function;
• small solid particles can penetrate the lungs and enter the bloodstream, leading to respiratory and other problems, particularly for the heart and blood vessels;
• gases like ozone and nitrogen dioxide can irritate the eyes, throat, and lungs, causing respiratory problems and reduced lung function;
• and chemicals like benzene, formaldehyde, and polycyclic aromatic hydrocarbons in the air can cause cancer and other health problems.

All these factors must be considered when evaluating the potential health effects of breathing in polluted air. The concentration of harmful substances in the air is also critical, with higher levels leading to greater harm.

Everyone is affected by breathing in dirty air, but the most vulnerable are children whose lungs have not fully developed, elderly individuals and those with chronic heart and respiratory diseases, as well as pregnant women. According to preliminary data, air pollution increases the risk of pregnancy complications such as miscarriage, premature birth, stillbirth, low birth weight, and increased blood pressure.

How does polluted air affect people’s well-being

It has already been proven that air pollution is a risk factor for several chronic diseases and overall mortality.

The connection between air pollution and cardiovascular diseases

The relationship between air pollution and cardiovascular diseases has been well documented through extensive observation of large populations over time. This research has revealed that exposure to contaminated air, consisting of solid particles, ozone, nitrogen oxides, and sulfur dioxide, increases the risk of heart attack and stroke both in the short-term and long-term.

Studies have found that the higher the concentration of pollutants in the air, the greater the likelihood of a heart attack. This effect can take place quickly, as shown by research on over one million Chinese residents, where the majority of heart attacks caused by polluted air occurred within an hour of exposure.

However, if the air quality improves, the incidence of heart and blood vessel diseases decreases. This was demonstrated by a large study in Ireland, where after a ban on coal burning in Dublin, the death rate from cardiovascular diseases decreased by 10.3% within six years.

Air pollution and respiratory illnesses

Air pollution and its effect on respiratory illnesses have been the subject of several observational studies. The presence of solid particles, dust, smoke, and organic compounds in the air increases the likelihood of developing chronic obstructive pulmonary disease (COPD). Prolonged exposure to these elements leads to emphysema, a condition where alveoli expand permanently.

Inhaling solid particles and nitrogen oxides from the air raises the risk of lung infections, chronic bronchitis, and COVID-19. Some experts hold the view that gasoline combustion products increase the chance of both children and adults developing asthma. However, the data regarding this issue is contradictory, with some studies indicating a link between dirty air and asthma, while others do not find such a connection. In New Zealand, despite the relatively clean air, asthma remains prevalent.

Air pollution and lung cancer

As more evidence accumulates, air pollution, particularly fine particulate matter, is becoming increasingly recognized as the second leading cause of lung cancer after smoking. A large study conducted in 2011 found that a 10 microgram per cubic meter increase in fine particulate matter concentration in the air leads to a 15-27% increase in the mortality rate from lung cancer among non-smokers. However, there is no strong evidence linking air pollution to an increased risk of other types of cancer. A study of over 57,000 participants in the US showed that white women living near major roads and breathing air with high levels of particulate matter and nitrogen oxides did not have a higher rate of breast cancer compared to those living far from roads and breathing cleaner air.

Air pollution and mortality from all causes.

A large study conducted in 652 cities from 24 countries clearly showed the effects of air pollution on mortality from all causes. The study found that a 10 microgram per cubic meter increase in the concentration of coarse and fine particulate matter in the air led to an increase in excess mortality from all causes by 0.44%, cardiovascular diseases by 0.36%, and respiratory diseases by 0.47% over just two days.

Assessing the Air Quality in Urban Areas

Due to the serious health effects of air pollution, American physicians and researchers have established the air quality index (AQI). This system assesses air quality based on five main pollutants, including ground-level ozone, fine and coarse particulate matter, nitrogen dioxide, sulfur dioxide, and carbon monoxide.

Air quality scores are indicated on a scale of 0 to 500 based on the concentration of pollutants in an area. The following is a breakdown of the AQI levels and their corresponding color codes:

• AQI 0 to 50: Good air quality, depicted in green
• AQI 51 to 100: Acceptable air quality for most individuals, indicated in yellow
• AQI 101 to 150: Harmful to vulnerable groups and may impact healthy people, denoted in orange
• AQI 151 to 200: Harmful to both vulnerable groups and healthy individuals, depicted in red
• AQI 201 to 300: Dangerous for all individuals, represented in purple
• AQI 301 or higher: Severe situation, such as a chemical plant accident, indicated in dark maroon.

Although the AQI was first developed in the United States, it is now used to monitor air quality globally. Data is collected by thousands of observation stations located in major cities worldwide and transmitted to organizations such as the AirNow and IQAir projects, who are partners of the United Nations. The information on air quality is processed by project staff and published in real-time on their websites.

Ways to Stay Safe in Cities with Air Pollution

It is unfortunate that it is challenging for individuals to make a significant impact on the air quality. The improvement of air quality requires a concerted effort from the government, such as promoting green transportation, transitioning to renewable energy sources, and reducing industrial emissions.

However, it is possible to reduce the harmful effects of polluted air. For those living in cities where the AQI index sometimes exceeds 100, it’s a good idea to check air quality websites, like AirNow and IQAir, before going outside.

For individuals who belong to vulnerable groups, or for those with outdoor activities planned, it is advisable to reconsider their plans if air quality is poor. Children, elderly people, and those with chronic illnesses should avoid going outside if possible, or limit their time outside. For instance, they can opt for taxis with air conditioning instead of walking, and healthy people can visit air-conditioned gyms instead of running outdoors.