air pollution

The State of Global Air is a report that brings to light the latest information on air quality and health for countries around the globe. It is produced annually by the Health Effects Institute and Institute for Health Metrics and Evaluation’s Global Burden of Disease project. The main idea of the report is to give people access to reliable information about air pollution exposure and health effects.

This article aims to summarize the key findings of the report and in turn, help people understand the risks and effects of air pollution in different parts of the world.


The effects of air pollution are felt by all people young, old, rich, and people in need. It is the fifth leading risk factor for mortality worldwide. A survey showed us that each year, more people die from air pollution than from road accidents or malaria


Air pollution has been linked to the cause of various cardiovascular and respiratory diseases and can also exacerbate diseases like asthma. The report focuses on two types of air pollution, outdoor (ambient) pollution and household pollution from the use of solid fuels for cooking.

When tracking outdoor pollution, two main pollutants are focused on—fine particle pollution (particulate matter measuring less than 2.5 micrometres) and ground-level ozone (tropospheric ozone). These forms collectively contribute to the impacts of air pollution on human health.

Exposure to Air Pollution

Detailed analysis shows that a majority of the world’s population lives in areas with a high concentration of air pollution. In fact, the latest data shows that in some areas of the world, air pollution is getting worse, while in other areas, it is getting better. Household air pollution is extremely important when considering the exposure to air pollution inside a home, but it can also be a substantial contributor to outdoor pollution.

Fine particle air pollution (PM25) primarily comes from vehicle emissions, the burning of coal in power plants, and industrial emissions. The constant exposure to this type of pollution is highly linked to cardiovascular, respiratory, and other types of diseases.


All-round the world, levels of fine particle pollution continue to exceed the Air Quality Guideline that was established by the World Health Organization (WHO). For regions that have the highest pollution, the WHO recommends three interim air quality targets: Interim Target 1 (IT-1, ≤35 μg/m3), Interim Target 2 (IT-2, ≤25 μg/m3), and Interim Target 3 (IT-3, ≤15 μg/m3). The figure below shows us where these guidelines were still exceeded in 2017. The findings show that in 2017, 92% of the world’s population lived in areas that exceed the WHO guideline for fine particle air pollution. It shows us that the least-developed countries are more likely to suffer worse air quality. Less-developed countries suffer fine particle exposures that are four to five times those of more-developed countries, although, in China, fine particle pollution has dropped markedly in recent years.

The statistic is mostly reversed for ozone pollution though. Ozone pollution is greater in more-developed countries and lesser in less-developed countries


This poses new challenges as the ozone is a gas consisting of both natural and human sources. The ozone plays a protective role by shielding the Earth from harmful UV rays of the sun. The problem arises when it is near the surface or ground-level ozone. In this case, it tends to act as a greenhouse gas that can have catastrophic consequences. Most of this ground-level ozone is produced from industrial processes and transportation that emit volatile organic compounds and nitrogen oxides into the atmosphere, these compounds react with sunlight to form the ozone. This increases the likelihood of mortality due to respiratory infections. Countries in North America continue to experience high ozone exposures, while China, a developing country with a rapidly growing economy has ozone-levels that are slowly rising. This will be a difficult problem to combat and will soon become a pressing issue in less-developed countries as their economies begin to grow.

Household Air Pollution

Fuels such as coal, wood, charcoal, dung, and other biomass forms are often burned in homes to cook food and heat homes in various countries. This process, however, produces high concentrations of air pollutants and in 2017, 3.6 billion people (47% of the global population) were exposed to household air pollution from the use of these fuels for cooking. Some of the most common areas affected were sub-Saharan Africa, South Asia, and East Asia. In India, an estimated 846 million people (60% of the population) was exposed to household air pollution in 2017.

Source Percentage of people exposed to Household Air Pollution

Efforts are currently underway to shift these households to cleaner energy sources that will improve both indoor and outdoor air considerably. The governments of these countries are working on increasing their citizen’s access to cleaner fuels using various campaigns and programs.

The Burden of Disease from Air Pollution


To quantify the exposure to air pollution, this report aims to assess the burden of disease in terms of increased mortality rates and disabilities borne by the population as a whole. Many studies conducted over several decades have provided evidence to identify which health problems have been caused by air pollution. Some of the effects on our health are short-term, for example, when high-pollution days trigger asthma attacks, while others result from exposure to air pollution over a long period of time. The long-term effects included chronic illnesses like heart disease, diabetes, and lung cancer. Air pollution ranks fifth among global risk factors for mortality, exceeded only by poor diet, high blood pressure, tobacco exposure, and high blood sugar. It is the leading environmental risk factor, surpassing other environmental risks like unsafe water and lack of sanitation.

Fine particle pollution contributed to nearly 3 million early deaths in 2017 (mostly people in China and India), while ozone pollution accounted from nearly half a million deaths worldwide.

Air Pollution’s Impact on Life Expectancy

Source Various sources leading to the loss of life expectancy

Studies found that air pollution has collectively reduced the life expectancy (the number of years a person is expected to live) by 1 year on average worldwide. The life expectancy is lower in less-developed countries where ambient air pollution is high and cooking with fuels is more common. In South Asia, household air pollution contributes to an additional loss of 9 months of life expectancy, bringing the total loss to 1 year and 8 months. However, the impact on more-developed countries is far lower (4 and a half months) than under-developed ones on average.


Although governments are taking action to reduce air pollution, a lot of work remains to be done to ensure overall human well-being. A better understanding of the sources of air pollution and key contributors to its health burden is critical for the effective implementation of air pollution control policies. 

To read the whole report, click here!

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