Air Quality Alert: Is Any Air Truly Clean?

Air pollution is a pressing global issue that poses significant risks to human health and the planet. It refers to the contamination of the indoor or outdoor environment by harmful substances, which can be released through human-made or natural sources. These substances include vehicle emissions, fuel oils, natural gas, manufacturing by-products, and fumes from chemical production, as well as smoke from wildfires and volcanic eruptions. According to the World Health Organization (WHO), air pollution is responsible for approximately seven million deaths annually worldwide, with 99% of people breathing air that exceeds the recommended guideline limits for pollutants. The issue of air pollution is closely tied to climate change, with increased heat and ultraviolet radiation intensifying the formation of smog and leading to the production of more allergenic air pollutants.

Air pollution and health

Air pollution is a significant threat to global health and prosperity. It is caused by the release of pollutants into the air, which are detrimental to human health and the planet. According to the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year. This figure has increased over the past two decades.

Indoor and outdoor air pollution cause respiratory and other diseases and are important sources of morbidity and mortality. Outdoor air pollution in both cities and rural areas causes fine particulate matter, which results in strokes, heart disease, lung cancer, acute and chronic respiratory diseases. Particulate matter (PM) is composed of chemicals such as sulfates, nitrates, carbon, or mineral dust. Sources of PM include vehicle and industrial emissions from fossil fuel combustion, cigarette smoke, and burning organic matter, such as wildfires.

The main pathway of exposure from air pollution is through the respiratory tract. Breathing in these pollutants leads to inflammation, oxidative stress, immunosuppression, and mutagenicity in cells throughout our bodies, impacting the lungs, heart, and brain, among other organs, and ultimately leading to disease. Fine particulate matter is especially dangerous because it can penetrate the lungs and bloodstream and cause systemic damage to tissues and cells. Exposure to high levels of particulate matter can lead to reduced lung function, respiratory infections, and aggravated asthma from short-term exposure. Long-term or chronic exposure to fine particulate matter increases a person's risk for diseases with a longer onset, like some non-communicable diseases, including stroke, heart disease, chronic obstructive pulmonary disease, and cancer.

In addition to particulate matter, other air pollutants of major public health concern include carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide. Ozone, an atmospheric gas, is often called smog when at ground level. It is created when pollutants emitted by cars, power plants, industrial boilers, refineries, and other sources chemically react in the presence of sunlight. Ozone exposure can shorten lives and has a serious effect on the respiratory system, causing inflammation and damage that can impact multiple body systems. Those at greatest risk from ozone pollution include pregnant women, children, older adults, and people living with chronic conditions, especially heart and lung disease.

Air pollution is a global issue, with 99% of human beings currently breathing air that exceeds the WHO's guideline limits for pollutants, and those living in low- and middle-income countries suffering the most. However, there are steps that can be taken to reduce air pollution and improve air quality. The WHO is working with countries to monitor air pollution and improve air quality, and policies and investments that support sustainable land use, cleaner household energy and transport, energy-efficient housing, and better municipal waste management can effectively reduce air pollution.

Sources of air pollution

Air pollution is a serious issue that affects people worldwide, causing approximately 8 million premature deaths in 2021 alone. The sources of air pollution are diverse and can be categorised into four main types: mobile sources, stationary sources, area sources, and natural sources.

Mobile sources, such as cars, buses, planes, trucks, and trains, are a significant contributor to air pollution. In the United States, mobile sources account for more than half of all air pollution, with automobiles being the primary culprit. These vehicles emit pollutants such as nitrogen oxides (NOx), carbon monoxide, and particulate matter, which have detrimental effects on human health and the environment.

Stationary sources, on the other hand, include large industrial facilities like power plants, oil refineries, factories, and boilers. These sources emit pollutants from a single location and are also known as point sources. Power plants, for instance, release pollutants such as ozone, a ground-level atmospheric gas often referred to as smog, and various noxious gases.

Area sources encompass smaller pollution sources that collectively have a significant impact. This category includes agricultural areas, cities, and wood-burning fireplaces. Residential wood burning has been increasing over time, contributing to fine particle emissions and air pollution. Cities, with their dense populations and various industrial and commercial activities, also fall under this category.

Lastly, natural sources of air pollution include wind-blown dust, wildfires, and volcanic activity. While these sources may not always cause ongoing pollution problems, they can have significant impacts, especially when combined with human-generated pollution. For example, wildfires release particulate matter and pollutants that contribute to haze and have biological effects.

It is important to note that air pollution is not limited to outdoor environments. Household combustion devices, such as wood-burning fireplaces and stoves, also contribute to indoor air pollution, which can have severe health consequences, especially for those with respiratory conditions. Additionally, certain household products like paints, cleaning supplies, and pesticides release volatile organic compounds (VOCs), which can have negative health effects.

Addressing air pollution requires a multi-faceted approach, including regulations, technological advancements, and sustainable practices. By understanding the diverse sources of air pollution, we can implement effective solutions to improve air quality and protect public health.

Air pollution and climate change

Air pollution is defined as the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. According to the World Health Organization (WHO), air pollution is responsible for nearly seven million deaths worldwide each year. Ninety-nine percent of people currently breathe air that exceeds the WHO's guideline limits for pollutants, with those living in low- and middle-income countries suffering the most.

The two most prevalent types of air pollution are smog and soot. Smog, or ground-level ozone, occurs when emissions from burning fossil fuels react with sunlight. Soot is a type of particulate matter composed of tiny particles of chemicals, soil, smoke, dust, or allergens that are carried in the air. The sources of smog and soot are similar and include cars, trucks, factories, power plants, and anything that burns fossil fuels.

Climate change can significantly impact air quality, and certain air pollutants can, in turn, affect climate change. For instance, hot sunny days associated with a warming climate can increase ground-level ozone in some areas. Ground-level ozone is a greenhouse gas that contributes to climate change by trapping heat in the atmosphere. Regulatory initiatives, partnership programs, and individual actions can help reduce air pollutants and greenhouse gas emissions.

Additionally, climate change can increase people's exposure to allergens like pollen and mold. Warmer temperatures and higher carbon dioxide concentrations can lengthen the pollen season and increase pollen production by plants. Extreme weather events, such as flooding, can create damp indoor conditions conducive to mold and bacteria growth, further impacting indoor air quality.

Furthermore, climate change can increase the occurrence of wildfires, which release smoke and particulate matter that can linger in the air and travel long distances, affecting air quality in downwind regions. Wildfires burned over 10 million acres of land in the United States in 2020, the highest amount ever recorded.

Reducing air pollution offers a "win-win" strategy for both health and climate. Lowering air pollution levels improves public health by reducing respiratory and cardiovascular issues. It also contributes to mitigating climate change by reducing emissions of short-lived climate pollutants, such as black carbon and methane, which have a more significant global warming potential than carbon dioxide.

Air quality monitoring

Air pollution is contamination by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. It is detrimental to human health and the planet, causing an estimated seven million deaths worldwide each year. According to the World Health Organization (WHO), 99% of people currently breathe air that exceeds the guideline limits for pollutants, with those in low- and middle-income countries suffering the most.

Air pollution has various sources, including household combustion devices, motor vehicles, industrial facilities, and forest fires. Major outdoor pollution sources include residential energy for cooking and heating, vehicles, power generation, agriculture/waste incineration, and industry.

To address this global issue, air quality monitoring is essential. It involves collecting and analyzing data on various pollutants to support human health objectives and inform interventions. Monitoring stations are typically established in population centers, such as near busy roads or in city centers, to measure pollutants like particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide, and carbon monoxide. These stations provide real-time data, helping people understand the local air quality and its potential health impacts.

There are several resources available to the general public that provide air quality data and interactive maps. For instance, AirNow.gov offers air quality information at the local, state, national, and world levels, utilizing the Air Quality Index (AQI) to help interpret health implications. The World Air Quality Index project also provides a real-time air quality map for over 80 countries, utilizing laser particle sensors to measure PM2.5 and PM10 particle pollution. Additionally, the US EPA's Air Data website grants access to outdoor air quality data collected by various agencies, allowing users to download, visualize, and create summary reports from the data.

Overall, air quality monitoring is a critical tool in the fight against air pollution, providing the data necessary to develop effective policies and interventions to reduce pollution and improve public health.

Reducing air pollution

Air pollution is contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. According to the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year. It is caused by the release of pollutants that are detrimental to human health and the planet as a whole.

• Limit the use of vehicles – In California, about half of the air pollution comes from cars and trucks. Opting to walk or ride a bike when possible can help improve air quality. Additionally, limiting idling time in vehicles to no more than 30 seconds and choosing the most efficient, lowest-polluting, or zero-emission electric car when purchasing a new vehicle can also help.
• Reduce energy consumption – Using less energy at home and choosing efficient appliances and heating systems can help reduce air pollution. This includes turning off electrical appliances when not in use, using energy-efficient light bulbs, and setting the thermostat to an energy-saving temperature.
• Choose sustainable products – Opting for sustainable and natural products over those that emit smog-forming chemicals can help reduce air pollution. This includes choosing products that do not contain volatile organic compounds (VOCs) and particulate matter (PM).
• Plant trees – Trees filter pollutants, absorb carbon dioxide, and release oxygen into the atmosphere, helping to improve air quality.
• Support clean air initiatives – Individuals can advocate for cleaner air by letting their elected representatives know that they support actions for cleaner air. This includes supporting initiatives like the Clean Air Act, which authorizes organizations like the U.S. Environmental Protection Agency (EPA) to regulate and reduce hazardous air pollutants.
• Reduce backyard fires – Smoke from backyard fires can negatively impact air quality, especially in cities with elevated pollution levels. Keeping fires small and brief, burning only dry firewood, and avoiding fires during air quality alerts can help reduce air pollution.

Frequently asked questions