In this article, we shall discuss whether change in air quality can trigger headaches. Furthermore, we shall discuss the various pollutants present in the ambient air which are responsible for triggering headaches, and their various sources.
Does air quality cause headaches?
Yes, exposure to poor air quality can cause headaches. Air quality is the measure of how clean the ambient air of a given region is. Higher the concentration of pollutants, the poorer the air quality gets.
Over the previous years, air quality has significantly deteriorated in both urban and rural areas, but is more pronounced in urban areas.
This is due to human activities, such as burning of fossil fuels and wood, emissions from industries, deforestation, change in land use pattern, and so on.
The various chemicals emitted by these processes have implications on human health, and short term exposure to elevated levels of pollutants causes issues, which also include headaches.
Pollutants that cause headaches
Certain studies have been carried out to find out which chemical species are responsible for triggering headaches in people. There were few species that showed a varying degree of affliction, but the ones consistent with reports of headaches were:
- Carbon monoxide
- Particulate matter
- Sulphur dioxide
- Nitrogen dioxide
We shall discuss these in brief.
Ozone is a colourless, pungent gas. It is present in the upper layers of atmosphere, where it blocks the harmful UV rays of the sun from reaching the surface.
However, when it is present in the ground level air, it acts as a pollutant, and can cause certain issues, which also include headaches.
The characteristic pungent odor acts as an irritant, where it can cause irritation in the nose and throat, and cause headaches near the sinus regions.
Ozone is produced when nitrous oxides (NOx) and polycyclic aromatic hydrocarbons (PAHs) react with each other in the presence of sunlight. These gases are emitted from exhausts of vehicles. Therefore, ozone is a traffic-related pollutant.
A study in Chile carried out to investigate the main proponents of headache due to air pollution found out that ozone was the most consistent in triggering headaches, when present in the ambient air.
Carbon monoxide (CO)
Carbon monoxide is a colourless, odorless gas that is formed due to incomplete combustion of gasoline, coal, and wood. It is a toxic gas, and since it cannot be detected by human senses, it can pose a serious threat to life.
Carbon monoxide forms a strong bond with haemoglobin, the compound present in the RBCs of blood, that is responsible for delivering oxygen from lungs to various tissues of the body.
In higher concentrations, this can inhibit the ability of RBCs to deliver oxygen, thereby can cause issues such as headaches, or even more serious problems like hypoxia, ischemia, and even death.
A study by Hampson et al. on patients of acute carbon monoxide poisoning found that all patients had presented a throbbing or a diffuse headache in the frontal region as one of the symptoms on examination.
Particulate matter (PM)
Particulate matter, or simply PM, refers to particles in the sub-micron range that are suspended in the ambient air. Over the previous years, PM has been a major pollutant in not just outdoor air, but in indoor air as well.
Particulate matter usually ranges between 2.5 to 10 microns (PM10 and PM2.5). They have a variety of natural and anthropogenic sources, and many studies that have shown progression of illnesses with an increase in PM concentration.
PM2.5 is of a major concern, as it can easily enter the lower respiratory tract, therefore causing more serious cardiac and respiratory issues.
Some PM species are vasoactive i.e., they interact with the blood vessels, causing them to dilate or constrict. This can trigger headaches, particularly in people who are ailing from migraines.
Lead is a metallic element that was earlier used as an additive in gasoline, to improve its efficiency of burning. However, with the rise in levels of lead in the atmosphere, it was banned for use in petroleum.
Nowadays, the main sources of lead in the air are industrial emissions, ores, and from aircrafts that use leaded jet fuel. It is also emitted from paints from antique houses.
Lead accumulation in the body can cause serious issues. Lead can cause high blood pressure, which in turn causes headaches.
Sulphur dioxide (SO2)
Sulphur dioxide is a major air pollutant. It is released from natural sources such as volcanic activities, and from human activities such as combustion of fossil fuels and industrial emissions.
Various studies have shown that children, old people, and people with preexisting respiratory illnesses are more prone to sulphur poisoning, which in lower levels, presents itself in the form of headaches.
SO2 acts as a sensory irritant, and thereby causes irritation in the eyes, nose, and throat. It also causes irritation in the inner linings of the sinus membrane, which can manifest in the form of headaches over the eyes.
Nitrogen dioxide (NO2)
Nitrogen dioxide is a part of the nitrous oxide (NOx) species, which refers to various compounds that contain nitrogen and oxygen atoms in varying numbers. These are a pollutant of concern, as they increase the risk of respiratory infection.
Nitrogen dioxide are primarily traffic-related pollutants, since they are emitted from vehicular exhausts. They are also emitted from coal-based thermal power plants (CTPPs), steel and iron manufacturing plants, and can also occur naturally during lightning.
When someone is subjected to prolonged exposure to lower levels of nitrogen dioxide, they experience conditions of throbbing headache.
Formaldehyde is a gaseous organic compound that belongs to a group of compounds called volatile organic compounds, or simply VOCs.
Formaldehyde is produced from many sources, such as dead and decaying remains of plants and animals, furniture, certain household products, and burning of fuel.
A study carried out on construction workers that used resin which contained formaldehyde found out that other than symptoms such as dizziness, inability to concentrate on task, and thirst, headaches too were reported as one of the major symptoms.
Formaldehyde acts as an irritant to the mucous membranes that are present in the nose and throat, and causes irritation in the eyes as well. This causes an inflammation of the membranes, and triggers headaches in the frontal region.
Sources of pollutants that contribute to headaches
We discussed the pollutants that are linked to headaches in people when they are subjected to higher elevations of the same. These pollutants emanate from various natural as well as anthropogenic (human based) activities.
Natural activities that give rise to pollutants include:
- Increased amount of pollen release
- Forest fires
- Suspension of dust from the ground by winds
There are many human-based sources of pollutants that cause headaches. These include:
- Industrial emissions
- Solid fuel combustion
We shall discuss these in more detail.
Certain events occur in nature that cause release of unwanted particles and gases in the air. We shall discuss some of the major activities below.
Increased pollen production
In seasons such as spring and summer, flowering plants are at the peak of their reproductive maturity.
They undergo pollination, the process of releasing pollen from the male flower parts, that on interaction with the female parts of a flower undergo fertilisation, which produces seeds.
These pollen are in the sub-micron range, which on an average are between 10-70μm in diameter. In favourable seasons, the average pollen count in a region rises significantly.
On inhalation, they cause a variety of symptoms, such as fever, runny nose, difficulty in breathing, wheezing, and headaches.
The term ‘hay fever’ is used to refer to the fever-like symptoms experienced by people when subjected to high pollen concentration. It usually occurs in spring and summer seasons.
In dry seasons, particularly in places where temperature is high, when dry plants are subjected to heat, they catch fire. Given the abundance of fuel i.e., other plants and trees, these fires spread in size, and are called forest fires, or wildfires.
Over time, the incidences of forest fires have increased, with some being triggered by human activities as well. These fires generate lots of soot, formaldehyde, and nitrous oxides.
When the pollutants spread to human settlements, symptoms of air pollution-related illness, including headaches, occur in high numbers.
Suspension of dust from the ground by winds
Dust refers to inorganic elements in the submicron range that are generated by natural as well as human activities. Given their small size, they are easily entrapped in blowing winds, and get suspended.
Over the past years, mainly due to pervasive change in land use patterns, the amount of dust suspended in the air has increased, particularly in areas with poor vegetation cover.
As a result, there have been increased cases of dust-related illnesses. Other than issues related to the respiratory and cardiovascular systems, headaches are also observed in people who were exposed to elevated levels of dust in the ambient air.
Human activities are the biggest culprit of degradation of air quality. We shall discuss the major sources that contribute to the rise of pollutants that cause headaches.
Over the past years, the number of automobiles used for transport has risen significantly. Traffic is one of the biggest polluters in metropolitan cities.
The exhaust gases released from vehicles contain pollutants such as NOx species, SO2, soot, heavy metals, carbon monoxide, and so on. These species have been shown to affect the air quality, and cause headaches when subjected to acute exposures.
In industrial areas, the air quality is much worse than compared to other places. The main contributors are steel and iron manufacturing plants, CTPPs, brick kilns, chemical manufacturing plants, and so on.
The majority of emissions from industries comprise PM, SO2, NOx species, and even carbon monoxide. Workers in such industries often present headaches and other symptoms related to poor air quality.
Solid fuel combustion
Globally, around 2-3 billion people rely on solid fuels as the primary source of energy. This includes firewood, crop residues, and cow dung.
However, combustion of solid fuels releases a high amount of soot, carbon monoxide, and formaldehyde. This is due to the poor combustion setup, which causes inefficient burning of these materials.
Many people, particularly women and children, suffer from respiratory and cardiovascular issues and short term exposures usually cause headaches.
Other FAQs about Air Quality that you may be interested in.
Poor air quality can cause headaches. Release of various pollutants, such as heavy metals, particulate matter, and gaseous compounds from natural and human activities have been shown to induce headaches in people.
Can indoor air also cause headaches?
Yes, indoor air can also cause headaches, as indoor air is also susceptible to pollution. Which can arise either from indoor sources, or can be due to infiltration of outside air pollution through openings such as doors, windows, seeps, etc.
How can I keep myself safe from pollution?
Avoid places with traffic congestion
As it is evident, traffic-related pollution is a major contributor to the onset of asthma. So, it is best practice to avoid areas which have high traffic congestion or are prone to it. If it is convenient, one should travel in off-peak hours when there’s no traffic.
On the other hand, one can choose an alternate way of transit via a route which doesn’t have much traffic and is economical as well.
Check pollution levels before leaving
If you live in an urban area, it would be a good idea to check the pollution levels before leaving, so that you can plan your trip accordingly.
There are many government and non-government organisations that are responsible for tracking the concentration of major air pollutants in the city and provide real-time data for the public.
Clean your indoor air
You can do this in the following ways:
- Improve ventilation in the house
- Use an air dehumidifier to reduce the relative humidity of the home, which would prevent development of fungal molds and bacteria.
- You can invest in an air purifier.
Can poor air quality cause migraines?
Yes, evidence suggests that air pollution can trigger migraines. Various air pollutants, including lead, carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matters have been linked to onset of migraines.
- Mukamal KJ, Wellenius GA, Suh HH, Mittleman MA. Weather and air pollution as triggers of severe headaches [published correction appears in Neurology. 2009 Oct 27;73(17):1428]. Neurology. 2009;72(10):922-927. doi:10.1212/01.wnl.0000344152.56020.94
- Hampson NB, Hampson LA. Characteristics of headache associated with acute carbon monoxide poisoning. Headache. 2002 Mar;42(3):220-3. doi: 10.1046/j.1526-4610.2002.02055.x. PMID: 11903546.
- National Research Council (US) Committee on Toxicology. Formaldehyde – An Assessment of Its Health Effects. Washington (DC): National Academies Press (US); 1980. EFFECTS ON HUMANS. Available from: https://www.ncbi.nlm.nih.gov/books/NBK217652/
- Kent Health Care Products. The Relation Between Indoor Air Quality and Frequent Headaches.
- Reuters. Polluted air may give you a headache.