Temperature classification
Temperature falls into two broad groups: hot and cold. A cold temperature means a lower degree of warmth, or even a chill in the air. A hot temperature means a higher level of warmth. Air conditioning systems help to control the temperature and bring relief in hot weather. Room heaters, in turn, provide warmth when the weather turns colder.
Temperature measurement units
Degrees Celsius
Degrees Fahrenheit
Kelvin
How temperature affects air quality
Temperature can affect air quality in many different ways. The effect it has on air quality varies and depends on the specific conditions at the time. For instance, high temperatures can make air pollution problems worse in a number of ways.
Hot temperatures
Indoor
High indoor temperatures can harm air quality. Indoor spaces can be a source of many air pollutants. These include TVOCs (Total Volatile Organic Compounds), radon, CO2 (carbon dioxide), CO (carbon monoxide), PM1 (particulate matter with a diameter of 1 micrometre), O3 (ozone), and more. Together, these pollutants can pose a risk to the health of an average person.
Outdoors
Stagnant air is more common in hot weather, and it stops pollutants from spreading out as they normally would. So pollutants can build up in the air, which lowers air quality. Extreme heat can also drive the formation of ozone gas and particle pollution. High temperatures can trigger forest fires too, which worsen air quality and shrink forest land.
Cold temperatures
Indoor
In colder temperatures, people often spend more time indoors than they do in hot weather. During this time, doors and windows also tend to stay closed to keep the warmth in. But this can trap pollutants inside the building, which can have harmful effects, above all on sensitive groups.
Outdoors
In colder temperatures, the air outdoors turns chilly. This cold air is denser than hot air, and that leads to an interesting effect: it traps pollutants. Because of its higher density, cold air tends to hold pollutants closer to the ground, which results in lower air quality. We often see this effect in the winter season, when fog becomes more common. On top of this, temperature inversions also tend to occur during the winter season.
In theory, absolute zero is the lowest temperature at which a substance has no heat energy. It is defined as zero Kelvin (0 Kelvin). That equals -273.16 degrees Celsius and -459.69 degrees Fahrenheit.
Temperature Inversion
Temperature inversion is common in winter. It shows up as an unusual pattern in how the temperature changes with height. Normally, the air goes from warm near the ground to cooler, and then to the coldest air higher up. But during a winter inversion, this order is sometimes reversed. The cooler layer sits right above the ground's surface. Warmer air lies above it, and the coldest air sits at higher altitudes.
This inversion effect traps air pollutants near the Earth's surface. Instead of spreading out into the atmosphere, the pollutants get stuck in the lower layer of colder air. This still, stagnant air makes it hard for the pollutants to clear, so the concentration of air pollution near the ground then goes up.
The problem gets even worse in winter, because people burn wood and coal for heating. These activities release extra pollutants into the air. Together with the inversion effect, these pollutants add to the poor air quality we see during the winter season.
Other weather conditions that affect air quality
Air quality in any given area depends a great deal on the local weather conditions there. These weather conditions play a key role in shaping and changing the quality of the air we breathe. Some of the weather conditions that affect air quality are listed below:
Wind Speed and Direction
Wind is a natural way to improve air quality. It can carry pollutants away from hotspots to less polluted areas.
Humidity
Humidity makes the air heavier and denser. This means it can trap air pollutants such as particle pollution, smoke and so on.
Density of air
The density of the air has a strong effect on how air pollution spreads. The higher the air density, the more pollutants get trapped inside it.
Solar radiation
Solar radiation plays a vital role in the photochemical reactions that take place on the earth's surface. The main one is the formation of ozone (O3) gas.
Rainfall
Rainfall helps clear the air of dust particles, particle pollution, smoke and so on. In this way, it affects air quality by washing the air clean in that area.
Atmospheric Pressure
Atmospheric pressure has a strong effect on how air pollutants mix up and down. This is where the concept of Temperature Inversion comes into play.
How does temperature affect human health?
Heat-related Illnesses
High temperatures can cause heat exhaustion and heat stroke. Symptoms range from dizziness to organ failure in extreme cases.
Cardiovascular Health
Hot weather puts stress on the heart and blood vessels. This can raise the risk of strokes, heart attacks and other cardiovascular problems.
Respiratory Effects
Swings in temperature can worsen breathing problems like asthma and COPD. This makes breathing harder and can make symptoms worse.
Dehydration
In a heatwave, it is vital to drink enough water. Hot weather and heavy sweating can cause dehydration, fatigue and heat-related illnesses.
Impact on Mental Health
Extreme temperatures can disrupt sleep, raise stress levels and cause irritation. They may also add to seasonal affective disorder (SAD).
Infectious Diseases
Temperature affects how often diseases occur and how they spread. It shapes how diseases like malaria and respiratory infections survive and pass on.
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