Back to: MICROBIOLOGY 400 LEVEL
Welcome to class!
Hello there, superstar! I hope you’re feeling curious and ready for another exciting session. Today’s topic is quite practical—you’ll love it. Have you ever wondered how scientists know what microbes are floating around in the air? Maybe in a hospital, a food factory, or even your classroom? That’s what we’re about to learn today: Air Sampling Techniques. These are the methods used to collect and study microorganisms in the air. Let’s get into it.
Air Sampling Techniques
What is Air Sampling?
Air sampling is the process of collecting air to detect and analyse the types and quantity of microbes present. It helps scientists and health workers monitor air quality, detect harmful pathogens, and prevent the spread of airborne diseases.
It’s very important in hospitals (like LUTH or UNTH), pharmaceutical industries, and even food processing factories in Nigeria, where maintaining clean air is critical to safety and hygiene.
There are two major categories of air sampling:
Passive Sampling
Active Sampling
Let’s break each one down.
1. Passive Sampling (Settle Plate Technique)
This is the simplest and most commonly used method. It does not need any machine.
How it works: A sterile nutrient agar plate (usually Petri dish) is left open in a location for a specific time—usually 15 to 60 minutes. Microbes in the air settle by gravity onto the surface of the agar.
Where it’s used: In classrooms, wards, laboratories, and food preparation areas.
Advantages:
Simple and cheap
Easy to carry out
Disadvantages:
Only captures microbes that settle by gravity
May not reflect the total microbial content in the air
2. Active Sampling
Active sampling uses mechanical devices to pull air through or onto a collecting medium, like filters or agar plates. It’s more accurate and efficient.
Types of active sampling include:
Impaction Method: Air is forced through a small opening and directed onto an agar surface. Microbes impact and stick to the agar. Example: Andersen air sampler.
Filtration Method: Air is drawn through a filter that traps microbes. The filter is then cultured or examined under a microscope.
Impingement Method: Air is bubbled through a liquid, and microbes get trapped in the liquid for further testing.
Advantages:
More accurate
Can detect microbes floating freely in air
Disadvantages:
More expensive
Needs electricity or batteries
Requires training
Applications in Nigeria
In hospitals to monitor airborne infections like tuberculosis
In breweries and pharmaceutical companies for air quality checks
In research institutions like NIMR to study disease-causing microbes in the air
Summary
- Air sampling is used to detect and study microbes in the air.
- It is important for monitoring air quality in hospitals, industries, and public spaces.
- Passive sampling involves leaving agar plates open for microbes to settle.
- The settle plate method is simple but limited to gravity-settling microbes.
- Active sampling uses machines to collect air onto agar, filters, or liquids.
- Impaction, filtration, and impingement are types of active sampling.
- Active sampling gives more accurate results but is more costly.
- Air sampling helps prevent infections and ensures clean environments.
- It is widely used in Nigerian hospitals, labs, and factories.
Evaluation
- What is the difference between passive and active air sampling?
- Name one device used in active air sampling and explain how it works.
- Why is air sampling important in hospitals and food industries?
You’ve just unlocked another key tool in microbiology. With your knowledge growing like this, there’s no limit to what you can do. Keep going—Afrilearn is cheering you on every step of the way. See you in the next class!