How to Check If Your Air Purifier Is Working? Use a PM2.5 Monitor Malaysia

How to Check If Your Air Purifier Is Working? Use a PM2.5 Monitor Malaysia

Your air purifier is running. The fan is spinning. The indicator light looks good. But is the PM2.5 level in your room actually decreasing?

For Malaysian households using air purifiers during haze, urban pollution or everyday indoor particulate events, this is an important question.

One practical way to evaluate what is happening is to use an independent PM2.5 monitor.

Instead of judging performance by noise, fan speed or the purifier's own indicator, you can measure:

PM2.5 before purification → PM2.5 during operation → PM2.5 after continued filtration

A smart PM2.5 monitor such as the Temtop S1+ can make this comparison much easier.

Why Use a Separate PM2.5 Monitor?

Many modern air purifiers already contain built-in particle sensors.

So why use another monitor?

Because the purifier's internal sensor measures air at or near the purifier itself.

That may not always represent conditions across the occupied area of your room.

An independent PM2.5 monitor can be positioned separately.

This allows you to ask a more useful question:

Is PM2.5 decreasing where people are actually sitting or sleeping?

That is especially useful in:

Bedrooms | Living Rooms | Condominiums | Home Offices | Small Offices

What Should an Air Purifier Reduce?

For particle filtration, one of the most useful parameters to monitor is:

PM2.5

PM2.5 refers to fine airborne particulate matter approximately 2.5 micrometres or smaller in aerodynamic diameter.

Potential sources include:

Haze

Traffic pollution

Smoke

Cooking

Combustion

Incense

Other fine airborne particles

If particulate removal is the purpose of your purifier, monitoring PM2.5 provides useful evidence of how the room responds.

The Simplest Air Purifier Test

You do not need a complicated laboratory setup to perform a basic household comparison.

Step 1 — Position Your PM2.5 Monitor

Place your monitor somewhere representative of the occupied room.

Do not put it directly beside the purifier outlet.

For example, in a bedroom you might position the monitor near the area where you normally spend time while keeping reasonable separation from the purifier.

Step 2 — Allow the Reading to Stabilise

Do not immediately record the first number after moving the monitor.

Give the instrument time to sample the new environment.

Then note the PM2.5 concentration.

This becomes your starting point.

Step 3 — Switch On the Air Purifier

Operate the purifier according to the manufacturer's instructions.

Keep other conditions as consistent as reasonably possible.

For a cleaner comparison, avoid suddenly:

Opening windows

Cooking

Burning incense

Smoking

Moving the monitor

Opening external doors repeatedly

Otherwise, you may introduce new variables into the test.

Step 4 — Watch the PM2.5 Trend

This is the important part.

Do not focus only on whether one reading changes.

Look for the trend.

For example:

Start: 42 μg/m³

↓

Later: 31 μg/m³

↓

Later: 20 μg/m³

↓

Later: 12 μg/m³

The exact numbers will vary from room to room.

What matters is whether PM2.5 shows a sustained downward trend after filtration begins.

Don't Test the Purifier by Putting the Monitor Beside It

This is one of the easiest mistakes to make.

Imagine placing your PM2.5 monitor directly in front of the purifier's clean-air outlet.

Naturally, the monitor may detect relatively clean air because it is sampling air immediately after filtration.

But that does not necessarily represent conditions:

on your bed,

at your desk,

or

on the other side of the living room.

If you want to understand overall room performance, position the independent monitor somewhere more representative of the occupied space.

Test 1: Air Purifier OFF vs ON

This is the easiest comparison.

Phase A — Purifier OFF

Record the room's PM2.5 level.

Phase B — Purifier ON

Switch on the purifier and observe PM2.5 over time.

What Are You Looking For?

A meaningful and sustained downward trend.

The rate of improvement will depend on multiple factors, including:

room volume + purifier airflow + filter condition + particle sources + outdoor infiltration + room layout.

Test 2: Low Speed vs High Speed

You can also compare purifier fan settings.

For example:

Low Speed

Observe how quickly PM2.5 changes.

Then, under reasonably comparable conditions:

High Speed

Observe the trend again.

A higher airflow setting may process room air faster, although actual performance depends on the purifier and room.

This type of test can help you understand whether a quieter low-speed setting is sufficient for normal use or whether higher airflow is useful when particulate levels increase.

Test 3: Bedroom Door Open vs Closed

This can produce interesting results.

Suppose the purifier is operating in your bedroom.

Try monitoring PM2.5 with:

Bedroom door closed

and compare it with:

Bedroom door open

Opening the door changes the air volume and allows air exchange with other parts of the home.

Your independent PM2.5 monitor can help you see whether that makes a noticeable difference.

Test 4: Window Open vs Closed

This is particularly relevant during Malaysia haze.

When outdoor particulate pollution is elevated, opening a window may allow additional fine particles into the room.

A simple comparison can reveal the effect.

Window closed → observe PM2.5

Then, when appropriate:

Window opened → observe the trend

During poor outdoor air quality, you may see indoor PM2.5 respond to increased outdoor air entry.

This demonstrates why outdoor and indoor air conditions should be considered together.

Test 5: Before and After Cooking

Your purifier is not only useful during haze.

Cooking can also generate airborne particles.

If your living area is connected to the kitchen, try monitoring:

Before cooking

↓

During cooking

↓

After cooking

↓

Purifier operating

You may see PM2.5 rise during certain cooking activities and then decline as ventilation and filtration remove particles.

This is an excellent way to understand why indoor air pollution does not always originate outdoors.

Why the Temtop S1+ Works Well for This Application

The Temtop S1+ focuses on four measurements:

PM2.5

The key parameter for this type of air-purifier comparison.

Specified measurement range:

0–999 μg/m³

Resolution:

0.1 μg/m³

AQI

Provides an easier-to-understand air-quality indication.

Temperature

Useful for monitoring basic room comfort conditions.

Relative Humidity

Particularly relevant in Malaysia's tropical indoor environment.

Together, these parameters make the S1+ useful for everyday home environmental monitoring.

App Connectivity Makes Trend Monitoring More Useful

The Temtop S1+ supports app connectivity.

For purifier testing, this is more useful than it may initially appear.

The question is not simply:

“What is PM2.5 right now?”

You may want to know:

How quickly did PM2.5 decrease?

When did the improvement begin?

Did PM2.5 increase again after a window was opened?

Did cooking create a spike?

Looking at changing conditions over time can provide more useful information than a single snapshot.

My Air Purifier Says the Air Is Good but My Separate Monitor Is Higher

This does not automatically mean either device is faulty.

The two sensors may be:

Located in different positions

Sampling different local air

Using different algorithms

Updating at different intervals

Applying different AQI calculations or display categories

The purifier may be sampling air close to its intake.

Your independent monitor may be several metres away.

Location matters.

For this reason, concentrate on trends and repeatable patterns rather than expecting every device in the room to display exactly the same number at every moment.

How Long Should an Air Purifier Take to Reduce PM2.5?

There is no single answer for every room.

The result depends on factors such as:

Room size

Ceiling height

Purifier capacity

Filter condition

Fan speed

Air circulation

Door and window position

Outdoor PM2.5

Indoor particle sources

A purifier in a small closed bedroom may behave differently from the same purifier operating in a large open-plan living room.

This is precisely why measuring your own room is useful.

What If PM2.5 Does Not Go Down?

If your monitor does not show a meaningful downward trend, investigate possible reasons.

Check the Filter

Is it due for replacement or maintenance?

Check the Purifier Size

Is the purifier appropriately sized for the room?

Check the Fan Setting

Is it operating at a very low airflow rate?

Check Windows and Doors

Is polluted outdoor air continuously entering?

Check Indoor Sources

Is somebody cooking, smoking or burning incense?

Check Placement

Is the purifier positioned where airflow is severely restricted?

The PM2.5 monitor does not tell you the cause automatically.

It tells you that further investigation is needed.

Can I Compare Two Air Purifiers with a PM2.5 Monitor?

Yes, but household comparisons should be performed carefully.

If you want a meaningful comparison, try to keep as many conditions as possible similar:

Same room

Similar starting PM2.5

Same monitor position

Similar door/window conditions

No additional particle sources

Then compare the PM2.5 reduction trend.

This is much more useful than simply comparing which purifier sounds more powerful.

Can I Use Temtop S1+ to Measure HEPA Filter Efficiency?

There is an important distinction here.

The S1+ can help you monitor room PM2.5 before and after operating an air purifier.

That is not the same as performing a controlled laboratory test of the filter media's certified filtration efficiency.

Professional filter testing requires appropriate methods, equipment and test conditions.

For home users, think of the S1+ as a way to answer:

“Is the PM2.5 concentration in my room actually decreasing?”

That is a very useful question—but it is different from laboratory certification.

Air Purifier Monitoring During Malaysia Haze

During a haze period, try this sequence:

1. Check outdoor conditions

↓

2. Measure indoor PM2.5

↓

3. Close unnecessary external openings

↓

4. Switch on your purifier

↓

5. Monitor the PM2.5 trend

↓

6. Adjust purifier operation if necessary

↓

7. Continue monitoring

This creates a simple feedback loop.

Instead of:

Haze → turn purifier on → hope for the best

you move toward:

Haze → measure → filter → verify → adjust

That is a much more useful way to manage indoor particulate conditions.

Why Independent Monitoring Matters

An independent PM2.5 monitor gives you something valuable:

a measurement from a location you choose.

You can put it near:

Your bed

Your work desk

Your living area

Your child's study area

Another occupied part of the room

This helps answer a question the purifier's own sensor may not fully address:

“What is the PM2.5 where I actually spend my time?”

Is Temtop S1+ a Good Companion for an Air Purifier?

For users primarily concerned about fine particulate pollution, it can be.

The S1+ combines:

PM2.5 + AQI + Temperature + Humidity + App Connectivity

It is therefore particularly relevant for:

Malaysia haze monitoring

Air purifier monitoring

Bedroom air quality

Condominium PM2.5 monitoring

Home-office environmental monitoring

Everyday indoor particulate tracking

It does not replace the purifier.

It provides the information needed to understand what is happening around it.

Air Purifier + PM2.5 Monitor: A Better Combination

An air purifier performs an action.

A PM2.5 monitor measures the result.

Those are two different jobs.

Used together, they create a much more useful system:

MONITOR → FILTER → MEASURE AGAIN → ADJUST

For Malaysian households concerned about haze and indoor particulate pollution, this approach can help turn air purification from an assumption into something you can actually observe.

The Temtop S1+ provides a straightforward way to do that.

Don't judge an air purifier only by its fan, sound or indicator light.

Watch what happens to the PM2.5 in your room.

Contact MTM Precision

MTM Precision Sdn. Bhd.

Showroom & Service Centre

No. 29-1 & 29-2, Jalan Bandar 18,

Pusat Bandar Puchong,

47160 Puchong, Selangor, Malaysia

🌐 Website: www.mtmpre.com.my

📧 Email: mtmpre@yahoo.com

📱 WhatsApp: 016-660 7346

For enquiries about Temtop S1+, PM2.5 monitors, indoor air quality monitors and environmental monitoring instruments in Malaysia, contact MTM Precision.

Serving customers throughout Selangor, Kuala Lumpur, Johor, Penang, Perak, Melaka, Negeri Sembilan, Pahang, Kedah, Perlis, Terengganu, Kelantan, Sarawak and Sabah.