Why Indoor Air Quality Monitoring Matters When Outdoor AQI Reaches 137 in Puchong, Malaysia
Why Indoor Air Quality Monitoring Matters When Outdoor AQI Reaches 137 in Puchong, Malaysia
When outdoor air quality deteriorates during haze conditions in Malaysia, many people immediately check the outdoor Air Pollution Index (API) or AQI and decide to stay indoors.
But there is an important question:
What is the air quality inside your home, office, school or building?
If outdoor AQI reaches around 137 in Puchong, the outdoor reading tells us about ambient conditions in the area. It does not tell us the actual PM2.5 concentration inside a particular building.
That is why indoor air quality monitoring becomes especially useful during haze.
Outdoor AQI Does Not Equal Indoor Air Quality
During haze, outdoor particulate pollution can enter buildings through:
Open doors
Open windows
Ventilation systems
Building gaps
Frequent movement through entrances
Outdoor air intake systems
However, every building behaves differently.
Two offices located in the same area can have very different indoor PM2.5 levels.
One building may have:
Better filtration
Better sealing
Fewer open doors
Effective air purifiers
while another may allow much more outdoor particulate pollution indoors.
Therefore:
Outdoor AQI ≠ Your Actual Indoor PM2.5
You need indoor measurements to understand what is happening inside your own space.
Why AQI 137 Gets Attention
An elevated outdoor AQI is a useful warning that ambient air quality has deteriorated.
For building owners, facility managers, schools, offices and households, this is the point where another question becomes important:
How much of that outdoor pollution is getting indoors?
Without an indoor monitor, it is difficult to know.
PM2.5 Is Especially Important During Haze
PM2.5 refers to fine particulate matter with an aerodynamic diameter of approximately 2.5 micrometres or smaller.
During haze events, PM2.5 can become one of the important pollutants to monitor.
Because these particles are extremely small, simply looking outside does not tell you the concentration indoors.
The room may look perfectly normal while a monitor detects elevated particulate levels.
“I Closed the Windows, So the Indoor Air Must Be Fine.”
Not necessarily.
Closing windows may reduce outdoor air entering naturally, but indoor particulate conditions can still depend on:
Building leakage
Door opening
HVAC operation
Filtration efficiency
Air purifier operation
Indoor particle sources
Measurement is therefore more useful than assumption.
Monitor Before and After Closing Windows
A simple haze investigation can be performed by observing PM2.5 trends.
For example:
Outdoor Haze Condition
↓
Measure Indoor PM2.5
↓
Close Windows and Doors
↓
Continue Monitoring
↓
Observe PM2.5 Trend
This can help users understand whether indoor particulate levels improve.
Test Your Air Purifier
An indoor PM2.5 monitor can also help answer a very practical question:
Is my air purifier actually reducing PM2.5?
A simple test can be:
Measure PM2.5 Before Purifier Operation
↓
Turn On Air Purifier
↓
Continue Monitoring
↓
Observe the Trend
If PM2.5 decreases over time, users have measurable information showing how indoor conditions are changing.
Different Rooms Can Have Different Results
Consider a house in Puchong during haze.
You might measure:
Living Room
PM2.5 higher
Bedroom
PM2.5 lower
Kitchen
Different particulate pattern
Room with Air Purifier
PM2.5 decreasing
One outdoor AQI number cannot show these differences.
Offices During Haze
For offices, indoor monitoring can help facility managers investigate:
Reception areas
Open offices
Meeting rooms
Production offices
Different floors
Areas near entrances
This can help identify locations where outdoor haze may be entering more easily.
Schools During Haze
Schools may also benefit from monitoring indoor particulate conditions during haze periods.
Potential monitoring areas include:
Classrooms
Staff rooms
Libraries
Laboratories
Indoor activity rooms
Instead of relying only on outdoor readings, schools can obtain information about conditions inside occupied spaces.
Public Buildings During Haze
Public buildings can also experience different indoor particulate conditions depending on:
Visitor traffic
Entrance doors
HVAC systems
Building filtration
Outdoor air intake
Monitoring can therefore support more informed facility-management decisions.
PM2.5 and PM10
During haze investigations, customers may ask about both PM2.5 and PM10.
In simple terms:
PM2.5
Fine particulate matter of approximately 2.5 m or smaller.
PM10
Particulate matter of approximately 10 m or smaller.
An instrument capable of monitoring both can provide additional information about particulate conditions.
Temtop M100 for Haze Monitoring
For users who want to monitor several useful indoor parameters, the Temtop M100 Air Quality Monitor can be considered.
Depending on the model configuration, it provides monitoring involving:
PM2.5
PM10
CO
AQI
This makes it useful for applications such as:
Homes
Offices
Schools
Public buildings
Haze investigations
Indoor air quality screening
The M100 is particularly useful when users want more information than a simple PM2.5 reading.
Temtop M10 for Smart Indoor Monitoring
For users who want connected indoor monitoring, the Temtop M10 can be considered.
It can monitor parameters including:
PM2.5
CO
VOC
Temperature
Relative humidity
with app connectivity for supported monitoring functions.
This makes it useful where users want to observe indoor environmental conditions over time rather than relying only on occasional manual readings.
Why CO Still Matters During Haze
During haze, people may close windows and doors to reduce outdoor pollution entering the building.
But this can create another issue.
With reduced ventilation and occupied rooms, CO may increase.
This creates an important indoor air management challenge:
Reduce outdoor PM2.5 infiltration
while also
Maintaining appropriate ventilation
That is why monitoring both particulate matter and CO can provide a more complete picture.
The Haze Ventilation Dilemma
Consider an occupied office.
Windows Open
CO may improve because of greater ventilation.
But outdoor PM2.5 may enter.
Windows Closed
PM2.5 infiltration may decrease.
But CO may rise if ventilation is insufficient.
Therefore, facility managers should not focus on only one parameter.
Monitoring helps show what is actually happening.
A Better Haze Monitoring Strategy
A practical approach is:
1. Check Outdoor Air Quality
Understand the general haze condition.
↓
2. Measure Indoor PM2.5
Determine actual indoor particulate conditions.
↓
3. Monitor CO
Understand occupied-space ventilation conditions.
↓
4. Review Doors, Windows and HVAC Operation
Identify potential outdoor air pathways.
↓
5. Use Appropriate Filtration or Air Cleaning
Where required.
↓
6. Continue Monitoring
Observe whether indoor conditions improve.
This turns haze management from guesswork into measurement.
Portable Monitoring vs Continuous Monitoring
A portable air quality monitor is useful for:
Spot checks
Comparing rooms
Testing air puifier performance
Haze investigations
Identifying problem locations
For larger facilities, continuous monitoring may be more appropriate.
Continuous Indoor Air Quality Monitoring
Schools, offices, factories and public buildings may eventually require:
Multiple monitoring points
24/7 measurements
Historical data
Remote access
Central dashboard
Alerts
At this stage, the requirement moves beyond one portable monitor toward a Continuous Indoor Air Quality Monitoring System.
Example Multi-Point Haze Monitoring
A building in Puchong could monitor:
Entrance
PM2.5 + CO
Open Office
PM2.5 + CO
Meeting Room
PM2.5 + CO
Upper Floor
PM2.5 + CO
↓
Central Monitoring Platform
↓
Historical Trends
↓
Facility Management
This helps the organisation understand how indoor conditions change throughout a haze event.
Compare Indoor and Outdoor Conditions
One particularly useful strategy is comparing:
Outdoor Air Quality
vs
Indoor PM2.5
This can help building managers evaluate how well the building is protecting occupants from outdoor particulate pollution.
The objective is not simply to collect numbers.
The objective is to understand the building.
Before and After Filtration
Monitoring can also be used to evaluate improvements.
Baseline Indoor PM2.5
↓
Introduce / Improve Filtration
↓
Continue Monitoring
↓
Compare PM2.5 Trends
↓
Evaluate Improvement
This provides measurable evidence instead of relying only on subjective impressions.
From One Temtop Monitor to a Complete IAQ Solution
The monitoring journey may begin with:
Temtop Portable Air Quality Monitor
↓
Indoor Haze Investigation
↓
PM2.5 + CO Monitoring
↓
Multiple Room Measurements
↓
Historical Data
↓
Fixed Sensors
↓
24/7 Monitoring
↓
Central Dashboard
↓
Complete Indoor Air Quality Monitoring Solution
This is especially relevant for:
Schools
Offices
Factories
Universities
Government buildings
Public facilities
Information Needed for an IAQ Monitoring Proposal
For larger projects, customers can provide:
Building type
Location
Number of floors
Number of rooms
Required parameters
Number of monitoring points
Portable or fixed monitoring requirement
PM2.5 / PM10 requirement
CO requirement
VOC requirement
24/7 monitoring requirement
Historical data requirement
Dashboard requirement
Alarm requirement
Floor plan if available
This allows the monitoring requirement to be evaluated more accurately.
Why Choose MTM Precision?
MTM Precision Sdn. Bhd. supplies Temtop air quality monitors and professional environmental monitoring solutions throughout Malaysia.
We support applications involving:
PM2.5 monitoring
PM10 monitoring
CO monitoring
Haze monitoring
Indoor air quality assessment
School air quality monitoring
Office air quality monitoring
Multi-point monitoring
Continuous environmental monitoring
Real-time dashboards
Whether the requirement begins with one portable Temtop monitor or develops into a larger multi-point monitoring project, the first step is to understand what needs to be measured and why.
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: +6016-660 7346
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13 Aug 2026
