PM2.5 vs PM10 vs Ozone During Haze - What Malaysians Need to Know

PM2.5 vs PM10 vs Ozone During Haze - What Malaysians Need to Know

During haze episodes in Malaysia, air pollution becomes a major concern for homeowners, parents, office managers, schools and industrial businesses.

People frequently hear terms such as PM2.5, PM10, Ozone, AQI and Malaysia Air Pollutant Index (API).

However, these terms describe different pollutants or air quality indicators.

Understanding their differences is important because not every air quality monitoring instrument measures the same pollutants.

For example, a PM2.5 Air Quality Monitor can measure or estimate fine particulate concentrations, but it cannot automatically detect ozone gas.

Similarly, a monitor that measures PM10 may not provide a complete picture of gaseous air pollution.

This guide explains the differences between PM2.5 vs PM10 vs Ozone during haze, their sources, health implications, measurement units and monitoring equipment.

It also introduces practical indoor air quality monitoring applications using instruments such as the Temtop S1 Up.

MTM Precision Sdn Bhd supplies portable air quality monitoring and industrial testing instruments for customers throughout Malaysia.

1. What Are PM2.5, PM10 and Ozone?

PM2.5, PM10 and ozone are important air pollutants, but they have different physical and chemical characteristics.

PM2.5 refers to fine airborne particles with an aerodynamic diameter of 2.5 micrometres or smaller.

PM10 refers to inhalable airborne particles with an aerodynamic diameter of 10 micrometres or smaller.

Ozone (O3) is a gas consisting of three oxygen atoms.

PM2.5 and PM10 are particulate pollutants.

Ozone is a gaseous pollutant.

The main difference is that PM2.5 and PM10 are particles, while ozone is a gas.

This distinction affects how each pollutant is measured and controlled.

2. PM2.5 vs PM10 vs Ozone - Comparison Table

ComparisonPM2.5PM10Ozone (O3)Pollutant typeFine particlesInhalable particlesGasSize or composition2.5 碌m or smaller10 碌m or smallerThree oxygen atomsCommon sourcesCombustion, smoke, secondary particlesDust, combustion, other particlesAtmospheric photochemical reactionsCommon measurement units碌g/m鲁碌g/m鲁ppb, ppm or 碌g/m鲁Monitoring technologySuitable particulate sensorSuitable particulate sensorDedicated ozone sensor or analyserHaze relevanceOften significantMay be elevatedMay also varyIndoor monitoringPortable PM2.5 monitorPM10-capable monitorDedicated ozone detectorRemoval or controlParticulate filtrationParticulate filtrationAppropriate gas-phase control and source management

Important: PM2.5 is included within the PM10 size fraction. The two categories are not completely separate groups of particles.

A PM10 concentration therefore includes particles within the PM2.5 size range as well as larger particles up to the PM10 cut-off.

3. What Is PM2.5?

PM2.5 refers to fine airborne particles with an aerodynamic diameter of 2.5 micrometres or smaller.

These particles may originate directly from pollution sources or form through atmospheric chemical reactions.

Common sources include:

Forest fires

Peatland fires

Vehicle exhaust

Industrial combustion

Open burning

Cigarette smoke

Cooking emissions

Secondary atmospheric particle formation

PM2.5 particles are small enough to penetrate deeply into the respiratory system.

Exposure to elevated PM2.5 concentrations is associated with respiratory and cardiovascular health risks.

Because these particles cannot reliably be identified through visual observation, monitoring equipment is useful for understanding particulate conditions.

PM2.5 monitoring is especially relevant when investigating fine particles associated with smoke and haze.

4. What Is PM10?

PM10 refers to airborne particles with an aerodynamic diameter of 10 micrometres or smaller.

This category includes fine particles as well as larger inhalable particles.

PM10 may originate from:

Road dust

Construction activities

Soil and mineral dust

Industrial processes

Mechanical particle generation

Combustion emissions

Outdoor particulate pollution

PM10 is commonly measured in 碌g/m鲁.

Larger particles within the PM10 fraction are more likely to deposit in the upper respiratory system than the finest PM2.5 particles.

However, PM10 exposure can also contribute to adverse health effects.

PM10 monitoring is relevant for general inhalable particulate pollution, including dust-related environments.

5. Is PM2.5 Part of PM10?

Yes.

PM2.5 represents the finer portion of the PM10 particle size fraction.

For example, an air sample may contain both fine combustion particles and larger dust particles.

The fine particles contribute to both the PM2.5 and PM10 mass concentration measurements.

The larger particles contribute to PM10 but not PM2.5.

This relationship is important when interpreting monitor readings.

PM2.5 and PM10 concentrations should not simply be added together to calculate total particulate concentration.

Doing so would double-count the PM2.5 fraction.

6. What Is Ground-Level Ozone?

Ground-level ozone (O3) is a gaseous air pollutant formed through photochemical reactions involving nitrogen oxides and volatile organic compounds in the presence of sunlight.

Important precursor sources include vehicle emissions, industrial activities and other combustion-related processes.

Ground-level ozone is different from the protective ozone layer in the upper atmosphere.

The stratospheric ozone layer helps absorb harmful ultraviolet radiation.

Ground-level ozone, however, is an air pollutant that can irritate the respiratory system.

Ozone is not a particle and cannot be directly measured using an ordinary PM2.5 sensor.

A dedicated ozone measurement instrument is required.

7. Can Ozone Increase During Haze?

Ozone behaviour during haze is complex.

Haze episodes may involve changes in sunlight, atmospheric chemistry, precursor emissions and weather conditions.

Depending on these factors, ozone concentrations may increase, decrease or vary over time.

For example, strong sunlight can support photochemical ozone formation when sufficient precursor pollutants are present.

However, heavy aerosol loading may also alter the amount of sunlight reaching the lower atmosphere.

Therefore, it is not scientifically correct to assume that every severe haze episode automatically produces high ozone concentrations.

PM2.5 and ozone must be evaluated as separate pollutants, even when they occur during the same air pollution episode.

8. Why Is PM2.5 Important During Haze in Malaysia?

Haze associated with open burning and smoke transport may contain substantial concentrations of fine particles.

PM2.5 can remain suspended in the atmosphere and may travel considerable distances under suitable weather conditions.

During haze episodes, outdoor fine particles may enter:

Residential homes

Bedrooms

Offices

Classrooms

Commercial buildings

Shopping areas

Industrial facilities

Indoor concentrations depend on ventilation, building leakage, filtration and indoor pollution sources.

Outdoor haze can influence indoor PM2.5 even when windows are closed.

A portable PM2.5 monitor can help users observe particulate changes in occupied indoor spaces.

9. What Are the Health Effects of PM2.5?

PM2.5 exposure is associated with respiratory and cardiovascular health effects.

Possible effects include:

Respiratory irritation

Coughing

Aggravation of asthma

Reduced respiratory comfort

Cardiovascular stress

Increased risk of certain respiratory and cardiovascular diseases

Health effects depend on exposure duration, concentration and individual susceptibility.

Children, older adults and people with certain underlying health conditions may be more vulnerable.

However, healthy adults can also be affected by elevated particulate pollution.

Reducing unnecessary exposure to elevated PM2.5 is an important part of haze health protection.

10. What Are the Health Effects of PM10?

PM10 particles can enter the respiratory system and contribute to irritation and inflammation.

Exposure to elevated PM10 concentrations may be associated with:

Respiratory symptoms

Coughing

Aggravation of asthma

Respiratory discomfort

Other adverse health effects

The effects depend on particle characteristics, exposure and individual susceptibility.

PM10 monitoring is useful for understanding inhalable particulate pollution, particularly in dust-related environments.

However, PM10 readings do not identify the chemical composition of the particles.

A PM10 monitor measures a particle size fraction, not a specific dust material or chemical substance.

11. What Are the Health Effects of Ozone?

Ground-level ozone can irritate the respiratory system.

Exposure may contribute to:

Throat irritation

Coughing

Chest discomfort

Reduced lung function

Aggravation of asthma

Increased respiratory symptoms

Ozone exposure may be particularly concerning during outdoor physical activity when breathing rates are elevated.

People with asthma and other respiratory conditions may be more susceptible.

Ozone is a respiratory irritant, and a low PM2.5 reading does not prove that ozone concentration is low.

If ozone monitoring is required, users should select a suitable dedicated ozone instrument.

12. PM2.5 vs PM10 vs Ozone - Measurement Units

Different pollutants may be reported using different units.

PM2.5

Commonly expressed in 碌g/m鲁.

PM10

Commonly expressed in 碌g/m鲁.

Ozone

May be expressed in:

Parts per billion (ppb)

Parts per million (ppm)

Micrograms per cubic metre (碌g/m鲁)

Conversions between gas concentration units depend on temperature, pressure and molecular properties.

Users should avoid directly comparing numerical readings with different units.

A PM2.5 value of 30 碌g/m鲁 and an ozone value of 30 ppb do not represent equivalent pollution concentrations or health risks.

13. WHO Air Quality Guidelines for PM2.5, PM10 and Ozone

The World Health Organization's 2021 global air quality guidelines include the following values.

PollutantAveraging periodWHO guidelinePM2.5Annual5 碌g/m鲁PM2.524-hour15 碌g/m鲁PM10Annual15 碌g/m鲁PM1024-hour45 碌g/m鲁OzonePeak-season average of daily maximum 8-hour means60 碌g/m鲁Ozone8-hour average100 碌g/m鲁

These are health-based guideline values for their specified averaging periods.

They are not instantaneous safety thresholds.

For example, a single PM2.5 reading of 20 碌g/m鲁 cannot establish whether the 24-hour guideline has been exceeded.

Likewise, an instantaneous ozone reading cannot be directly compared with an 8-hour guideline without appropriate averaging.

Always interpret air pollution readings using the correct pollutant, units and averaging period.

14. PM2.5 vs AQI vs Malaysia API

Consumers frequently confuse particulate concentrations with air quality indices.

PM2.5 Concentration

A measured or estimated fine particulate concentration, generally expressed in 碌g/m鲁.

Air Quality Index (AQI)

A calculated index based on a defined methodology.

Malaysia Air Pollutant Index (API)

Malaysia's official outdoor air quality index.

The general Malaysia API categories are:

API rangeCategory0-50Good51-100Moderate101-200Unhealthy201-300Very UnhealthyAbove 300Hazardous

Malaysia's official API methodology considers prescribed pollutant measurements and index calculations.

An API value is not the same as a PM2.5 concentration.

Do not compare a portable monitor's PM2.5 reading numerically with Malaysia's API as though both use the same scale.

For official outdoor air quality information, refer to Malaysia's Department of Environment APIMS service.

15. Can Temtop S1 Up Measure PM2.5, PM10 and Ozone?

The Temtop S1 Up Air Quality Monitor is suitable for general indoor PM2.5 monitoring according to its supported functions.

However, customers should not assume that one instrument measures every air pollutant.

For example:

PM2.5 Monitoring

Requires suitable particulate measurement capability.

PM10 Monitoring

Requires confirmed PM10 measurement capability.

Ozone Monitoring

Requires a dedicated ozone measurement function or instrument.

A PM2.5 sensor cannot directly measure ozone gas.

Customers should refer to the latest official Temtop S1 Up datasheet to confirm the exact measurement parameters, range, accuracy and operating conditions.

Temtop S1 Up should not be marketed as an ozone detector unless ozone measurement capability is explicitly confirmed by the manufacturer.

16. Which Air Quality Monitor Should You Buy?

The correct instrument depends on the intended monitoring application.

ApplicationSuitable monitoring categoryIndoor haze fine particlesPM2.5 monitorHome air purifier observationPM2.5 monitorGeneral inhalable dustPM10-capable monitorConstruction-related particulate monitoringSuitable particulate monitoring equipmentGround-level ozoneDedicated ozone monitorClassroom ventilationSuitable CO2 monitorIndoor VOC screeningSuitable VOC monitoring instrumentFormal environmental assessmentAppropriate professional or reference methods

A portable PM2.5 monitor may be sufficient for general home or office particulate observations.

However, specialised industrial or regulatory applications may require additional equipment.

Selecting the correct pollutant measurement capability is more important than purchasing an instrument with the largest number of advertised functions.

17. How to Monitor Indoor PM2.5 During Haze

A portable PM2.5 monitor can support general indoor particulate observations.

Step 1 - Select a Representative Location

Place the instrument in an occupied indoor area.

Avoid direct air purifier outlets and obvious local particle sources.

Step 2 - Allow the Reading to Stabilise

Follow the manufacturer's operating instructions.

Step 3 - Record PM2.5 Concentration

Document the reading in 碌g/m鲁.

Step 4 - Record Environmental Conditions

Note:

Window position

Door position

Air purifier operation

Ventilation arrangement

Recent indoor activities

Outdoor haze conditions

Step 5 - Repeat Measurements

Record readings at consistent intervals.

Step 6 - Investigate Changes

If concentrations increase, consider outdoor particle infiltration or indoor sources.

A portable PM2.5 monitor is useful for observing trends but does not replace professional reference measurement methods.

18. Can an Air Purifier Remove PM2.5, PM10 and Ozone?

Different air purifier technologies target different pollutants.

PM2.5 and PM10

Suitable particulate filtration can help remove airborne particles.

HEPA filtration is commonly used for particle removal.

Ozone

Ozone is a gas and is not removed by ordinary particle filtration in the same way as PM2.5 or PM10.

Certain properly designed gas-phase treatment technologies may reduce ozone, but performance depends on the materials, design and operating conditions.

Some electronic air-cleaning technologies may generate ozone as an unwanted by-product.

An air purifier advertised for PM2.5 removal should not automatically be assumed to remove ozone.

Customers should verify the purifier's tested performance for the specific pollutant.

19. Should You Close Windows During Haze?

During periods of elevated outdoor particulate pollution, reducing unnecessary entry of polluted outdoor air may help limit indoor PM2.5.

However, ventilation remains important for managing indoor-generated pollutants.

Closing windows without adequate alternative ventilation may allow some pollutants to accumulate.

For example, carbon dioxide may rise in heavily occupied rooms with insufficient fresh-air exchange.

A PM2.5 monitor does not directly measure ventilation adequacy.

Effective indoor air quality management requires a balance between outdoor pollution control, suitable filtration and appropriate ventilation.

Where available, filtered mechanical ventilation may help manage this balance.

20. Common Mistakes When Comparing PM2.5, PM10 and Ozone

Mistake 1 - Assuming PM2.5 and PM10 Are Completely Separate

PM2.5 is included within the PM10 particle size fraction.

Correct approach: Understand the particle size definitions.

Mistake 2 - Assuming Ozone Is a Type of Dust

Ozone is a gas, not a particle.

Correct approach: Use a dedicated ozone monitor when O3 measurement is required.

Mistake 3 - Assuming a PM2.5 Monitor Measures Every Pollutant

A PM2.5 sensor does not automatically measure PM10, CO2, ozone or VOCs.

Correct approach: Verify the exact instrument specifications.

Mistake 4 - Confusing AQI with PM2.5 Concentration

AQI and PM2.5 concentration use different numerical scales.

Correct approach: Check the measurement units and index methodology.

Mistake 5 - Assuming All Haze Episodes Produce High Ozone

Ozone depends on atmospheric chemistry and meteorological conditions.

Correct approach: Evaluate ozone separately from particulate pollution.

Mistake 6 - Assuming HEPA Filtration Removes Every Gas

HEPA filters are designed for particulate filtration.

Correct approach: Verify gas-removal capability separately.

Mistake 7 - Using Consumer Monitors for Formal Compliance Testing

General-purpose portable monitors may not meet reference or regulatory measurement requirements.

Correct approach: Use appropriate professional methods when formal assessment is required.

21. Frequently Asked Questions

What is the difference between PM2.5 and PM10?

PM2.5 includes particles with an aerodynamic diameter of 2.5 micrometres or smaller, while PM10 includes particles with an aerodynamic diameter of 10 micrometres or smaller.

Is PM2.5 part of PM10?

Yes. PM2.5 is included within the PM10 size fraction.

Is ozone the same as PM2.5?

No. Ozone is a gas, while PM2.5 consists of airborne particles.

Which pollutant is most important during haze?

Fine particulate pollution is often an important concern during smoke-related haze. However, other pollutants may also be relevant depending on the event.

Can Temtop S1 Up measure ozone?

A PM2.5 sensor cannot measure ozone. Customers should verify the exact model specifications and use a dedicated ozone instrument when O3 measurement is required.

Can Temtop S1 Up measure PM10?

Customers should verify whether PM10 is included in the exact model's official measurement specifications.

Can an air purifier remove PM2.5?

A suitable purifier with effective particulate filtration can help reduce airborne PM2.5.

Can a HEPA filter remove ozone?

HEPA filtration primarily targets particles. Ozone removal requires separate consideration of gas-phase treatment capabilities.

Is Malaysia API the same as PM2.5?

No. API is a calculated air quality index, while PM2.5 is a pollutant concentration.

Where can I buy a PM2.5 or ozone monitor in Malaysia?

Customers can contact MTM Precision Sdn Bhd for assistance identifying suitable particulate or gas monitoring equipment based on the intended application.

22. Buy Air Quality Monitoring Instruments Malaysia

MTM Precision Sdn Bhd supplies portable air quality monitoring and industrial testing instruments for residential, commercial and industrial applications throughout Malaysia.

Customers looking for PM2.5, PM10 or ozone monitoring equipment in Malaysia should select instruments according to the specific pollutant they need to measure.

For general indoor PM2.5 monitoring, the Temtop S1 Up is one product option.

For PM10, ozone or other specialised measurements, customers should confirm the required parameters before selecting an instrument.

MTM Precision can assist with:

Temtop S1 Up pricing and stock availability

PM2.5 air quality monitor selection

PM10 monitoring enquiries

Ozone detector enquiries

Indoor haze monitoring applications

Home and office air quality monitoring

Industrial environmental testing requirements

General instrument comparisons

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

Contact MTM Precision Sdn Bhd

Showroom & Service Centre

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

Pusat Bandar Puchong,

47160 Puchong, Selangor, Malaysia.

Tel: 03-8080 7172

WhatsApp: +6016-660 7346

Email: mtmpre@yahoo.com

Website: www.mtmpre.com.my

Not Sure Whether You Need a PM2.5, PM10 or Ozone Monitor?

Contact MTM Precision for product selection assistance, current pricing and stock availability.

You may send us your intended application, required measurement parameters or existing instrument model through WhatsApp for an initial recommendation.

Conclusion

Understanding the differences between PM2.5, PM10 and ozone is essential for choosing suitable air quality monitoring equipment.

PM2.5 and PM10 are particulate pollutants, while ozone is a gaseous pollutant formed through atmospheric chemical reactions.

Although these pollutants may all be relevant to air quality, they require different measurement capabilities.

A portable PM2.5 monitor such as the Temtop S1 Up can help users observe indoor fine particulate changes during haze.

However, it should not be assumed to measure ozone or every other pollutant.

Accurate air quality monitoring begins with identifying the pollutant, selecting the correct instrument and interpreting measurements using the proper units and averaging periods.

For PM2.5 Air Quality Monitor Malaysia and specialised air quality instrument enquiries, contact MTM Precision Sdn Bhd in Puchong, Selangor.