Smog Season in Europe: What PM2.5 and PM10 Mean and How to Choose the Right Ventilation Filter

date_range 15 February 2026

Understanding Smog Season in Europe

Most people notice air pollution only when it becomes obvious: a hazy skyline, a smoky smell, a scratchy throat after a walk. But the most important pollution is often the least noticeable.

That’s why late winter and early spring (roughly January to early March) can be the trickiest time in Europe. Heating, traffic and certain weather patterns can trap pollution close to the ground — creating sudden smog days even in places that are usually considered “clean.”

In this guide, you'll learn:

What PM10 and PM2.5 mean
Explained in clear, simple terms.

How to interpret air pollution numbers
What “good,” “moderate,” and “poor” levels actually mean.

How to monitor pollution easily
Without buying specialized equipment.

How pollution travels
And why it’s not only about your immediate surroundings.

Which ventilation filter to choose
When a G4 (coarse filter) is enough, when to upgrade to ePM10 (M5), and when an ePM1 (F7 / PM1 filter) — especially ePM1 70% — makes the most sense.

1) What is air pollution, really?

Air pollution is a mix of gases and particles. For homes, the biggest “filterable” problem is particulate matter — tiny solid or liquid fragments floating in the air.

Source	What it usually means
🚗 Urban pollution	Traffic exhaust + brake dust + tire wear (common in cities and near busy roads).
🔥 Solid fuel heating	Wood/coal/pellet burning — a major driver of winter PM2.5 spikes in many regions.
🏭 Industry	Emissions from manufacturing and energy production (often regional, not just local).
🏗️ Construction dust	Larger particles that often raise PM10 (more noticeable as “dusty air”).
🌬️ Regional transport	Pollution drifting in from nearby cities or even other countries — especially during stable winter weather.

In Europe, air pollution is still considered a major environmental health risk — even though overall levels have improved over time.

2) PM10 vs PM2.5: the difference you can feel vs the one you can’t

Both are particles in the air — but they behave differently, come from different sources, and affect your body in different ways.

🌪️ PM10 = the “dust” category

👀 often visible / “gritty”

PM10 are particles up to 10 micrometres. Think of them as “bigger dust” that can make the air look hazy.

🛣️ Road dust	🏗️ Construction dust
🌿 Pollen fragments	🛞 Brake & tire dust

This is the pollution more likely to show up as visible haze or that “dusty air” feeling.

🌫️ PM2.5 = the “smog / combustion” category

🫁 often invisible / deeper impact

PM2.5 are much finer particles (≤ 2.5 micrometres). They’re closely linked to combustion — and are a key driver of winter smog.

🚗 Traffic exhaust particles	🔥 Wood/coal burning smoke
🌁 Winter smog particles	🏙️ Urban pollution peaks

Because these particles are so small, they’re more likely to go deep into the lungs. This is one reason health guidance for PM2.5 is stricter.

⚠️ Important reality check

You can’t reliably “smell” PM2.5. Sometimes a high PM2.5 day smells normal. And sometimes “smelly air” is not the highest PM2.5 day.

3) “What numbers are normal?” (PM10 and PM2.5 without the headache)

Here’s a simple way to read the numbers. Think of it as a “traffic-light” guide — from clean air to smog conditions.

✅ Good

⚠️ Moderate

🚫 Poor

🚨 Very poor

🌪️ PM10 (dust) — EU daily limit reference: 50 µg/m³

The EU PM10 daily limit is 50 µg/m³ (with limited allowed exceedance days per year).

✅ 0–20 µg/m³ — good	⚠️ 20–50 µg/m³ — moderate
🚫 50–100 µg/m³ — poor	🚨 100+ µg/m³ — very poor

🌫️ PM2.5 (smog) — the number that matters most in winter

WHO guideline levels are stricter than many legal limits: 5 µg/m³ annual and 15 µg/m³ 24-hour (ideally only a few days/year).

✅ 0–10 µg/m³ — good	⚠️ 10–25 µg/m³ — moderate
🚫 25–50 µg/m³ — poor	🚨 50+ µg/m³ — very poor

4) How to tell the air is polluted (without looking at a chart)

Your senses can give useful clues — but they are not a measurement. Here’s what to watch for, and what can mislead you.

✅ What you may notice on higher PM days

🌫️ Haze that makes the horizon look “washed out”

😖 Dry throat, irritated eyes

🤧 More coughing during/after outdoor activity

🫁 A heavier feeling in the chest (especially for sensitive groups)

❌ What you cannot fully trust

👃 Smell alone (PM2.5 can be high without a smell)

🌡️ Temperature alone (cold doesn’t always mean pollution)

🧠 “I’m used to it” (people adapt and stop noticing)

🎯 Best approach

Treat your senses as a warning bell, not a measurement. When in doubt, check PM2.5 and PM10 values from a local air quality dashboard or forecast.

5) How to monitor PM10 and PM2.5 (simple and practical)

You don’t need expensive devices to check air quality. The following tools and dashboards provide reliable, up-to-date information about particulate matter (PM10 and PM2.5) in your area — including real-time measurements and short-term forecasts.

📍 Local city or national air quality dashboard

Many countries and major cities have official air quality dashboards showing PM10 and PM2.5 from nearby monitoring stations. Search by your city name for the most accurate local data.

Example – EU interactive map with station data: European Air Quality Index (real-time PM2.5 & PM10)

📊 EEA up-to-date monitoring data

The European Environment Agency aggregates official monitoring station readings across Europe — including PM10 and PM2.5 concentrations you can filter by country or city.

View it here: European Air Quality Now – EEA Portal

🔮 Copernicus CAMS forecasts

The Copernicus Atmosphere Monitoring Service (CAMS) provides multi-day forecasts of air pollutants — including PM2.5 and PM10 — useful for planning outdoor activities or ventilation filter timing.

Explore forecasts here: Copernicus European Air Quality Forecasts

📱 Bonus: use AQI apps or maps

Many mobile apps and public maps show the Air Quality Index (AQI) — a simplified scale where a higher number = poorer air quality. While µg/m³ values give you exact PM2.5/PM10 measurements, AQI is great for quick decisions like “should I open windows?” or “is it safe to jog outside?”

Example global AQI map for Europe: Live Europe AQI Map

6) Why late winter & early spring are often the worst (Europe’s “smog season”)

This time of year is a perfect recipe for pollution peaks. Even places that feel “clean” can get short smog episodes when emissions and weather conditions line up.

🔥 Heating emissions

In many European regions, winter heating — especially solid fuels (wood, coal, pellets) — increases PM2.5. This is one of the main reasons winter days can suddenly turn into smog days.

🧊 Temperature inversion (the “invisible lid”)

On cold, windless days, a weather pattern called temperature inversion can trap pollution near the ground — like an invisible lid. This is why particulate levels can stay high for days, especially in valleys and basins.

📍 Example: The Po Valley in Northern Italy is well known for persistent winter pollution because geography and weather can trap polluted air.

🛣️ Early spring road dust

When roads dry out after winter, debris and fine dust get lifted by wind and traffic. This can cause PM10 spikes even if heating emissions are already declining.

🎯 Practical takeaway

If you notice a run of cold, still days — or a dusty early spring week — it’s a good time to check PM2.5 and PM10 levels and make sure your ventilation filter is up to the season.

Europe: typical PM pollution patterns in late winter & early spring

More affected (winter PM episodes) Moderate (city/industrial spikes) Often very good overall

Note: This map shows typical patterns. Air quality is regional: valleys/basins and traffic corridors can experience higher PM peaks than national averages, especially during temperature inversions.

8) How does Europe compare to the USA, Canada, Australia, and Asia?

A simple mental model: different regions have different “main drivers” of PM2.5. Some places are usually clean but occasionally extreme, others are consistently challenged.

🇦🇺 Australia

Often very clean overall — until bushfire smoke turns PM2.5 extreme. Wildfire seasons can quickly change the air from “excellent” to “unhealthy.”

🇺🇸 USA / 🇨🇦 Canada

Often moderate overall — but wildfire seasons can push PM2.5 very high, even far away from the fire itself.

🌏 Asia (many regions)

Some of the most severe PM2.5 levels globally occur in parts of South and East Asia, with frequent high-PM episodes and longer polluted periods.

🇪🇺 Europe

Europe usually sits in the middle: not the worst globally, but still regularly affected — especially during winter inversions and in known regional hotspots (for example, basins and valley areas).

🎯 Practical takeaway

If you live in Europe, the biggest risk is often seasonal peaks: a few winter or early-spring weeks can contribute a large share of your annual exposure — which is why monitoring PM2.5 during “smog season” matters.

9) Which ventilation filter should you choose?

Modern ventilation filters are classified by particle size performance (PM1 / PM2.5 / PM10). Here’s a simple comparison.

Filter type	Best for	Choose it if…
G4 / ISO Coarse	Large dust, insects, basic unit protection	You live in a low-pollution area and PM2.5 is usually low.
ePM10 (M5)	City dust, road dust, spring dust	PM10 is often moderate (20–50 µg/m³) but PM2.5 spikes are rare.
ePM1 (F7 / PM1)	Fine particles (PM2.5 / smog)	You live in a city, near traffic, or experience winter smog episodes.

Why ePM1 70% is often the sweet spot:
It provides meaningful fine particle (PM2.5) reduction while remaining practical for residential airflow and everyday use.

10) Quick filter picker

PM2.5 mostly under ~10–15 µg/m³	→ G4 (Coarse)
PM10 often 20–50 µg/m³ (traffic / spring dust)	→ ePM10 (M5)
PM2.5 often >15–25 µg/m³ in winter or smog peaks	→ ePM1 (F7 / PM1) – ideally ePM1 70%

Winter and early spring are exactly when these choices matter most.

A Simple Rule for Late Winter and Early Spring

If the following sounds familiar:

📍 You check your local air quality index

📈 You see PM2.5 rising during cold, still days

🚗🔥 You live near traffic corridors or solid fuel heating areas

✅ Then this is the practical upgrade

A higher-grade PM1 filter (F7 / ISO ePM1 70%) is not an overreaction — it’s a smart seasonal protection strategy for smog peaks.

Clean outdoor air cannot always be guaranteed.

Clean indoor air can.

Categories: Indoor air quality

Manufacturer of MVHR	Zehnder
Manufacturer	CleanFilter
Air handling unit	ComfoAir Q 450 ComfoAir Q 350 ComfoAir Q 600
Filter dimensions	500x159x22
Class EN779	G4+G4
Class ISO16890	Coarse 75%
Protection level	Basic: larger solid particles, dust, fluff.
Quantity of filters	2
Advantages	Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air ISO 16890 tested – performance verified by an accredited laboratory in Germany Premium replacement filter – tested quality, airtight construction with fully bonded media, and reliable performance Lower running costs – lower filter price, lower energy use, and usually longer time between replacements than higher-efficiency filters.
Manufacturer product number	400502012 400502014
Remarks	⚠️ Remarks: ComfoAir ≠ ComfoAir Q. Different dimensions, not interchangeable. Check your ventilation unit model/version before ordering.

Manufacturer of MVHR	Brink
Manufacturer	CleanFilter
Air handling unit	Brink Flair 325 Brink Flair 400
Filter dimensions	245x510x5
Class EN779	G4+G4
Class ISO16890	Coarse 65%
Protection level	Basic: larger solid particles, dust, fluff.
Quantity of filters	2
Advantages	ISO 16890 tested – performance verified by an accredited laboratory in Germany Lower running costs – lower filter price, lower energy use, and usually longer time between replacements than higher-efficiency filters. Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air
Manufacturer product number	1669551
Remarks	ℹ️ This filter set protects the MVHR from larger particles. For finer filtration (pollen, smog), use an F7 supply air filter, available in our shop.

Manufacturer of MVHR	Paul
Manufacturer	CleanFilter
Air handling unit	Paul Novus 300 Paul Novus 450
Filter dimensions	180x475x50
Class EN779	G4+G4
Class ISO16890	Coarse 75%
Protection level	Basic: larger solid particles, dust, fluff.
Quantity of filters	2
Advantages	Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air ISO 16890 tested – performance verified by an accredited laboratory in Germany Lower running costs – lower filter price, lower energy use, and usually longer time between replacements than higher-efficiency filters.
Manufacturer product number	527004250

Manufacturer of MVHR	Mitsubishi
Manufacturer	CleanFilter
Air handling unit	Lossnay VL 100
Filter dimensions	300x98x15
Class EN779	G4x4
Class ISO16890	Coarse 65%
Protection level	Basic: larger solid particles, dust, fluff.
Quantity of filters	4
Advantages	Lower running costs – lower filter price, lower energy use, and usually longer time between replacements than higher-efficiency filters. Made in the EU – reliable quality and strict safety standards ISO 16890 tested – performance verified by an accredited laboratory in Germany
Manufacturer product number	P-100F5-E
Remarks	ℹ️ In ventilation devices, filtering material is used only with filter frames.

Manufacturer of MVHR	Salda
Manufacturer	CleanFilter
Air handling unit	Smarty 3XV Smarty 4XV
Filter dimensions	475x134x25 475x180x25
Class EN779	G4+G4
Class ISO16890	Coarse 75%
Protection level	Basic: larger solid particles, dust, fluff.
Quantity of filters	2
Advantages	Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air ISO 16890 tested – performance verified by an accredited laboratory in Germany Lower running costs – lower filter price, lower energy use, and usually longer time between replacements than higher-efficiency filters.

Smog Season in Europe: What PM2.5 and PM10 Mean and How to Choose the Right Ventilation Filter

Understanding Smog Season in Europe

In this guide, you'll learn:

1) What is air pollution, really?

2) PM10 vs PM2.5: the difference you can feel vs the one you can’t

3) “What numbers are normal?” (PM10 and PM2.5 without the headache)

4) How to tell the air is polluted (without looking at a chart)

5) How to monitor PM10 and PM2.5 (simple and practical)

6) Why late winter & early spring are often the worst (Europe’s “smog season”)

Europe: typical PM pollution patterns in late winter & early spring

8) How does Europe compare to the USA, Canada, Australia, and Asia?

9) Which ventilation filter should you choose?

10) Quick filter picker

Zehnder ComfoAir Q 350/450/600 G4+G4 Filter set (Standard)

Brink Flair 325/400 G4+G4 Filter set (Standard)

Paul Novus 300/450 G4+G4 Filter set (Standard)

Mitsubishi Lossnay VL 100 G4 Replacement Filter – 300×98×15 mm (Set...

Smarty 3XV / 4XV G4+G4 Filter set (Economy)

PLUGGIT Avent P460 G4+G4 Filter set (Standard)

WS 150 G4x4 Filter set (Standard) ⭐%

SIBER DF EVO / EVO2 1xG4 Filter (Basic protection)

Zehnder ComfoAir Q 350/450/600 F7+G4 Filter set (Efficient)

Brink Flair 325/400 1xF7 Filter (Smog&Pollen)

Paul Climos 200 F7+G4 Filter set (Efficient)

Mitsubishi Lossnay VL-500 1xF7 Filter (Smog&Pollen)

Vaillant Recovair VAR 150/4 F7+G4 Filter set (Efficient)

WS 320 / WS 470 / WR 310/410 1xF7 Filter (Smog&Pollen)

Domekt R 450 V C6M F7+M5 Filter set (Efficient) 517x278x46 mm

VALLOX 096 MC/SE/MV / VALLOPLUS 270 MV/SE/SC F7+2xG4 Filter set...

A Simple Rule for Late Winter and Early Spring

Questions? We’re here to help!

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Klimtera JSC

Manufacturer of MVHR	Pluggit
Manufacturer	CleanFilter
Air handling unit	PLUGGIT Avent P460
Filter dimensions	561x158x48
Class EN779	G4+G4
Class ISO16890	Coarse 75%
Protection level	Basic: larger solid particles, dust, fluff.
Quantity of filters	2
Advantages	ISO 16890 tested – performance verified by an accredited laboratory in Germany Lower running costs – lower filter price, lower energy use, and usually longer time between replacements than higher-efficiency filters. Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air
Manufacturer product number	087997

Manufacturer of MVHR	Maico
Manufacturer	CleanFilter
Air handling unit	WS 150
Filter dimensions	350x247
Class EN779	G4x4
Class ISO16890	Coarse 65%
Protection level	Basic: larger solid particles, dust, fluff.
Quantity of filters	4
Advantages	Made in the EU – reliable quality and strict safety standards Premium class safe synthetic filtering material from SANDLER AG (Germany) Lower running costs – lower filter price, lower energy use, and usually longer time between replacements than higher-efficiency filters.

Manufacturer of MVHR	Siber
Manufacturer	CleanFilter
Air handling unit	SIBER DF EVO SIBER DF EVO2
Filter dimensions	139x175x48
Class EN779	G4
Class ISO16890	Coarse 75%
Protection level	Basic: larger solid particles, dust, fluff.
Quantity of filters	1
Advantages	Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air ISO 16890 tested – performance verified by an accredited laboratory in Germany Lower running costs – lower filter price, lower energy use, and usually longer time between replacements than higher-efficiency filters.
Manufacturer product number	DFFG4

Manufacturer of MVHR	Vaillant
Manufacturer	CleanFilter
Air handling unit	Recovair VAR 150/4
Filter dimensions	167x280x47 162x280x47
Class EN779	F7+G4
Class ISO16890	ePM1 70%
Protection level	High: fine particles, dust, pollen, mold spores, combustion particles, smog particles, insecticide dust.
Quantity of filters	2
Advantages	Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air ISO 16890 tested – performance verified by an accredited laboratory in Germany Maximum protection – ePM1 70% removes up to 40% more smog, pollen and fine dust than standard filters (50–60%).
Manufacturer product number	0020180808

Manufacturer of MVHR	Komfovent
Manufacturer	CleanFilter
Air handling unit	Domekt R 450 V C6M
Filter dimensions	517x278x46
Class EN779	F7+M5
Class ISO16890	ePM1 70%
Protection level	High: fine particles, dust, pollen, mold spores, combustion particles, smog particles, insecticide dust.
Quantity of filters	2
Advantages	Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air ISO 16890 tested – performance verified by an accredited laboratory in Germany Maximum protection – ePM1 70% removes up to 40% more smog, pollen and fine dust than standard filters (50–60%).
Manufacturer product number	1038339 1038339
Remarks	⚠️ Suitable only for C6M models (from 10/2020). Please check model or filter dimensions before ordering. 🌟 High-quality replacement filter: made from certified materials (Germany, SANDLER AG) with tested performance. Provides reliable air filtration and optimal service life.

Manufacturer of MVHR	VALLOX
Manufacturer	CleanFilter
Air handling unit	VALLOX 096 MC VALLOX 096 SE VALLOX 096 MV VALLOPLUS 270 MV VALLOPLUS 270 SE VALLOPLUS 270 SC
Filter dimensions	225x194 225x194x96 350x138
Class EN779	F7+2xG4
Class ISO16890	ePM1 70%
Protection level	High: fine particles, dust, pollen, mold spores, combustion particles, smog particles, insecticide dust.
Quantity of filters	3
Advantages	Made in the EU – reliable quality and strict safety standards German filtration material – hygienic (VDI 6022) and PFAS-free, for cleaner and safer air ISO 16890 tested – performance verified by an accredited laboratory in Germany Maximum protection – ePM1 70% removes up to 40% more smog, pollen and fine dust than standard filters (50–60%).
Manufacturer product number	3356900

Smog Season in Europe: What PM2.5 and PM10 Mean and How to Choose the Right Ventilation Filter

Understanding Smog Season in Europe

In this guide, you'll learn:

1) What is air pollution, really?

2) PM10 vs PM2.5: the difference you can feel vs the one you can’t

3) “What numbers are normal?” (PM10 and PM2.5 without the headache)

4) How to tell the air is polluted (without looking at a chart)

5) How to monitor PM10 and PM2.5 (simple and practical)

6) Why late winter & early spring are often the worst (Europe’s “smog season”)

Europe: typical PM pollution patterns in late winter & early spring

8) How does Europe compare to the USA, Canada, Australia, and Asia?

9) Which ventilation filter should you choose?

10) Quick filter picker

G4 – Coarse Filters – for low pollution areas

F7 – ePM1 Filters – fine particle & smog protection

A Simple Rule for Late Winter and Early Spring