index

Six months ago, I bought my first air quality monitor on a whim. What it revealed about my flat’s air was genuinely concerning—and fixing it was easier than I expected.

The Wake-Up Call

I’d been getting mild headaches most evenings and waking up with a scratchy throat. Nothing dramatic, just annoying enough to mention to my GP, who suggested it might be allergies. Fair enough.

Then I bought a Temtop M10 air quality monitor and stuck it in my bedroom. The first reading: PM2.5 of 32 μg/m³.

For context, WHO guidelines recommend 24-hour average PM2.5 below 15 μg/m³. I was hitting double that just lying in bed.

Turns out my “allergies” might have been my flat’s air quality all along.

The Starting Point: How Bad Was It?

I measured air quality in different rooms for a week before changing anything. Here’s what I found:

Baseline readings (before fixes):

• Bedroom: 28-35 μg/m³ PM2.5 (consistently high)
• Living room: 18-24 μg/m³ PM2.5
• Kitchen: 15-45 μg/m³ PM2.5 (spikes during cooking)
• Bathroom: 12-18 μg/m³ PM2.5 (surprisingly the cleanest room)

My ground-floor London flat was basically sitting in a cloud of particles. Not hazardous, but definitely not good.

Problem 1: The Bedroom Carpet Was a Dust Trap

The discovery: My bedroom has old fitted carpet—probably original from when the building was converted in the 1990s. Every time I walked across it, the air quality monitor spiked. Every. Single. Time.

I borrowed a mate’s UV light and… yeah. The carpet was disgusting. Decades of accumulated dust, skin cells, and who knows what else, all getting kicked up into the air whenever I moved.

The fix: Ripped out the carpet. Had the floorboards underneath sanded and sealed. I hired a floor sanding service for two rooms.

Result:

• Bedroom PM2.5 dropped from 32 μg/m³ to 12 μg/m³ (63% improvement)
• Living room dropped from 22 μg/m³ to 14 μg/m³ (36% improvement)

Genuinely shocked at how much difference this made. The carpet was the single biggest problem.

Bonus: The flat looks better, is easier to clean, and my morning throat scratchiness disappeared within a week.

Problem 2: I Was Cooking Wrong

The discovery: I’d been frying food without using the extractor fan because I thought it was pointless (it seemed weak and noisy).

My kitchen monitor during breakfast: bacon frying, no fan, PM2.5 hit 87 μg/m³. That’s “unhealthy” territory.

The fix: Two changes:

1. Always run the extractor fan when cooking anything beyond boiling water
2. Open a window during high-heat cooking (creates airflow)

I also realized my extractor fan filter was clogged. Cleaned it, massive difference. Picked up some replacement filters to keep on hand.

Result:

• Cooking PM2.5 peaks dropped from 87 μg/m³ to 34 μg/m³ (60% reduction)
• Return to baseline faster: 45 minutes instead of 2+ hours

Side benefit: The flat smells less like old cooking oil.

Problem 3: My “Ventilation Strategy” Was Making Things Worse

The discovery: I’d been opening windows in the morning to “air out” the flat. Seemed sensible. My monitor showed otherwise.

Morning rush hour (7-9 AM) outdoor PM2.5: 35-45 μg/m³ Late evening (10 PM-midnight) outdoor PM2.5: 8-12 μg/m³

I was opening windows during the worst possible time for outdoor air quality—when traffic was heaviest.

The fix: Changed my ventilation timing:

• Morning: Windows closed during rush hour
• Late evening: Open windows for 20-30 minutes (10 PM onwards)
• Weekends: Morning ventilation is fine (less traffic)

Result:

• Indoor PM2.5 stopped spiking from outdoor pollution in the mornings
• Better air exchange in the evening when outdoor air is actually clean

This felt counterintuitive but the data doesn’t lie. Urban air quality varies massively by time of day.

Problem 4: I Needed an Air Purifier (And I Was Skeptical)

The discovery: Even after the carpet removal and better ventilation, my bedroom still wasn’t great. Background PM2.5 was around 12-15 μg/m³—not terrible, but not ideal for 8 hours of sleep.

I was skeptical about air purifiers. Seemed like snake oil.

The fix: Bought a mid-range HEPA air purifier and ran it in my bedroom during sleep. I went for one with a proper HEPA filter, not the cheap ionizer types.

Result:

• Bedroom PM2.5 during sleep: 12 μg/m³ → 5-7 μg/m³ (50% improvement)
• Noticeable difference in sleep quality (possibly placebo, but I’ll take it)
• Morning throat issues: Gone completely

The purifier works. I was wrong to be skeptical. On high speed it can clean the room air in about 20 minutes.

Important: This only works if you also fix the sources (carpet, cooking, ventilation). A purifier can’t solve everything.

Problem 5: My Front Door Was Basically a Pollution Highway

The discovery: My flat is ground floor, front door opens directly onto the street. Every time someone opened the door, outdoor air (and traffic pollution) rushed in.

I measured PM2.5 near the door: consistently 5-8 μg/m³ higher than the rest of the flat.

The fix: Added a draft excluder and weather stripping around the door frame. Not a perfect seal (need ventilation), but it stopped the worst of the outdoor air infiltration.

Result:

• Hallway PM2.5 dropped from 18 μg/m³ to 12 μg/m³ (33% improvement)
• Flat holds clean air better after evening ventilation
• Bonus: Lower heating bills in winter

Simple, cheap, effective.

The Total Picture: Before and After

Before fixes (6 months ago):

• Bedroom: 32 μg/m³ average
• Living room: 22 μg/m³ average
• Overall flat: 24 μg/m³ average
• Health: Headaches, scratchy throat, generally felt rubbish

After all fixes (now):

• Bedroom: 7 μg/m³ average (78% improvement)
• Living room: 10 μg/m³ average (55% improvement)
• Overall flat: 9 μg/m³ average (63% improvement)
• Health: Headaches gone, sleep better, generally feel fine

The improvement to daily life has been worth the investment.

What I Learned

1. Measure before you fix I nearly bought an air purifier as my first step. Turns out the carpet was the real problem. The monitor showed me what actually mattered.

2. The obvious solutions aren’t always right Opening windows in the morning seemed sensible. The data showed it was making things worse.

3. Multiple small changes add up No single fix got me from 24 μg/m³ to 9 μg/m³. It was the combination of all five changes.

4. Old buildings have hidden problems That carpet had been there for 30 years. I didn’t realize how much dust it was harboring until I measured the before/after.

5. Air purifiers aren’t snake oil I was genuinely skeptical. But in combination with source control (carpet removal, better ventilation), they work.

Would I Do It Again?

Absolutely. The cost was manageable, the improvement was measurable, and the health benefits were real.

The headaches stopped. The morning throat scratchiness vanished. I sleep better. These aren’t abstract improvements—they’re daily quality of life changes.

If You’re Thinking About Doing This

Start with measurement: Get a basic air quality monitor and measure for a week. You might be surprised by what you find.

Prioritize by impact: I fixed things in order of how much improvement they made. Carpet removal had the biggest effect, so I did that first.

Don’t expect perfection: I’m at 9 μg/m³ average, not the WHO guideline of 5 μg/m³. That’s fine. Perfect is the enemy of good enough.

Consider your situation: I’m a renter who got lucky with a landlord who agreed to the carpet removal (I paid, he agreed). Your situation might be different. Even without major changes, the ventilation timing and extractor fan habits are free.

The Unexpected Benefits

Beyond the air quality numbers:

• Energy awareness: I now notice when I’m wasting energy on heating/cooling while windows are open
• Cleaning habits: Floorboards are easier to clean than carpet, flat stays cleaner overall
• Humidity control: The monitor tracks humidity too—helped me realize my bathroom fan wasn’t working properly
• Peace of mind: Knowing the air I’m breathing is reasonably clean reduces one source of background anxiety

Final Thoughts

Six months ago, I was living with air quality twice as bad as WHO guidelines recommend. I’d gotten used to feeling slightly rubbish all the time.

Now my flat’s air is cleaner than most outdoor air in London. The changes weren’t complicated, they just required actually measuring the problem first.

If you’re reading this and thinking “I wonder if my air quality is bad,” buy a monitor. You might be surprised by what you find. And unlike me, you’ll know exactly what to fix before you start throwing money at solutions.

Next project: I’m going to measure air quality in different parts of London during my runs. Curious whether parks are actually cleaner than streets. Watch this space.

---

Want to measure air quality in your home? Check out our portable monitor buying guide for reliable devices that won’t break the bank.