Indoor coffee place

Description

CO2 builds up when occupants exhale faster than the ventilation system introduces fresh air. This can lead to cognitive fatigue and drowsiness.

What happened

Levels rose most consistently around the lunchtime rush and returned toward baseline after occupancy eased.

Recommendations

1. Start the HVAC system on outdoor-air mode at least 30 minutes before opening, and check that outdoor-air intakes and dampers are open, clean, and unobstructed rather than operating in recirculation-only mode.
2. Use 800 ppm as an early operational ventilation alert—not a universal health limit—after confirming the outdoor baseline: when CO2 keeps rising, increase outdoor-air delivery before the lunchtime rush and reduce entry until the trend reverses.
3. Have an HVAC professional measure and rebalance outdoor airflow for the design occupancy if lunchtime peaks continue; do not rely on a portable air cleaner for CO2 because particle filters do not remove it.
4. Keep the increased ventilation running for at least 30 minutes after the rush, then compare the next occupied period with this baseline to confirm that peaks and time above 1000 ppm have fallen.

Data

Average CO2

1,008 ppm

Peak CO2

1,740 ppm

Number of datapoints above 1000 ppm

49 %

Description

Radon is a naturally occurring radioactive gas. It accumulates in the soil beneath a building and climbs through the path of least resistance. Even with a solid, seamless foundation slab, the microscopic gaps around utility pipes act like chimneys that pull this gas into your space.

What happened

The simulated short-term readings stayed low and stable, with no daily peak above 90 Bq/m³.

Recommendations

1. Place a long-term radon monitor for at least 30 days in the lowest regularly occupied, ground-contact area, especially in the heating season; this short, above-ground result should not be used as the building-wide annual baseline.
2. Inspect floor-wall joints, service penetrations, drains, and sump covers now, and repair visible gaps with compatible airtight materials; sealing supports mitigation but should not be treated as the only radon-control method.
3. Check that kitchen extraction and the HVAC system do not leave ground-contact areas under sustained negative pressure; provide balanced makeup air where exhaust systems operate.
4. If the long-term average reaches or exceeds the WHO reference of 100 Bq/m³, engage a qualified radon professional to assess active sub-slab depressurization or another building-specific system, then retest after installation.

Data

Average radon

59 Bq/m³

Peak radon

86 Bq/m³

Description

Fine airborne particles accumulate from daily operations, cooking, cleaning agents, and incoming outdoor air. Left unmanaged, these microscopic particulates degrade indoor air quality and can trigger respiratory irritation or long-term health issues.

What happened

Short particle peaks appeared around food preparation, then declined once extraction and filtration caught up.

Recommendations

1. Switch the externally vented cooking hood on before food preparation starts, use the back burners and lids where practical, and leave extraction running until PM2.5 returns toward its pre-cooking baseline.
2. Clean grease filters now and replace HVAC filters on their pressure-drop or service schedule; use MERV 13 (approximately ISO ePM1 50%) or the highest rating the system can accommodate without reducing airflow.
3. Add a non-ozone-producing portable HEPA cleaner sized by smoke CADR for the occupied zone, especially where cooking peaks spread beyond the capture hood.
4. Move aerosol cleaning, candles, and other particle-producing tasks outside occupied hours; if a peak persists for 30 minutes, pause the source, increase extraction, and verify that makeup air is available.

Data

Average PM2.5

15 µg/m³

Peak PM2.5

44 µg/m³

Average recovery time

27 minutes