**Houseplants can absorb some pollutants, but ordinary numbers of potted plants won’t meaningfully clean your apartment’s air.** A HEPA air cleaner can help with dust; the headaches and rapid stuffiness also warrant checking the apartment’s ventilation and possible pollution sources.

A useful quantitative answer comes from Cummings and Waring’s review, published online in 2019. They analyzed 196 results from 12 studies and estimated that **10–1,000 plants per square metre** would be needed to match the VOC removal provided by typical building ventilation. Your 670-square-foot apartment is about 62 square metres: that translates to roughly **620–62,000 plants**. This is a scale comparison, not a prescription for your apartment. The underlying experiments used small, sealed chambers, where slow pollutant removal can become measurable over hours or days. [Research review](https://researchdiscovery.drexel.edu/esploro/outputs/journalArticle/Potted-plants-do-not-improve-indoor/991019168419404721)

**Address the headaches first.** Carbon monoxide is odorless and can cause headaches, dizziness and nausea. Check that you have a working CO alarm, especially if the building has fuel-burning heating, water heaters or an attached garage. If an alarm sounds, or you suspect CO exposure while having symptoms, leave immediately and contact emergency services from outside. Recurring headaches associated with the apartment deserve medical attention even if an alarm stays silent. [CDC guidance](https://www.cdc.gov/carbon-monoxide/about/index.html)

For improving the air, I would proceed in this order:

1. **Ask the landlord to investigate ventilation and combustion appliances promptly.** Your description suggests inadequate air exchange may be contributing, although it cannot identify the cause. Ask whether the apartment receives outdoor air and whether kitchen and bathroom exhausts work properly. Ventilate with clean outdoor air when conditions permit. EPA identifies source control and ventilation as the main ways to improve indoor air quality. [EPA guidance](https://www.epa.gov/indoor-air-quality-iaq/inside-story-guide-indoor-air-quality)

2. **Use a properly sized HEPA cleaner if dust is a concern.** Look for a published clean air delivery rate, or CADR. EPA’s sizing rule is a smoke CADR of at least two-thirds of the room’s area in square feet. For one open 670-square-foot space, that means about **450 cubic feet per minute**, assuming an eight-foot ceiling. Separate rooms may need separate units. Check noise at the speed you will actually use; advertised CADR usually reflects maximum speed. Avoid ozone-generating cleaners. [EPA sizing guidance](https://www.epa.gov/wildfires/indoor-air-filtration), [air-cleaner guide](https://www.epa.gov/sites/default/files/2018-07/documents/guide_to_air_cleaners_in_the_home_2nd_edition.pdf)

3. **Match gas filtration to an identified problem.** HEPA filters capture particles; they do not remove formaldehyde, CO or accumulated CO₂. Substantial gas-filter media can remove some gases, but ordinary activated carbon performs poorly against formaldehyde. A thin carbon sheet is insufficient evidence that a purifier will solve your symptoms. [EPA technical review](https://www.epa.gov/sites/default/files/2018-07/documents/residential_air_cleaners_-_a_technical_summary_3rd_edition.pdf)

The flooring and ceiling deserve two qualifications:

- **Laminate can emit formaldehyde, but its presence doesn’t establish harmful exposure.** Five weeks without improvement also doesn’t rule out continuing emissions. Emissions generally decline over time, while indoor concentrations depend on ventilation, temperature and humidity. Persistent symptoms justify professional assessment and targeted testing. [EPA laminate guidance](https://www.epa.gov/formaldehyde/questions-and-answers-regarding-laminate-flooring)
- **Older popcorn ceilings can contain asbestos.** Leave an intact ceiling alone. If it is crumbling or shedding material, ask for professional assessment before anyone scrapes, brushes or samples it. [EPA asbestos guidance](https://www.epa.gov/asbestos/protect-your-family-exposures-asbestos)

Get the plants you want for enjoyment. Budget for ventilation assessment and, if dust is present, a suitably sized HEPA cleaner to address the air-quality problem.