Source: Brett W. Stinson, Aurélie Laguerre, Elliott T. Gall, Portland State University; ACS EST Air, published March 11, 2024 美国化学学会出版社
This study systematically evaluated a set of air cleaners—both commercial and DIY—under indoor wildfire smoke conditions. The researchers tested 13 air cleaner models, including two DIY configurations (box fan + MERV-13 filter) to assess how effectively they remove particulate matter (PM), black carbon, brown carbon, and volatile organic compounds (VOCs). The smoke was simulated so that particle sizes, composition, and concentrations approximated those from real wildfire events. 美国化学学会出版社
Key results:
The two DIY designs achieved very high Clean Air Delivery Rates (CADRs) for particles in the 1-2.5 µm diameter range. One design had an average CADR of ~1467 m³/h, the other about 842 m³/h. These are impressive numbers, competitive with many commercial purifiers. 美国化学学会出版社
The performance was measured not only for PM removal but also for black and brown carbon—a nod to real smoke complexity, since wildfire smoke includes many carbon species that absorb light (brown/black carbon) and contribute to health and climate effects. VOC removal was also included, though typically air cleaners have more difficulty dealing with gaseous pollutants compared to particles. 美国化学学会出版社
Results varied by model; some commercial devices excelled at particle filtering but less so with VOCs or carbonaceous particles. The DIY models, surprisingly, performed well in the particle range, although likely less effective with gases/VOCs. Also, trade-offs: airflow, noise, energy consumption, filter degradation over time are relevant. While the study reports the performance under test conditions, real-world operational behavior can affect outcomes. 美国化学学会出版社
This paper is highly relevant in the context of increasing wildfire events globally—particularly for people forced to spend time indoors because outside air is hazardous. A few insights and reflections:
DIY air cleaners can be a viable option: The fact that DIY designs with box fans and MERV-13 filters achieved CADRs in the hundreds to thousands m³/h shows that for many households, especially in moderate-income settings, DIY systems could offer strong mitigation of smoke exposure at lower cost. This matters because many commercial purifiers capable of similar performance are expensive.
Importance of particle size: Most dangerous smoke particulates are in the fine range, particularly PM2.5 or even ultrafine (<1 µm). This study shows that many air cleaners are effective in the 1-2.5 µm range, but performance at smaller size or under fluctuating load demands is still critical. Smoke includes very small particles and aerosols that can penetrate deep into lungs; thus, clean air delivery for smaller size fractions is a strong advantage.
VOC and carbonaceous pollutants remain harder: While particulate removal is well addressed, removing gases and complex carbon species is more challenging. Activated carbon layers, better adsorbent materials, or hybrid filters are needed. Many air cleaners don’t focus on VOCs, and test conditions may underrepresent long-term VOC off-gassing or deposition from surfaces.
Trade-offs & realistic usage: Noise, power consumption, filter lifespan, size of unit, filter replacement cost—all influence real-world adoption. A fridge-quiet, energy-inefficient unit with a high CADR is less likely to be used as needed. Also, filter clogging from heavy smoke load will reduce effectiveness over time. The study gives a benchmark, but real homes may suffer infiltration, leaks, improper operation (e.g. turning off the purifier or placing it poorly).
Policy & public health implications: These findings support recommending air cleaners as part of protective measures during wildfire seasons. Authorities could issue guidelines for which units are effective, or promote DIY designs for communities under financial constraint. Another route: subsidies, public awareness campaigns, or inclusion in building codes (for new houses) to ensure provision for smoke-mitigation.
The study is still lab-based; indoor conditions (spread of smoke, ventilation, doors/windows opening) are more variable. Follow-up field studies in real homes in wildfire-affected regions could help assess cumulative exposure and user behavior.
Filter aging and maintenance impact over long smoke exposure periods should be quantified. For example, how much does CADR fall after hours or days of heavy smoke? Does the pressure drop increase? Does energy cost go up?
More research on multi-pollutant removal (particles + VOCs + black/brown carbon) is needed. Hybrid filters may be more expensive; balancing cost vs performance is important.
Consideration of acoustic comfort, power usage, unit size, and safety (especially for DIY units) is critical for widespread uptake.
This case study demonstrates that both commercial and DIY air cleaners can significantly reduce indoor smoke particle burdens during wildfire events. It underscores that accessible, reasonably affordable mitigation measures exist. For public health and policy, encouraging such measures—especially in high-risk zones—can significantly reduce respiratory health risks. Houses built or retrofitted to be more airtight, paired with effective air cleaning, give the best protection. For technological development, the focus should be improving VOC and gas-phase pollutant removal, enhancing durability, and making high-performance units more affordable and user-friendly.
