This Week in Victoria and New South Wales and many other parts of Australia we're reopening and a lot of the lockdown restrictions are being lifted. So what does that mean? Well, many of our children will be returning to school - so this week I want to be focusing on a very important non-pharmaceutical intervention, which revolves around indoor air quality. And this is a particularly relevant and topical, because if you've picked up any of the news media over the last couple of weeks, you may have noticed a range of different stories focusing on both the Victorian announcement regarding the $190 million package for air purifiers to be put into all public schools. Similarly, in New South Wales people are calling for stronger ventilation Standards, and this is shining a spotlight on a very important engineering control step to address public health concerns around respiratory viruses. And so today we're going to be focusing on HEPA which stands for High-Efficiency Particulate Air, and I'm going to be reviewing and answering the following questions: 

- Are portable air purifiers effective? 
- What to look for in an air purifier? 
- What are some of the definitions you should be aware of when you look online if you want to purchase one of these HEPA air purifiers for your own home or office?
- Do portable air purifiers work against covid?
- Is there research showing HEPA is of benefit for particulate matter and in turn bacteria, fungi, pollen, and even viruses when they are put to the test? 
- What are the best portable air purifiers according to science?

And this should help you out when you return to your High street retailer and look on the box for specifications or DYOR online. 

I also want to talk about some of the scientific evidence that is the premise for why HEPA is a valuable intervention. Then, what is the evidence for whether they work or not against the SARS-CoV-2 virus? 

I'll also be reviewing some of the writings from expert panels, such as OzSage, and their recommendations regarding carbon dioxide, and ventilation standards for buildings. 

Importantly, I will review where HEPA air purifiers fail, and some of the common mistakes that can occur when people are trying to match a portable HEPA air purifier for a particular space. 

Finally, I'll round out with some of the benefits that are validated from the literature, such as improving or reducing the probability of hospital-acquired infections, specifically around fungal pathogens.

Then, I'll conclude with some very recent research looking at the benefits of HEPA air quality and depression. 

REFERENCES:

1. Hammond A, Khalid T, Thornton HV, Woodall CA, Hay AD (2021) Should homes and workplaces purchase portable air filters to reduce the transmission of SARS-CoV-2 and other respiratory infections? A systematic review. PLoS ONE 16(4): e0251049. https://doi.org/10.1371/journal.pone.0251049

2. Rodríguez, M., Palop, M., Seseña, S. and Rodríguez, A., 2021. Are the Portable Air Cleaners (PAC) really effective to terminate airborne SARS-CoV-2?. Science of The Total Environment, 785, p.147300.
https://doi.org/10.1016/j.scitotenv.2021.147300

3. Protecting children from COVID-19 and making schools and childcare safer.
https://www.burnet.edu.au/news/1523_ozsage_advice_on_protecting_children_from_covid_19
https://www.burnet.edu.au/system/asset/file/4947/OzSAGE_Children_and_Schools_and_Childcare.pdf
https://ozsage.org/ventilation-and-vaccine-plus/

4. Tamana, S., Gombojav, E., Kanlic, A., Banzrai, C., Batsukh, S., Enkhtuya, E., Boldbaatar, B., Lanphear, B., Lear, S., McCandless, L., Venners, S. and Allen, R., 2021. Portable HEPA filter air cleaner use during pregnancy and children's body mass index at two years of age: The UGAAR randomized controlled trial. Environment International, 156, p.106728.

5. Curtis L. HEPA