New research: Trees protect us from pollutants
The Research
Within the next 35 years, the majority of the world’s population will live in cities. Already, densely packed urban centers pose challenges to preserving residents’ quality of life and health and the city’s air quality. Fine particulate matter (PM2.5) is chief among the concerns. In fact, as city populations rise, the mortality rate from diseases caused by PM will also spike. So research team at The Nature Conservancy, a nonprofit focused on finding solutions to large environmental problems, set out to figure out how well urban vegetation might help offset air pollution.
The Results
The team focused on 245 cities, which currently house some 910 million people or one-quarter of the global population. They collected PM2.5 levels and information on the density of trees, focusing primarily on street trees. They found that trees, through a process called dry deposition, already provide some level of PM2.5 relief for more than 63 million people in their study group. Trees have the greatest impact to areas within 30 meters (roughly 100 feet) of where they’re planted, but can have some effect up to 300 meters (1,000 feet) away. Most notably, homes on a tree-lined street experience a 50-percent drop in indoor PM concentrations.
The Takeaway
If done strategically — that is in high-population areas and with a selection of species known to trap particles well, such as red cedar, red maple, and elm trees — a further 115 million people could experience some reduction in PM exposure. Tree-planting, especially in densely packed neighbourhoods, is part of an effective strategy to reduce particulate-based air pollution both indoors and outdoors.
Disclaimers
1Coway air purifiers has been proven to trap dust, pollen, dander, viruses and bacteria in the air based on KCL (Korea Conformity Laboratories) testing.They have been tested in a 30㎥ size chamber according to the Korea Air Cleaning Association standard (SPS-KACA 002-132:2022 Modified) to measure the 0.01㎛ size of particle removal rate. It was tested on maximum airflow speed in normal room temperature and humidity conditions. The performance may vary in the actual living environment of customers.
→ Tested with Airmega Aim, 150, 160, AP-1216L, AP-1512HH, AP-1512HHS, 200M, Icon, IconS, 230, 240, 250, 250 Art, 250S, 300, 300S, 400, 400S, ProX
299.97% of viruses, bacteria, fungi and pollen were verified to be removed from the air for Coway air purifiers which have Green True HEPA™ filter applied based on the Japan Food Research Laboratories(JFRL) testing according to JEM 1467 standard.
→ Tested with Coway Airmega AP-1512HH, AP-1512HHS, 250, 250 Art, 250S, 300, 300S, 400, 400S
→ All tested by JFRL and received above result within below time.
All tested by JFRL and received above result within below time.
- Virus: Tested with Escherichia coli phage ΦX174 NBRC 103405, 60 minutes
- Bacteria: Tested with Staphylococcus epidermidis NBRC 12993, 60 minutes
- Fungi/Mold: Tested with Penicillium citrinum NBRC 6352, 60 minutes
- Pollen: Tested with Cedar Pollen extract, 60 minutes
3Aerosol test conducted in a Biosafety level 3 laboratory with two Coway air purifier models, Coway Airmega 250 and 400 for removal of SARS-CoV-2 Aerosol by US based MRI Global, a not-for-profit laboratory and partner of US Department of Defense. The test was conducted in a 13.1ft3 chamber. Virus was aerosolized for 15 minutes and the product was turned on high for 2 minutes. Result showed each product effectively removed over 99.98% of the SARS-CoV-2 in 2 minutes. This is a result from a laboratory experiment condition and result may vary in different conditions. This result does not imply it kills SARS-CoV-2 or prevents the transmission of Covid-19. Coway Airmega 250S and 400S are identical to the tested models and has equal performance with an additional mobile connectivity function.
4The concentration of ammonia, acetaldehyde and acetic acid were proven to be removed within 30 minutes by FCG Research Institute, Inc. Human Life Science Lab. It is not a demonstration result in the actual use space. Not all odors and gases may be supported. → Tested with Coway Airmega 150, 160, AP-1512HH, AP-1512HHS, 400, 400S
5The coverage area of the air purifier is based on an area where the air cleaner can make two air changes per hour (ACPH). An air change per hour translates to how many times an air purifier can clean an area, assuming the height of a ceiling to be 8 ft, in one hour. Therefore ** means two air changes per hour means that the cleaner can clean the area once every 30 minutes and * means air changes per hour means that the air purifier can clean the area once every 60 minutes.
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