The project had reviewed articles concerning using plants to reduce indoor benzene concentrations. And tested benzene removing ability of plants. The five studied public locations had carbon dioxide concentrations lower than EPA standard, with the exceptions of beauty salons. Beauty salons also had higher formaldehyde concentrations than the other locations. PM concentrations did not exceed EPA standard in all locations. Beauty salons had higher total volatile organic compounds (TVOC) concentrations, while print center, gallery, and laundry shop had occasional higher concentration if underwent poster printing, oil painting, or dry cleaning. Beauty salons and laundry shop had higher benzene concentrations, while print center and gallery had occasional higher concentrations. Beauty salon#1 had CO2 concentration lower than EPA standard after placing plants. Print center and beauty salon#1 had formaldehyde concentration lower than EPA standard after placing plants. All tested locations had PM concentrations lower than EPA standard after placing plants. All tested locations, except beauty salon#2, had TVOC concentrations lower than EPA standard after placing plants. All locations, except gallery, had lower benzene concentrations after placing plants. Spathiphyllum ‘Palas’, Asplenium nidus, and Nephrolepis exaltata ‘Bostoniensis’ plants were placed in chambers with one block wooden board under 100% blue, 100% red, white (red:blue:green ratio is 19:29:52) LED light, and T5 fluorescent lamp. Results showed tested plant species could remove formaldehyde released from the wooden board. Spathiphyllum placed under 100% red LED light removed less formaldehyde than those under 100% blue LED light. Asplenium placed under T5 fluorescent lamp removed more formaldehyde than 100% blue, 100% red, and white LED light treatments. Nephrolepis placed under 100% blue LED light removed more formaldehyde than those placed under 100% red LED light. Potted plants of Cordyline terminalis ‘Baby Doll’, Asplenium nidus, or Aglaonema ‘Silver Queen’ plants were placed in chambers containing an initial 5 μL•L-1 benzene. Asplenium had lower benzene removal rate than Cordyline and Aglaonema. Potted Cordyline plants had increased benzene removal rate with increasing light intensity from 20-40 to 80-100 μmol•m-2•s-1. Benzene removal rate also increased linearly with increasing initial benzene concentration (R2 = 0.96). Initial benzene concentration did not affect CO2 uptake and evolution. Wrapped-root zone treatment significantly increased time to 50% benzene removal. Root zone of potted Cordyline had significant contribution to benzene removal. Cordyline plants grown with bark-based medium had lower benzene removal rate than those grown with peat-based medium. Those grown with peat-based medium showed higher benzene removal with root-zone only. Sterilized root zone showed consistently lower benzene removal rate than whole plant and non-sterilized root zone, especially for those grown with bark-based medium. Twenty tutor conferences were held on Apr 8, 11, 18, 22,24, May 2, 9, 27, June 22, 26, 28, Sept 13, 18, 25, Oct 18, 30, Nov 1, 4, and 6 in main towns and cities of Taiwan for promoting community greening. A total of 1,506 people joined and 1,421 people passed the test.

indoor plants, carbon dioxide, formaldehyde