Improving Household Safety via a Dynamic Air Terminal Device in Order to Decrease Carbon Monoxide Migration from a Gas Furnace

New Methodology to Evaluate and Optimize Indoor Ventilation Based on Rapid Response Sensors

The recent pandemic increased attention to the need for appropriated ventilation and good air quality as efficient measures to achieve safe and healthy indoor air. This work provides a novel methodology for continuously evaluating ventilation in public areas using modern rapid response sensors (RRS). This methodology innovatively assesses the ventilation of a space by combining a quantitative estimation of the real air exchange in the space-obtained from CO2 experimental RRS measurements and the characteristics of and activity in the space-and indoor and outdoor RRS measurements of other pollutants, with healthy recommendations from different organisations. The methodology allows space managers to easily evaluate, in a continuous form, the appropriateness of their ventilation strategy, thanks to modern RRS measurements and direct calculations (implemented here in a web app), even in situations of full activity. The methodology improves on the existing standards, which imply the release of tracer gases and expert intervention, and could also be used to set a control system that measures continuously and adapts the ventilation to changes in indoor occupancy and activity, guaranteeing safe and healthy air in an energy-efficient way. Sample public concurrence spaces with different conditions are used to illustrate the methodology.

Experimental study on the purification capacity of potted plants on low-concentration carbon monoxide in indoor environment

Indoor low-concentration carbon monoxide (CO) exposure is widespread worldwide, and potted plants may be a potential means for CO purification. The objective is to evaluate common indoor plants' CO purification and tolerance capacities. Epipremnum aureum (Linden ex André) G.S.Bunting, Chlorophytum comosum (Thunb.) Jacques, Spathiphyllum kochii Engl. & K.Krause, and Sansevieria trifasciata Hort. ex Prain with similar sizes were tested in the glass chamber with initial CO concentrations of 10, 25, 50, 100, 200, and 400 ppm, respectively. (1) The CO purification capacity of the four potted plants is ranked as Epipremnum aureum (Linden ex André) G.S.Bunting > Chlorophytum comosum (Thunb.) Jacques > Spathiphyllum kochii Engl. & K.Krause > Sansevieria trifasciata Hort. ex Prain. Under the purification effect of each plant, the CO concentration in the chamber decreases linearly and significantly (p < 0.05), and within a specific time period, the time-weighted average (TWA) CO concentrations can be reduced to below the corresponding permissible exposure limits specified by some countries and organizations. (2) With the increase of the stomatal number of each plant and the increase in CO concentration, the hourly and cumulative absorbed CO of each plant increase linearly and significantly (p < 0.05). (3) With the increase in CO concentration, the CO purification efficiency of each plant decreases exponentially and significantly (p < 0.05). (4) When the CO concentration was ≤ 50 ppm, all plants could effectively purify CO without damage. When the CO concentration was in the range of 100 ~ 400 ppm, within 2 weeks after the 48-h experiment, the leaf tips of Chlorophytum comosum (Thunb.) Jacques and Epipremnum aureum (Linden ex André) G.S.Bunting were damaged one after another, and the damaged leaf area increased with the increase of CO concentration. However, each plant as a whole still survived. This study demonstrated that different species of potted plants can effectively absorb low concentrations of CO to varying degrees, but higher concentrations of CO will damage the survival of specific species of potted plants.

Strategy for Improving the Indoor Environment of Office Spaces in Subtropical Cities

Taiwan is located in a subtropical region with high temperatures and humidity. Office spaces are located in air-enclosed rooms in buildings, where doors and windows remain closed and only a central air-conditioning system provides temperature adjustment and ventilation. Most offices in this area have office seating areas, document storage areas on both sides of the office, and multi-function devices, which can cause sick office syndrome in the employees. This study applied environmental monitoring technology to analyze the architectural form and indoor and outdoor air quality to propose improvement strategies addressing indoor temperature, relative humidity and air quality. Quality indices were used created to evaluate the improvement efficiency. The analysis results showed that the indoor temperature and relative humidity in staff seating areas can be effectively improved. The statistical analysis results of improved efficiency for PM2.5, PM10 concentrations and total suspended particulates showed that the average indicator values have been raised from 0.05 to 1.5, 2.45 to 4.02 and 0.91 to 3.54, respectively, for staff seating area and −0.01 to 2.82, 0.15 to 3.91 and 1.25 to 7.25, respectively, for photocopier areas. The ambient air quality of this office space has been significantly improved. This study can serve as an example of air quality improvement in traditional common office spaces.