3.2.1. Alternative Old Moxa Wool
Mean levels of moisture, ash, and volatile matter in fresh moxa wools were 5.98%, 19.53%, and 74.57%, respectively, by comparison, those in the aged moxa wools were 9.92%, 6.80%, and 83.27%, respectively. After combustion at 850 °C, fresh moxa wools were transformed into white and smaller particulates, but old moxa wools were converted into gray and coarse particulates. Old moxa wools contained more volatile matter and less ash than did fresh moxa wools because they retained more leaf fibers without adding any chemicals or moxa powder during manufacture. Conversely, a part of the leaves was removed from and smoke suppressants as well as moxa powder were added to fresh moxa wools during manufacture, resulting in relatively less volatile matter and lots of ash. Burning rates for fresh and old moxa wools are 0.31 g/min and 0.23 g/min, respectively. Fresh moxa wools had a faster burning rate that did old moxa wools.
In this study, when an old moxa wool was burned, CO2
concentrations exhibited a similar trend to that observed during burning fresh moxa wool, with an average value of 560 ppm during the background stage and 598 ppm during the moxibustion stage. CO2
concentrations slightly increased comparing burning an alternative old moxa wool with a fresh one. CO, TVOC, and HCHO mean concentrations obviously improved when an old moxa wool was replaced. By contrast, PM10
concentrations were elevated substantially (Figure 4
In this study, the CO2
concentration increased when old moxa wools were used and the percentage increase of CO2
was 41%. By contrast, CO, TVOC and HCHO concentrations differed substantially during burning new and old moxa wools. The average value of CO concentrations during the background and moxibustion stages when burning old moxa wools were <0.1 and 1.4 ppm, respectively. Compared with burning a fresh moxa wool, the CO concentrations decreased by 57%. The combustion of a fresh moxa wool likely produced a large amount of CO because of incomplete combustion. Compared with burning a fresh moxa wool, the emissions of HCHO and TVOCs decreased by 75% and 83%, respectively, possibly because for an old moxa wool the prolonged exposure to air and sunlight during the manufacturing process results in volatilization of some of the volatile oil. However, burning an old moxa wool produced more PM10
than did burning a fresh moxa wool. Compared with the emissions while burning new moxa wools, PM10
exhibited 1.94- and 1.75-fold increases, respectively, possibly because calcium carbonate, sodium chloride, and other compounds were added to new moxa wools to improve their combustion efficiency in the manufacturing process and these further increased the incomplete combustion (Table 1
In the qualitative analysis, benzene, toluene, ethylbenzene, styrene, 2-methylfuran, 1-octene, acetone and 1-hexene were found in the emissions from burning fresh moxa wools; while benzene, toluene, ethylbenzene, styrene, 1-decene, D-limonene, phenol, 1-heptene and p-xylene existed in old ones. Benzene, toluene, ethylbenzene and styrene were the compounds existing in the emissions from combustion of both fresh and old moxa wools. In the quantitative analysis, the concentrations of benzene, toluene, ethylbenzene and styrene in the emissions from moxibustion of fresh moxa wools were 0.280, 0.178, <0.038 and 0.042 ppm, and those from moxibustion of old ones were 0.068, 0.095, <0.039 as well as <0.034 ppm, respectively. The average TVOC values during the sampling periods for combustion of fresh and old moxa wools were separately 0.93 ppm, ranging from 0.01 to 1.72 ppm, and 0.37 ppm, ranging from 0.02 to 1.10 ppm.
3.2.3. Air Cleaner
Before moxibustion, the background mean levels were 542 ppm for CO2
, less than 0.1 ppm for CO, 0.025 ppm for HCHO, 0.02 ppm for TVOCs, 6 μg/m3
, and 39 μg/m3
when the air cleaner was used (Figure 3
and Table 3
). Compared with burning a fresh moxa wool without using an air cleaner, the emissions decreased by 22% (from 27 ppm to 21 ppm) for CO2
, 4% (from 2.8 ppm to 2.7 ppm) for CO, 13% (from 0.024 ppm to 0.021 ppm) for HCHO, and 35% (from 0.24 ppm to 0.16 ppm) for TVOCs when an air cleaner was used. This demonstrates that a light photocatalyst maybe not the best method for controlling gaseous pollutants (Figure 4
and Table 3
The emissions of PM2.5 and PM10 were respectively decreased by 71% (from 270 μg/m3 to 79 μg/m3) and 60% (from 262 μg/m3 to 104 μg/m3), compared with burning a fresh moxa wool without air cleaner, showing that although the air cleaner can remove more than half of the particulates released from moxibustion, PM2.5 and PM10 levels remained higher than the standards in the Taiwan Indoor Air Quality Management Act of 35 and 75 μg/m3, respectively (8-h average). Although the air cleaner with a HEPA air filter combined with an air ion generator can remove particulates released from moxibustion, however, it seems still has less efficient than local exhaust ventilation.