Portable apparatus for estimating air quality and methods of operating the same
A portable apparatus for estimating air quality is provided. The portable apparatus includes a light source unit suitable for emitting incident light having a predetermined wavelength toward air to generate scattered light which is reflected by particles in the air, a light detection unit suitable for collecting information on the scattered light, and an arithmetic unit suitable for analyzing the information on the scattered light which is collected by the light detection unit. The arithmetic unit generates information on a size and a concentration of the particles in the air. Related methods are also provided.
1. A portable apparatus for estimating air quality, the portable apparatus comprising:
a light source configured to emit incident light having a predetermined wavelength toward air, the emitted incident light is scattered by particles in the air to generate scattered light;
a light detector configured to detect the scattered light and collect information on the scattered light; and
a calculator configured to analyze the collected information on the scattered light from the light detector and to provide air quality indicator information including a size and a concentration of the particles in the air;
wherein the calculator is configured to perform an arithmetic operation using an equation including variables “r”, “λ”, “n 0 ” and “θ”,
wherein the variable “r” represents a mean value of distances between the particles and the light detector, the variable “λ” represents a wavelength of the scattered light, the variable “n 0 ” represents a refractive index of the air in a target space including the particles, and the variable “θ” represents an angle between the incident light and the scattered light,
wherein the equation includes a first scattered light detection equation and a second scattered light detection equation;
wherein the first scattered light detection equation is expressed by the following equation:
I
I
0
=
64
π
4
n
0
2
a
6
9
λ
4
r
2
(
ⅆ
n
0
ⅆ
φ
)
2
(
1
+
(
cos
θ
)
2
)
,
wherein the second scattered light detection equation is expressed by the following equation:
g
2
(
θ
;
τ
)
=
1
+
β
[
exp
(
-
(
4
π
n
0
λ
sin
(
θ
2
)
)
2
Dτ
)
]
2
where
,
D
=
k
B
T
6
η
a
(
1
-
1.976
φ
)
,
wherein, “I” represents intensity of the scattered light, “I 0 ” represents intensity of the incident light, “a” represents a diameter of the particles, “φ” represents a volume percentage of the particles in the target space, “β” represents a correlation term “k B ” represents a Boltzmann constant, “η” represents an intrinsic viscosity of the air in the target space, “τ” represents a step time, “g(θ,τ)” represents an autocorrelation function, “D” represents a diffusion coefficient of the particles in the target space, and “T” represents an absolute temperature of the air in the target space.
2. The portable apparatus of claim 1 ,
wherein the light source and the light detector are disposed at opposite sides of the portable apparatus; and
wherein the portable apparatus further includes a detection conduit disposed between the light source and the light detector to allow generation of the scattered light in the detection conduit.
3. The portable apparatus of claim 1 ,
wherein the light source and the light detector are disposed to be adjacent to each other.
4. The portable apparatus of claim 1 , further comprising:
a display configured to display air quality indicator information produced by the arithmetic unit.
5. The portable apparatus of claim 1 , further comprising:
a controller configured to control the light source and the light detector.
6. The portable apparatus of claim 5 , further comprising: a transmitter configured to transmit the air quality indicator information to an external device.
7. The portable apparatus of claim 5 , wherein the controller is installed in a personal digital assistant (PDA), a portable computer, a wireless phone, a mobile phone, or a smart phone.
8. The portable apparatus of claim 5 ,
wherein the controller is disposed in a portable terminal device and is configured to control operations of the light source and the light detector using application programs loaded in the portable terminal device.
9. A method of operating a portable apparatus for estimating air quality, the method comprising:
emitting incident light having a predetermined wavelength toward air, the emitted incident light is scattered by particles in the air to generate a scattered light;
collecting information on scattered light;
analyzing the collected information on the scattered light to produce air quality indicator information including a size and a concentration of the particles in the air,
wherein the analyzing of the collected information on the scattered light includes performing an arithmetic operation using an equation including variables “r”, “λ”, “n 0 ” and “θ”;
wherein the variable “r” represents a mean value of distances between the particles and a light detector collecting information on the scattered light, the variable “λ” represents a wavelength of the scattered light, the variable “n 0 ” represents a refractive index of the air in a target space including the particles, and the variable “θ” represents an angle between the incident light and the scattered light,
wherein the equation includes a first scattered light detection equation and a second scattered light detection equation;
wherein the first scattered light detection equation is expressed by the following equation;
I
I
0
=
64
π
4
n
0
2
a
6
9
λ
4
r
2
(
ⅆ
n
0
ⅆ
φ
)
2
(
1
+
(
cos
θ
)
2
)
wherein the second scattered light detection equation is expressed by the following equation; and
g
2
(
θ
;
τ
)
=
1
+
β
[
exp
(
-
(
4
π
n
0
λ
sin
(
θ
2
)
)
2
Dτ
)
]
2
where
,
D
=
k
B
T
6
η
a
(
1
-
1.976
φ
)
wherein, “I” represents intensity of the scattered light, “I 0 ” represents intensity of the incident light, “a” represents a diameter of the particles, “φ” represents a volume percentage of the particles in the target space, “β” represents a correlation term, “k B ” represents a Boltzmann constant, “η” represents an intrinsic viscosity of the air in the target space, “τ” represents a step time, “g(θ,τ)” represents an autocorrelation function, “D” represents a diffusion coefficient of the particles in the target space, and “T” represents an absolute temperature of the air in the target space.
10. The method of claim 9 , further comprising displaying the air quality indicator information.
11. The method of claim 9 , further comprising transmitting the air quality indicator information to an external communication device.
12. The portable apparatus of claim 1 , wherein the calculator is disposed to be attachable to and detachable from the light source and the light detector.
13. The portable apparatus of claim 1 , wherein the calculator is disposed in a portable terminal device and is configured to control operations of the light source and the light detector using application programs loaded in the portable terminal device.
14. The portable apparatus of claim 1 , wherein the calculator is installed in a personal digital assistant (PDA), a portable computer, a wireless phone, a mobile phone, or a smart phone.