Indoor air detection method
We all know that after the renovation of the new house, we have to wait a while to stay in. This is due to indoor air pollution during the renovation. Formaldehyde is one of the biggest "enemies" of house renovation, and toxic pollutants like formaldehyde will endanger our health. Today, I will explain the relevant knowledge of indoor air testing. What are the indoor air testing instruments and methods? Let's look at it together.
Indoor air detection is a scientific activity that uses modern scientific and technological methods to quantitatively measure environmental factors and other indoor environmental pollutants that are harmful to human health in a discontinuous or continuous manner, and to observe and analyze the environmental impact process and extent. The indoor environmental testing research shows that the environmental population with a good indoor environmental testing index is generally older than the living age in a poor environment. This is also a major basis for the family to pay so much attention to indoor environmental testing.
Indoor environmental testing standards:
1. The living room shall be closed for 12 hours in strict accordance with the National Indoor Air Quality Standard (GB/T18883-2002). Air-conditioning and other air-conditioning equipment and air purification equipment shall not be used when closed.
2. When indoor environmental testing personnel conduct on-site inspection, the number of indoors should not exceed three.
3. When the indoor environment is on-site, all the persons present are strictly prohibited from smoking.
4, do not leave residual decorative debris, such as plates, paint, paint, thinner and so on.
5, the use of decoration deodorant should be avoided indoors within one week before the test.
6. The detection time is related to the number of layout points. It takes about 1 hour for 2-3 test points.
When the civil construction project is accepted, the indoor air pollutant concentration detection point shall be set according to the room area:
1. When the room area is <50m2, set a detection point; <>
2. When the room area is 50~100m2, set 2 detection points;
3. When the room area is >100m2, set 3-5 detection points.
Indoor air testing equipment:
For indoor air testing, formaldehyde is the main item of testing. It also includes other toxic gases and pollutants that are harmful to human health. The indoor environmental testing instruments used mainly include formaldehyde detectors, air samplers (pumps) and calibrators, and particles. Counter, ammonia detector, ozone detector, voc detector, CO2|CO|temperature and humidity detector, helium detector, dust meter, air quality tester, gas flow meter, etc.
Indoor air detection method:
1. Method for detecting formaldehyde. According to national standards, there are four methods for the determination of formaldehyde: the first one is AHMT spectrophotometry, the formaldehyde in the air is absorbed by the absorption liquid, and in the alkaline solution with 4-amino-3- hydrazine-5-thio-three Ammonia is reacted, oxidized by potassium periodate to form a red compound, colorimetric quantification; the second is phenol reagent spectrophotometry, formaldehyde in air reacts with phenol reagent to form a azine, and azine is oxidized by high-iron ions in an acidic solution. Forming a blue-green compound, according to the color depth, colorimetric quantification; the third is meteorological chromatography, formaldehyde in the air under acidic conditions, on the 2,4-dinitrophenylhydrazine 6201 carrier, to form a stable formaldehyde oxime After elution with carbon disulfide, the well OV-column was separated and determined by hydrogen flame ionization detector, and the retention time was qualitative and the peak height was quantified. The fourth type was acetylacetone spectrophotometry, and the formaldehyde in the air was acetylacetone. The ammonium salt solution is absorbed and heated to form a yellow compound, which is quantified by colorimetry.
2. Determination methods of benzene, toluene and xylene. Meteorological chromatography: Benzene, toluene and xylene in air were collected with activated carbon tube, then extracted with carbon disulfide, separated by polyethylene glycol 6000 column, detected by hydrogen flame ion detector, and characterized by retention time. Peak height is quantified.
3. Determination of ammonia. According to national standards, there are two methods for testing ammonia in indoor air: the first one is indophenol blue spectrophotometry, the ammonia in the air is absorbed by the sulfuric acid absorption liquid, and then the nitrous iron qinghuana green compound is then quantified. Colorimetric, the method can measure the range of 0.05-0.8mg/m3, suitable for the environment containing lower ammonia; the second is the Nessler reagent spectrophotometry, absorb ammonia with dilute sulfuric acid solution, and form ammonium with ammonium The reagent reflects the formation of a brown-yellow complex and then performs quantitative colorimetry. The measurable range of this method is 0.13-1.00mg/m3, which is suitable for environments with higher ammonia.
4. Determination of total volatile organic compounds. Meteorological chromatography was used according to the national standard GB/T18883 Appendix C. The volatile organic matter in the air is collected by a suitable solid adsorbent. After sampling, the sampling tube is heated while passing nitrogen gas, and the adsorbed compound is analyzed, separated by a capillary column, detected by a hydrogen flame ion detector, and characterized by retention time. High or peak area is quantified.
5. Determination of ozone. There are two methods according to the national standard: the first one is the sub-appearance reading method, which uses the ultraviolet ozone analyzer to quantitatively determine the ultraviolet light of 254 nm wavelength according to ozone; the second is the indigo blue disulphonate sodium spectrometry. Photometric method, ozone in the air is the fading of indigo disulphonate in the absorption liquid, which produces sodium disulfate, which is quantified according to the degree of color reduction.
6, the detection method of cockroaches. There are four methods according to national standards: the first is the scintillation flat measurement method; the second is the track etching method; and the third is the double filter membrane method. At present, the MODEL1027 continuous measuring instrument can continuously measure points. This method has been approved by the US EPA.
Attached
Beijing Zhongyi Yusheng Technology Co., Ltd.
Dedicated gas chromatograph configuration for indoor environment (TVOC) testing:
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