PAHS

Polycyclic Aromatic Hydrocarbons (PAHs) refer to two or more benzene organic compounds. PAHs are hydrocarbons containing more than two benzene rings in molecules, including more than 150 kinds of compounds such as naphthalene, anthracene, phenanthrene, pyrene. Some PAHs contain nitrogen, sulfur, and cyclopentane and carcinogenic PAHs are usually four to six fused ring compounds. International Cancer Research Center (IARC) (1976) listed 94 kinds of carcinogenic compounds in experimental animals fifteen of which are PAHs. Benzo[a]pyrene is the first found hazardous environmental chemical carcinogen which accounts for 1% -20% of total carcinogenic PAHs, so it is always as a representative of PAHs.
   PAHs Components
   PAHs contain 18 main compounds: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo (a) anthracene, chrysene, benzo (b) fluoranthene, Benzo (k) fluoranthene, benzo (a) pyrene, indeno (1,2,3-cd) pyrene, dibenzo (a, h) anthracene and benzo (g, h, i) perylene, 1 - A Kenai and 2 - A Kenai.
   16 common PAHs mainly include :

   Main Source of PAHs and Way of Contact
   Pollution sources of PAHs are natural or man-made.
   Natural pollution is mainly formed by volcanic eruption, forest fire and biological synthesis.
   Man-made pollution refers to toxic substance pollution formed by the incomplete combustion of fossil fuels (such as coal, oil, natural gas, etc.), wood, paper, and other hydrocarbons or their pyrolysis  in a restoring state.
   In addition food also contains some active PAHs of which benzo(a )pyrene generates from dripping hot grease mainly in food processing, especially in smoking, roasting or baking processing. Certain PAHs contain in oil extracted from window or wrapping paper in storage and in the sunning grain on the asphalt road. PAHs in air, water and soil can pollute food, fruits and vegetables.
   PAHs are usually found not only in petrochemicals such as crude oil, creosote, tar, dyes, plastics, rubber, lubricants, anti-rust oil, release agent, gasoline dispersion stabilizer, capacitor electrolyte, mineral oil, asphalt, but also in daily chemicals products such as pesticides, charcoal, fungicides, mosquito coils and so on.
In electrical and electronic manufacturing, PAHs are usually used as plastic additives in production. For example, PAHs may contain in the release agent which will be added in extruded plastic particles because of adhesion between particles and the mold.
   Scope of PAHs test
   1． Electronic and electrical consumer products
   2．Rubber products, plastic products, auto plastic, rubber parts
   3． Food packaging materials, toys, container materials
   4． Other materials
   PAHs harm to human bodies, animals and plants
   PAHs have bad effects on respiratory tract and skin. long-term PAHs polluted environment can cause acute or chronic harm including solar dermatitis, acne-type dermatitis, folliculitis, and verrucous organisms.
   PAHs falling in plant leaf will plug leaves breathing hole, resulting in discoloration, shrinking, curling until shedding, affecting plants growth and its fruit. For example, PAHs polluted soybean leaves will become red and be away from the plant resulting in little seed pods or no seed pods.
   Carcinogenic effects of PAHs in animals have already been proved by experiment which show mouse’s systemic reaction to PAHs. Sunlight can speed up death of the mouse. When PAHs concentration is 0.01mg / L, its conditioned reflex activities change a lot.
   All regulation requirements on PAHs
   So far, requirements specified by written laws or regulations are as follows: Europe: 76/769/EEC; German: GS Certification and LFGB；USA: EPA；China: GB, GB/T and GHZ.
   After the discussion between ALDI Süd and ALDI Nord, Germany initially sets the limits for PAHS as we can see below:
   A: General consumer goods
   More than 30S in touch (eg, handlegrips, steering wheel, etc.):  BaP<1mg/kg   Sum of 16 PAHs <10mg/kg
   Less than 30S in touch with plastic and in occasional touch with particles:  BaP<20mg/kg     Sum of 16 PAHs <200mg/kg
   B: Food, food contact material, products that may be placed in the mouth and children???s products
   BaP<1mg/kg     Sum of 16 PAHs <10mg/kg
   C: Other products
   BaP<1mg/kg     Sum of 16 PAHs <10mg/kg
   D: GS certification needs compulsory PAHs test----PAHS standard
   Source interpretation: on November 20, 2007, a resolution (see the ZLS website bulletin document No. ZEK 01-08) was passed by AtAV Committee of the Central              Experience Exchange Office (ZEK) in German Security Technology Certification Center (ZLS), requiring compulsory PAHs test in the GS mark certification. The rule has   become effective since 1 April 2008 when products that is not qualified for the PAHs standard will be failed to get the GS mark certification and keep out of the German market.

According to the new regulation PAHs limits in consumer materials must accord with the table below:
Class1: food contact materials or products and toys which can be placed in the mouth of children under 3 years old.
BaP<0.2mg/kg        Sum of 16 PAHs<0.2 mg/kg
Class2: plastic and particles in touch with skin more than 30S as well as unregulated toys in class1.
BaP：1 mg/kg         Sum of PAHs: 10mg/kg
Class3: particles in touch with skin less than 30S or without touch.
BaP：20mg/kg      Sum of 16 PAHs: 200mg/kg
If test data is more than limits of class 1 but in line with limits of class 2, migration tests should be performed according to DIN EN1186 and the 64 LFBG80.30-1 standard to confirm test results.
16 PAHs listed by EPA
Sum of 16 PAHs:  10mg/kg  200mg/kg
BaP: 1mg/kg  20mg/kg
 Prevention and control measures
PAHs prevention measures
Fuel must burn completely, which can reduce PAHs amount. Indoor ventilation increase PAHs content.
Productive inorganic dust mainly causes lung tissue-based systemic diseases, pneumoconiosis and dust hemosiderosis. Organic dust can cause bronchial asthma, cotton dust disease, occupational hypersensitivity pneumonitis, non-specific chronic obstructive pulmonary diseases. Some dust such as metal dust (nickel, chromium, arsenic,) and asbestos can cause lung cancer.
Dust acts on respiratory tract mucosa, initially for telangiectasia and a large secretion of mucus and hyperfunction which are protective reaction, followed by hypertrophy, ultimately formation of atrophy due to malnutrition. Regular contact with dust can also cause skin, ear and eye and other organ diseases. Toxic dust of lead, arsenic, manganese can be absorbed by the bronchial and alveolar walls, causing toxin.
PAHs control measures
   1. organizational measures  For productive dust, guarantee regular dust control from aspects of its organization; adopt technological innovations to cleaner production; strengthen personal protection and conduct pre-employment medical examination and periodic physical examination; develop hygienic standards of dust.
   2. Improve energy structures  Develop hydroelectric power generation instead of wind generation and study new energy sources; adopt and develop smoke and dust removal technology; taking regional collective heating measures to reduce particulate matter pollution in the air.