Air Quality monitoring is well known and established science which started back in the 80's. At that time, the technology was quite limited, and the solution used to quantify the air pollution complex, cumbersome and really expensive.
Patent US7947503: Monitor and methods for characterizing airborne particulates
Fortunately, now days, with the most recent and modern technologies, the solutions used for Air Quality monitoring are becoming not only more precise, but also faster at measuring. Devices are becoming smaller, and cost much more affordable than ever before. For instance, new technologies like the Tapered element oscillating micro balance (TOEM) provide significant advantages over the traditional Beta Attenuation Monitors (BAM)
Even more recently, ultra-affordable sensors are starting to appear on the market - many of them linked to the IOT trend of sensing everything. While most of them are purely gimmick, and so definitely useless toys, some of them are starting to achieve performances comparable to professional monitors, at one hundred time less of cost of them. In order to asses the reliability of those sensors, the Earth Sensing Labs from the World Air Quality Index project is and has been conducting many Air Quality Sensor research and live-data experiments from many years.
Particle Sensors
The particle sensors can detect the amount of dust in the Air. While the first generation was just able to detect the amount of opacity, most recent sensors can now detect not PM2.5 and PM10 but also up to 7 different particle size (aka bins).
Dylos DC1100 Laser based PM2.5/PM10 integrated monitor 300USD (2000CN¥)
Comming Soon
Alphasense OPC-N2 Laser based PM2.5/PM10 sensor 500USD (3333CN¥)
Gas Sensors
On the opposite of particle sensors, the gas sensor can detect and count the type of particle present in the air, such as for instance Ozone (O3), Nitrogen Dioxide (NO2), Sulfur Dioxide (SO2), ...
Note1: The USD/CNY conversion rate is based on 1 CNY = 0.15 USD. The price are based on direct purchase from the vendors without shipping cost.
Note2: The Dylos monitor does not really belong to the PM sensor category since it is a completely integrated and standalone monitoring equipment, much more expensive than any other sensor, but it is listed here for historical reason.
Note 3: The Alpha Sense OPCN2 is expensive, and the the price you pay is for the traceable calibration (done using Polystyrene Spherical Latex Particles). Otherwise, from a technology side, it does not include anything better than what the $20 sensors can do, except from an IC.
Note4: There are many scientific article on low-cost sensor. See the one from NCAS and WACL for an excellent and brief overview on the evaluation of low cost chemical sensors for air pollution measurement.
Note5: If you would like to suggest news sensors, please contact us or just post a message in the discussion board at the bottom of this page.
Last 5 days PM2.5 comparative measurement
The graph "BAM PM2.5" is the reference measurement from a professional BAM monitor. A loess smoothing is applied to all the other graphs in order to minimize the noise. You can move your mouse over the graph labels to see the actual output vs. the averaged values.
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For the list of all air quality sensors, check the Sensor Overview page
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Sobre a medição da aualidade do ar e poluição
Sobre os níveis de qualidade do ar
-
Valores do Índice de Qualidade do Ar (AQI)
Níveis de preocupação de saúde
0 - 50
Boa
0-50: Boa - A qualidade do ar é considerada satisfatória, a poluição do ar representa pouco ou nenhum risco
51 -100
Moderado
50-100: Moderado - A qualidade do ar é aceitável; No entanto, para alguns poluentes pode haver um problema de saúde moderada para um número muito pequeno de pessoas que são mais sensíveis à poluição do ar.
101-150
Não Saudável para Grupos Sensíveis
Membros de grupos sensíveis podem ter efeitos na a saúde. O público em geral não é susceptível de ser afetado.
151-200
Não saudável
150-200: Insalubre - Toda a população pode começar a sentir os efeitos na saúde; membros de grupos sensíveis podem apresentar efeitos mais sérios de saúde.
201-300
Muito Prejudical à Saúde
200-300: Muito Insalubre - As advertências de saúde de situações de emergência. Toda a população é mais susceptível de ser afectada.
300+
Perigoso
300+: Perigoso - alerta de saúde: todos podem experimentar efeitos mais graves para a saúde
Para informações sobre saúde muito úteis em Pequim, procure Doutor Richard Saint Cyr MD, consulte www.myhealthbeijing.com blogue.
Aviso de uso: Todos os dados da Qualidade do Ar não são validados no momento da publicação e, devido à garantia de qualidade, esses dados podem ser alterados, sem aviso prévio, a qualquer momento. O projeto Índice de Qualidade do Ar Mundial exerceu todas as habilidades e cuidados razoáveis na compilação do conteúdo desta informação e sob nenhuma circunstância o A equipe do projeto World Air Quality Index ou seus agentes podem ser responsabilizados em contrato, responsabilidade civil ou de outra forma por qualquer perda, lesão ou dano decorrente direta ou indiretamente do fornecimento desses dados.