Seattle is dangerous

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The top graph shows the forecast for the Common Air Quality Index (CAQI), which has been used in Europe since 2006. This shows a value on a scale from 1 to 100, with a low value (green colors) indicating good air quality and a high value (red colors) indicating poor air quality. The CAQI color coding is used in all air pollution forecasts of the meteogram to indicate the level of pollution. There are no official color coding guidelines for pollen forecast, as pollen is not included in the forecast of the air quality index. The air quality index is defined separately near roads ("roadside index") or away from roads ("background index"). meteoblue uses the background index because weather models cannot depict small differences on the streets. Measurements along roads therefore show higher values ​​than those forecast here.

The second panel shows the forecast of particles (PM and desert dust) for Seattle. Atmospheric Particle (PM) are microscopic solid or liquid matter that is suspended in the air. Sources of particulate matter can be natural or human. Of paramount importance to the health of the population are those particles that are small enough to be inhaled into the deepest parts of the lungs. These particles are less than 10 micrometers in diameter (approximately 1/7 the thickness of a human hair) and are defined as PM10. PM10 is a mixture of materials such as smoke, soot, dust, salt, acids and metals. Particles are also formed when the gases emitted by automobiles and industry react with one another in the atmosphere. PM10 is often perceived as fog, also known as smog. PM10 is one of the most harmful of all air pollutants.

  • PM10 can increase the number and severity of asthma attacks
  • PM10 causes or worsens bronchitis and other lung diseases
  • PM10 reduces the body's ability to fight infection

PM10 includes fine particles known as PM2.5, which are fine particles with a diameter of 2.5 µm or less. The greatest public health impacts come from long-term exposure to PM2.5:

  • PM2.5 increases the age-specific mortality risk, particularly from cardiovascular causes.

Desert dust consists of particles that are smaller than 62 μm and come from deserts. Often times the dust particles are small, which leads to high levels of PM10 and PM2.5 and all of the associated health effects.

The third diagram shows the concentrations of air pollution gases. The Ozone pollution (O₃) in the lower troposphere is mainly caused in urban areas. Ozone can:

  • make it difficult to breathe deeply and forcefully
  • Cause shortness of breath and pain when breathing
  • Cough, sore throat, or scratchy throat
  • inflame and damage the airways
  • Worsen lung diseases such as asthma, emphysema and chronic bronchitis
  • Increase the frequency of asthma attacks
  • make the lungs more prone to infection
  • Lung damage intensifies, even if symptoms have disappeared
  • cause chronic obstructive pulmonary disease (COPD)

Sulfur dioxide (SO₂) is a gas that is invisible and has an unpleasant, pungent odor. It reacts easily with other substances, producing harmful compounds such as sulfuric acid, sulphurous acid and sulphate particles.

  • Even brief exposure to SO₂ can damage the human respiratory system and make breathing difficult.
  • SO₂ and other sulfur oxides can contribute to acid rain, which can damage sensitive ecosystems.
  • Children, the elderly and asthmatics are particularly sensitive to SO₂.

Nitrogen dioxide (NO₂) is a reddish-brown gas that has a characteristic pungent, pungent odor and is a known air pollutant. The main source of NO₂ is the burning of fossil fuels: coal, oil and gas. Most of the nitrogen dioxide in cities comes from vehicle exhaust. Nitrogen dioxide is an important air pollutant because it contributes to the formation of ozone, which can have a significant impact on human health.

  • NO₂ can cause pneumonia and reduce immunity to lung infections
  • NO₂ can cause problems like wheezing, coughing, colds, flu and bronchitis

For Europe, the meteogram has a fourth panel, showing the pollen forecast for Seattle.

Birch pollen are some of the airborne allergens in spring or later in the year at higher latitudes. When the trees bloom, they release tiny pollen that is blown away by the wind. A single birch can produce up to five million pollen grains. Pollen is dispersed by air currents and can be transported over great distances.

Grass pollen are the main trigger for pollen allergies during the summer months. They cause some of the most serious and difficult-to-treat symptoms. In humid climates, the grass pollen season lasts for several months. In drier climates, the grass pollen season is significantly shorter, as is the birch and olive pollen season.

Precipitation can purify pollen from the air. However, thunderstorms combined with strong winds initially increase the pollen concentration.

Disclaimer of liability

Neither the European Commission nor ECMWF or meteoblue are responsible for the use that may be made of the information presented here. The predictions are given by an atmosphere model with a resolution of 12 km. The results may therefore not correlate with real concentrations. For information on maximum values ​​or for pollution warnings, please contact your local air quality agency.